Study On Modification Of ZnIn₂S₄ Photocatalyst And Its Hydrogen Production Performance

Energy issues have become one of the key issues of concern in the 21st century.The development of new energy sources is imminent.Hydrogen energy is widely studied as a green energy source.ZnIn₂S₄ is an important?-?₂-?₄ ternary sulfide semiconductor.Its unique crystal structure makesit have many unique optical and optoelectronic characteristics,with a suitable band gap width can respond to visible light,and has quite good chemical stability.However,the bulk ZnIn₂S₄ electron-hole pair is very easy to recombine,and the electron utilization rate is very low,which limits its photocatalytic hydrogen production activity.In order to solve the above problems,ZnIn₂S₄ was modified by surface modification and heterojunction compounding method,the relationship between its structure,morphology and performance was studied,and the catalytic mechanism of the modified catalyst was explored.?1?Ultra-thin ZnIn₂S₄ nanosheets were prepared by a simple thermal reflux method,and the effect of nanolayer thickness on the hydrogen production performance of the catalyst was explored.The experimental results show that the ultra-thin ZnIn₂S₄ nanosheets have improved performance in photocatalytic hydrogen production.The reason is that the electrons of ultra-thin ZnIn₂S₄ nanosheets are more easily transferred to the surface of the material to participate in the hydrogen production reaction.On this basis,the ultra-thin ZnIn2S4 nanosheets were subjected to Ni metal doping modification treatment and found that its catalytic activity was further enhanced,the reason is that the doping of Ni metal provides more active sites for ZnIn₂S₄ nanosheets,and it increases the visible light absorption of ZnIn₂S₄ nanosheets.?2?The CdS quantum dot/ZnIn₂S₄ nanoflower heterogeneous composite photocatalyst was synthesized by hydrothermal method and coprecipitation method,and the effect of CdS loading on the photocatalytic hydrogen production performance of the CdS/ZnIn₂S₄ composite photocatalyst was investigated.The experimental results show that the CdS/ZnIn₂S₄ composite photocatalyst exhibits excellent photocatalytic hydrogen production activity,and the photocatalyst with the best loading?0.01M CdS/ZnIn₂S₄?has a hydrogen production rate of 2581?mol·g^-1·h^-1,and it is 30 times that of pure CdS and about 2.5 times thatof pure ZnIn₂S₄.The reasons are:the load of CdS increases the visible light response of ZnIn₂S₄;The formation of the multi-level structure of ZnIn₂S₄ nanoflowers loaded with CdS quantum dots effectively increases the contact between the two semiconductor interfaces and accelerates the charge transfer efficiency of the two semiconductor interfaces;the successful construction of type? heterostructure effectively inhibits the recombination of electron-hole pairs.