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Research Progress on High-Temperature-Resistant Electromagnetic Wave Absorbers Based on Ceramic Materials: A Review
Shutter-Synchronized Molecular Beam Epitaxy for Wafer-Scale Homogeneous GaAs and Telecom Wavelength Quantum Emitter Growth
New Strategy for Microbial Corrosion Protection: Photocatalytic Antimicrobial Quantum Dots
Tin(IV)Porphyrin-Based Porous Coordination Polymers as Efficient Visible Light Photocatalyst for Wastewater Remediation
Inverted Pyramid Nanostructures Coupled with a Sandwich Immunoassay for SERS Biomarker Detection

Journal Description

Nanomaterials

Nanomaterials is an international, peer-reviewed, interdisciplinary scholarly open access journal, published semimonthly online by MDPI. It publishes reviews, regular research papers, communications, and short notes that are relevant to any field of study that involves nanomaterials, with respect to their science and application. The Spanish Carbon Group (GEC) and The Chinese Society of Micro-Nano Technology (CSMNT) are affiliated with Nanomaterials and their members receive discounts on the article processing charges.

Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
High Visibility: indexed within Scopus, SCIE (Web of Science), PubMed, PMC, CAPlus / SciFinder, Inspec, and other databases.
Journal Rank: JCR - Q2 (Chemistry, Multidisciplinary) / CiteScore - Q1 (General Chemical Engineering )
Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 14.1 days after submission; acceptance to publication is undertaken in 1.9 days (median values for papers published in this journal in the second half of 2024).
Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
Companion journals for Nanomaterials include: Nanomanufacturing and Applied Nano.

Impact Factor: 4.4 (2023); 5-Year Impact Factor: 4.7 (2023)

Imprint Information Journal Flyer Open Access ISSN: 2079-4991

Latest Articles

35 pages, 7059 KiB

Open AccessReview

Recent Advances in Nanostructured Conversion-Type Cathodes: Fluorides and Sulfides

by Mobinul Islam, Md. Shahriar Ahmed, Sua Yun, Basit Ali, Hae-Yong Kim and Kyung-Wan Nam

Nanomaterials 2025, 15(6), 420; https://doi.org/10.3390/nano15060420 (registering DOI) - 8 Mar 2025

This review paper explores the emerging field of conversion cathode materials, which hold significant promises for advancing the performance of lithium-ion (LIBs) and lithium–sulfur batteries (LSBs). Traditional cathode materials of LIBs, such as lithium cobalt oxide, have reached their limits in terms of [...] Read more.

This review paper explores the emerging field of conversion cathode materials, which hold significant promises for advancing the performance of lithium-ion (LIBs) and lithium–sulfur batteries (LSBs). Traditional cathode materials of LIBs, such as lithium cobalt oxide, have reached their limits in terms of energy density and capacity, driving the search for alternatives that can meet the increasing demands of modern technology, including electric vehicles and renewable energy systems. Conversion cathodes operate through a mechanism involving complete redox reactions, transforming into different phases, which enables the storage of more lithium ions and results in higher theoretical capacities compared to conventional intercalation materials. This study examines various conversion materials, including metal oxides, sulfides, and fluorides, highlighting their potential to significantly enhance energy density. Despite their advantages, conversion cathodes face numerous challenges, such as poor conductivity, significant volume changes during cycling, and issues with reversibility and stability. This review discusses current nanoengineering strategies employed to address these challenges, including nano structuring, composite formulation, and electrolyte optimization. By assessing recent research and developments in conversion cathode technology, this paper aims to provide a comprehensive overview of their potential to revolutionize lithium-ion batteries and contribute to the future of energy storage solutions. Full article

(This article belongs to the Special Issue Nanomaterials for Battery Applications)

16 pages, 9996 KiB

Open AccessArticle

Polycarboxylate Superplasticizer-Modified Graphene Oxide: Dispersion and Performance Enhancement in Cement Paste

by Haiming Zhang, Xingyu Gan, Zeyu Lu, Laibo Li and Lingchao Lu

Nanomaterials 2025, 15(6), 419; https://doi.org/10.3390/nano15060419 (registering DOI) - 8 Mar 2025

Graphene oxide (GO) significantly enhances cement hydration at the nanoscale; however, its tendency to complex and agglomerate with Ca²⁺ in cement paste remains an unresolved issue. To improve the dispersibility and enhance the reinforcing effect of GO in cement paste, polycarboxylate [...] Read more.

Graphene oxide (GO) significantly enhances cement hydration at the nanoscale; however, its tendency to complex and agglomerate with Ca²⁺ in cement paste remains an unresolved issue. To improve the dispersibility and enhance the reinforcing effect of GO in cement paste, polycarboxylate (PC) superplasticizer was used to disperse GO (PC@GO). This study uniquely divided PC into two parts, with one modifying GO and the other acting as a water-reducing agent, to explore the effects on GO dispersion and analyze the rheological, carbon emission, mechanical, and hydration properties of cement paste. The experimental results show that the dispersion of GO modified by PC was improved, resulting in a significant enhancement in the performance of the cement paste containing PC@GO. The flexural and compressive strength of cement paste containing PC@GO₄ cured for 7 days increased by 23.7% and 12.6%, respectively, meanwhile, the carbon-to-strength ratio (CI) decreased by 14.8%. In addition, the hydration acceleration period shortened by 7.50%, and the water absorption and porosity of the cement paste containing PC@GO₄ decreased by 35.2% and 45.3%, respectively. Incorporating PC@GO into cement paste significantly enhances the dispersion of GO, substantially improves its mechanical properties, and positions it as a promising solution for the development of high-performance cementitious materials. Full article

(This article belongs to the Special Issue Colloid Chemistry and Applications of Nanomaterials)

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<p>Particle size distribution of OPC.</p> Full article ">Figure 2
<p>(<b>a</b>) SEM image, (<b>b</b>) N<sub>2</sub> adsorption–desorption isotherm, and (<b>c</b>) particle size distribution of GO.</p> Full article ">Figure 3
<p>Rotary rheometer test procedure.</p> Full article ">Figure 4
<p>The dispersion states of PC@GOs in pore solution over time: (<b>a</b>) 1 h; (<b>b</b>) 3 h; (<b>c</b>) 6 h; (<b>d</b>) 12 h and (<b>e</b>) 24 h. In order from left to right, the samples placed in the bottles were as follows: PC@GO<sub>0</sub>, PC@GO<sub>1</sub>, PC@GO<sub>2</sub>, PC@GO<sub>4</sub>, PC@GO<sub>8</sub>.</p> Full article ">Figure 5
<p>UV–vis spectrum of PC@GOs: (<b>a</b>) PC@GO<sub>0</sub>; (<b>b</b>) PC@GO<sub>1</sub>; (<b>c</b>) PC@GO<sub>2</sub>; (<b>d</b>) PC@GO<sub>4</sub> and (<b>e</b>) PC@GO<sub>8</sub>.</p> Full article ">Figure 6
<p>The yield stress of cement paste mixed with PC@GOs: (<b>a</b>) PC@GO<sub>0</sub>; (<b>b</b>) PC@GO<sub>1</sub>; (<b>c</b>) PC@GO<sub>2</sub>; (<b>d</b>) PC@GO<sub>4</sub> and (<b>e</b>) PC@GO<sub>8</sub>.</p> Full article ">Figure 7
<p>(<b>a</b>) The flexural strength and (<b>b</b>) compressive strength of cement paste mixed with PC@GOs.</p> Full article ">Figure 8
<p>The compressive to flexural ratio of cement paste mixed with PC@GOs.</p> Full article ">Figure 9
<p>The carbon-to-strength ratio of cement-hardened paste.</p> Full article ">Figure 10
<p>The pore structure of cement paste mixed with PC@GOs curing for seven days: (<b>a</b>) pore volume size distribution and (<b>b</b>) cumulative pore volume.</p> Full article ">Figure 11
<p>The porosity of cement pastes mixed with PC@GOs curing for seven days.</p> Full article ">Figure 12
<p>(<b>a</b>) Water absorption, (<b>b</b>) bulk density and (<b>c</b>) the relationship between porosity, water absorption and bulk density of cement hardened paste mixed with PC@GOs curing for seven days.</p> Full article ">Figure 13
<p>Hydration heat evolution of cement paste mixed with PC@GOs: (<b>a</b>) PC@GO<sub>0</sub>; (<b>b</b>) PC@GO<sub>1</sub>; (<b>c</b>) PC@GO<sub>2</sub>; (<b>d</b>) PC@GO<sub>4</sub> and (<b>e</b>) PC@GO<sub>8</sub>.</p> Full article ">Figure 14
<p>XRD pattern of cement hydration products.</p> Full article ">

10 pages, 2729 KiB

Open AccessArticle

High-Mobility Tellurium Thin-Film Transistor: Oxygen Scavenger Effect Induced by a Metal-Capping Layer

by Seung-Min Lee, Seong Cheol Jang, Ji-Min Park, Jaewon Park, Nayoung Choi, Kwun-Bum Chung, Jung Woo Lee and Hyun-Suk Kim

Nanomaterials 2025, 15(6), 418; https://doi.org/10.3390/nano15060418 (registering DOI) - 8 Mar 2025

With the ongoing development of electronic devices, there is an increasing demand for new semiconductors beyond traditional silicon. A key element in electronic circuits, complementary metal-oxide semiconductor (CMOS), utilizes both n-type and p-type semiconductors. While the advancements in n-type semiconductors have been substantial, [...] Read more.

With the ongoing development of electronic devices, there is an increasing demand for new semiconductors beyond traditional silicon. A key element in electronic circuits, complementary metal-oxide semiconductor (CMOS), utilizes both n-type and p-type semiconductors. While the advancements in n-type semiconductors have been substantial, the development of high-mobility p-type semiconductors has lagged behind. Recently, tellurium (Te) has been recognized as a promising candidate due to its superior electrical properties and the capability for large-area deposition via vacuum processes. In this work, an innovative approach involving the addition of a metal-capping layer onto Te thin-film transistors (TFTs) is proposed, which significantly enhances their electrical characteristics. In particular, the application of an indium (In) metal-capping layer has led to a dramatic increase in the field-effect mobility of Te TFTs from 2.68 to 33.54 cm²/Vs. This improvement is primarily due to the oxygen scavenger effect, which effectively minimizes oxidation and eliminates oxygen from the Te layer, resulting in the production of high-quality Te thin films. This progress in high-mobility p-type semiconductors is promising for the advancement of high-performance electronic devices in various applications and industries. Full article

(This article belongs to the Section Nanoelectronics, Nanosensors and Devices)

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<p>Schematic diagram of cross-sectional In-capped Te TFT and fabrication procedure.</p> Full article ">Figure 2
<p>(<b>a</b>) X-ray diffraction (XRD) patterns. (<b>b</b>) Te 3d XPS spectra. (<b>c</b>) Optical transmittance of the pristine and annealed Te films at 150 °C.</p> Full article ">Figure 3
<p>(<b>a</b>) Transfer curves of Te TFTs under various conditions, and (<b>b</b>) output curves of 7-nanometer-thick annealed Te TFTs at 150 °C.</p> Full article ">Figure 4
<p>XPS Te 3d spectra of pristine Te, annealed Te at 150 °C, and In-capped annealed Te at 150 °C for (<b>a</b>) back, (<b>b</b>) bulk, and (<b>c</b>) front channels.</p> Full article ">Figure 5
<p>Schematic representation of the oxygen scavenger effect in In-capped Te.</p> Full article ">Figure 6
<p>(<b>a</b>) Optical image of an In-capped Te TFT. (<b>b</b>)Transfer curves of an In-capped Te TFTs. (<b>c</b>) Output curves of an In-capped Te TFT.</p> Full article ">Figure 7
<p>Transfer curves under bias stress stability test for Te TFTs (<b>a</b>,<b>b</b>) and In-capped Te TFTs (<b>c</b>,<b>d</b>), for NBS (<b>a</b>,<b>c</b>) and PBS (<b>b</b>,<b>d</b>).</p> Full article ">

13 pages, 4135 KiB

Open AccessArticle

On-Chip Electrochemical Sensor Based on 3D Graphene Assembly Decorated Ultrafine RuCu Alloy Nanocatalyst for In Situ Detection of NO in Living Cells

by Haibo Liu, Kaiyuan Yao, Min Hu, Shanting Li, Shengxiong Yang and Anshun Zhao

Nanomaterials 2025, 15(6), 417; https://doi.org/10.3390/nano15060417 (registering DOI) - 8 Mar 2025

In this work, we developed 3D ionic liquid (IL) functionalized graphene assemblies (GAs) decorated by ultrafine RuCu alloy nanoparticles (RuCu-ANPs) via a one-step synthesis process, and integrated it into a microfluidic sensor chip for in situ electrochemical detection of NO released from living [...] Read more.

