Method for preparing BiOI / CdWO4 heterojunction photocatalyst

A photocatalyst and heterojunction technology, applied in physical/chemical process catalysts, chemical instruments and methods, chemical/physical processes, etc., can solve problems such as limiting photoelectric conversion efficiency

Inactive Publication Date: 2016-06-08
JIANGSU UNIV
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  • Abstract
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  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Cadmium tungstate (CdWO 4 ) is the earliest known solar hydrogen production semiconductor, however, due to the CdWO 4 The wide band gap (about 3.2eV) can only respond to ultraviolet light (about 5% of sunlight), which greatly limits the ability of CdWO 4 The photoelectric conversion efficiency; bismuth oxyiodide is a semiconductor material with a very narrow bandgap, and has a good energy band matching with cadmium tungstate, and has a good photocatalytic effect in theory; bismuth oxyiodide has the ability to promote Photogenerated charge transfer and enhanced degradation of organic pollutants, graphene as an excellent charge transport medium has been applied to BiOI / C 3 N 4 and BiOI / Bi 2 MoO 6 Heterogeneous photocatalysts; study finds that CdWO 4 The visible-light photocatalytic performance of C is significantly enhanced by recombination with narrow-bandgap semiconductors to form heterojunctions, for example; C 3 N 4 / CdWO 4 and CdS / CdWO 4 etc. Among them, the most effective one is a new type of C designed by TianNa teacher team. 3 N 4 / wxya 4 Heterogeneous junction photocatalyst, and the composition of the heterogeneous junction improves the transfer efficiency of the charge conversion efficiency, and C 3 N 4 / CdWO 4 The heterostructure can further improve the visible light absorption of cadmium tungstate. This unique heterostructure can effectively promote the charge separation efficiency, and finally transfer to the narrow bandgap semiconductor, so through C 3 N 4 / CdWO 4 Heterojunction photocatalysts can effectively promote the separation of electrons and holes, enhance photocatalytic activity, and degrade organic pollutants

Method used

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  • Method for preparing BiOI / CdWO4 heterojunction photocatalyst

Examples

Experimental program
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Effect test

Embodiment 1B

[0020] Example 1BiOI / CdWO 4 Preparation of nanorods

[0021] The solution containing 1mmol of chromium acetate was added to the solution containing 1mmol of sodium tungstate. After ultrasonic and magnetic stirring, the hydrothermal reaction was carried out. The hydrothermal reaction was carried out at 160℃ for 24 hours. After the reaction, the precipitate was filtered, washed, and at 60℃. Drying to obtain cadmium tungstate; take the prepared cadmium tungstate and disperse it in deionized water, add equimolar potassium iodide and bismuth nitrate under stirring conditions, control the molar ratio of bismuth nitrate to cadmium tungstate to 1.0, 1.5 and 2.0 respectively , After ultrasonic stirring and uniform dispersion, the precipitate is washed with deionized water and ethanol, filtered, and dried in a constant temperature drying box at 60°C to obtain BiOI / CdWO 4 Heterojunction composite photocatalyst.

Embodiment 2B

[0022] Example 2BiOI / CdWO 4 Characterization and Analysis of Heterojunction Composite Photocatalyst

[0023] Such as figure 1 As shown, it can be seen from the figure that the composite sample has both BiOI and CdWO 4 The characteristic peaks indicate that we have successfully prepared BiOI / CdWO 4 Heterojunction composite photocatalyst.

[0024] Such as figure 2 As shown, (A) you can see the nanorod-shaped CdWO 4 Irregular nano-particle BiOI is loaded on the surface.

[0025] Such as image 3 As shown, the spectrum shows the presence of Bi, O, I, Cd, W and O elements.

[0026] Such as Figure 4 As shown, the figure shows the heterojunction BiOI / CdWO 4 After four cyclic tests, the performance of the catalyst did not decrease significantly, which proves that the catalyst we synthesized has strong stability.

Embodiment 3B

[0027] Example 3BiOI / CdWO 4 Visible light catalytic activity experiment of heterojunction composite photocatalyst

[0028] (1) Prepare a rhodamine B solution with a concentration of 10 mg / L, and place the prepared solution in a dark place.

[0029] (2) Weigh BiOI / CdWO 4 Heterojunction composite photocatalyst 100mg (when BiOI and CdWO 4 The samples obtained with the molar ratio of 1:1, 1.5:1 and 2.0:1 are denoted as BC-1.0, BC-1.5, BC-2.0), respectively, placed in the photocatalytic reactor, and added 100 mL of step (1) After the prepared target degradation solution is magnetically stirred for 30 minutes, after the composite photocatalyst is uniformly dispersed, the water source and light source are turned on, and the photocatalytic degradation experiment is carried out.

[0030] (3) Aspirate the photocatalytic degradation liquid in the reactor every 10 minutes, and use it for the measurement of UV-visible absorbance after centrifugation.

[0031] (4) by Figure 5 It can be seen that t...

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Abstract

The present invention relates to a transition metal tungstate, and in particular to a method for preparing a BiOI / CdWO4 heterojunction composite photocatalyst. The method uses bismuth nitrate, sodium tungstate, potassium iodide and chromium acetate as raw materials for preparing the BiOI / CdWO4 heterojunction composite photocatalyst. The prepared nano-composite photocatalyst has excellent visible light catalytic activity, especially a sample supplemented with 1.5mmol of bismuth nitrate has the best activity in degradation of rhodamine B, and reaches degradation rate of 90% after 90min of visible reaction, and has higher degradation activity than pure BiOI and CdWO4.

Description

Technical field [0001] The present invention relates to transition metal tungstates, in particular to a preparation of BiOI / CdWO 4 Heterojunction composite photocatalyst method, BiOI / CdWO prepared with bismuth nitrate, sodium tungstate, potassium iodide and chromium acetate as raw materials 4 The method of heterojunction composite photocatalyst, especially a preparation method of nano composite photocatalyst with simple preparation process and good visible light catalytic activity. Background technique [0002] Since the 21st century, the excessive use of fossil energy has caused serious damage to the global environment. Therefore, the development and utilization of green energy has become one of the most important challenges facing mankind; semiconductor photocatalyst technology to degrade organic pollutants is a very important issue. A promising technology that can realize the conversion of solar energy to chemical energy and degrade organic pollutants in a pollution-free way. T...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J27/08C02F1/30C02F101/38
CPCB01J27/08B01J35/004C02F1/30C02F2101/308C02F2305/10
Inventor 施伟东冯翌宋橙杰樊明山陈继斌车慧楠
Owner JIANGSU UNIV
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