CN104190406A

CN104190406A - C/Bi2MoO6 composite photocatalyst and preparation method thereof

Info

Publication number: CN104190406A
Application number: CN201410445576.9A
Authority: CN
Inventors: 段芳; 张琴; 黎小芬; 王特宠; 郭灵霞; 施冬健; 陈明清
Original assignee: Jiangnan University
Current assignee: Jiangnan University
Priority date: 2014-09-03
Filing date: 2014-09-03
Publication date: 2014-12-10

Abstract

The invention discloses a C/Bi2MoO6 composite photocatalyst and a preparation method thereof, belonging to the technical field of photocatalytic materials. The method is mainly characterized by comprising the following steps: allowing carbon and Bi2MoO6 to form the C/Bi2MoO6 composite photocatalyst according to different ratios through a one-step solvothermal method. Carbon is introduced through a one-step method, so that not only is absorption of the carbon on visible light is increased, but also the photogenerated electron-hole recombination is inhibited, and the prepared C/Bi2MoO6 composite photocatalyst has high-efficiency photocatalytic activity under the visible light. The method comprises the following preparation steps: dissolving bismuth salt in alcohol of a certain volume, adding a proper amount of molybdate and thiourea, uniformly stirring, reacting the mixture in a reaction kettle, centrifugally separating the obtained product, and performing vacuum drying. The method is simple in process and low in cost, and the prepared C/Bi2MoO6 composite photocatalyst has high-efficiency photocatalytic activity under the visible light.

Description

A kind of C/Bi 2moO 6composite photo-catalyst and preparation method thereof

Technical field

The invention belongs to catalysis material and technical field, relate to and adopt solvent-thermal method one step to prepare C/Bi ₂moO ₆composite photo-catalyst, utilize the modification of carbon, significantly increased the absorption of photochemical catalyst to visible ray and suppressed the combination again in light induced electron-hole, obtains efficient C/Bi ₂moO ₆composite photo-catalyst.

Background technology

The seriousness of environmental pollution at present, has become one and has directly threatened human survival, needs the focal issue of solution badly.Photocatalysis technology be progressively grow up the seventies from twentieth century have the green technology of important application prospect at the energy and environmental area.This technology utilizes the semi-conducting material can catalyze and degrade organic pollutants as photochemical catalyst, and catalyst is by organic matter degradation under light radiation, and final permineralization is CO ₂, H ₂organic matter, inorganic ions etc. that O and toxicity are little, demonstrating its unique effect aspect the energy, Green Chemistry.But through research extensively and profoundly in more than 30 years, photocatalysis technology was still difficult to realize the solar energy conversion of efficient cheapness, and a chief reason is with TiO ₂for a series of semiconductor light-catalysts of representative generally have larger energy gap (as anatase TiO ₂energy gap Eg=3.2eV), only in ultraviolet light range, there is response, and the not enough total solar energy of the ultraviolet light of wavelength below 400nm 5%, the visible ray that accounts for 43% left and right of sunshine gross energy mainly concentrates on 400-700nm wave band, and this has greatly limited their photocatalytic applications under radiation of visible light.Therefore, how to make full use of visible ray, it is to improve solar energy utilization ratio that design and development has visible light-responded semiconductor light-catalyst, finally realizes the key of commercial application.

Under such background, there is the green safety characteristics such as easy processing, hypotoxicity and low-activity due to bismuth, bismuth series photocatalyst is researched and developed by researcher, and has obtained a series of great achievements.Bi ₂moO ₆the scope of optical absorption characteristics only from ultraviolet light to visible wavelength, be less than between about 450nm, only accounted for the sub-fraction in solar spectrum.In addition, the right quick restructuring in light induced electron-hole has seriously limited energy conversion efficiency.In order to widen visible light-responded scope, promote Bi ₂moO ₆the photo-generated carrier separating is introduced carbon and is formed C/Bi in photochemical catalyst preparation process ₂moO ₆composite photo-catalyst, can increase the absorption of photochemical catalyst to visible ray greatly, and can effectively suppress the combination again in light induced electron-hole.It is compound that the method that tradition is prepared composite photo-catalyst often adopts two-step method to carry out, and the present invention only needs a step solvent-thermal method at preparation Bi ₂moO ₆time, successfully generate carbon, and and Bi ₂moO ₆can be effectively compound, obtain efficient C/Bi ₂moO ₆composite photo-catalyst.

Summary of the invention

The invention reside in and solve Bi ₂moO ₆photochemical catalyst is lower to visible absorption, the easy combination in light induced electron-hole, thus the not high problem of photocatalysis efficiency provides a kind of C/Bi ₂moO ₆composite photo-catalyst and preparation method thereof, the method technique is simple, with low cost, and synthetic composite photo-catalyst photocatalytic degradation effect is better.