In this work, we developed 3D ionic liquid (IL) functionalized graphene assemblies (GAs) decorated by ultrafine RuCu alloy nanoparticles (RuCu-ANPs) via a one-step synthesis process, and integrated it into a microfluidic sensor chip for in situ electrochemical detection of NO released from living cells. Our findings have demonstrated that RuCu-ANPs on 3D IL-GA exhibit high density, uniform distribution, lattice-shaped arrangement of atoms, and extremely ultrafine size, and possess high electrocatalytic activity to NO oxidation on the electrode. Meanwhile, the 3D IL-GA with hierarchical porous structures can facilitate the efficient electron/mass transfer at the electrode/electrolyte interface and the cell culture. Moreover, the graft of IL molecules on GA endows it with high hydrophilicity for facile and well-controllable printing on the electrode. Consequently, the resultant electrochemical microfluidic sensor demonstrated excellent sensing performances including fast response time, high sensitivity, good anti-interference ability, high reproducibility, long-term stability, as well as good biocompatibility, which can be used as an on-chip sensing system for cell culture and real-time in situ electrochemical detection of NO released from living cells with accurate and stable characteristics in physiological conditions. Full article

(This article belongs to the Special Issue The 15th Anniversary of Nanomaterials—Women in Nanomaterials)

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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>Schematic depiction for the synthesis of RuCu-ANPs/IL-GA nanohybrid electrode material and the fabrication of a microfluidic electrochemical cell sensing chip.</p> Full article ">Figure 2
<p>(<b>a</b>) TEM image of GON; (<b>b</b>) dark-field TEM image of IL-GA, inset of (<b>b</b>) is the photograph of IL-GA hydrogel cylinder; (<b>c</b>) SEM images of IL-GA, inset of (<b>c</b>) is the photograph of IL-GA dispersed in aqueous solution to form a homogenous ink; (<b>d</b>) TEM image and (<b>e</b>) dark-field TEM image of RuCu-ANPs/IL-GA. Inset of (<b>d</b>) is the HR-TEM image of RuCu-ANP on IL-GA; (<b>f</b>) AC-STEM image of RuCu-ANPs on IL-GA. (<b>g</b>) EDX elemental mapping images of C, Ru, and Cu and elements over IL-GA.</p> Full article ">Figure 3
<p>(<b>a</b>) XRD pattern of RuCu-ANPs/IL-GA, Ru-NPs/IL-GA, and IL-GA. (<b>b</b>) XPS survey spectrum of RuCu-ANPs/IL-GA. High-resolution XPS spectra of Ru 3p regions in (<b>c</b>) Ru-NPs/IL-GA and (<b>d</b>) RuCu-ANPs/IL-GA.</p> Full article ">Figure 4
<p>(<b>a</b>) CV curves of different electrodes in 0.1 M PBS (PH 7.0) containing 0.5 mM NO, scan rate: 50 mV s<sup>−1</sup>. (<b>b</b>) Amperometric current response of RuCu-ANPs/IL-GA-based sensor to successive addition of NO in PBS at 0.74 V (vs. Ag/AgCl); inset of (<b>b</b>) is the linear dependence of the amperometric current response vs. NO concentration. (<b>c</b>) Amperometric curve to 3.0 mM NO<sub>3</sub><sup>−</sup> and NO<sub>2</sub><sup>−</sup>, and 1.0 mM UA, AA, DA, Glu and 0.3 mM NO. (<b>d</b>) Relative current responses of 0.3 mM NO on the same sensor after being stored for different days; inset of (<b>d</b>) is the relative current responses of ten sensors towards 0.3 mM NO. Error bars represent the standard deviation from six parallel tests.</p> Full article ">Figure 5
<p>(<b>a</b>) Quantitative cell viability results of CCK-8 assay for MCF-7 cells incubated with RuCu-ANPs/IL-GA electrode from 0 to 72 h; inset of (<b>a</b>) is the dark-field fluorescent images of MCF-7 cells after the calcein-AM/PI assay to stain the viable cells green by calcein-AM. (<b>b</b>) Amperometric current responses of the electrochemical sensor to the addition of 5.0 mM L-Arg and L-NAME into the culture medium in the chip containing MCF-7 cells (5 × 10<sup>6</sup> cells mL<sup>−1</sup>) by microfluidic channels.</p> Full article ">

14 pages, 3518 KiB

Open AccessArticle

On the Current Conduction and Interface Passivation of Graphene–Insulator–Silicon Solar Cells

by Hei Wong, Jieqiong Zhang, Jun Liu and Muhammad Abid Anwar

Nanomaterials 2025, 15(6), 416; https://doi.org/10.3390/nano15060416 (registering DOI) - 8 Mar 2025

Interface-passivated graphene/silicon Schottky junction solar cells have demonstrated promising features with improved stability and power conversion efficiency (PCE). However, there are some misunderstandings in the literature regarding some of the working mechanisms and the impacts of the silicon/insulator interface. Specifically, attributing performance improvement [...] Read more.

Interface-passivated graphene/silicon Schottky junction solar cells have demonstrated promising features with improved stability and power conversion efficiency (PCE). However, there are some misunderstandings in the literature regarding some of the working mechanisms and the impacts of the silicon/insulator interface. Specifically, attributing performance improvement to oxygen vacancies and characterizing performance using Schottky barrier height and ideality factor might not be the most accurate or appropriate. This work uses Al₂O₃ as an example to provide a detailed discussion on the interface ALD growth of Al₂O₃ on silicon and its impact on graphene electrode metal–insulator–semiconductor (MIS) solar cells. We further suggest that the current conduction in MIS solar cells with an insulating layer of 2 to 3 nm thickness is better described by direct tunneling, Poole–Frenkel emission, and Fowler–Nordheim tunneling, as the junction voltage sweeps from negative to a larger forward bias. The dielectric film thickness, its band offset with Si, and the interface roughness, are key factors to consider for process optimization. Full article

(This article belongs to the Special Issue Advancing the Sustainable Application of Nanostructured Materials in Solar Cells)

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Figure 1
<p>Illustration of Si surface interfacing to different materials: (<b>a</b>) native silicon surface; (<b>b</b>) silicon surface with hydrogen and hydroxyl passivation; (<b>c</b>) oxidized silicon surface; (<b>d</b>) metal-covered Si surface; (<b>e</b>) native silicon surface covered by graphene; (<b>f</b>) Si-carbon covalent bonding [<a href="#B4-nanomaterials-15-00416" class="html-bibr">4</a>]. © 2021 Elsevier. Reproduced with permission.</p> Full article ">Figure 2
<p>(<b>a</b>) SEM on the cross-sectional view of the graphene/Si structure; (<b>b</b>) Comparison of the forward current–voltage characteristics in dark and under light illumination. (<b>c</b>) Bi-directional sweep for the I–V measurement showing hysteresis effect. (<b>d</b>) Proposed photon-assisted silicon surface defect detrapping model for graphene/Si Schottky junction under light illumination (<b>left</b>) and the suppression of photon effect by surface oxidation (<b>right</b>). (<b>e</b>) Band diagram of graphene/Si structure showing the possible involvement of acceptor-like and donor-like silicon P<sub>b0</sub> centers in the current conduction.</p> Full article ">Figure 3
<p>(<b>a</b>) Decomposed Al 2p spectrum of the Al<sub>2</sub>O<sub>3</sub> film showing the Al-OH component. (<b>b</b>) Si 2s XPS spectrum taken at the Al<sub>2</sub>O<sub>3</sub>/Si interface, showing the components of SiO<sub>2</sub> and SiOx phases. (<b>c</b>) Three oxygen bonding states were found in the as-deposited Al<sub>2</sub>O<sub>3</sub> sample. (<b>d</b>) Post-metallization annealing (PMA) at 300 °C resulted in a significant reduction in the OH peak.</p> Full article ">Figure 4
<p>Band diagram and conduction mechanism of Schottky contact under (<b>a</b>) equilibrium, (<b>b</b>) forward bias; and (<b>c</b>) reverse bias. Reproduced from [<a href="#B28-nanomaterials-15-00416" class="html-bibr">28</a>].</p> Full article ">Figure 5
<p>(<b>a</b>) Illustration of the “Ideality Factor” evaluation of three different graphene/Al<sub>2</sub>O<sub>3</sub>/Si MIS Schottky diodes reported by Kim et al. [<a href="#B16-nanomaterials-15-00416" class="html-bibr">16</a>]. Large gaps for the linear fitting in the forward bias region were noted. © 2022 Elsvier. Reproduced with permission. (<b>b</b>) Ideality factor and Schottky barrier calculated by Kadam et al. [<a href="#B13-nanomaterials-15-00416" class="html-bibr">13</a>]. © 2023 American Chemical Society. Reproduced with permission.</p> Full article ">Figure 6
<p>(<b>a</b>) Measured current–voltage characteristics of graphene/Al<sub>2</sub>O<sub>3</sub>/Si MIS diodes and proposed conduction mechanisms for three different biasing conditions. (<b>b</b>) Reverse characteristics fit well with the quadratic equation, indicating the conduction is due to direct tunneling. (<b>c</b>) Fowler–Nordheim plot of the forward characteristics suggests that the current conduction is due to FN tunneling at high voltage.</p> Full article ">Figure 7
<p>Fowler–Nordheim plot of the forward current–voltage characteristics at large forward bias for MIS structures with Al<sub>2</sub>O<sub>3</sub> prepared by different precursors. Data taken from Ref. [<a href="#B16-nanomaterials-15-00416" class="html-bibr">16</a>].</p> Full article ">

18 pages, 6287 KiB

Open AccessArticle

Folic Acid-Conjugated Magnetic Oleoyl-Chitosan Nanoparticles for Controlled Release of Doxorubicin in Cancer Therapy

by Banendu Sunder Dash, Yi-Chian Lai and Jyh-Ping Chen

Nanomaterials 2025, 15(6), 415; https://doi.org/10.3390/nano15060415 - 7 Mar 2025

To develop an efficient drug delivery system, we co-entrapped superparamagnetic Fe₃O₄ and the chemotherapeutic drug doxorubicin (DOX) in oleoyl-chitosan (OC) to prepare DOX-entrapped magnetic OC (DOX-MOC) nanoparticles (NPs) through ionic gelation of OC with sodium tripolyphosphate (TPP). The NPs provide [...] Read more.

To develop an efficient drug delivery system, we co-entrapped superparamagnetic Fe₃O₄ and the chemotherapeutic drug doxorubicin (DOX) in oleoyl-chitosan (OC) to prepare DOX-entrapped magnetic OC (DOX-MOC) nanoparticles (NPs) through ionic gelation of OC with sodium tripolyphosphate (TPP). The NPs provide magnetically targeted delivery of DOX in cancer therapy. Using folic acid (FA)-grafted OC, FA-conjugated DOX-entrapped magnetic OC (FA-DOX-MOC) NPs were prepared similarly for FA-mediated active targeting of cancer cells with overexpressed folate receptors. Considering DOX loading and release, the best conditions for preparing DOX-MOC NPs were an OC:TPP mass ratio = 1:4 and OC concentration = 0.2%. These spherical NPs had a particle size of ~250 nm, 87.9% Fe₃O₄ content, 53.1 emu/g saturation magnetization, 83.1% drug encapsulation efficacy, and 2.81% drug loading efficiency. FA did not significantly change the physico-chemical characteristics of FA-DOX-MOC compared to DOX-MOC, and both NPs showed pH-dependent drug release behaviors, with much faster release of DOX at acidic pH values found in endosomes. However, FA could enhance the intracellular uptake of the NPs and DOX accumulation in the nucleus. This active targeting effect led to significantly higher cytotoxicity towards U87 cancer cells. These results suggest that FA-DOX-MOC NPs can efficiently deliver DOX for controlled drug release in cancer therapy. Full article

(This article belongs to the Section Biology and Medicines)

