| In industry,n industry,the large-scale use of traditional fossil fuels has made environmental pollution increasingly prominent,and the subsequent exhaustion of resources has led to a serious energy crisis and hindered social development.Therefore,the exploration of green,clean,and recyclable energy has become the consensus of researchers,including the development of new energy sources such as wind energy,hydropower,and nuclear energy.Among many new energy sources,due to the clean and pollution-free and huge reserves of solar energy,as well as the high energy density of hydrogen energy and the pollution-free combustion,etc.,the scheme of using solar energy to produce hydrogen through semiconductor materials by photocatalysis has become popular The subject of this process can not only improve the environmental pollution problem,but also alleviate the energy crisis.For the photocatalytic hydrogen production technology,how to improve the utilization rate of the material's light energy,increase the catalytic active site of the material and improve the stability of the catalysis is the key to the technology's wide application in the environmental and energy fields.Among many semiconductor materials,cadmium sulfide has attracted much attention due to its suitable energy band structure and strong light response capability.However,cadmium sulfide itself is more severely photocorroded,and the intrinsic photogenerated electron-hole recombination rate is very high.The above factors make its application in the field of photocatalysis severely limited.Based on the above reasons,this thesis is based on energy band structure adjustment,electron transport path optimization and active crystal plane control.By introducing transition group metal sulfide and synergistically modifying cadmium sulfide to optimize the photogenerated carrier transport path,it effectively Enhance the performance of photocatalytic hydrogen evolution in cadmium sulfide system.The main research is divided into the following two parts:(1)First,hollow cubic CdS was prepared by precipitation,surface vulcanization,and calcination.Subsequently,the 2D ultra-thin bimetallic Ni-Co-S nanosheets were introduced into the CdS system by hydrothermal method,and its high electron transport performance and abundant surface active sites were used to synergistically modify the photocatalytic performance of CdS Through hydrogen production performance test under visible light,the optimal hydrogen production of bimetallic Ni-Co-S modified CdS system(Ni-Mo-S-5%)is up to 838.17?mol/g · h,which is about unmodified 80 times of CdS.(2)Based on the above research,rod-shaped CdS with higher active crystal plane was prepared by hydrothermal method.The results show that compared with ordinary CdS and hollow cubic CdS,rod-shaped CdS with more catalytic active crystal plane has higher hydrogen evolution efficiency.Compared with other transition metals,the atomic radius between Ni-Co is closer and thus has better lattice adaptability.Therefore,a CdS system modified by Ni-Co-S nanoparticles is introduced.Through photocatalytic tests,the hydrogen production performance of NiCoS modified CdS is as high as 6.56mmol/g·h,which is about 55 times that of pure rod CdS,150 times of hollow cubic CdS and 240 times of ordinary CdS.The main reason is that the bimetallic NiCoS can quickly transfer photogenerated electrons and provide sufficient active sites,thereby effectively improving the performance of photocatalytic hydrogen production.This conclusion can be further confirmed by a series of structural characterization and electrochemical tests. |
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