Preparation And Photocatalytic Activity Of Fixed Z-scheme TiO₂ Composite Film Photocatalytic Materials

Photocatalysis technology has unique advantages in the photocatalytic decomposition water and photocatalytic solar cells and is an effective way to solve the shortage of fossil fuel energy.TiO₂ has been deeply studied for its advantages such as suitable band potential,excellent optical activity,chemical stability,low cost and toxicity.In this paper,fixed Z-scheme TiO₂ composite film photocatalytic materials were prepared and their photocatalytic activities in photocatalytic hydrogen production from water splitting and photocatalytic quantum dot sensitized solar cells were studied and explored,respectively.1.In the first part,the fixed Z-scheme TiO₂|Ti|WO₃ composite film photocatalyst was prepared,and the photocatalytic activity of the fixed Z-scheme TiO₂|Ti|WO₃composite film photocatalyst in photocatalytic hydrogen production from water splitting was studied.TiO₂ and WO₃ films were prepared on both sides of a Ti foil by corrosion-calcination and sol-gel spin coating methods,respectively.A new type of fixed Z-scheme TiO₂|Ti|WO₃ composite film photocatalyst was successfully constructed.The morphological structure,optical properties and electrochemical performance of the prepared samples were characterized by various testing techniques such as XRD,SEM,EDX,UV-Vis,XPS,EIS and I-t.The influences of Ti foil corrosion times,Ti foil thickness and WO₃ layer number on the photocatalytic activity of the fixed Z-scheme TiO₂|Ti|WO₃ composite film photocatalyst were also investigated.In addition,the photocatalytic activity and stability of the fixed Z-scheme TiO₂|Ti|WO₃ composite film photocatalyst were studied through four times of cyclic photocatalytic hydrogen production.Based on the experimental results and theoretical knowledge,we analyzed and discussed the photocatalytic mechanism of fixed Z-scheme TiO₂|Ti|WO₃ composite film photocatalyst.The final research results show that the prepared fixed Z-scheme TiO₂|Ti|WO₃ composite film photocatalyst is a promising Z-scheme photocatalytic system for hydrogen production from solar energy.It is of great significance to the future preparation of clean energy and the resolution of the energy crisis.2.In the second part,composite film photoanode?TiO₂/CdS,TiO₂/CdS/SnS₂ and TiO₂/CdS/CdSe/SnS₂?based on TiO₂ were prepared and the photoelectric properties of quantum dot sensitized solar cells were preliminarily explored.The composite film photoanode based on TiO₂ was prepared by successive ionic layer adsorption and reaction?SILAR?method,and adsorbing different quantum dot sensitizers on the surface to prepare three different photoanodes.The composition,morphology,size and optical properties of photoanode materials?TiO₂/CdS,TiO₂/CdS/SnS₂ and TiO₂/CdS/CdSe/SnS₂?were characterized by XRD,SEM,EDX and Uv-vis techniques.The prepared three different photoelectrodes were used as photoanodes.Polysulfide and Cu₂S were assembled as electrolyte and counter electrode respectively to prepare a quantum dot sensitized solar cell with a sandwich structure.Photocurrent density-voltage?J-V?curves and incident photon-current conversion efficiency?IPCE?tests were carried out on different quantum dot-sensitized solar cells based on TiO₂ composite film photoanodes by photoelectrochemical method.And through these results,the mechanism of TiO₂/SnS₂ photoanode CdS/CdSe quantum dot sensitized solar cells was explored.