Papers by Maurizio Muniz-miranda
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American Mineralogist, 1996
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Journal of Molecular Structure, 2021
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Environmental Science and Pollution Research, 2013
Microbial colonization has a relevant impact on the deterioration of stone materials with consequ... more Microbial colonization has a relevant impact on the deterioration of stone materials with consequences ranging from esthetic to physical and chemical changes. Avoiding microbial growth on cultural stones therefore represents a crucial aspect for their long-term conservation. The antimicrobial properties of silver nanoparticles (AgNPs) have been extensively investigated in recent years, showing that they could be successfully applied as bactericidal coatings on surfaces of different materials. In this work, we investigated the ability of AgNPs grafted to Serena stone surfaces to inhibit bacterial viability. A silane derivative, which is commonly used for stone consolidation, and Bacillus subtilis were chosen as the grafting agent and the target bacterium, respectively. Results show that functionalized AgNPs bind to stone surface exhibiting a cluster disposition that is not affected by washing treatments. The antibacterial tests on stone samples revealed a 50 to 80 % reduction in cell viability, with the most effective AgNP concentration of 6.7 μg/cm2. To our knowledge, this is the first report on antimicrobial activity of AgNPs applied to a stone surface. The results suggest that AgNPs could be successfully used in the inhibition of microbial colonization of stone artworks.
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Molecules
Density functional theory (DFT) calculations allow us to reproduce the SERS (surface-enhanced Ram... more Density functional theory (DFT) calculations allow us to reproduce the SERS (surface-enhanced Raman scattering) spectra of molecules adsorbed on nanostructured metal surfaces and extract the most information this spectroscopy is potentially able to provide. The latter point mainly concerns the anchoring mechanism and the bond strength between molecule and metal as well as the structural and electronic modifications of the adsorbed molecule. These findings are of fundamental importance for the application of this spectroscopic technique. This review presents and discusses some SERS–DFT studies carried out in Italy as a collaboration between the universities of Modena and Reggio-Emilia and of Florence, giving an overview of the information that we can extract with a combination of experimental SERS spectra and DFT modeling. In addition, a selection of the most recent studies and advancements on the DFT approach to SERS spectroscopy is reported with commentary.
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ChemistrySelect, 2017
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Nanomaterials, 2020
Magneto-plasmonic nanoparticles constituted of gold and iron oxide were obtained in an aqueous en... more Magneto-plasmonic nanoparticles constituted of gold and iron oxide were obtained in an aqueous environment by laser ablation of iron and gold targets in two successive steps. Gold nanoparticles are embedded in a mucilaginous matrix of iron oxide, which was identified as magnetite by both microscopic and spectroscopic analyses. The plasmonic properties of the obtained colloids, as well as their adsorption capability, were tested by surface-enhanced Raman scattering (SERS) spectroscopy using 2,2′-bipyridine as a probe molecule. DFT calculations allowed for obtaining information on the adsorption of the ligand molecules that strongly interact with positively charged surface active sites of the gold nanoparticles, thus providing efficient SERS enhancement. The presence of iron oxide gives the bimetallic colloid new possibilities of adsorption in addition to those inherent to gold nanoparticles, especially regarding organic pollutants and heavy metals, allowing to remove them from the aq...
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ACS Applied Nano Materials, 2019
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Beilstein Journal of Nanotechnology, 2018
Highly stable Ag–SiO2 nanoparticle composites were first obtained by laser ablation of a silver t... more Highly stable Ag–SiO2 nanoparticle composites were first obtained by laser ablation of a silver target in an aqueous colloidal dispersion of silica and examined by UV–vis absorption spectroscopy, transmission electron microscopy and Raman spectroscopy. The surface enhanced Raman scattering (SERS) activity of these nanocomposites was tested using 2,2’-bipyridine as a molecular reporter and excitation in the visible and near-IR spectral regions. The computational DFT approach provided evidence of ligand adsorption on positively charged adatoms of the silver nanostructured surface, in a very similar way to the metal/molecule interaction occurring in the corresponding Ag(I) coordination compound.
