Systhesis And Photocatalystic Hydrogen Production Of Noble-metai Loading Metal Sulfides Based Photocatalysts

At present,with the rapid economic and social development and the escalation of human needs,energy has become an important indicator of human social progress and it has also received much attention.Exploring clean、green and environmentally friendly renewable energy has become a great challenge for researchers all over the world.Among them,hydrogen energy is the best candidate,at the meantime,H₂production from water splitting using sunlight is very promising,which will complete the conversion between solar energy and chemical energy.This thesis aims to explore the inherent relationship between the interface of semiconductor heterojunction and photogenerated charge migration and separation and photocatalytic activity by designing and constructing a series of high-performance and high-stability heterojunction structures.A series of metal sulfide-based composite photocatalysts with non-noble metals as cocatalysts were designed and applied to the study of the properties of hydrogen production by water splitting.It will provide some powerful data support for the design and preparation of non-noble metal-supported photocatalyst systems in the future.The research content of this paper is mainly composed of the following four parts:1.CdS considered as main catalyst was synthesized by a simple solvothermal method,and CuCl₂?2H₂O and Na₂S₂O₃?5H₂O were used as copper and sulfur sources,respectively.They were combined to form a CuS/CdS complex.The optimal loading amount was explored to obtain the best photocatalytic hydrogen production activity.The above research results show that the systhesis of composites has significantly improved the performance compared with single semiconductor CdS,at the same time,it has provided some new ideas for the construction of low-cost and efficient CdS-based photocatalytic materials.2.CdS was regarded as the main catalyst and Cu₂（OH）₂CO₃ cocatalyst as the research object to prepare a series of Cu₂（OH）₂CO₃/CdS composite materials.Under visible light irradiation,the photocatalytic hydrogen generation was performed using synthetic materials.In conclusion,when the content of the co-catalyst Cu₂（OH）₂CO₃was 2%,the effect of hydrogen production from water splitting was best.This research provided new design ideas and experimental basis for the preparation of Cu₂（OH）₂CO₃ cocatalyst.3.ZnIn₂S₄ nanoflower-like structure was synthesized by using zinc nitrate,indium nitrate and thioacetamide as raw materials.Then,tin chloride and thioacetamide were used as tin and sulfur sources construct a heterojunction SnS₂/ZnIn₂S₄ composite.A series of SnS₂/ZnIn₂S₄ photocatalysts were characterized and produce hydrogen by water splitting was studied.The maximum hydrogen production rate of SnS₂/ZnIn₂S₄ under visible light irradiation with Na₂S-Na₂SO₃ as a sacrificial agent is 277.335μmol/g/h.Compared with pure ZnIn₂S₄,it exhibits better catalytic performance.4.This work takes solid solution Mn_0.5Cd_0.5S as the research object and builds a heterojunction with g-C₃N₄ to improve the photocatalytic performance of Mn_0.5Cd_0.5S.When the mass fraction of g-C₃N₄ is 10%,the activity is the best.The cycling experiment of water splitting shows that the catalysts have good stability.