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<p>The effects of OC:TPP mass ratio on drug release in vitro at pH 5.5 (<b>A</b>) and 7.4 (<b>B</b>). OC concentration = 0.1%.</p> Full article ">Figure 2
<p>The effects of OC concentration on drug release in vitro at pH 5.5 (<b>A</b>) and 7.4 (<b>B</b>). OC:TPP mass ratio = 1:4.</p> Full article ">Figure 3
<p>The drug release curves at pH 5.5 (<b>A</b>) and 7.4 (<b>B</b>) for FA-DOX-MOC and DOX-MOC NPs.</p> Full article ">Figure 4
<p>The transmission electron microscope (TEM) images and particle size distribution of Fe<sub>3</sub>O<sub>4</sub> in MOC, DOX-MOC, and FA-DOX-MOC nanoparticles (bar = 100 nm). The particle size distribution is shown below the TEM image, determined by counting the size of discrete particles for Fe<sub>3</sub>O<sub>4</sub>, while it was determined by dynamic light scattering (DLS) for MOC, DOX-MOC, and FA-DOX-MOC NPs. The insert in the TEM image of FA-DOX-MOC is the selected area electron diffraction (SAED) pattern of the dark Fe<sub>3</sub>O<sub>4</sub> nanoparticles.</p> Full article ">Figure 5
<p>Fourier-transform infrared (FTIR) spectroscopy (<b>A</b>,<b>B</b>), X-ray diffraction (XRD) (<b>C</b>), and superconducting quantum interference device (SQUID) (<b>D</b>) analyses.</p> Full article ">Figure 6
<p>The thermogravimetric analysis (TGA) curves (<b>A</b>) and derivative thermogravimetric (DTG) curves (<b>B</b>,<b>C</b>).</p> Full article ">Figure 7
<p>The intracellular uptake of FITC-labeled MOC or FA-MOC by U87 cells was examined by confocal microscopy. The cell nuclei were labeled with DAPI to show blue fluorescence. The green fluorescence is the FITC-labeled MOC or FA-MOC. Bar = 50 μm. The FA-block group used excess free FA to treat U87 cells for one hour before adding FITC-labeled FA-MOC.</p> Full article ">Figure 8
<p>The localization of intracellular DOX by confocal microscopy 3 h after contacting U87 cells with DOX-MOC or FA-DOX-MC NPs. The cell nuclei were labeled with DAPI to show blue fluorescence. The red fluorescence is DOX. Bar = 20 μm.</p> Full article ">Figure 9
<p>(<b>A</b>) The biocompatibility of MOC NPs and FA-MOC NPs (concentration = 83.3 μg/mL) was determined at different cell culture times. (<b>B</b>) The in vitro cytotoxicity of DOX and FA-DOX-MOC NPs (concentration of DOX = 25 μg/mL) was determined at 24 h cell culture time. <sup>α</sup> <span class="html-italic">p</span> < 0.05 compared with DOX; <sup>β</sup> <span class="html-italic">p</span> < 0.05 compared with DOX-MOC. (<b>C</b>) The effect of DOX concentration on the in vitro cytotoxicity of DOX, DOX-MOC, and FA-DOX-MOC was determined at 24 h cell culture time. The dash line is 50% cell viability for calculating IC<sub>50</sub>.</p> Full article ">Figure 10
<p>The Live/Dead staining of U87 cells after cell culture with FA-MOC, DOX (25 μg/mL), FA-DOX-MOC (25 μg/mL DOX). The FA-DOX-MOC (magnetic targeted) group included cell culture with FA-DOX-MOC (25 μg/mL DOX) in the presence of a magnetic field created by placing a magnet at the bottom of the well. Bar = 100 μm. Live cells emit green fluorescence and dead cells emit red fluorescence.</p> Full article ">Scheme 1
<p>A schematic representation of the preparation process of doxorubicin (DOX)-loaded folic acid (FA)-conjugated magnetic oleoyl-chitosan (OC) (DOX-FA-MOC) nanoparticles.</p> Full article ">

10 pages, 6041 KiB

Open AccessArticle

Investigating the Effects of Long-Term Ambient Air Storage on the Sliding Properties of N-Alloyed MoSe₂ Coatings

by Talha Bin Yaqub, Irfan Nadeem, Muhammad Aneeq Haq, Muhammad Yasir, Albano Cavaleiro and Mitjan Kalin

Nanomaterials 2025, 15(6), 414; https://doi.org/10.3390/nano15060414 - 7 Mar 2025

Transition metal dichalcogenide coatings have emerged as potential candidates for terrestrial and aerospace mobility applications. Among these, the alloyed MoSe₂ coatings have displayed promising results while sliding in diverse environments. N-alloyed Mose₂ coatings provide the additional benefit of overcoming the impact [...] Read more.

Transition metal dichalcogenide coatings have emerged as potential candidates for terrestrial and aerospace mobility applications. Among these, the alloyed MoSe₂ coatings have displayed promising results while sliding in diverse environments. N-alloyed Mose₂ coatings provide the additional benefit of overcoming the impact of PVD compositional variations on dry sliding, making them promising solid lubricants for mobility-sector applications. However, the impact of long-term storage has never been investigated for this rarely studied solid-lubricant system. This study investigates the tribological performance of direct current magnetron sputtered MoSeN coatings after 40 months of storage in an ambient atmosphere. Sliding tests were conducted under conditions consistent with pre-storage conditions. The results showed that coatings with 0 at. %, 22 at. %, 33 at. %, and 35 at. % N-alloying exhibited COF values nearly identical to the pre-storage results, with only a negligible increase in ~0.01. Similarly, all coatings displayed specific wear rates in the range of 10⁻⁷, aligning with earlier findings. The obtained results show that the sliding performance of MoSeN coatings does not deteriorate over time, highlighting their suitability for critical aerospace applications, where components and assembled parts may be stored for years before launching into space or in actual applications. Full article

(This article belongs to the Special Issue Design and Applications of Heterogeneous Nanostructured Materials)

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13 pages, 7449 KiB

Open AccessArticle

A Study on the Microstructure and Mechanical Properties of Improved 25Ni-20Cr Steel via in Situ Testing

by Penghui Lei, Xiaoyu Ji, Jiahao Chen, Yunhao Huang, Nan Lv, Yulin Fan, Yongchao Hou, Xinsheng Shi and Di Yun

Nanomaterials 2025, 15(6), 413; https://doi.org/10.3390/nano15060413 - 7 Mar 2025

To meet the application requirements for structural components in Gen-IV nuclear reactors, it is essential to improve the high-temperature mechanical properties of 25Ni-20Cr (S35140) austenitic stainless steel. In this research, an improved austenitic stainless steel (N-S35140), derived from S35140 steel, was investigated. The [...] Read more.

To meet the application requirements for structural components in Gen-IV nuclear reactors, it is essential to improve the high-temperature mechanical properties of 25Ni-20Cr (S35140) austenitic stainless steel. In this research, an improved austenitic stainless steel (N-S35140), derived from S35140 steel, was investigated. The scanning transmission electron microscopy (STEM) results indicate that the addition of titanium (Ti) microalloying elements to S35140 steel led to the precipitation of new strengthening nano phases, including M(C, N), MC, MN and Ti(C, N), in N-S35140. These precipitates effectively compensated for the loss of high-temperature strength resulting from the substantial reduction in carbon content. During the in situ transmission electron microscopy (TEM) compressive process at room temperature, the yield strength of N-S35140 steel is 618.4 MPa. At room temperature, the tensile strength of N-S35140 steel is 638.5 MPa, with a yield strength of 392.8 MPa and an elongation of 32.7%, which surpasses those of S35140 steel at room temperature. N-S35140 steel exhibits a tensile strength of 330.6 MPa, a yield strength of 228.2 MPa, and an elongation of 51.4% during the in situ scanning electron microscopy (SEM) tensile test conducted at 650 °C. As a consequence, the improved N-S35140 steel demonstrates significantly enhanced mechanical properties compared to the original S35140 steel, positioning it as a promising candidate for structural components in Gen-IV nuclear reactors. Full article

(This article belongs to the Special Issue Multiscale Modeling and Characterization Technique of Advanced Nanostructured Materials for Extreme Service)

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<p>Dimensions of room-temperature tensile specimen (unit: mm).</p> Full article ">Figure 2
<p>Dimensions of high-temperature tensile specimen (unit: mm).</p> Full article ">Figure 3
<p>The microstructure morphologies of N-S35140 steel (<b>a</b>–<b>c</b>); (<b>d</b>) SAED of grain A.</p> Full article ">Figure 4
<p>STEM image (<b>a</b>) and EDS results (<b>b</b>–<b>i</b>) of the intragranular structure in N-S35140 steel.</p> Full article ">Figure 5
<p>STEM image (<b>a</b>) and EDS results (<b>b</b>–<b>i</b>) of N-S35140 steel near the grain boundary.</p> Full article ">Figure 6
<p>TEM in situ compression process of N-S35140 steel nano pillar: (<b>a</b>) starting loading stage; (<b>b</b>) compression process stage; (<b>c</b>) unloading stage.</p> Full article ">Figure 7
<p>The stress–strain curves of N-S35140 steel during TEM in situ compression at room temperature.</p> Full article ">Figure 8
<p>The stress–strain curves (<b>a</b>) and tensile strength and yield strength (<b>b</b>) of N-S35140 steel during SEM in situ tensile testing at different temperatures.</p> Full article ">Figure 9
<p>The EBSD results based on inverse pole figure (IPF) map along the <span class="html-italic">Z</span>-axis of N-S35140 steel: initial morphologies (<b>a</b>,<b>c</b>); SEM in situ tensile testing at 350 °C (<b>b</b>) and at 650 °C (<b>d</b>).</p> Full article ">Figure 10
<p>Morphologies of N-S35140 steel during in situ tensile fracture at (<b>a</b>) room temperature; (<b>b</b>) 350 °C; and (<b>c</b>) 650 °C.</p> Full article ">

18 pages, 5239 KiB

Open AccessArticle

A Facile Two-Step High-Throughput Screening Strategy of Advanced MOFs for Separating Argon from Air

by Xiaoyi Xu, Bingru Xin, Zhongde Dai, Chong Liu, Li Zhou, Xu Ji and Yiyang Dai

Nanomaterials 2025, 15(6), 412; https://doi.org/10.3390/nano15060412 - 7 Mar 2025

Metal–organic frameworks (MOFs) based on the pressure swing adsorption (PSA) process show great promise in separating argon from air. As research burgeons, the number of MOFs has grown exponentially, rendering the experimental identification of materials with significant gas separation potential impractical. This study [...] Read more.

Metal–organic frameworks (MOFs) based on the pressure swing adsorption (PSA) process show great promise in separating argon from air. As research burgeons, the number of MOFs has grown exponentially, rendering the experimental identification of materials with significant gas separation potential impractical. This study introduced a high-throughput screening through a two-step strategy based on structure–property relationships, which leveraged Grand Canonical Monte Carlo (GCMC) simulations, to swiftly and precisely identify high-performance MOF adsorbents capable of separating argon from air among a vast array of MOFs. Compared to traditional approaches for material development and screening, this method significantly reduced both experimental and computational resource requirements. This research pre-screened 12,020 experimental MOFs from a computationally ready experimental MOF (CoRE MOF) database down to 7328 and then selected 4083 promising candidates through structure–performance correlation. These MOFs underwent GCMC simulation assessments, showing superior adsorption performance to traditional molecular sieves. In addition, an in-depth discussion was conducted on the structural characteristics and metal atoms among the best-performing MOFs, as well as the effects of temperature, pressure, and real gas conditions on their adsorption properties. This work provides a new direction for synthesizing next-generation MOFs for efficient argon separation in labs, contributing to energy conservation and consumption reduction in the production of high-purity argon gas. Full article

(This article belongs to the Section Inorganic Materials and Metal-Organic Frameworks)

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<p>Workflow for high-throughput screening of MOF adsorbents designed to separate argon from air.</p> Full article ">Figure 2
<p>The structure–property relationship based on oxygen as the adsorbent; the structure–property relationship based on nitrogen as the adsorbent is described in <a href="#app1-nanomaterials-15-00412" class="html-app">Figure S6</a>. (<b>a</b>) LCD; (<b>b</b>) PLD; (<b>c</b>) density; (<b>d</b>) VSA; (<b>e</b>) GSA; (<b>f</b>) VF.</p> Full article ">Figure 3
<p>t-SNE algorithm visualized the sampling points and the pre-screening database.</p> Full article ">Figure 4
<p>The relationship between the working capacity and selectivity of MOF adsorbents within the optimal structural range. The yellow, green, and purple spheres separately refer to MOFs with top 10%, top 20%, and bottom 80% APSs for nitrogen or oxygen as the target adsorbate. The grey boxes refer to MOFs with high adsorption capabilities for nitrogen or oxygen. (<b>a</b>) The target adsorbate is nitrogen; (<b>b</b>) the target adsorbate is oxygen.</p> Full article ">Figure 5
<p>The relationship between the APS and R% of MOF adsorbents. The purple spheres refer to MOFs with R% > 80%, the yellow spheres refer to MOFs with R% < 80% and the top 10% APSs, and the green spheres refer to MOFs with R% < 80% and bottom 90% APSs for nitrogen or oxygen as the target adsorbate. (<b>a</b>) The target adsorbate is nitrogen; (<b>b</b>) the target adsorbate is oxygen.</p> Full article ">Figure 6
<p>(<b>a</b>) Proportion of OMSs in top MOFs; (<b>b</b>) proportion of OMSs in MOFs of the same metal.</p> Full article ">Figure 7
<p>Metal ligand types and numbers of all candidate MOFs.</p> Full article ">Figure 8
<p>Comparison of adsorption properties of top MOFs and zeolites.</p> Full article ">Figure 9
<p>The impact of temperature and desorption pressure on the adsorbent’s APSA and regenerability. With the changes in temperature: (<b>a</b>) the variation of the APSA; (<b>b</b>) the variation of the R% for nitrogen as the target adsorbate; (<b>c</b>) the variation of the R% for oxygen as the target adsorbate. With the changes in pressure: (<b>d</b>) the variation of the APSA; (<b>e</b>) the variation of the R% for nitrogen as the target adsorbate; (<b>f</b>) the variation of the R% for oxygen as the target adsorbate.</p> Full article ">

12 pages, 4047 KiB

Open AccessArticle

Multilayer Core-Sheath Structured Nickel Wire/Copper Oxide/Cobalt Oxide Composite for Highly Sensitive Non-Enzymatic Glucose Sensor

by Yuxin Wu, Zhengwei Zhu, Xinjuan Liu and Yuhua Xue

Nanomaterials 2025, 15(6), 411; https://doi.org/10.3390/nano15060411 - 7 Mar 2025

The development of micro glucose sensors plays a vital role in the management and monitoring of diabetes, facilitating real-time tracking of blood glucose levels. In this paper, we developed a three-layer core-sheath microwire (NW@CuO@Co₃O₄) with nickel wire as the [...] Read more.

