Preparation Of Novel BiVO₄ Materials And Applications In Photo（Electro） Catalysis

As a clean energy,solar energy is widely distributed and abundant in reserves.It is considered to be the most promising clean and sustainable energy.If the inefficiency of traditional photocatalyst can be solved,it can be further applied on a large scale to alleviate the energy crisis and environmental problems.BiVO₄is a semiconductor with a very good prospect.Compared with Ti O₂,which is a traditional photocatalytic material,it has a very good light response under visible light.Therefore,in recent years,there has been an endless number of research contents on BiVO₄.The main research content of this thesis is using a variety of ways to improve the BiVO₄efficiency on the basis of traditional BiVO₄material,combined with literature reports and the modification design within our group.To solve large crystal size,small specific surface area,poor adsorption ability,high carrier recombination and other problems,a series of efficient BiVO₄-based catalysts is prepared and will be applied to different photo（electro）catalytic reactions.Based on the background discussed above,this paper mainly carries out the following three parts:（1）Large-specific-surface BiVO₄was obtained by the template method.Further,by introducing oxygen vacancy into the material by organic reducing agent BPA,black BVO material was prepared and used in the study of photocatalytic degradation of organic pollutant Rh B.The introduction of high concentration of oxygen vacancies changes the original color of BiVO₄to black,improving the absorption of light.At the same time,BVO shows a strong adsorption capacity,because the oxygen vacancy changes the charged property of the surface of the material.It has a strong adsorption capacity for cationic pollutants because of negative-charged surface which is conducive to pollutants degradation（2）On the basis of the above work,a series of allochroic BVO with different oxygen vacancy content was prepared.In the oxygen evolution reaction,BVO 5:1 has the best OER activity because of its optimal ratio of oxygen vacancy concentration.When the oxygen vacancy concentration is excessive,itself would become the composite center of photogenerated carriers,decreasing the photocurrent.At the same time,through a series of characterization and contrast tests,three important factors affecting the magnitude of photocurrent were explored.The results show that:oxygen vacancy has a promoting effect on light absorption and interface transport between semiconductor and electrolyte,but has a hindering effect on the electron transport in the bulk phase.（3）In this part of the work,BiVO₄quantum dots with small size and large specific surface area were prepared by continuous ion layer adsorption reaction method.In order to avoid agglomeration in the reaction process,BiVO₄quantum dots were loaded on coral-like WO₃electrode etched by anodic oxidation method and TANF amorphous layer cocatalyst play a promotion activity for the purpose of further package.The experimental results show that WO₃/W-10BQDs@TANF has the best activity under visible light and can degrade 10 ppm Rh B within 60 min,and the hydrogen production efficiency reaches 15.10μmol·cm^-1·h^-1.WO₃and BiVO₄interact strongly to form a heterojunction,which accelerates the separation of photogenerated carriers.Meanwhile,TANF amorphous layer can not only enrich the holes but also solve the problems of poor stability of BiVO₄quantum dots,and improve the efficiency and life of the materials.