The invention provides the C/Bi for degradable organic pollutant ₂moO ₆composite photo-catalyst, is characterized in that: by carbon and the Bi of different quality ratio ₂moO ₆one step solvent-thermal method is composited, and utilizes the modification of carbon, has strengthened Bi ₂moO ₆to the absorption of visible ray, suppress the combination again in light induced electron-hole, prepared C/Bi ₂moO ₆composite photo-catalyst has efficient visible light catalytic performance, and its preparation process is: a certain amount of bismuth salt is dissolved in alcoholic solution, forms transparent liquid, under stirring, slowly add a certain amount of molybdate, stir 0.5～1h, then add a certain amount of thiocarbamide, continue to stir 0.5～1h, then proceed to 50mL containing in teflon-lined stainless steel autoclave, 100～220 DEG C of reaction 5～30h, by products therefrom centrifugation, and 50～100 DEG C of vacuum drying, obtain C/Bi ₂moO ₆composite photo-catalyst.

The present invention compared with prior art, has remarkable advantage:

(1) the present invention C/Bi that adopted solvent-thermal method one-step synthesis ₂moO ₆composite photo-catalyst, the method technique is simple, easy to operate, with low cost.

(2) the present invention utilizes the modification of carbon, has strengthened Bi ₂moO ₆to the absorption of visible ray, suppress the combination again in light induced electron-hole, prepared C/Bi ₂moO ₆composite photo-catalyst has efficient visible light catalytic performance.

Brief description of the drawings

The pure Bi of Fig. 1 ₂moO ₆and C/Bi ₂moO ₆the scanning electron microscopy of composite photo-catalyst;

The pure Bi of Fig. 2 ₂moO ₆and C/Bi ₂moO ₆the X-ray diffraction style of composite photo-catalyst;

The pure Bi of Fig. 3 ₂moO ₆and C/Bi ₂moO ₆fourier's infrared spectrogram of composite photo-catalyst;

The pure Bi of Fig. 4 ₂moO ₆and C/Bi ₂moO ₆the UV-Vis DRS spectrogram of composite photo-catalyst;

The pure Bi of Fig. 5 ₂moO ₆and C/Bi ₂moO ₆the photocatalysis performance of composite photo-catalyst

Detailed description of the invention

For a better understanding of the present invention, further illustrate content of the present invention below in conjunction with example, but content of the present invention is not limited to given example below.

The side's of enforcement example 1: a kind of C/Bi of the present invention ₂moO ₆the preparation method of composite photo-catalyst, its preparation process is: 3mmoL bismuth nitrate is dissolved in ethylene glycol, forms transparent liquid, under stirring, slowly add the sodium molybdate of 2.5mmoL, stir 0.5h, then add the thiocarbamide of 0.75mmoL, continue to stir 0.5h, then proceed to 50mL containing in teflon-lined stainless steel autoclave, 150 DEG C of reaction 10h, by products therefrom centrifugation, and 60 DEG C of vacuum drying, obtain C/Bi ₂moO ₆composite photo-catalyst.

Through SEM to pure Bi ₂moO ₆and C/Bi ₂moO ₆the pattern of composite photo-catalyst characterizes, and from Fig. 1 a and 1b, can find out, synthetic bismuth molybdate glomeration can see after amplification that the surface of ball is made up of a lot of granules, can find out the C/Bi obtaining after carbon is compound from Fig. 1 c and 1d ₂moO ₆the form of sample is still spherical, but the surface of ball is mainly nanometer sheet composition, with respect to pure Bi ₂moO ₆size does not significantly change.Bi before and after carbon is modified ₂moO ₆thing characterize mutually, as shown in Figure 2, carbon modify before and after Bi ₂moO ₆thing do not change mutually, can index the Bi that is orthogonal phase ₂moO ₆(JCPDS 21-0102), but there is certain variation in the intensity of diffraction maximum, and the introducing of carbon has increased Bi ₂moO ₆crystallinity.Utilize Fourier's infrared spectrum to modify front and back Bi to carbon ₂moO ₆structure characterize, as shown in Figure 3, at 1112cm ^-1place's compound is than pure Bi ₂moO ₆having more a peak, is the stretching vibration of O-C, darker than pure bismuth molybdate color in conjunction with the color of prepared composite sample, is grey, shows to utilize synthetic method of the present invention successfully to obtain C/Bi ₂moO ₆composite photo-catalyst.Utilize UV-vis DRS spectrum to the compound front and back Bi of carbon ₂moO ₆absorbing state to visible ray characterizes, as shown in Figure 4, and the as can be seen from the figure compound C/Bi obtaining of carbon later ₂moO ₆composite photo-catalyst significantly strengthens the absorption of visible ray.C/Bi ₂moO ₆the photocatalysis performance of composite photo-catalyst is that rhodamine B degradation under the radiation of visible light providing by 300W xenon lamp (Rhodamine B, RhB) solution is weighed, and concrete experimentation is as follows: taking 50mg photochemical catalyst, to add concentration be 10 ^-5in the 100mL RhB solution of M, the solution preparing is placed in to dark place dispersed with stirring and within 2 hours, makes it reach adsorption equilibrium.Then solution is carried out to light-catalyzed reaction, get at regular intervals the solution of about 5mL, catalyst is fallen in centrifugal filtration, measures RhB absorbance residual in solution with ultraviolet specrophotometer.Pure Bi ₂moO ₆and C/Bi ₂moO ₆the photocatalysis performance of composite photo-catalyst as shown in Figure 5, C/Bi ₂moO ₆photocatalysis performance is obviously better than pure Bi ₂moO ₆photocatalysis performance under visible ray.