The development of micro glucose sensors plays a vital role in the management and monitoring of diabetes, facilitating real-time tracking of blood glucose levels. In this paper, we developed a three-layer core-sheath microwire (NW@CuO@Co₃O₄) with nickel wire as the core and copper oxide and cobalt oxide nanowires as the sheath. The unique core-sheath structure of microwire enables it to have both good conductivity and excellent electrochemical catalytic activity when used as an electrode for glucose detecting. The non-enzymatic glucose sensor base on a NW@CuO@Co₃O₄ core-sheath wire exhibits a high sensitivity of 4053.1 μA mM⁻¹ cm⁻², a low detection limit 0.89 μM, and a short response time of less than 2 s. Full article

(This article belongs to the Special Issue Recent Developments in Nanomaterials and Their Composite for Electrochemical Sensors, Energy Conversion, and Storage Applications)

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<p>(<b>a</b>) XRD spectrum of the NW@CuO@Co<sub>3</sub>O<sub>4</sub> electrode. XPS spectra of the NW@CuO@Co<sub>3</sub>O<sub>4</sub> electrode, (<b>b</b>) full spectrum, (<b>c</b>) Cu 2p spectrum, (<b>d</b>) Ni 2p spectrum, (<b>e</b>) Co 2p spectrum, and (<b>f</b>) O 1s spectrum.</p> Full article ">Figure 2
<p>(<b>a</b>) SEM image of pure nickel wire. (<b>b</b>,<b>c</b>) SEM image of nickel wire after “alloy/de-alloy” treatment. (<b>d</b>–<b>f</b>) SEM image of NW@CuO@Co<sub>3</sub>O<sub>4</sub> electrode.</p> Full article ">Figure 3
<p>(<b>a</b>) TEM image of CuO–Co<sub>3</sub>O<sub>4</sub> composite. (<b>b</b>) TEM image of Co<sub>3</sub>O<sub>4</sub> nanowires, (<b>c</b>,<b>d</b>) TEM images of CuO nanoparticles.</p> Full article ">Figure 4
<p>(<b>a</b>) Cyclic voltammograms of pure nickel wire electrode and NW@CuO@Co<sub>3</sub>O<sub>4</sub> electrode at 50 mV s<sup>−1</sup> in 0.1 M NaOH solution with and without 1mM glucose added. (<b>b</b>) Cyclic voltammograms of NW@CuO@Co<sub>3</sub>O<sub>4</sub> electrode at 50 mV s<sup>−1</sup> in different 0.1M NaOH solutions with different concentrations of glucose added. (<b>c</b>) Cyclic voltammograms of NW@CuO@Co<sub>3</sub>O<sub>4</sub> electrode in 0.1 M NaOH at different scan rates (25~125 mv s<sup>−1</sup>). (<b>d</b>) Linear fitting diagram of cyclic voltammograms of oxidation peak current and reduction peak current at different scan rates and the half of the scan rate.</p> Full article ">Figure 5
<p>Glucose detection performance of NW@CuO@Co<sub>3</sub>O<sub>4</sub> electrode (<b>a</b>) Current versus time curves of adding 0.5 mM glucose six times at 50 s intervals to 0.1 M NaOH solution at different voltages (0.5~0.65 V). (<b>b</b>) Selectivity curve after adding 1 mM glucose, ascorbic acid (AA), dopamine hydrochloride (UA), uric acid (DA), and glucose to 0.1 M NaOH solution in sequence. (<b>c</b>) Amperometric response curve of adding different concentrations of glucose in 0.1 M NaOH solution in sequence at 0.55 V. (<b>d</b>) Linear fitting diagram of current and glucose concentration in alkaline solution.</p> Full article ">Figure 6
<p>(<b>a</b>) Stability of NW@CuO@Co<sub>3</sub>O<sub>4</sub> glucose sensors in 0.1 mM glucose solution. (<b>b</b>) EIS curves of NW and NW@CuO@Co<sub>3</sub>O<sub>4</sub>. (<b>c</b>) Current responses of five NW@CuO@Co<sub>3</sub>O<sub>4</sub> electrodes in 0.1 M NaOH with 2 mM glucose at 0.55 V.</p> Full article ">

18 pages, 4393 KiB

Open AccessArticle

A Z-Scheme Heterojunction g-C₃N₄/WO₃ for Efficient Photodegradation of Tetracycline Hydrochloride and Rhodamine B

by Yongxin Lu, Shangjie Gao, Teng Ma, Jie Zhang, Haixia Liu and Wei Zhou

Nanomaterials 2025, 15(5), 410; https://doi.org/10.3390/nano15050410 - 6 Mar 2025

The construction of heterojunctions can effectively inhibit the rapid recombination of photogenerated electrons and holes in photocatalysts and offers great potential for pollutant degradation. In this study, a Z-scheme heterojunction g-C₃N₄/WO₃ photocatalyst was synthesized using a combination of [...] Read more.

The construction of heterojunctions can effectively inhibit the rapid recombination of photogenerated electrons and holes in photocatalysts and offers great potential for pollutant degradation. In this study, a Z-scheme heterojunction g-C₃N₄/WO₃ photocatalyst was synthesized using a combination of hydrothermal and calcination methods. The photocatalytic degradation performance was tested under visible light; the degradation efficiency of Rh B reached 97.9% within 15 min and that of TC-HCl reached 93.3% within 180 min. The excellent photocatalytic performance of g-C₃N₄/WO₃ composites can be attributed to the improved absorption of visible light, the increase in surface area, and the effective separation of photogenerated electron–hole pairs. In addition, after four cycles of experiments, the photocatalytic performance of g-C₃N₄/WO₃ did not decrease obviously, remaining at 97.8%, which proved that the g-C₃N₄/WO₃ heterojunction had high stability and reusability. The active radical capture experiment confirmed that h⁺ and ·O₂⁻ played a leading role in the photocatalytic degradation. The Z-scheme heterojunction g-C₃N₄/WO₃ designed and synthesized in this study is expected to become an efficient photocatalyst suitable for environmental pollution control. Full article

(This article belongs to the Special Issue Research Progress of Nanomaterials for Photocatalysis)

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<p>XRD patterns of all prepared samples (<b>a</b>), and FTIR spectra of g-C<sub>3</sub>N<sub>4</sub>, WO<sub>3</sub>, and g-C<sub>3</sub>N<sub>4</sub>/WO<sub>3</sub>-4 (<b>b</b>).</p> Full article ">Figure 2
<p>SEM micrographs of (<b>a</b>) g-C<sub>3</sub>N<sub>4</sub>, (<b>b</b>) WO<sub>3</sub>, (<b>c</b>) g-C<sub>3</sub>N<sub>4</sub>/WO<sub>3</sub>-4. TEM, HRTEM results of (<b>d</b>) g-C<sub>3</sub>N<sub>4</sub>, (<b>e</b>) WO<sub>3</sub>, (<b>f</b>,<b>g</b>) g-C<sub>3</sub>N<sub>4</sub>/WO<sub>3</sub>-4, (<b>h</b>–<b>l</b>) EDS images of g-C<sub>3</sub>N<sub>4</sub>/WO<sub>3</sub>-4:C (red), N (green), O (yellow), and W (blue).</p> Full article ">Figure 3
<p>(<b>a</b>) N<sub>2</sub> adsorption and desorption isotherms and pore size distribution curves (inset) of g-C<sub>3</sub>N<sub>4</sub>, WO<sub>3</sub>, and g-C<sub>3</sub>N<sub>4</sub>/WO<sub>3</sub>-4, (<b>b</b>) PL spectra of g-C<sub>3</sub>N<sub>4</sub>, WO<sub>3</sub>, and g-C<sub>3</sub>N<sub>4</sub>/WO<sub>3</sub>-4, (<b>c</b>) XPS survey spectrum of g-C<sub>3</sub>N<sub>4</sub>/WO<sub>3</sub>-4, high-resolution XPS spectra: (<b>d</b>) C 1s, (<b>e</b>) N 1s, (<b>f</b>) O 1s, (<b>g</b>) W 4f, (<b>h</b>) XPS of WO<sub>3</sub> and g-C<sub>3</sub>N<sub>4</sub>/WO<sub>3</sub>-4 in the region of W 4f.</p> Full article ">Figure 4
<p>(<b>a</b>) Transient photocurrent response tests of all the catalysts and (<b>b</b>) EIS plots of all the samples.</p> Full article ">Figure 5
<p>(<b>a</b>) UV-vis spectra of all the catalysts and (<b>b</b>) the bandgaps of g-C<sub>3</sub>N<sub>4</sub>, WO<sub>3</sub>.</p> Full article ">Figure 6
<p>Rh B: [Rh B] = 20.0 mg/L, [catalyst] = 1.0 g/L, pH = 5.7. (<b>a</b>) Photocatalytic degradation curves and (<b>b</b>) fitted kinetics curves of all the samples, (<b>c</b>) cyclic degradation curve of g-C<sub>3</sub>N<sub>4</sub>/WO<sub>3</sub>-4, and (<b>d</b>) the XRD pattern of the g-C<sub>3</sub>N<sub>4</sub>/WO<sub>3</sub>-4 sample after 4th run cycle photocatalytic experiments.</p> Full article ">Figure 7
<p>TC-HCl: [TC-HCl] = 30.0 mg/L, [catalyst] = 1.0 g/L, pH = 4.4. (<b>a</b>) Photocatalytic degradation curves and (<b>b</b>) fitted kinetics curves of all the samples.</p> Full article ">Figure 8
<p>(<b>a</b>) Effects of g-C<sub>3</sub>N<sub>4</sub>/WO<sub>3</sub>-4 catalyst dosage on Rh B photodegradation ([Rh B] = 20.0 mg/L, pH = 5.7), (<b>b</b>) effects of Rh B initial concentration on the yield of Rh B photodegradation ([catalyst] = 1.0 g/L, pH = 5.7), (<b>c</b>) effects of pH on the photocatalytic activity of g-C<sub>3</sub>N<sub>4</sub>/WO<sub>3</sub>-4 in Rh B photodegradation ([Rh B] = 20.0 mg/L, [catalyst] = 1.0 g/L), (<b>d</b>) effects of g-C<sub>3</sub>N<sub>4</sub>/WO<sub>3</sub>-4 catalyst dosage on TC-HCl photodegradation ([TC-HCl] = 30.0 mg/L, pH = 4.4), (<b>e</b>) effects of TC-HCl initial concentration on the yield of TC-HCl photodegradation ([catalyst] = 1.0 g/L, pH = 4.4), (<b>f</b>) effects of pH on the photocatalytic activity of g-C<sub>3</sub>N<sub>4</sub>/WO<sub>3</sub>-4 in TC-HCl photodegradation ([TC-HCl] = 30.0 mg/L, [catalyst] = 1.0 g/L).</p> Full article ">Figure 9
<p>Active species trapping experiments.</p> Full article ">Figure 10
<p>DMPO spin-trapping ESR spectra of g-C<sub>3</sub>N<sub>4</sub>, WO<sub>3</sub>, and g-C<sub>3</sub>N<sub>4</sub>/WO<sub>3</sub>-4 in aqueous dispersion (for DMPO-·OH) (<b>a</b>) and in methanol dispersion (for DMPO-·O<sub>2</sub><sup>−</sup>) (<b>b</b>) under visible light irradiation.</p> Full article ">Scheme 1
<p>Schematic diagram of the preparation of g-C<sub>3</sub>N<sub>4</sub>/WO<sub>3</sub>.</p> Full article ">Scheme 2
<p>Schematic diagram of crystal structure transformation.</p> Full article ">Scheme 3
<p>Two possible photocatalytic mechanisms of the g-C<sub>3</sub>N<sub>4</sub>/WO<sub>3</sub>-4 composite, (<b>a</b>) Type II mechanism and (<b>b</b>) Z-scheme mechanism.</p> Full article ">

37 pages, 9890 KiB

Open AccessReview

Ferroelectric and Non-Linear Optical Nanofibers by Electrospinning: From Inorganics to Molecular Crystals

by Rosa M. F. Baptista, Etelvina de Matos Gomes, Michael Belsley and Bernardo Almeida

Nanomaterials 2025, 15(5), 409; https://doi.org/10.3390/nano15050409 - 6 Mar 2025

In recent decades, substantial progress has been made in embedding molecules, nanocrystals, and nanograins into nanofibers, resulting in a new class of hybrid functional materials with exceptional physical properties. Among these materials, functional nanofibers exhibiting ferroelectric, piezoelectric, pyroelectric, multiferroic, and nonlinear optical characteristics [...] Read more.

