Preparation Of ZnIn₂s₄-Based Composite Materials And Their Photocatalytic Performance Study

ZnIn2S4 possesses desirable characteristics such as an appropriate bandgap,efficient visible light absorption,and easy synthesis,which makes it highly promising for photocatalytic applications.However,pure ZnIn2S4 semiconductor photocatalysts still suffer from issues such as severe recombination of photogenerated charge carriers and low photocatalytic activity,leading to poor overall photocatalytic efficiency.In this study,the performance of ZnIn2S4 was enhanced through the utilization of approaches such as constructing heterojunctions,doping,or the synergistic effect of both.The catalytic activities of ZnIn2S4 were investigated for hydrogen evolution,catalytic reduction of nitrophenol,and photocatalytic degradation of 2-mercaptobenzothiazole,along with the study of their respective mechanisms.This research provides insights and methodologies for the development of ZnIn2S4-based photocatalytic materials.ZnIn2S4 was synthesized using zinc acetate,indium nitrate,and thiourea as precursors via a hydrothermal method.Subsequently,PtS QDs/ZnIn2S4（PtS QDs/ZIS）composite was prepared using a photo-deposition method,demonstrating efficient photocatalytic and catalytic reduction performance.The photocatalytic hydrogen evolution rate of PtS QDs/ZnIn₂S₄ reached a maximum of 20777.07μmol?g^-1?h^-1,and it exhibited excellent reduction performance and good stability in the catalytic reduction of nitrophenol,achieving a reduction efficiency of 99.87%in 7 min.The enhanced photocatalytic activity and reduction performance can be attributed to the strong interaction between PtS QDs and ZnIn2S4,which promotes the efficient separation of photogenerated charge carriers.A double heterojunction was constructed to further improve the photocatalytic activity of ZnIn2S4.Bi VO4 nanofibers composed of nanoparticles assemblies were prepared by electrospinning and metal phthalocyanines（MPc）,specifically copper phthalocyanine（Cu Pc）and nickel phthalocyanine（Ni Pc）,were selected.ZnIn2S4/Bi VO4/MPc（ZIS/BV-3/MPc）ternary heterojunction was prepared by water bath method.Bi VO4 forms a Z-type heterojunction with ZnIn2S4 and MPc,while MPc forms a Type-II heterojunction with ZnIn2S4,effectively delaying the recombination of photogenerated charge carriers.Under visible light irradiation for 50 min,the degradation efficiency of 2-mercaptobenzothiazole by ZIS/BV-3/Cu Pc-0.5 reached 95.54%,and ZIS/BV-3/Ni Pc-0.5 also reached 96.08%.Moreover,the photocatalysts exhibited good durability after four cycles.The photocatalytic hydrogen production activity of ZnIn2S4 was significantly improved by doping and constructing double heterojunction.Cu doped ZnIn2S4 was synthesized by using copper nitrate as Cu source,zinc chloride,indium chloride,and thioacetamide.Subsequently,Cu-ZnIn2S4/WO3/WS2 composites material was prepared by a secondary hydrothermal method using WCl6 as the W source.The excellent photocatalytic hydrogen evolution performance of Cu-ZnIn2S4/WO3/WS2 is due to the fact that Cu doping improves the absorption of visible light and WO3/WS2 and ZnIn2S4further form Z-type and Type-I heterojunctions to enhance the transfer and separation of photogenerated carriers.The optimal hydrogen evolution rate is 93032.29μmol?g^-1?h^-1,which is 37.82 and 3.33 times that of ZnIn2S4 and Cu-ZnIn2S4,respectively.Moreover,the quantum efficiency at 430 nm was determined to be 37.04%.