Preparation Of Indium Cadmium Sulfide-based Semiconductor Catalyst And Its Photocatalytic Decomposition Of Aquatic Hydrogen

The sharp decline of fossil fuel reserves in recent decades and the environmental pollution caused by their combustion have become one of the world’s problems.Seeking new energy sources to replace fossil energy has become the goal of people’s pursuit.As a pure renewable natural resource,solar energy produces far more energy per hour than global human consumption per day,and it is of great significance to solve the energy crisis faced by mankind to make good use of solar energy.With the advantages of high energy density and no greenhouse gases after combustion,hydrogen energy has become the ideal energy carrier in people’s minds.Photocatalytic hydrogen decomposition is an emerging technology for hydrogen production.Ideally,it involves the decomposition of water into hydrogen and oxygen by the action of a catalyst under the irradiation of sunlight,a process of converting solar energy into chemical energy,the core of which is an efficient catalyst.At present,the main problems faced by this technology are the low utilization rate of photocatalysts for sunlight,the optical quantum yield,the easy recombination of photo-generated carriers,and the susceptibility to light corrosion.The development of new types,high efficiency,high stability,and economic photocatalyst has become the key to the practical application of this technology.CdIn₂S₄ is a ternary metal sulfide,an n-type semiconductor,which has received a lot of attention due to its photosensitive properties,narrow band gap,suitable conduction band,and valence band potential,and it is considered a photocatalyst with great potential for applications in solar cells,photocatalysts,and light-emitting diodes.However,its performance in photocatalytic decomposition of water for hydrogen production is not outstanding due to the low charge separation rate.Therefore,it is important to modify CdIn₂S₄ using implementable strategies to improve its photocatalytic decomposition of water for hydrogen production performance.In this paper,the hydrothermal synthesis technology was used to prepare CdIn₂S₄,and it was used together with ZnS,ZnO,and PAN semiconductor materials to construct the heterojunction.The study and its conclusions mainly include:1:A series of CdIn₂S₄/x ZnS（x=4,8,12,and14）composites were synthesized by a hydrothermal synthesis method.Among them,in the CdIn₂S₄/12ZnS catalyst,the hydrogen production amount reached 3743μmol·g^-1·h^-1,which is 59.1 times that of pure CdIn₂S₄ and 14.4times that of pure ZnS,indicating that the composites have good performance in photocatalytic decomposition of water for hydrogen production.The intense interaction between CdIn₂S₄ and ZnS,the formation of Z-scheme heterojunction,more efficient charge separation,extended photoresponse,higher electron migration,and more robust redox properties enhance the photocatalytic activity of CdIn₂S₄/x ZnS.2:A series of CdIn₂S₄/XZnO（X=6.1,9.2,12.3,and18.4）photocatalytic materials were prepared by a hydrothermal synthesis method.Among them,CdIn₂S₄/12.3ZnO has the best photocatalytic decomposition of water for hydrogen production activity.The hydrogen production rate reaches 2320μmol·g^-1·h^-1,which is about 46.11 times the hydrogen production rate of pure CdIn₂S₄ and 2.76 times of the hydrogen production rate of ZnO,indicating that the composites possess good photocatalytic hydrogen production.The electric field generated by the interaction between ZnO and CdIn₂S₄ effectively separates the electrons and holes,and the appropriate ratio between the two results in the better performance of the composite.3:A series of CdIn₂S₄/12.3ZnO-PANx（x=20,30,and40）photocatalysts were prepared and their photocatalytic decomposition activity for hydrogen production from the water was evaluated.the hydrogen production rate of CdIn₂S₄/12.3ZnO-PAN was 4.33 mmol·g^-1·h^-1,more than 54.5times that of PAN photocatalyst and more than 5.7 times that of CdIn₂S₄/12.3ZnO photocatalyst.The results indicate that the formation of CdIn₂S₄/12.3ZnO and PAN nanocomposites facilitates the separation of photogenerated electrons and holes and improves its activity in the photocatalytic decomposition of water for hydrogen production.