In recent decades, substantial progress has been made in embedding molecules, nanocrystals, and nanograins into nanofibers, resulting in a new class of hybrid functional materials with exceptional physical properties. Among these materials, functional nanofibers exhibiting ferroelectric, piezoelectric, pyroelectric, multiferroic, and nonlinear optical characteristics have attracted considerable attention and undergone substantial improvements. This review critically examines these developments, focusing on strategies for incorporating diverse compounds into nanofibers and their impact on enhancing their physical properties, particularly ferroelectric behavior and nonlinear optical conversion. These developments have transformative potential across electronics, photonics, biomaterials, and energy harvesting. By synthesizing recent advancements in the design and application of nanofiber-embedded materials, this review seeks to highlight their potential impact on scientific research, technological innovation, and the development of next-generation devices. Full article

(This article belongs to the Special Issue Advances in Micro and Nanofiber: Fabrication, Properties and Applications)

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<p>Electrospinning process, with (<b>a</b>) the typical experimental setup, (<b>b</b>) the Taylor cone formation and (<b>c</b>) the resulting fibers.</p> Full article ">Figure 2
<p>SEM images of the barium titanate fibers (<b>a</b>) As-electrospun and (<b>b</b>) after annealing. Scale bar: 20 µm. (<b>c</b>) Evolution of the alignment degree (orientational index) of the nanofibers, with the rotation velocity of the collector drum. Open and filled circles correspond to As-electrospun and annealed nanofibers, respectively. (<b>d</b>) The normalized SHG intensity as a function of temperature observed in nanofibers of BaTiO<sub>3</sub> calcined at 900 °C (squares) and 1100 °C (circles). The solid curves are the derivatives of I(T), showing a minimum at the ferroelectric transition temperature of bulk BaTiO<sub>3</sub>. Reprinted with permission from Ref. [<a href="#B85-nanomaterials-15-00409" class="html-bibr">85</a>].</p> Full article ">Figure 3
<p>SEM images of the BaTiO<sub>3</sub> nanofibers calcined at (<b>a</b>) 750 °C, (<b>b</b>) 850 °C, (<b>c</b>) 950 °C, and (<b>d</b>) 1150 °C for 6 h. All images have the same scale. Reprinted with permission from Ref. [<a href="#B108-nanomaterials-15-00409" class="html-bibr">108</a>].</p> Full article ">Figure 4
<p>(<b>a</b>,<b>b</b>) Barium titanate flexible nanofiber mat. Reprinted with permission from Ref. [<a href="#B109-nanomaterials-15-00409" class="html-bibr">109</a>].</p> Full article ">Figure 5
<p>Scanning electron microscopy (SEM) micrograph of (<b>a</b>) coaxial fibers of sample A with a barium titanate (BTO) core and a nickel ferrite (NFO) shell and (<b>b</b>) a single fiber of sample A. (<b>c</b>) Atomic force microscopy (AFM) topography for fibers of sample B with an NFO core–BTO shell. (<b>d</b>) Magnetic force microscopy (MFM) phase image for sample B. Reprinted with permission from Ref. [<a href="#B131-nanomaterials-15-00409" class="html-bibr">131</a>]. (<b>e</b>) Core–shell nanofibers composed by a CFO core inside a BFO shell. Reprinted with permission from Ref. [<a href="#B129-nanomaterials-15-00409" class="html-bibr">129</a>].</p> Full article ">Figure 6
<p>Magnetoelectric coupling of CFO–BTO composite nanofibers. (<b>a</b>) Conceptual diagram of the VFM investigation of multiferroic nanofibers with an external magnetic field. (<b>b</b>) Amplitude-voltage butterfly curves and (<b>c</b>) phase–voltage curves of the nanofibers with and without an external applied magnetic field. Reprinted with permission from Ref. [<a href="#B136-nanomaterials-15-00409" class="html-bibr">136</a>]. (<b>d</b>) Composite NFO–PZT multiferroic nanofibers, reprinted with permission from Ref. [<a href="#B139-nanomaterials-15-00409" class="html-bibr">139</a>]. (<b>e</b>) CFO–BTO Janus nanofibers, reprinted with permission from Ref. [<a href="#B145-nanomaterials-15-00409" class="html-bibr">145</a>]. Characterization of calcined Janus nanofibers composed of CoFe<sub>2</sub>O<sub>4</sub>–BaTiO<sub>3</sub>. (<b>f</b>) A scanning electron microscope image (SEM) of a mat of randomly aligned Janus fibers. (<b>g</b>) An additional fiber from which further energy dispersive spectroscopy (EDS) spectra were obtained. (<b>h</b>) EDS spectra indicating the localization of CoFe<sub>2</sub>O<sub>4</sub> to the darker semicylinder, and (<b>i</b>) EDS spectra confirming the localization of BaTiO<sub>3</sub> to the lighter semicylinder. Reprinted with permission from Ref. [<a href="#B143-nanomaterials-15-00409" class="html-bibr">143</a>].</p> Full article ">Figure 7
<p>(<b>a</b>) Morphology of the dabcoHReO<sub>4</sub> individual fiber obtained by AFM; (<b>b</b>) vertical and (<b>c</b>) lateral PFM images of dabcoHReO<sub>4</sub> nanofibers; (<b>d</b>) piezoelectric response hysteresis loop; (<b>e</b>) voltage output of the fabricated nanofiber mat under 1 Hz (left) and 5 Hz (right) repeated compressive impacts. Nanofiber mat thickness of 100 μm, working area of 1 cm<sup>2</sup>. The temperature cyclic change, and derivative and output pyroelectric current obtained in dabcoHReO4 nanofiber mat at pulsed (<b>f</b>) and ramp (<b>g</b>) temperature changes. Reprinted with permission from Ref. [<a href="#B24-nanomaterials-15-00409" class="html-bibr">24</a>].</p> Full article ">Figure 8
<p>(<b>a</b>) Normalized emission spectra of BZT nanofibers and the pure compound in absolute ethanol; (<b>b</b>) single-photon fluorescence image (50 × 50 µm) of BZT 1 nanofibers. The fluorescence was observed in the wavelength range of 430–470 nm following excitation at a wavelength of 405 nm. Vertical PFM images observed in an individual BZT nanofiber: (<b>c</b>) As-electrospun nanofibers (before poling), (<b>d</b>) PFM image after applying a voltage of +100 V at the fixed tip during 10 s, (<b>e</b>) image after applying a voltage of −100 V. Reprinted with permission from Ref. [<a href="#B150-nanomaterials-15-00409" class="html-bibr">150</a>].</p> Full article ">Figure 9
<p>(<b>a</b>) Dielectric permittivity of an MDABCO–NH<sub>4</sub>I<sub>3</sub> polycrystalline sample showing its (<b>a</b>) real and (<b>b</b>) imaginary parts as functions of temperature and frequency. The ferroelectric–paraelectric phase transition occurs at 440 K; (<b>c</b>) piezoelectric current as a function of the applied forces and (<b>d</b>) output voltage and current as a function of time from MDABCO–NH<sub>4</sub>I<sub>3</sub> incorporated into different electrospun polymer nanofibers; (<b>e</b>–<b>g</b>) schematic of MDABCO–NH<sub>4</sub>I<sub>3</sub>@PVC piezoelectric nanogenerator, reprinted with permission from Ref. [<a href="#B152-nanomaterials-15-00409" class="html-bibr">152</a>].</p> Full article ">Figure 10
<p>(<b>a</b>) SEM image of MNA@PLLA nanofiber arrays; (<b>b</b>) the MNA molecule; (<b>c</b>) MNA molecular packing and (<b>d</b>) its projection onto the (010) plane (<b>d</b>); (<b>e</b>) XRD pattern of MNA_PLLA fiber arrays; (<b>f</b>,<b>g</b>) sketch of the SGH ellipsometry experiment and SHG polarization patterns in the in-plane aligned array of the MNA@PLLA fibers, reprinted with permission from Ref. [<a href="#B21-nanomaterials-15-00409" class="html-bibr">21</a>]. Here, the generated second harmonic light, which passed through an analyzer, was oriented either parallel (<span class="html-italic">q</span>–<span class="html-italic">p</span> configuration, <span class="html-italic">q</span> indicates an incident polarization angle) or perpendicular (<span class="html-italic">q</span>–<span class="html-italic">s</span> configuration) to the longitudinal axis of the aligned fibers.</p> Full article ">Figure 11
<p>(<b>a</b>,<b>b</b>) Single-photon fluorescence image of MNA–PLLA nanofibers showing a uniform distribution of MNA nanocrystals embedded within the PLA nanofiber. The excitation wavelength was 405 nm, and fluorescence was observed in the range of 430–470 nm. (<b>c</b>) SHG efficiency of MNA–PLLA nanofibers as a function of the average fiber diameter and MNA particle size. Reprinted with permission from Ref. [<a href="#B156-nanomaterials-15-00409" class="html-bibr">156</a>].</p> Full article ">Figure 12
<p>(<b>a</b>) X-ray diffraction pattern revealing strong orientation observed in a <span class="html-italic">p</span>NA mesocrystalline structure produced by electrospinning; (<b>b</b>) four-unit cells of <span class="html-italic">p</span>NA with the shown (202) plane terminated the periodic crystal lattice by the surface; (<b>c</b>) 50 × 50 μm micrograph of <span class="html-italic">p</span>NA nanofibers obtained by fluorescence lifetime imaging microscope; (<b>d</b>) double exponential fluorescence decay obtained from <span class="html-italic">p</span>NA single crystal (black curve), nanofibers (red curve), and solution (blue curve). Reprinted with permission from Ref. [<a href="#B161-nanomaterials-15-00409" class="html-bibr">161</a>].</p> Full article ">Figure 13
<p>(<b>a</b>) 3NA@PCL electrospun fiber mat deposited on a substrate; (<b>b</b>) corresponding SEM image; (<b>c</b>) measured X-ray diffraction pattern of a 3NA@PCL nanofiber mat (the insets show the calculated powder patterns for crystalline 3NA and PCL polymer); (<b>d</b>) unit cell of 3NA showing the molecular dipoles (represented by arrows) added to a net dipole parallel to (400); (<b>e</b>) polar plot of SHG polarimetry data collected on a single 3NA@PCL electrospun nanofiber for <span class="html-italic">q–p</span> and <span class="html-italic">q–s</span> configurations; (<b>f</b>) polar plot of SHG polarimetry data collected on a (100) 3NA crystal platelet for <span class="html-italic">q–p</span> and <span class="html-italic">q–s</span> configurations. The radial axis values are expressed in the unit of counts. The maximum intensity corresponds to the case where the polarization of incident and emitted light are parallel to each other and aligned with the fiber longitudinal axis; (<b>g</b>) output voltage and current measured on a 3NA@PCL electrospun fiber mat; (<b>h</b>) plot of output voltage versus applied force with a schematic piezoelectric setup of a 3NA@PCL fiber mat. There is a linear relationship between the measured output voltage and the applied force. Reprinted with permission from Ref. [<a href="#B26-nanomaterials-15-00409" class="html-bibr">26</a>].</p> Full article ">Figure 14
<p>(<b>a</b>) Electrospun 2A4NA@PLLA fiber array deposited on a substrate, (<b>b</b>) corresponding scanning electron microscope image. Monochromatic images of the second harmonic light emitted by single fibers of (<b>c</b>) 3NA@PLLA and (<b>d</b>) 2A4NA@PLLA. Polar plots of SHG polarimetry data collected on a single nanofiber of (<b>e</b>) 2A4NA@PLLA, (<b>f</b>) 3NA@PLLA and (<b>g</b>) 3NA@PCL [<a href="#B26-nanomaterials-15-00409" class="html-bibr">26</a>] for <span class="html-italic">q</span>–<span class="html-italic">p</span> and <span class="html-italic">q</span>–<span class="html-italic">s</span> configurations. The radial axis values are expressed in units of 106 counts. Reprinted with permission from Ref. [<a href="#B164-nanomaterials-15-00409" class="html-bibr">164</a>].</p> Full article ">Figure 15
<p>(<b>a</b>) Wide-angle X-ray diffraction 2θ diagrams for (<b>a</b>) the bulk PEO−urea inclusion complex (IC) and (<b>b</b>) electrospun fibers. (<b>c</b>) Cross-polarized optical micrograph of electrospun fibers of the PEO−urea inclusion complex. Reprinted with permission from Ref. [<a href="#B168-nanomaterials-15-00409" class="html-bibr">168</a>]. Representative cross-polarized optical micrographs of fibers prepared by electrospinning solutions with (<b>d</b>) 4:9 and (<b>e</b>) 3:2 PEO:urea molar ratios. Reprinted with permission from Ref. [<a href="#B166-nanomaterials-15-00409" class="html-bibr">166</a>].</p> Full article ">Figure 16
<p>(<b>a</b>) SEM micrographs and thickness distribution of electrospun PEO–urea and (<b>b</b>) PVA–urea nanofibers. (<b>c</b>) X-ray diffraction patterns of electrospun fibers of PEO–urea (dashed line) and PVA–urea (solid line). Crosses indicate diffraction peaks of pure crystalline urea. (<b>d</b>,<b>e</b>) SHG polarimetry curves of PEO–urea and PVA–urea nanofibers, respectively. Reprinted with permission from Ref. [<a href="#B154-nanomaterials-15-00409" class="html-bibr">154</a>].</p> Full article ">

11 pages, 2799 KiB

Open AccessArticle

Research on Wet Etching Techniques for GaInAs/AlInAs/InP Superlattices in Quantum Cascade Laser Fabrication

by Shiya Zhang, Lianqing Zhu, Han Jia, Bingfeng Liu, Jintao Cui, Tuo Chen and Mingyu Li

Nanomaterials 2025, 15(5), 408; https://doi.org/10.3390/nano15050408 - 6 Mar 2025

Wet etching is the mainstream fabrication method for single-bar quantum cascade lasers (QCLs). Different etching solutions result in varying etching effects on III-V semiconductor materials. In this study, an efficient and nearly ideal etching solution ratio was proposed for simultaneously etching both InP [...] Read more.

