Preparation Of Cadmium Sulfide-based Organic-inorganic Hybrid Photocatalytic Materials And Their Photocatalytic Hydrogen Production Performance

With the depletion of some traditional fossil energy sources and the increasing environmental pollution,the development of green and pollution-free renewable energy has become an urgent task for today's society.Hydrogen is attracting more and more attention as a pollution-free and renewable green energy.However,the traditional hydrogen production process mainly produces hydrogen from hydrocarbon-containing fossil fuels,electrolyzes water to produce hydrogen and thermochemically produces hydrogen.Although these methods can generate a large amount of hydrogen,there are problems of high energy consumption and generation of harmful substances in the conversion process.Therefore,the use of solar energy to convert water into hydrogen is one of the most promising ways to solve the energy crisis.In recent years,cadmium sulfide?Cd S?has been widely used as a classic semiconductor with a suitable band gap in the field of visible-light-driven photocatalysis,such as degradation of organic pollutants,production of photocatalytic hydrogen,carbon dioxide reduction.However,the problem of photo-corrosion resistance caused by the high recombination rate of photogenerated electrons and holes limits the further application and development of Cd S.In order to solve these problems,scientists have improved the photocatalytic performance and photo-corrosion resistance of Cd S under visible light by changing its morphology,structural modification,doping and formation of Cd S-based compound plates.On the basis of predecessors,this paper explores the hydrogen production activity and stability of Cd S photocatalyst under visible light from three aspects: increasing the specific surface area of Cd S,doping and semiconductor with matching load energy.The enhanced method has mainly achieved the following results:First,we used the in-situ growth method to prepare Cd S-based composite semiconductor photocatalysts on the basis of previous ones,which improved the performance and stability of photocatalytic hydrogen production by photocatalysts.We used cadmium chloride and sublimed sulfur as precursors for the synthesis of Cd S-Diethylenetriamine?DETA?organic-inorganic hybrid materials.The Ceric dioxide?CeO₂?/Cd S-DETA composites and Mo₁₅S₁₉/Cd S-DETA composites were prepared under low temperature and hydrothermal conditions.The results show that the band gap of CeO₂ can match Cd S well.CeO₂ promotes the separation of photogenerated electrons and holes,and improving the photocatalytic performance and stability of Cd S.However,we still use Pt as a cocatalyst in this work,and Pt as a precious metal material cannot be widely promoted.Therefore,we use Mo₁₅S₁₉ as a cocatalyst to replace Pt,which improves the photocatalytic performance and stability of Cd S.In addition,we have further explored the mechanism of the prepared composite photocatalyst,using theoretical calculations and practical methods to confirm our results,laying a theoretical foundation for the subsequent Cd S-based photocatalysts.Second,Cd S-DETA was selected as the base material to formBi-Bi₂MoO₆/Cd S-DETA organic-inorganic hybrid material by in-situ growth and p H adjustment.Bi-Bi₂MoO₆/Cd S-DETA organic-inorganic hybrid materials were successfully prepared by hydrothermal method using ammonium molybdate,lanthanum nitrate,cadmium chloride,diethylenetriamine and sodium hydroxide as raw materials.Moreover,the photocatalytic activity and stability of Bi-Bi₂MoO₆/Cd S-DETA changed with the change of Bi-Bi₂MoO₆.Among them,the plasma resonance effect of Bi has some influence on the photocatalytic activity and stability of the whole photocatalytic system.Therefore,Bi-Bi₂MoO₆/Cd S-DETA organic-inorganic hybrid materials can bring excellent photocatalytic performance and stability,which have broad application prospects.Thirdly,we prepared Zn1-x Cdx S-DETA organic-inorganic hybrid solid solution photocatalysts under low temperature conditions using zinc chloride,cadmium chloride,diethylenetriamine,water and sublimed sulfur as raw materials.The experimental results show that the band gap of the solid solution can be changed by changing the value of x,thus the photocatalytic performance and stability of the photocatalyst can be changed.Moreover,the photocatalytic performance and stability of the solid solution material have been significantly improved.Therefore,the Zn1-x Cdx S-DETA organic-inorganic hybrid solid solution material can bring excellent photocatalytic performance and stability,which has a good application prospect,and it can be used as a base material for supporting other semiconductors.