Preparation And Properties Of SnS₂-based Photocatalysts

In this paper,SnS₂ is used as the base material.Considering that the current SnS₂material has the advantages of non-toxic,low price,oxidation and thermal stability in the air,traditional and new photocatalysts,such as CdS,Pt/Bi and g-C₃N₄,are used to construct composite photocatalyst materials and improve the activity of SnS₂ products.The phase,morphology,photoresponse,electrochemical and photocatalytic properties of CdS/SnS₂,SnS₂/g-C₃N₄ and SnS₂/Bi/Pt composites were investigated.These research work deepens the application of products in pollutant treatment and energy utilization.The main research contents are as follows:（1）0D-CdS/2D-SnS₂ heterojunction was successfully prepared by hydrothermal method combined with water bath.The structure and physicochemical characteristics of0D-CDS/2D-SnS2 composites were studied by means of characterization.The catalytic degradation of methylene blue（MB）by visible light was studied.The results showed that with the increasing of the content of cadmium,the removal rate of SS/CS-3 reached 90%after 40min of light irradiation.Free radical species capture experiments showed that the degradation of MB by 0D-CdS/2D-SnS₂ was mainly caused by·O₂^-and·OH.At the same time the hydrogen evolution performance of 0D-CdS/2D-SnS₂visible light photocatalytic cracking water was studied.Finally,we propose possible photocatalytic mechanisms.The improved photocatalytic activity of the composite is not only due to the widening of visible light response value but also due to the formation of typeⅡheterojunction between0D-CdS nanoparticles and 2D-SnS₂ nanoparticles,which enhances the photogenic separation of e^-and h⁺and enhances the photocatalytic performance of the composite.（2）SnS₂/g-C₃N₄ nanocomposites were prepared with different morphology by high temperature calcination,hydrothermal and solvothermal methods.The pure samples and composite samples were analyzed by some characterization and performance testing methods.Photoelectric chemical performance test showed that 0D-SnS₂/2D-g-C₃N₄ has better photoelectric chemical properties than 2D-SnS₂/2D-g-C₃N₄.The photocatalytic degradation of rhodamine B（Rh B）by SnS₂/g-C₃N₄ heterojunction under visible light irradiation was studied.The removal rates of 5%CN/SS-k and 5%CN/SS-p samples can reach 95%and 67%after 5min of visible light irradiation.In addition,by trapping experiment identified·O₂^-and h⁺were as the main active substances.The improvement of its photocatalytic activity is mainly attributed to open source and throttle.The structure of CN/SS-k heterojunction and CN/SS-p broadens the photoresponse ability,inhibits photogenic e^-and h⁺recombination,and improves the catalytic efficiency through synergistic action.（3）A bimetallic SnS₂/Bi/Pt photocatalyst was prepared by hydrothermal photoreduction deposition.The phase,morphology,photophysical response ability and photophysical carrier binding rate of the samples were analyzed by means of characterization.The photocatalytic performance of SnS₂/Bi-0.3%/Pt-1.5%photocatalyst showed that the degradation performance of Rh B and hydrogen evolution performance were improved after Bi replaced part of Pt.At the same time,the mechanism of photocatalyst activity enhancement may be that the electrons on SnS₂ surface transfer to Bi metal and then to Pt metal surface until its Fermi energy level is equal.The photocarriers of SnS₂ were effectively separated by electron conduction,and the catalytic activity of SnS₂/Bi-0.3%/Pt-1.5%photocatalyst was improved compared with the deposition of metal Bi and precious metal Pt.