Wet etching is the mainstream fabrication method for single-bar quantum cascade lasers (QCLs). Different etching solutions result in varying etching effects on III-V semiconductor materials. In this study, an efficient and nearly ideal etching solution ratio was proposed for simultaneously etching both InP and GaInAs/AlInAs, and the surface chemical reactions induced by each component of the etching solution during the process were investigated. Using univariate and single-component experiments, coupled with various characterization techniques such as atomic force microscopy (AFM), stylus profilometer, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM), we found that the ratio of HBr to hydrogen peroxide significantly determines the etching rate, while the ratio of HCl to hydrogen peroxide affects the interface roughness. The aim of this study was to provide a comprehensive understanding of the effects of different etching solution components, thereby enhancing the understanding of the wet etching process for InP/GaInAs/AlInAs materials. These findings offer valuable insights into efficient QCL fabrication processes and contribute to the advancement of the field. Full article

(This article belongs to the Special Issue Nano-Photonics: Subwavelength Optical Elements, Metasurfaces, Plasmonics and Quantum Photonics: 2nd Edition)

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10 pages, 4851 KiB

Open AccessArticle

Room-Temperature Synthesis of Carbon Nanochains via the Wurtz Reaction

by Juxiang Pu, Yongqing Gong, Menghao Yang and Mali Zhao

Nanomaterials 2025, 15(5), 407; https://doi.org/10.3390/nano15050407 - 6 Mar 2025

In the field of surface synthesis, various reactions driven by the catalytic effect of metal substrates, particularly the Ullmann reaction, have been thoroughly investigated. The Wurtz reaction facilitates the coupling of alkyl halides through the removal of halogen atoms with a low energy [...] Read more.

In the field of surface synthesis, various reactions driven by the catalytic effect of metal substrates, particularly the Ullmann reaction, have been thoroughly investigated. The Wurtz reaction facilitates the coupling of alkyl halides through the removal of halogen atoms with a low energy barrier on the surface; however, the preparation of novel carbon nanostructures via the Wurtz reaction has been scarcely reported. Here, we report the successful synthesis of ethyl-bridged binaphthyl molecular chains on Ag(111) at room temperature via the Wurtz reaction. However, this structure was not obtained through low-temperature deposition followed by annealing even above room temperature. High-resolution scanning tunneling microscopy combined with density functional theory calculations reveal that the rate-limiting step of C–C homocoupling exhibits a low-energy barrier, facilitating the room-temperature synthesis of carbon nanochain structures. Moreover, the stereochemical configuration of adsorbed molecules hinders the activation of the C–X (X = Br) bond away from the metal surface and, therefore, critically influences the reaction pathways and final products. This work advances the understanding of surface-mediated reactions involving precursor molecules with stereochemical structures. Moreover, it provides an optimized approach for synthesizing novel carbon nanostructures under mild conditions. Full article

(This article belongs to the Special Issue Functionalized Nanostructures on Surfaces and at Interfaces)

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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>Trans-BBMBN molecules after deposition on Ag(111) at low temperature. (<b>a</b>) Large-scale and (<b>b</b>) zoomed STM images of the hinged molecular self-assembly after deposition at 135 K. The dashed lines are the vectors in each self-assembled unit cell. (<b>c</b>) Large-scale and (<b>d</b>) zoomed STM images of the parallelogram-like molecular self-assembly after deposition at 150~180 K. (<b>e</b>) Top and side views of the DFT-optimized trans-BBMBN configuration adsorbed on Ag(111). (<b>f</b>) Simulated STM image based on DFT-calculated geometry. Scanning parameters: V<sub>t</sub> = −1.25 V, I = 0.8~1.6 nA. C: gray; H: pink; Br: brown; Ag substrate: blue.</p> Full article ">Figure 2
<p>(<b>a</b>) Large-scale and (<b>b</b>) zoomed STM images of monoradical intermediates BBMBN* after molecular deposition on Ag(111) at low temperature with post-annealing at 350 K. (<b>c</b>) Top and side views of the partial debrominated BBMBN molecule on Ag(111); (<b>d</b>) simulated STM image based on the DFT-optimized geometry in Panel (<b>c</b>); (<b>e</b>) large-scale and (<b>f</b>) zoomed STM images of the coexisting monoradical species and dimerized products.</p> Full article ">Figure 3
<p>Formation of the biradical species after BBMBN molecular deposition on Ag(111) held at room temperature. (<b>a</b>) Large-scale and (<b>b</b>) zoomed STM images of the completely debrominated molecules. The spots in white circles are the removed bromine atoms. (<b>c</b>) Top and side views of the completely debrominated molecular structural models. (<b>d</b>) Simulated STM image based on the DFT-calculated geometry. Scanning parameters: V<sub>t</sub> = −1.25 V, I = 0.85~1.1 nA. C: gray; H: pink; Ag substrate: blue.</p> Full article ">Figure 4
<p>Formation of the one-dimensional chain-like structure after room-temperature deposition of BBMBN molecules on Ag(111) with subsequent annealing at 300 K for 12 h. (<b>a</b>) Large-scale and (<b>b</b>) zoomed STM images of the molecular chains; (<b>c</b>) high-resolution and (<b>d</b>) simulated STM image of the single molecular chain; (<b>e</b>) top and side views of the ethyl-bridged binaphthyl structural model. Scan parameters: V<sub>t</sub> = −1.25 V, I = 0.6–0.9 nA. C: gray; H: pink; Ag substrate: blue.</p> Full article ">Figure 5
<p>DFT-calculated energy profiles for (<b>a</b>) C-Br bond cleavage, (<b>b</b>) radical migration, and (<b>c</b>) C–C homocoupling of 2-(Bromomethyl)naphthalene on Ag(111). The structural models of the initials states (ISs), the transition states (TSs), and the final states (FSs) along the pathways are shown below.</p> Full article ">Scheme 1
<p>The upper route shows partial debromination and coupling after low-temperature deposition with post-annealing at 350 K, resulting in a predominant population of monoradical species coexisting with a minority of dimerized product. The lower route illustrates the complete debromination and coupling of C<sub>22</sub>H<sub>16</sub>Br<sub>2</sub> molecules after room-temperature deposition with subsequent annealing at 300 K, leading to the formation of the molecular chain.</p> Full article ">

13 pages, 5253 KiB

Open AccessArticle

Microwave Absorption Properties of Graphite Nanosheet/Carbon Nanofiber Hybrids Prepared by Intercalation Chemical Vapor Deposition

by Yifan Guo, Junhua Su, Qingfeng Guo, Ling Long, Jinlong Xie and Ying Li

Nanomaterials 2025, 15(5), 406; https://doi.org/10.3390/nano15050406 - 6 Mar 2025

Carbon-based microwave absorption materials have garnered widespread attention as lightweight and efficient wave absorbers, emerging as a prominent focus in the field of functional materials research. In this work, FeNi₃ nanoparticles, synthesized in situ within graphite interlayers, were employed as catalysts to [...] Read more.

Carbon-based microwave absorption materials have garnered widespread attention as lightweight and efficient wave absorbers, emerging as a prominent focus in the field of functional materials research. In this work, FeNi₃ nanoparticles, synthesized in situ within graphite interlayers, were employed as catalysts to grow carbon nanofibers in situ via intercalation chemical vapor deposition (CVD). We discovered that amorphous carbon nanofibers (CNFs) can exfoliate and separate highly conductive graphite nanosheets (GNS) from the interlayers. Meanwhile, the carbon nanofibers eventually intertwine and encapsulate the graphite nanosheets, forming porous hybrids. This process induces significant changes in the electrical conductivity and electromagnetic parameters of the resulting GNS/CNF hybrids, enhancing the impedance matching between the hybrids and free space. Although this process slightly reduces the microwave loss capability of the hybrids, the balance between these effects significantly enhances their microwave absorption performance, particularly in the K_u band. Specifically, the optimized GNS/CNF hybrids, when mixed with paraffin at a 30 wt% ratio, exhibit a maximum microwave reflection loss of −44.1 dB at 14.6 GHz with a thickness of 1.5 mm. Their effective absorption bandwidth, defined as the frequency range with a reflection loss below −10 dB, spans the 12.5–17.4 GHz range, covering more than 80% of the K_u band. These results indicate that the GNS/CNF hybrids prepared via intercalation CVD are promising candidates for microwave absorption materials. Full article

(This article belongs to the Special Issue Porous Nanomaterials: Preparation, Performance, and Practical Application)

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<p>Schematic illustration of the mechanism for the preparation of graphite nanosheet/carbon nanofiber hybrids via the intercalation CVD technique.</p> Full article ">Figure 2
<p>Electron microscopy characterizations of the samples. (<b>a</b>,<b>b</b>) SEM images of (<b>a</b>) natural graphite, (<b>b</b>) FeNi<sub>3</sub>-intercalated graphite. (<b>c</b>,<b>d</b>) Graphite nanosheet/carbon nanofiber hybrids prepared by intercalation CVD. (<b>e</b>) TEM images of the grown carbon nanofibers. The inset in the top left shows the high-resolution transmission electron microscopy (HR-TEM) image of the carbon fiber wall. (<b>f</b>) HRTEM images of a FeNi<sub>3</sub> nanoparticle embedded between the graphite nanosheets. High-resolution lattice of FeNi<sub>3</sub> (111) and graphite (002) planes are labeled.</p> Full article ">Figure 3
<p>Scanning electron microscopy (SEM) images of graphite nanosheet/carbon nanofiber hybrids grown for different CVD durations. The specific CVD growth times are (<b>a</b>) 0 min, (<b>b</b>) 10 min, (<b>c</b>) 30 min, (<b>d</b>) 60 min, (<b>e</b>) 120 min, and (<b>f</b>) 240 min.</p> Full article ">Figure 4
<p>Structural characterizations and electrical conductivities of graphite nanosheet/carbon nanofiber hybrids grown for different CVD durations. (<b>a</b>) XRD patterns, (<b>b</b>) Raman spectra, and (<b>c</b>) electrical conductivities tested by four-point probe resistivity measurement.</p> Full article ">Figure 5
<p>Frequency-dependent electromagnetic parameters of graphite nanosheet/carbon nanofiber hybrids grown for different CVD durations. (<b>a</b>) Real part and (<b>b</b>) imaginary part of the complex permittivity. (<b>c</b>) Real part and (<b>d</b>) imaginary part of the complex permeability.</p> Full article ">Figure 6
<p>Microwave absorption performances of graphite nanosheet/carbon nanofiber hybrids grown for different CVD durations. (<b>a</b>) Reflection loss curves of the hybrids with a thickness of 1.5 mm. The black dashes indicate effective absorption regions (RL < −10 dB). (<b>b</b>,<b>c</b>) Three-dimensional representations of the hybrids grown for (<b>c</b>) 30 min and (<b>c</b>) 60 min. Note that the RL values are derived from the measured electromagnetic parameters.</p> Full article ">Figure 7
<p>Impedance matches of graphite nanosheet/carbon nanofiber hybrids grown for different CVD durations. (<b>a</b>) 0 min, (<b>b</b>) 10 min, (<b>c</b>) 30 min, (<b>d</b>) 60 min, (<b>e</b>) 120 min, (<b>f</b>) 240 min.</p> Full article ">Figure 8
<p>Microwave dissipation abilities of graphite nanosheet/carbon nanofiber hybrids. (<b>a</b>) Dielectric dissipation factors, (<b>b</b>) magnetic dissipation factor, and (<b>c</b>) attenuation value as a function of microwave frequency.</p> Full article ">

13 pages, 1893 KiB

Open AccessArticle

Catalytic Activity of Water-Soluble Palladium Nanoparticles with Anionic and Cationic Capping Ligands for Reduction, Oxidation, and C-C Coupling Reactions in Water

by Jan W. Farag, Ragaa Khalil, Edwin Avila and Young-Seok Shon

Nanomaterials 2025, 15(5), 405; https://doi.org/10.3390/nano15050405 - 6 Mar 2025

The availability of water-soluble nanoparticles allows catalytic reactions to occur in highly desirable green environments. The catalytic activity and selectivity of water-soluble palladium nanoparticles capped with 6-(carboxylate)hexanethiolate (C6-PdNP) and 5-(trimethylammonio)pentanethiolate (C5-PdNP) were investigated for the reduction of 4-nitrophenol, the oxidation of α,β-conjugated aldehydes, [...] Read more.

