Surface Modification Of Bismuth Vanadate Photoanode To Improve Its Photoelectrocatalysis Performance

With the development of society,the consumption of energy in human society is also increasing.Solar energy is the most abundant and clean renewable resource on the earth.If we can make full use of the energy released by the sun in one hour,it will be enough to meet the energy consumption of the entire human world for a year.But the diurnal and unequal distribution of solar energy requires us to find an efficient way to store it.Photoelectrochemical water splitting is an effective method to convert solar energy into hydrogen energy for storage and utilization,the design of an efficient and stable photoanode is crucial to the overall water decomposition reaction.Among many metal-oxide semiconductor photoanode materials with photocatalytic activity,Bi VO₄has been widely studied and applied in photoelectrochemical water splitting.However,in the process of photo-electrocatalysis water oxidation of Bi VO₄,there are also some problems such as photogenic carrier recombination and serious photogenic corrosion,resulting in poor activity and stability of the whole reaction system.In order to solve the above limitations,we need to solve the problem of how to effectively improve the photogenerated carrier separation and transfer of Bi VO₄ phase and surface,and improve the stability of the reaction.In this paper,Bi VO₄ was impregnated in cesium borate buffer solution,and a Cs Bi VO amorphous layer was formed on the surface of Bi VO₄ photoanode by potentiostatic photopolarization method,which could effectively extract and store holes.The formed Cs Bi VO layer can effectively improve the photogenerated carrier transfer,reduce the occurrence of recombination phenomenon,and further improve the performance of Bi VO₄.The photocurrent density of Bi VO₄ photoanode at 1.23 V_RHE can reach 3.3 m A cm^-2.The photocurrent density reached 5.1 m A cm^-2 at 1.23 V_RHE after Fe OOH cocatalyst was loaded.Photoelectrochemical water oxidation is a key step in converting solar energy into hydrogen energy.Modification of photoanode with appropriate water oxidation catalyst is effective in promoting oxidation and inhibiting photo-corrosion.However,the stability of photoanode is severely limited by the corrosion of semiconductor caused by photo-holes and co-catalyst caused by protons generated in the reaction.Here,we report a simple strategy to improve the stability of the Bi VO₄ photoanode by sequentially coating the electrode surface with a cationic polymer film.The modified Bi VO₄ photoanode can run stably for 200 h at a test voltage of 0.6 V_RHE Under the joint action of bimolecular ionomer membranes without significant performance attenuation.This provides a new idea for protecting composite photoanode and improving electrode stability in the future.