The Controlled Preparation Of Nanoalloy/CQDs-Semiconductor Composite Photocatalytic Materials With Photoelectrochemical Performance Research

In the field of material science,using the semiconductor photocatalysts preparing H₂ by photocatalysis or photoelectric catalysis method to solve the energy and environmental issues has received increasing attention.Among lots of semiconductor materials,TiO₂ photocatalyst has been widely studied and applied in many fields due to its inherent natures,such as low-cost,photostable and nontoxic.However,TiO₂photocatalyst was limited for its large bandgap?³.2 eV?as well as low quantum efficiency under the visible light.Therefore,it is very important to develop some materials with higher efficiency to replace TiO₂ semiconductor photocatalyst.The photoelectrochemical?PEC?performance of single semiconductor photocatalyst could be improved through doping or loading bimetallic alloy,quantum dots and other semiconductor materials.Based on the above discussion,we prepared three kinds of composite photocatalysts,which are different from TiO₂ sample,in order to enhance the PEC performance of the corresponding pure photocatalysts.?1?1D AuPd/ZnO composite sample was successfully synthesized by hydrothermal and sodium borohydride reduction methods.The crystal structure,microstructure and optical properties of the sample were investigated by various techniques,and the composite photocatalysts were further applied in photoelectrochemical?PEC?water splitting to study its performance.According to the experimental result analyses,it can be concluded that the improvement of PEC activity was attributed to the absorption properties of ZnO nanorod arrays,the SPR effect of AuPd alloy and the unique catalytic activity of Pd.?2?The CQDs/WO₃ composites with higher photocatalytic activity were prepared by electrolysis and impregnation measures.The effect of soaking time on the performance of the composite photocatalysts was also investigated.The experimental results show that CQDs can effectively reduce the recombination rate of photo-generated electron-hole pairs,promote the separation of photogenerated carriers and thus enhancing the photocatalytic performance of WO₃ nanorods.?3?In this paper,CdS/BiVO₄ composite photocatalyst was synthesized by dip-coating and successive ionic layer absorption and reaction?SILAR?methods.In the experiment,we explored the effect of heat treatment temperature and loading on the PEC property and morphology of the composite photocatalyst.The final experimental results showed that the heterojunction was formed between CdS and BiVO₄ which were two n-type semiconductor photocatalysts,and promotes the separation of photogenerated carriers and thus improves PEC characteristic of BiVO₄.