The availability of water-soluble nanoparticles allows catalytic reactions to occur in highly desirable green environments. The catalytic activity and selectivity of water-soluble palladium nanoparticles capped with 6-(carboxylate)hexanethiolate (C6-PdNP) and 5-(trimethylammonio)pentanethiolate (C5-PdNP) were investigated for the reduction of 4-nitrophenol, the oxidation of α,β-conjugated aldehydes, and the C-C coupling of phenylboronic acid. The study showed that between the two PdNPs, C6-PdNP exhibits better catalytic activity for the reduction of 4-nitrophenol to 4-aminophenol in the presence of sodium borohydride and the selective oxidation of conjugated aldehydes to conjugated carboxylic acids. For the latter reaction, molecular hydrogen (H₂) and H₂O act as oxidants for the surface palladium atoms on PdNPs and conjugated aldehyde substrates, respectively. The results indicated that the competing addition activities of Pd-H and H₂O toward the π-bond of different unsaturated substrates promote either reduction or oxidation reactions under mild conditions in organic solvent-free environments. In comparison, C5-PdNP exhibited higher catalytic activity for the C-C coupling of phenylboronic acid. Gas chromatography–mass spectrometry (GC-MS) was mainly used as an analytical technique to examine the products of catalytic reactions. Full article

(This article belongs to the Section Energy and Catalysis)

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<p>TEM images and histograms of (<b>a</b>) C6-PdNP and (<b>b</b>) C5-PdNP.</p> Full article ">Figure 2
<p>(<b>a</b>) UV–vis spectra for the catalytic reduction of 4-nitrophenol using C6-PdNP. (<b>b</b>) Absorbance dependence of the time for the reduction of 4-nitrophenol. (Conditions: [4-Nitrophenol] = 1 × 10<sup>−2</sup> M; [NaBH<sub>4</sub>] = 0.1 M; [Pd] = 0.1 mol% Pd). (k<sub>app</sub> = 1.09 × 10<sup>−2</sup> S<sup>−1</sup>). (<b>c</b>) UV–vis spectra for the catalytic reduction of 4-nitrophenol using C5-PdNP. (<b>d</b>) Absorption dependence of the time for the reduction of 4-nitrophenol. (Conditions: [4-nitrophenol] = 1 × 10<sup>−2</sup> M; [NaBH<sub>4</sub>] = 0.1 M; [Pd] = 0.1 mol% Pd). (k<sub>app</sub> = 6.04 × 10<sup>−3</sup> S<sup>−1</sup>).</p> Full article ">Scheme 1
<p>4-Nitrophenol reduction using NaBH<sub>4</sub> with C6-PdNP or C5-PdNP.</p> Full article ">Scheme 2
<p>Catalytic oxidation of crotonaldehyde and cinnamaldehyde using water-soluble C6-PdNP and H<sub>2</sub>.</p> Full article ">Scheme 3
<p>Proposed mechanism of selective oxidation of conjugated aldehyde.</p> Full article ">Scheme 4
<p>Catalytic C-C coupling reaction of phenylboronic acid using water-soluble PdNPs in water.</p> Full article ">

12 pages, 8103 KiB

Open AccessArticle

A Thermally Controlled Ultra-Wideband Wide Incident Angle Metamaterial Absorber with Switchable Transmission at the THz Band

by Liansheng Wang, Fengkai Xin, Quanhong Fu and Dongyan Xia

Nanomaterials 2025, 15(5), 404; https://doi.org/10.3390/nano15050404 - 6 Mar 2025

We demonstrate a thermally controlled ultra-wideband wide incident angle metamaterial absorber with switchable transmission at the THz band in this paper. The underlying hybrid structure of FSS-VO₂ thin films make them switchable between absorption mode and transmission mode by controlling the temperature. [...] Read more.

We demonstrate a thermally controlled ultra-wideband wide incident angle metamaterial absorber with switchable transmission at the THz band in this paper. The underlying hybrid structure of FSS-VO₂ thin films make them switchable between absorption mode and transmission mode by controlling the temperature. It can achieve ultra-wideband absorption with above 90% absorption from 1 THz to 10 THz and exhibits excellent absorption performance under a wide range of incident and polarization angles at a high temperature (80 °C). At room temperature (27 °C), it acts in transmission mode with a transmission coefficient of up to 60% at 3.1278 THz. The transmission region is inside the absorption band, which is very important for practical applications. The metamaterial absorber has the advantage of easy fabrication, an ultra-wideband, a wide incident angle, switchable multi-functions, and passivity with wide application prospects on terahertz communication and radar devices. Full article

(This article belongs to the Special Issue Metamaterials and Metasurfaces for Advanced Electromagnetic Wave Manipulation and Applications)

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Figure 1
<p>A schematic of our designed metamaterial absorber: (<b>a</b>) at a high temperature (80 °C); (<b>b</b>) at room temperature (27 °C).</p> Full article ">Figure 2
<p>Geometry of a unit cell: (<b>a</b>) perspective view; (<b>b</b>) back view.</p> Full article ">Figure 3
<p>The conductivity of VO<sub>2</sub> during heating and cooling processes.</p> Full article ">Figure 4
<p>The absorption, transmission coefficient, and reflection coefficient of the metamaterial absorber: (<b>a</b>) the VO<sub>2</sub> thin film is in the metallic phase at a high temperature of 80 °C; (<b>b</b>) the VO<sub>2</sub> thin film is in the insulating phase at a room temperature of 27 °C.</p> Full article ">Figure 5
<p>The normalized input impedance of the metamaterial absorber: (<b>a</b>) the VO<sub>2</sub> thin film is in the metallic phase at a high temperature of 80 °C; (<b>b</b>) the VO<sub>2</sub> thin film is in the insulating phase at a room temperature of 27 °C.</p> Full article ">Figure 6
<p>The top-layer surface current of a metamaterial absorber when the VO<sub>2</sub> thin film is in the metallic phase at a high temperature (80 °C): (<b>a</b>) 3 THz; (<b>b</b>) 5 THz; (<b>c</b>) 7 THz.</p> Full article ">Figure 7
<p>The bottom-layer surface current of a metamaterial absorber when the VO<sub>2</sub> thin film is in the metallic phase at a high temperature (80 °C): (<b>a</b>) 3 THz; (<b>b</b>) 5 THz; (<b>c</b>) 7 THz.</p> Full article ">Figure 8
<p>The electric field distributions of the metamaterial absorber when the VO<sub>2</sub> thin film is in the metallic phase at a high temperature (80 °C): (<b>a</b>) 3 THz; (<b>b</b>) 5 THz; (<b>c</b>) 7 THz.</p> Full article ">Figure 9
<p>The electric field distributions of the metamaterial absorber when the VO<sub>2</sub> thin film is in the insulating phase at a room temperature of 27 °C: (<b>a</b>) 1 THz; (<b>b</b>) 3.1278 THz; (<b>c</b>) 10 THz.</p> Full article ">Figure 10
<p>The absorption and transmission coefficient of the metamaterial absorber under different polarization angles when the VO<sub>2</sub> film is in high-temperature (80 °C) and room-temperature (27 °C) environments: (<b>a</b>) the absorption; (<b>b</b>) the transmission.</p> Full article ">Figure 11
<p>The absorption of the metamaterial absorber at various incident angles when the VO<sub>2</sub> film is subjected to a high-temperature environment of 80 °C: (<b>a</b>) TE mode; (<b>b</b>) TM mode.</p> Full article ">Figure 12
<p>The transmission coefficients of the metamaterial absorber at different incident angles when the VO<sub>2</sub> film is in a room-temperature environment (27 °C): (<b>a</b>) TE mode; (<b>b</b>) TM mode.</p> Full article ">Figure 13
<p>The absorption of the metamaterial absorber with different structural dimensional parameters when the VO<sub>2</sub> thin film is at a high temperature (80 °C): (<b>a</b>) <span class="html-italic">r</span>; (<b>b</b>) <span class="html-italic">c</span>; (<b>c</b>) <span class="html-italic">d</span>; (<b>d</b>) <span class="html-italic">l</span>; (<b>e</b>) <span class="html-italic">e</span>.</p> Full article ">Figure 14
<p>The transmission coefficient of the metamaterial absorber with different structural dimensional parameters when the VO<sub>2</sub> thin film is at room temperature (27 °C): (<b>a</b>) <span class="html-italic">r</span>; (<b>b</b>) <span class="html-italic">c</span>; (<b>c</b>) <span class="html-italic">d</span>; (<b>d</b>) <span class="html-italic">l</span>; (<b>e</b>) <span class="html-italic">e</span>.</p> Full article ">

15 pages, 6315 KiB

Open AccessArticle

Effect of Various Nanofillers on Piezoelectric Nanogenerator Performance of P(VDF-TrFE) Nanocomposite Thin Film

by Sangkwon Park and Hafiz Muhammad Abid Yaseen

Nanomaterials 2025, 15(5), 403; https://doi.org/10.3390/nano15050403 - 6 Mar 2025

Flexible polymer-based piezoelectric nanogenerators (PENGs) have gained significant interest due to their ability to deliver clean and sustainable energy for self-powered electronics and wearable devices. Recently, the incorporation of fillers into the ferroelectric polymer matrix has been used to improve the relatively low [...] Read more.

Flexible polymer-based piezoelectric nanogenerators (PENGs) have gained significant interest due to their ability to deliver clean and sustainable energy for self-powered electronics and wearable devices. Recently, the incorporation of fillers into the ferroelectric polymer matrix has been used to improve the relatively low piezoelectric properties of polymer-based PENGs. In this study, we investigated the effect of various nanofillers such as titania (TiO₂), zinc oxide (ZnO), reduced graphene oxide (rGO), and lead zirconate titanate (PZT) on the PENG performance of the nanocomposite thin films containing the nanofillers in poly(vinylidene fluoride-co-trifluoro ethylene) (P(VDF-TrFE)) matrix. The nanocomposite films were prepared by depositing molecularly thin films of P(VDF-TrFE) and nanofiller nanoparticles (NPs) spread at the air/water interface onto the indium tin oxide-coated polyethylene terephthalate (ITO-PET) substrate, and they were characterized by measuring their microstructures, crystallinity, β-phase contents, and piezoelectric coefficients (d₃₃) using SEM, FT-IR, XRD, and quasi-static meter, respectively. Multiple PENGs incorporating various nanofillers within the polymer matrix were developed by assembling thin film-coated substrates into a sandwich-like structure. Their piezoelectric properties, such as open-circuit output voltage (V_OC) and short-circuit current (I_SC), were analyzed. As a result, the PENG containing 4 wt% PZT, which was named P-PZT-4, showed the best performance of V_OC of 68.5 V with the d₃₃ value of 78.2 pC/N and β-phase content of 97%. The order of the maximum V_OC values for the PENGs of nanocomposite thin films containing various nanofillers was PZT (68.5 V) > rGO (64.0 V) > ZnO (50.9 V) > TiO₂ (48.1 V). When the best optimum PENG was integrated into a simple circuit comprising rectifiers and a capacitor, it demonstrated an excellent two-dimensional power density of 20.6 μW/cm² and an energy storage capacity of 531.4 μJ within 3 min. This piezoelectric performance of PENG with the optimized nanofiller type and content was found to be superior when it was compared with those in the literature. This PENG comprising nanocomposite thin film with optimized nanofiller type and content shows a potential application for a power source for low-powered electronics such as wearable devices. Full article

(This article belongs to the Special Issue Nanomaterials in Analytical Methods for Biomedical, Environmental, and Energy Applications)