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ChemistrySelect, 2018
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Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2018
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Beilstein journal of nanotechnology, 2017
A new synthetic approach for the production of carbon nanomaterials (CNM) decorated with organoph... more A new synthetic approach for the production of carbon nanomaterials (CNM) decorated with organophosphorus moieties is presented. Three different triphenylphosphine oxide (TPPO) derivatives were used to decorate oxidized multiwalled carbon nanotubes (ox-MWCNTs) and graphene platelets (GPs). The TPPOs chosen bear functional groups able to react with the CNMs by Tour reaction (an amino group), nitrene cycloaddition (an azido group) or CuAAC reaction (one terminal C-C triple bond). All the adducts were characterized by FTIR, Raman spectroscopy, TEM, XPS, elemental analysis and ICP-AES. The cycloaddition of nitrene provided the higher loading on ox-MWCNTs and GPs as well, while the Tour approach gave best results with nanotubes (CNTs). Finally, we investigated the possibility to reduce the TPPO functionalized CNMs to the corresponding phosphine derivatives and applied one of the materials produced as heterogeneous organocatalyst in a Staudinger ligation reaction.
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Journal of Optics, 2015
ABSTRACT
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Journal of Luminescence, 2016
We have synthesized the Fe doped titania (TiO2) nanopowders using sol–gel process. These samples ... more We have synthesized the Fe doped titania (TiO2) nanopowders using sol–gel process. These samples are formed in anatase form of titania as revealed by X-ray diffraction patterns. The UV/Vis absorption spectra exhibit that Fe-doping causes a considerable red shift of the absorption edge. Energy bandgap estimated using Tauc’s relation is found be of direct transition nature and Fe doping decreases the bandgap significantly. Raman spectra indicate an anatase structure of tetragonal crystal symmetry that belongs to the space group D4h19. Photoluminescence spectra recorded in ultraviolet and visible regions reveal that Fe doping increases the photocatalytic activity of our samples. FTIR spectra show that characteristic Ti–O band is observed around 680 cm−1 for pure TiO2 sample and on iron doping it shifted to 592 cm−1.
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Physical Chemistry Chemical Physics, 2016
The SERS/DFT study of methimazole chemisorbed on Au nanoparticles paves the way for the use of th... more The SERS/DFT study of methimazole chemisorbed on Au nanoparticles paves the way for the use of these nanohybrids in biomedicine.
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Journal of Raman Spectroscopy, 2015
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ECS Transactions, 2013
Tin sulfides present electrical and optical properties, which give them high potential use in opt... more Tin sulfides present electrical and optical properties, which give them high potential use in opto-electronic devices and photoconductive cells, i.e. photovoltaic applications. In this paper we report an electrochemical study of a tin solution, carried out by cyclic and stripping voltammetry. These techniques allow to establish the presence of surface limited processes and, hence, to define the experimental conditions for the Underpotential Deposition of Sn on Ag(111) previously covered by a S monolayer. Moreover, we studied the growth of the first layers of tin sulfides.
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Catalysis Communications, 2001
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ACS Omega, 2018
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Nanomaterials, 2019
A Surface-Enhanced Raman Scattering (SERS) spectrum of 4-cyanopyridine (4CNPy) was recorded on si... more A Surface-Enhanced Raman Scattering (SERS) spectrum of 4-cyanopyridine (4CNPy) was recorded on silver plasmonic nanoparticles and analyzed by using Density Functional Theory (DFT) calculations. Two simple molecular models of the metal–4CNPy surface complex with a single silver cation or with a neutral dimer (Ag+–4CNPy, Ag2–4CNPy), linked through the two possible interacting sites of 4CNPy (aromatic nitrogen, N, and nitrile group, CN), were considered. The calculated vibrational wavenumbers and intensities of the adsorbate and the isolated species are compared with the experimental Raman and SERS results. The analysis of the DFT predictions and the experimental data indicates that 4CNPy adsorbs preferentially on neutral/charged active sites of the silver nanoparticles through the nitrogen atom of the aromatic ring with a perpendicular orientation.
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Papers by Maurizio Muniz-miranda