Embodiment 2: a kind of C/Bi of the present invention ₂moO ₆the preparation method of composite photo-catalyst, its preparation process is: 3mmoL bismuth nitrate is dissolved in ethylene glycol, forms transparent liquid, under stirring, slowly add the sodium molybdate of 1.25mmoL, stir 0.5h, then add the thiocarbamide of 0.75mmoL, continue to stir 0.5h, then proceed to 50mL containing in teflon-lined stainless steel autoclave, 160 DEG C of reaction 15h, by products therefrom centrifugation, and 60 DEG C of vacuum drying, obtain C/Bi ₂moO ₆composite photo-catalyst.

Embodiment 3: a kind of C/Bi of the present invention ₂moO ₆the preparation method of composite photo-catalyst, its preparation process is: 3mmoL bismuth nitrate is dissolved in ethylene glycol, forms transparent liquid, under stirring, slowly add the sodium molybdate of 3mmoL, stir 1h, then add the thiocarbamide of 1mmoL, continue to stir 0.5h, then proceed to 50mL containing in teflon-lined stainless steel autoclave, 150 DEG C of reaction 12h, by products therefrom centrifugation, and 60 DEG C of vacuum drying, obtain C/Bi ₂moO ₆composite photo-catalyst.

Embodiment 4: a kind of C/Bi of the present invention ₂moO ₆the preparation method of composite photo-catalyst, its preparation process is: 3mmoL bismuth nitrate is dissolved in glycerine, forms transparent liquid, under stirring, slowly add the sodium molybdate of 2.5mmoL, stir 1h, then add the thiocarbamide of 1mmoL, continue to stir 1h, then proceed to 50mL containing in teflon-lined stainless steel autoclave, 160 DEG C of reaction 10h, by products therefrom centrifugation, and 60 DEG C of vacuum drying, obtain C/Bi ₂moO ₆composite photo-catalyst.

Claims

1. a C/Bi ₂moO ₆composite photo-catalyst and preparation method thereof, is characterized in that: by carbon and the Bi of different quality ratio ₂moO ₆one step solvent-thermal method is composited, and utilizes the modification of carbon, has strengthened Bi ₂moO ₆to the absorption of visible ray, suppress the combination again in light induced electron-hole, prepared C/Bi ₂moO ₆composite photo-catalyst has efficient visible light catalytic performance, and its preparation process is: a certain amount of bismuth salt is dissolved in alcoholic solution, forms transparent liquid, under stirring, slowly add a certain amount of molybdate, stir 0.5～1h, then add a certain amount of thiocarbamide, continue to stir 0.5～1h, then proceed to 50mL containing in teflon-lined stainless steel autoclave, 100～220 DEG C of reaction 5～30h, by products therefrom centrifugation, and 50～100 DEG C of vacuum drying, obtain C/Bi ₂moO ₆composite photo-catalyst.

2. C/Bi according to claim 1 ₂moO ₆the preparation method of composite photo-catalyst, is characterized in that bismuth salt is the one in bismuth nitrate, bismuth chloride, and molybdate is the one in sodium molybdate, ammonium molybdate.

3. C/Bi according to claim 1 ₂moO ₆the preparation method of composite photo-catalyst, is characterized in that in bismuth salt in bismuth element and molybdate that the mol ratio of molybdenum element is 1: 1～3: 1.

4. C/Bi according to claim 1 ₂moO ₆the preparation method of composite photo-catalyst, is characterized in that the alcohol that bismuth salt dissolves can be any in ethylene glycol, 1,2-PD, glycerine.

5. C/Bi according to claim 1 ₂moO ₆the preparation method of composite photo-catalyst, is characterized in that in molybdate, the mol ratio of molybdenum element and thiocarbamide is 20: 1～1: 20.