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Figure 1

Figure 1
<p>Illustration of preparation procedure of nanocomposite LS film and their PENG device.</p> Full article ">Figure 2
<p>SEM micrographs of nanocomposite LS thin films of (<b>a</b>) P, (<b>b</b>) P-TiO<sub>2</sub>-4, (<b>c</b>) P-TiO<sub>2</sub>-40, (<b>d</b>) P-ZnO-2, (<b>e</b>) P-ZnO-20, (<b>f</b>) P-ZnO-40, (<b>g</b>) P-PZT-2, (<b>h</b>) P-PZT-20, and (<b>i</b>) P-PZT-40 with 50 μm scale bars.</p> Full article ">Figure 3
<p>XRD patterns, FT-IR spectra, crystallinity, and β-phase content profiles as a function of nanofiller content for the nanocomposite thin films of (<b>a</b>–<b>c</b>) P-TiO<sub>2</sub>, (<b>d</b>–<b>f</b>) P-ZnO, (<b>g</b>–<b>i</b>) P-rGO, and (<b>j</b>–<b>l</b>) P-PZT series.</p> Full article ">Figure 4
<p>Piezoelectric coefficient (<span class="html-italic">d</span><sub>33</sub>) values as a function of nanofiller content for the nanocomposite thin films of (<b>a</b>) P-TiO<sub>2</sub>, (<b>b</b>) P-ZnO, (<b>c</b>) P-rGO, and (<b>d</b>) P-PZT series.</p> Full article ">Figure 5
<p><span class="html-italic">V<sub>OC</sub></span> signals of PENG devices and maximum peak-to-peak <span class="html-italic">V<sub>OC</sub></span> values as a function of nanofiller content for the nanocomposite thin films of (<b>a</b>,<b>b</b>) P-TiO<sub>2</sub>, (<b>c</b>,<b>d</b>) P-ZnO, (<b>e</b>,<b>f</b>) P-rGO, and (<b>g</b>,<b>h</b>) P-PZT series.</p> Full article ">Figure 5 Cont.
<p><span class="html-italic">V<sub>OC</sub></span> signals of PENG devices and maximum peak-to-peak <span class="html-italic">V<sub>OC</sub></span> values as a function of nanofiller content for the nanocomposite thin films of (<b>a</b>,<b>b</b>) P-TiO<sub>2</sub>, (<b>c</b>,<b>d</b>) P-ZnO, (<b>e</b>,<b>f</b>) P-rGO, and (<b>g</b>,<b>h</b>) P-PZT series.</p> Full article ">Figure 6
<p>(<b>a</b>) The maximum <span class="html-italic">V<sub>OC</sub></span> values for different optimum PENGs containing different nanofillers (with the surface pressure of 5 mN/m), (<b>b</b>) <span class="html-italic">I<sub>SC</sub></span> signals for the PZT PENGs as a function of nanofiller content, and (<b>c</b>) stability of the optimized PZT-based PENG for 1000 s.</p> Full article ">Figure 7
<p>(<b>a</b>) Potential profiles and (<b>b</b>) energy storage values for the optimal PENG of thin film containing 4 wt% PZT with different capacitors.</p> Full article ">

14 pages, 4821 KiB

Open AccessArticle

Controllable Hydrothermal Synthesis of 1D β-Ga₂O₃ for Solar-Blind Ultraviolet Photodetection

by Lingfeng Mao, Xiaoxuan Wang, Chaoyang Huang, Yi Ma, Feifei Qin, Wendong Lu, Gangyi Zhu, Zengliang Shi, Qiannan Cui and Chunxiang Xu

Nanomaterials 2025, 15(5), 402; https://doi.org/10.3390/nano15050402 - 6 Mar 2025

Gallium oxide (Ga₂O₃), an ultrawide bandgap semiconductor, is an ideal material for solar-blind photodetectors, but challenges such as low responsivity and response speed persist. In this paper, one-dimensional (1D) Ga₂O₃ nanorods were designed to achieve high [...] Read more.

Gallium oxide (Ga₂O₃), an ultrawide bandgap semiconductor, is an ideal material for solar-blind photodetectors, but challenges such as low responsivity and response speed persist. In this paper, one-dimensional (1D) Ga₂O₃ nanorods were designed to achieve high photodetection performance due to their effective light absorption and light field confinement. Through modulating source concentration, pH value, temperature, and reaction time, 1D β-Ga₂O₃ nanorods were controllably fabricated using a cost-effective hydrothermal method, followed by post-annealing. The nanorods had a diameter of ~500 nm, length from 0.5 to 3 μm, and structure from nanorods to spindles, indicating that different β-Ga₂O₃ nanorods can be utilized controllably through tuning reaction parameters. The 1D β-Ga₂O₃ nanorods with a high length-to-diameter ratio were chosen to construct metal-semiconductor-metal type photodetectors. These devices exhibited a high responsivity of 8.0 × 10⁻⁴ A/W and detectivity of 4.58 × 10⁹ Jones under 254 nm light irradiation. The findings highlighted the potential of 1D Ga₂O₃ nanostructures for high-performance solar-blind ultraviolet photodetectors, paving the way for future integrable deep ultraviolet optoelectronic devices. Full article

(This article belongs to the Special Issue Advanced Nanomaterials and Energetic Application: Experiment and Simulation)

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Figure 1

Figure 1
<p>Schematic diagram of the synthesis process of the 1D porous β-Ga<sub>2</sub>O<sub>3</sub> nanorods.</p> Full article ">Figure 2
<p>The influence of reaction source concentration on the produced GaOOH morphology: (<b>a</b>–<b>f</b>) SEM images and (<b>g</b>) XRD spectra of the samples fabricated with different Ga ion concentrations.</p> Full article ">Figure 3
<p>The influence of solution pH on the produced GaOOH morphology: (<b>a</b>–<b>d</b>) SEM images and (<b>e</b>) XRD spectra of the samples fabricated in different solution pH values.</p> Full article ">Figure 4
<p>The influence of reaction temperature on the produced GaOOH morphology: (<b>a</b>–<b>c</b>) SEM images and (<b>d</b>) XRD spectra of the samples fabricated in different growth temperatures.</p> Full article ">Figure 5
<p>The influence of reaction time on the produced GaOOH morphology: (<b>a</b>–<b>d</b>) SEM images, elements distribution mappings, and snapshots of the samples in different times (50~200 min), and (<b>e</b>) XRD spectra of various samples. The red circles on the snapshots displays the precursor products in the reaction vessel.</p> Full article ">Figure 6
<p>Thermal annealing in situ process: (<b>a</b>–<b>c</b>) XRD spectra of the same samples at different temperatures and (<b>d</b>) a comparison of different phases.</p> Full article ">Figure 7
<p>Thermal annealing speed influence on β-Ga<sub>2</sub>O<sub>3</sub> nanorod: (<b>a</b>–<b>f</b>) SEM images and (<b>g</b>) XRD and (<b>h</b>) Raman spectra of the samples annealed at 850 °C with different rising temperature speeds.</p> Full article ">Figure 8
<p>Thermal annealing speed influence on β-Ga<sub>2</sub>O<sub>3</sub> nanorods: (<b>a</b>,<b>b</b>) high-resolution XPS spectra of O 1s and Ga 3d, and (<b>c</b>,<b>d</b>) normalized absorption spectra of the samples annealed at 850 °C with different rising temperature speeds.</p> Full article ">Figure 9
<p>Photodetector parameters of 1D β-Ga<sub>2</sub>O<sub>3</sub> nanorods: (<b>a</b>) I-V characteristics in the dark and under different power light irradiation, (<b>b</b>) I-T plots under different light power, (<b>c</b>) single periodic I-T plots irradiated under 3.6 mW/cm<sup>2</sup>, and (<b>d</b>) the relationship of PDCR, responsivity, and detectivity with light power density.</p> Full article ">

19 pages, 8848 KiB

Open AccessArticle

Tribological Behavior and Mechanism of Silane-Bridged h-BN/MoS2 Hybrid Filling Epoxy Solid Lubricant Coatings

by Xiaoxiao Peng, Haiyan Jing, Lan Yu, Zongdeng Wu, Can Su, Ziyu Ji, Junjie Shu, Hua Tang, Mingzhu Xia, Xifeng Xia, Wu Lei and Qingli Hao

Nanomaterials 2025, 15(5), 401; https://doi.org/10.3390/nano15050401 - 6 Mar 2025

To significantly improve the tribological performance of epoxy resin (EP), a novel h-BN/MoS₂ composite was successfully synthesized using spherical MoS₂ particles with lamellar self-assembly generated through the calcination method, followed by utilizing the “bridging effect” of a silane coupling agent to [...] Read more.

To significantly improve the tribological performance of epoxy resin (EP), a novel h-BN/MoS₂ composite was successfully synthesized using spherical MoS₂ particles with lamellar self-assembly generated through the calcination method, followed by utilizing the “bridging effect” of a silane coupling agent to achieve a uniform and vertically oriented decoration of hexagonal boron nitride (h-BN) nanosheets on the MoS₂ surface. The chemical composition and microstructure of the h-BN/MoS₂ composite were systematically investigated. Furthermore, the enhancement effect of composites with various contents on the frictional properties of epoxy coatings was studied, and the mechanism was elucidated. The results demonstrate that the uniform decoration of h-BN enhances the chemical stability of MoS₂ in friction tests, and the MoS₂ prevents oxidation and maintains its self-lubricating properties. Consequently, due to the protective effect of h-BN and the synergistic interaction between h-BN and MoS₂, the 5 wt % h-BN/MoS₂ composite exhibited the best friction and wear resistance when incorporated into EP. Compared to pure EP coatings, its average friction coefficient and specific wear rate (0.026 and 1.5 × 10⁻⁶ mm³ N⁻¹ m⁻¹, respectively) were significantly reduced. Specifically, the average friction coefficient decreased by 88% and the specific wear rate decreased by 99%, highlighting the superior performance of the h-BN/MoS₂-enhanced epoxy composite coating. Full article

(This article belongs to the Section 2D and Carbon Nanomaterials)

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Figure 1

Figure 1
<p>The schematic diagrams of the preparation processes for (<b>a</b>) KH560-MoS<sub>2</sub>, (<b>b</b>) KH550-BN, and (<b>c</b>) h-BN/MoS<sub>2</sub>.</p> Full article ">Figure 2
<p>(<b>a</b>) XRD patterns of BN, KH550-BN, MoS<sub>2</sub>, KH560-MoS<sub>2</sub>, and h-BN/MoS<sub>2</sub> hybrids, FT-IR spectra of (<b>b</b>) BN, BN-OH, KH550-BN, and (<b>c</b>) MoS<sub>2</sub>, KH560-MoS<sub>2</sub>, and h-BN/MoS<sub>2</sub> hybrids, and (<b>d</b>) Raman spectroscopy of MoS<sub>2</sub> and KH560-MoS<sub>2</sub>.</p> Full article ">Figure 3
<p>(<b>a</b>) Full-range XPS spectra and high-resolution spectra of h-BN/MoS<sub>2</sub> hybrids including (<b>b</b>) B 1s, (<b>c</b>) Mo 3d, (<b>d</b>) C 1s, (<b>e</b>) N 1s, and (<b>f</b>) S 2p.</p> Full article ">Figure 4
<p>(<b>a</b>) TEM images of h-BN/MoS<sub>2</sub> hybrids, (<b>b</b>–<b>e</b>) HRTEM image, and the corresponding SAED patterns of h-BN/MoS<sub>2</sub> hybrids. (<b>f</b>) Elemental mapping of h-BN/MoS<sub>2</sub> hybrids.</p> Full article ">Figure 5
<p>(<b>a</b>,<b>c</b>) The friction coefficients of the samples as a function of sliding time. (<b>b</b>,<b>d</b>) The friction coefficients’ error bar for different samples.</p> Full article ">Figure 6
<p>(<b>a</b>) Wear rates and wear track width of the coatings for different samples. (<b>b</b>) Vickers hardnesses of the coatings with different samples. (<b>c</b>) The long-cycle tribological performance of 5 wt % h-BN/MoS<sub>2</sub>.</p> Full article ">Figure 7
<p>(<b>a</b>,<b>b</b>) TGA and (<b>c</b>,<b>d</b>) DTG curves of pure EP, 5 wt % MoS<sub>2</sub>/EP, and 5 wt % h-BN/MoS<sub>2</sub> /EP under N<sub>2</sub> and air atmospheres.</p> Full article ">Figure 8
<p>Fracture sections for different coatings: (<b>a</b>) EP, (<b>b</b>) 5 wt % MoS<sub>2</sub>/EP, (<b>c</b>) 1 wt % h-BN/MoS<sub>2</sub>/EP, (<b>d</b>) 2 wt % h-BN/MoS<sub>2</sub>/EP, (<b>e</b>) 5 wt % h-BN/MoS<sub>2</sub>/EP, and (<b>f</b>) 10 wt % h-BN/MoS<sub>2</sub>/EP.</p> Full article ">Figure 9
<p>SEM morphology of worn surfaces of the composites with different contents of h-BN/MoS<sub>2</sub> (<b>a</b>) 1 wt %, (<b>b</b>) 2 wt %, (<b>c</b>) 5 wt %, (<b>d</b>) 10 wt %), (<b>e</b>) the pure EP coating, and (<b>f</b>) the single MoS<sub>2</sub> coating.</p> Full article ">Figure 10
<p>XPS spectra of 5 wt % h-BN/MoS<sub>2</sub> composite coating after friction: (<b>a</b>) C 1s, (<b>b</b>) Mo 3d, (<b>c</b>) S 2p, (<b>d</b>) Si 2p, and (<b>e</b>) Fe 2p.</p> Full article ">Figure 11
<p>Schematic of wear mechanism of EP composite coatings enhanced via h-BN/MoS<sub>2</sub> hybrids.</p> Full article ">

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