Preparation Of Z-type BiVO₄/rGO/gC₃N₄ Photocatalyst And Research On Its Visible Light Catalytic Performance

With the development of the economy,the problem of environmental pollution has become more and more serious.Dyes in wastewater and VOCs in the air have brought great harm to the ecological environment and human health.Photocatalytic technology is one of the effective technologies to solve the problem of environmental pollution and repair the ecological environment.The key to its large-scale application is to prepare efficient catalytic materials that respond under visible light.Among the many preparation methods,the construction of Z-scheme heterojunction photocatalysts is widely believed to promote interface charge transfer and photocarriers separation.BiVO₄ is a non-toxic photocatalyst,which has the advantages of good stability,low cost and easy availability.In addition,the lower band gap energy?2.4 e V?makes it have a wide range of visible light absorption.However,the poor electron-hole pair migration strategy and high carrier recombination rate severely limit the photocatalytic performance of a single BiVO₄.In view of the above problems,in this paper,BiVO₄ and g-C₃N₄ are connected by reduced graphene oxide?rGO?bridges to form a Z-scheme photocatalytic heterojunction.thereby the recombination of photogenerated carriers are improved and the photocatalytic reaction rate is increased.The specific research content is as follows:?1?Graphene oxide?GO?was prepared by the improved Hummers method,and GO was combined with g-C₃N₄ to form rGO/g-C₃N₄ by the calcination method.The samples were characterized by XRD,TEM,SEM,FTIR and other methods.The results show that the prepared graphene oxide is thin,contains a large number of oxygen-containing groups,and is successfully compounded with g-C₃N₄.The serious problems of carrier recombination and limited visible light absorption of g-C₃N₄ were solved.Therefore the efficiency of g-C₃N₄ visible light degradation of Rh B was improved.?2?A monoclinic BiVO₄ was grown in situ on the surface of rGO/g-C₃N₄ by hydrothermal method to obtain a BiVO₄/rGO/g-C₃N₄ ternary Z-scheme heterojunction,and the successful preparation of heterojunction was proved by various instrument characterization.After 120min of visible light irradiation,compared with the degradation rate of single BiVO₄?15.3%?and g-C₃N₄?20.4%?,the B2GC8 three-way catalyst with the best proportion of catalyst ratio can degrade Rh B to 85.2%.In addition,the catalytic efficiency of different light intensities was studied,the stability of the catalyst was explored,and holes were determined as the main reactants based on the active material capture experiments.Through the analysis and discussion of the photoelectrochemical test results,the mechanism of the photocatalytic reaction is expounded.?3?A reactor for photocatalytic degradation of VOCs was designed and manufactured.The prepared BiVO₄/rGO/g-C₃N₄ photocatalytic material was used in this experiment.By testing the efficiency of photocatalytic degradation of VOCs under different conditions,the effects of reaction conditions on catalytic efficiency were explored.