Preparation And Hydrogen Production Performance Of Metal Sulfide-based Composite Photocatalysts

In recent years,the use of semiconductor composite photocatalysts for photocatalytic hydrogen evolution has caused more research interest.Metal sulfide-based photocatalysts are considered to be one of the most promising photocatalysts due to their excellent visible light response range,mild preparation conditions and controllable morphology and size.However,the disadvantages of metal sulfide-based photocatalysts,such as poor structural stability,susceptibility to photocorrosion,and high recombination rate of photogenerated carriers,greatly limit their application in the field of photocatalytic hydrogen evolution.In order to solve the problems existing in metal sulfide based photocatalysts,a series of metal sulfide based photocatalysts with high hydrogen evolution efficiency,good cycle stability,and low cost have been obtained through energy band regulation,element doping,and heterostructure construction strategies.The main research contents are as follows:1.A novel and efficient Z-scheme composite photocatalyst of core-shell Cd S/iron phthalocyanine（Fe Pc）was prepared by a simple pure solid-state reaction method.When the preparation temperature is 300°C and the addition amount of iron phthalocyanine is 40 mg,the photocatalytic hydrogen evolution rate of Cd S/Fe Pc is the highest,reaching 73.01μmol/h,which is 2.6 times that of single Cd S（26.67μmol/h）.The excellent hydrogen evolution performance of the composite photocatalyst is mainly due to the formation of Z-scheme heterostructure and core-shell structure between Cd S and iron phthalocyanine.2.By in-situ growth of Zn In₂S₄ nanoflowers on P-doped BN（PBN）with a wet chemical method,a sandwich-like Z-scheme heterojunction of PBN/Zn In₂S₄ bifunctional photocatalyst was successfully prepared.The experimental results show that P doping regulates the band gap of BN and enhances its light absorption performance,making it have semiconductor properties.More importantly,Zn In₂S₄ nanoflowers can grow uniformly on PBN nanosheets.When the addition amount of PBN is 50 mg,the composite photocatalyst can achieve the highest hydrogen evolution rate and hydrogen peroxide production rate,which is 59.46μmol/h and122.82μmol/L/h,respectively.3.Hexagonal hollow tubular nitrogen-doped and carbon-coated（N-C）In₂O₃/Cd Zn S heterojunction photocatalysts were prepared by solvothermal and oil bath heating methods.When the N-C/In₂O₃ addition amount is 20 mg,the N-C/In₂O₃/Cd Zn S nanocomposite exhibits the highest hydrogen evolution rate（22.87μmol/h）,which is 54.5 times that of single In₂O₃（0.42μmol/h）.Furthermore,it has an apparent quantum efficiency of 6.75%under 400 nm monochromatic light irradiation.Its excellent photocatalytic hydrogen evolution performance benefits from the hollow tubular structure and nitrogen-doped carbon layer,which enhances the electron transport rate and light absorption performance of the photocatalyst,respectively.