Study On The Preparation And Photoelectrochemical Properties Of Sulfide Based Semiconductor Photoanode

The continuous innovation of energy technology promotes the progress of human society.As the main energy used by human beings,fossil fuel is not only drying up,but also seriously damaging the environment together with medicine,dye,heavy metal and element enrichment.Therefore,looking for alternative clean energy and purifying the polluted environment are two major problems that need to be solved at present.Hydrogen is a kind of green secondary energy with abundant resource,renewable,high combustion calorific value and only water as combustion products,which has been widely concerned.Photoelectrochemical water splitting of producing hydrogen and pollutants degradation by semiconductor photoanode is a promising way of solar energy utilization,and the performance of semiconductor photoanode materials is the key to improve the utilization efficiency.Due to the advantages of rich resources,high chemical stability,simple preparation method and narrow band gap,sulfide semiconductor materials such as cadmium sulfide?CdS?,copper sulfide?CuS?,bismuth sulfide?Bi₂S₃?are widely used in the field of photoelectrochemistry.However,due to low visible light utilization and high electron hole recombination,the photoelectric conversion efficiency of single sulfide semiconductor is very low.In order to improve the efficiency of solar energy conversion and photocatalytic degradation of sulfide semiconductor,the heterogeneous structure and element doping were adopted in this paper and the photoanodes were fabricated.We studied the photoelectrochemical water splitting of hydrogen production and dyes degradation.The work of this paper is as follows:In the first part,ZnO/CuS heterojunction composite photoanodes were successfully prepared by hydrothermal,sol-gel,spin-coating,successive ionic layer absorption and reaction?SILAR?methods.By depositing CuS nanoclusters,the photoelectrochemical properties of photoanode had been improved significantly.After that,we adjusted the load of CuS by changing the circles of SILAR method,and researched its influence on the photoelectrochemical performance.When the number of SILAR cycles reached 10,ZnO/CuS composite photoanode showed the best PEC performance,the maximum photocurrent density of ZnO/CuS-10 photoanode was1.55 mA?cm^-2 at 0.37?V vs.Ag/AgCl?.At 0.984?V vs.RHE?,the maximum ABPE of ZnO/CuS-10 photoanode was 0.368%.The second part is about the preparation of TiO₂/Bi₂S₃ heterojunction composite photoanode and its photodegradation performance research.TiO₂/Bi₂S₃ heterojunction composite photoanodes were successfully prepared by hydrothermal and SILAR methods.We adjusted the load of Bi₂S₃ by different circles of SILAR,and studied its influence on the PEC performance.When SILAR cycle reached 28 times,the PEC performance of TiO₂/Bi₂S₃ was the most outstanding.In addition,Rhodamine B was used as a pollutant to study the PEC degradation ability of TiO₂/Bi₂S₃ with different cycles under different conditions.The results showed that TiO₂/Bi₂S₃-28 had the maximum photocurrent density of 2.8 mA?cm^-2,it could degrade nearly 25%of Rhodamine B at most,and its solar energy conversion efficiency was about 0.43%at 0.73?V vs.RHE?.Part three:preparation and the research of PEC performance and photodegradation ability of TiO₂/Au/PbS heterojunction composite photoanodeTiO₂/Au/PbS heterojunction composite photoanodes were successfully constructed by hydrothermal,SILAR and chemical bath deposition?CBD?methods.By adjusting the deposition times of SILAR and the amount of Au doping,the photoelectrochemical properties of the composite photo electrode were studied.The results showed that TiO₂/Au/PbS-2 had the best PEC degradation performance.At 1.2?V vs.Ag/AgCl?,the photocurrent was about 4.7 mA?cm^-2,the most degradation of Rhodamine B was close to 50%,the highest ABPE was 0.643%at 0.727?V vs.RHE?.