Study On The Synthesis And PHotocatalytic Properties Of ZnIn₂S₄ Based Composite PHotocatalytic Materials

Hydrogen production from semiconductor catalyzed water splitting is one of the most promising ways to solve energy and environmental problems.ZnIn₂S₄ has good catalytic activity in the hydrogen evolution process due to its suitable band gap width,low toxicity and stable p Hysico-chemical properties.However,the problems of pHotocorrosion and high electron hole recombination rate limit its pHotocatalytic performance.In order to improve the catalytic performance of ZnIn₂S₄,ZnIn₂S₄ is used as the main catalyst to modify the supporting co-catalyst,so as to synthesize a high-performance binary composite pHotocatalytic system.The research work consists of the following three parts:（1）Hollow Cu₂MoS₄cube was synthesized using Cu₂O as the sacrificial template,followed by in situ synthesis of Cu₂MoS₄/ZnIn₂S₄ hollow nanocomposite pHotocatalytic materials.XRD,TEM,XPS,DRS,M-S curves and other p Hysical properties were characterized to verify the composite state and band matching of the material,and the mechanism for improving the pHotocatalytic performance of the hollow composite system was proposed:（1）A heterogeneous structure was formed between ZnIn₂S₄ and Cu₂MoS₄and the interfacial energy band was bent to form a built-in electric field,which could effectively promote the separation and transfer of p Hotogenerated electron hole pairs;（2）The addition of Cu₂MoS₄ of the hollow nanocube structure increased the light absorption.The specific surface area of the reaction is increased,thereby improving the p Hotolysis of hydrogen production in aquatic water,so that the pHotocatalyticity of the15%CMS/ZIS composite sample is increased by 4 times compared with that of pure ZnIn₂S₄,and the composite material has excellent stability.The results of this chapter provide new ideas for the design of efficient hollow pHotocatalytic systems（2）The derived spindle-like CoFeP co-catalyst was synthesized by MOF template method,and it was combined with ZnIn₂S₄ in situ to form a binary pHotocatalytic material,and the hydrogen production rate of p Hotolysis aquatic products was greatly improved,and the maximum hydrogen evolution rate reached 10474μmol·h^-1·g^-1,which was 5.8times that of ZnIn₂S₄.The successful compounding of CoFeP and ZnIn₂S₄ was confirmed by the characterization results of TEM,EDS and XPS.According to the results of the study,a reasonable pHotocatalytic reaction mechanism is proposed,that is,CoFeP,as an electron trapping agent,can effectively capture the p Hotogenerated electrons generated on ZnIn₂S₄ and improve the separation efficiency of p Hotogenerated carriers.In addition,the nanotube-like CoFeP has a small charge transfer impedance,high surface area,and low overpotential,and provides a rich set of active sites,increasing light absorption and thus improving pHotocatalytic performance.（3）Ni-NT nanotube cocatalysts were synthesized using MOFs as templates,and ZnIn₂S₄ nanosheets were subsequently grown on the surface of their nanotubes by oil bath method.The TEM,XPS,XRD and other characterization techniques were used to explore the composite state of the prepared samples and the hydrogen production performance of p Hotolysis water.The results show that the hydrogen evolution performance of the 38%Ni-NT/ZIS composite sample is the best,which is 6 times higher than that of pure ZnIn₂S₄,and the apparent quantum efficiency reaches 11.3%.The pHotocatalytic reaction mechanism study found that the contact interface between ZnIn₂S₄ and Ni-NT was tightly combined to form a complete charge transmission channel,so that the electrons on the ZnIn₂S₄conduction band migrated to the new active site Ni metal cluster through highly conductive nitrogen-doped carbon nanotubes,so that the p Hotogenerated electron-hole pair inside ZnIn₂S₄ was directed separation,which significantly increased the hydrogen evolution activity of the catalyst.The results of this chapter provide a reference for the development of high-performance composite pHotocatalytic systems...