Method for preparing CdS/MnWO4 heterojunction compound photo-catalyst

A technology of composite light and catalyst, applied in and transition fields, can solve problems such as low catalytic activity

Inactive Publication Date: 2016-04-06
JIANGSU UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Metal tungstates have been widely used in many fields due to their unique electrical and optical properties, among which transition metal tungstates (MnWO 4 ) has stable chemical properties, suitable band gap can respond to visible light, so it has become the focus of attention in the field of photocatalysis; however, the catalytic activity of existing transition metal tungstate catalysts is still very low, which cannot meet the requirements of practical applications. Therefore, improving the separation efficiency of electrons and holes to improve the catalytic activity of this type of photocatalyst is still a challenging issue.
[0003] Due to its special energy band structure and carrier transport characteristics, the heterojunction can effectively inhibit the recombination of photogenerated electrons and holes in the photocatalytic reaction, improve the quantum efficiency, and then greatly improve the catalytic activity of the photocatalyst. Cadmium sulfide (CdS) Due to its narrow energy band and higher conduction band position, it is an ideal semiconductor photocatalyst for constructing heterostructures. At present, there is no information about the heterojunction between manganese tungstate and cadmium sulfide and its application in photocatalysts. Study on Catalytic Degradation of Organic Pollutants

Method used

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Examples

Experimental program
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Effect test

Embodiment 1

[0017] Example 1 CdS / MnWO 4 Preparation of nanorods

[0018] The solution containing 1mmol of manganese chloride was added to the solution containing 1mmol of sodium tungstate, the pH of the mixed solution was adjusted to 9 with 1mmol / L sodium hydroxide solution, magnetically stirred, and then hydrothermally reacted at 180℃ for 24 hours , The precipitate obtained by centrifugal water washing, and drying at 60 ℃ to obtain manganese tungstate nanorods; take the prepared manganese tungstate nanorods and dissolve in deionized water, ultrasonically disperse, add equimolar thiourea and under stirring conditions Cadmium acetate, control the molar ratio of cadmium acetate to manganese tungstate to 0.3, 0.5, 0.7, 1.1 and 1.5 respectively. After stirring and mixing uniformly, proceed to hydrothermal reaction at 180°C for 24 hours, and use the resulting yellow product Wash with ionized water and ethanol, filter, and dry in a constant temperature drying box at 60°C.

Embodiment 2

[0019] Example 2CdSMnWO 4 / MnWO 4 Characterization and Analysis of Heterojunction Composite Photocatalyst

[0020] Such as figure 1 As shown, it can be seen from the figure that the composite sample has both CdS and MnWO 4 The characteristic peaks indicate that we have successfully prepared CdS / MnWO 4 Heterojunction composite photocatalyst.

[0021] Such as figure 2 As shown, the pure MnWO can be seen in the picture (A) 4 It is a nanorod. In the picture (B), you can see the existence of CdS nanoparticles. The size of the nanoparticles is 10-30nm, and they are loaded on MnWO. 4 On the nanorod.

[0022] Such as image 3 As shown, the spectrum shows the presence of manganese, tungsten, sulfur, cadmium, and oxygen.

[0023] Such as Figure 4 As shown in the figure, the impedance difference between cadmium sulfide, manganese tungstate, cadmium sulfide and manganese tungstate heterojunction can be clearly seen.

Embodiment 3

[0024] Example 3 CdS / MnWO 4 Visible light catalytic activity experiment of heterojunction composite photocatalyst

[0025] (1) Prepare a methylene blue or methyl violet solution with a concentration of 10 mg / L, and place the prepared solution in a dark place.

[0026] (2) Weigh CdS / MnWO 4 Heterojunction composite photocatalyst 100mg (when CdS and MnWO 4 The molar ratio of 0.3:1, 0.5:1, 0.7:1, 1:1, 1.5:1 and the samples obtained are denoted as CdS-1, CdS-2, CdS-3, CdS-4, CdS-5), Placed in the photocatalytic reactor respectively, add 100mL of the target degradation solution prepared in step (1), magnetically stir for 30min after the composite photocatalyst is evenly dispersed, turn on the water source and light source, and perform the photocatalytic degradation experiment.

[0027] (3) Aspirate the photocatalytic degradation liquid in the reactor every 10 minutes, and use it for the measurement of UV-visible absorbance after centrifugation.

[0028] (4) by Figure 5 It can be seen that...

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Abstract

The invention relates to transition metal tungstate, in particular to a method for preparing a CdS/MnWO4 heterojunction compound photo-catalyst. Tungstic acid nanometer rods are dispersed into deionized water, then, thiourea and cadmium acetate are added, uniform stirring and mixing are performed to be subjected to a hydrothermal reaction, and then the CdS/MnWO4 heterojunction compound photo-catalyst is obtained, wherein the mole ratio of CdS to MnWO4 is 0.3-1.5:1. The obtained heterojunction compound photo-catalyst can effectively achieve photocatalyzing and degrading of methylene blue and methyl violet under visible light.

Description

Technical field [0001] The invention relates to transition metal tungstates, in particular to a preparation of CdS / MnWO 4 Heterojunction composite photocatalyst method, using sodium hydroxide, sodium tungstate, manganese chloride, thiourea and cadmium acetate as raw materials to prepare CdS / MnWO 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] Metal tungstates have been widely used in many fields due to their unique electrical and optical properties. Among them, transition metal tungstates (MnWO 4 ) Has stable chemical properties and a suitable forbidden band width can respond to visible light, so it has become the focus of attention in the field of photocatalysis; however, the catalytic activity of the existing transition metal tungstate catalysts is still very low and cannot meet the practical application r...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J27/04B01J23/34A62D3/17A62D101/26A62D101/28
CPCB01J27/04A62D3/17A62D2101/26A62D2101/28B01J23/34
Inventor 施伟东延旭黄凯洪远志黄长友吕涛涛肖立松刘奎立顾巍
Owner JIANGSU UNIV
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