Preparation Of BiVO₄ Photocatalytic Composites And Study On Photocatalytic Degradation Of Methylene Blue

With the rapid development of industry,the discharge of organic waste water is increasing,water pollution is also getting worse,and human health and ecological environment are seriously threatened.Photocatalysis based on semiconductor materials can directly use solar energy to degrade organic pollutants,which has become one of the technical means to solve environmental pollution and energy shortage.Among various semiconductors with visible light response capability,BiVO₄ has relatively long hole diffusion distance（60 nm）,long carrier life（40 ns）,appropriate band gap（2.4-2.5 e V）,controllable crystal surface,clear electronic structure and other advantages,showing great potential in the degradation of organic matter.However,the shortcomings of BiVO₄,such as low separation efficiency of photogenerated carriers and serious carrier recombination,restrict its further application.In recent years,the photocatalytic activity of BiVO₄ has been significantly improved by ion doping,constructing heterogeneous and surface modification.In this work,Al doping and semiconductor BiVO₄/ZnFe₂O₄ composite were used to enhance the photocatalytic performance of BiVO₄.Meanwhile,surface photovoltage technology（SPV）and transient photovoltage technology（TPV）were used to study the photogenerated charge behavior of the composite materials and the relationship between the photogenerated charge behavior and catalytic degradation effect.It provides a new idea for the design of photocatalyst.The specific work is as follows:1.A series of Al³⁺doped BiVO₄ composite materials were synthesized by hydrothermal method,which were used to degrade methylene blue solution.The photogenerated charge behavior was studied by surface photovoltaic technology and the mechanism of photocatalytic activity enhancement was investigated.2.BiVO₄/ZnFe₂O₄ heterojunction photocatalyst was synthesized by hydrothermal method and used for photocatalytic degradation of methylene blue solution.The interaction between H₂O₂,BiVO₄ and ZnFe₂O₄ was revealed by active species capture experiment combined with surface photovoltaic technology and solid fluorescence tests,and the possible photocatalytic mechanism was discussed...