| In recent years,the search for new energy materials is an effective way to solve energy and environmental problems,and photoelectrocatalysis(PEC)uses solar energy to decompose water to produce hydrogen,which has attracted the attention of many scientists.Among them,BiVO4 is a 2.4 eV narrow band gap n-type semiconductor with good visible light response,which can be used as a photoanode for hydrogen evolution and oxygen evolution.However,the recombination rate of its photogenerated carriers is high,which affects the efficiency of STH.Therefore,in order to improve the photocatalytic efficiency of BiVO4,reduce the recombination of photo-generated carriers,and accelerate the separation and transmission of photogenerated electron-hole pairs is one of the effective ways.In view of this,a series of BiVO4 based composite photoanode materials were prepared by electrodeposition,calcination and hydrothermal methods.Not only through a series of characterizations to explore the physicochemical properties of BiVO4-based composite photoanode materials,but also by linear sweep voltammetry(LSV),time-ampere curve(It),electrochemical impedance spectroscopy(EIS),charge separation efficiency,charge inj ection efficiency and photoelectric conversion efficiency(IPCE).And the photocatalytic hydrogen production performance of a series of BiVO4-based composite photoanode materials prepared was evaluated.The main research contents are as follows:1.NiS/BiVO4 and CoS/BiVO4 composite photoanode materials were synthesized by simple hydrothermal method and electrodeposition method.The electrode was applied to a photoelectrochemical water decomposition hydrogen production experiment.The experimental results show that the hydrogen production of NiS/BiVO4 and CoS/BiVO4 is 4.7 and 7.3 times that of pure BiVO4 film,respectively.The possible photoelectrochemical water decomposition reaction mechanism of this new photoanode material is also proposed.2.NiO nanoparticles were prepared by simple hydrothermal method and loaded on BiVO4 film to form NiO/BiVO4 composite photoanode materials.All electrodes were tested for photoelectrochemical performance under visible light and photoelectrochemical water decomposition experiments.The experimental results show that the NiO/BiVO4 composite electrode improves the charge separation efficiency and charge injection efficiency,which directly increases the Faraday efficiency of the composite electrode.The possible reaction mechanism of photoelectrochemical water decomposition of composite electrode is proposed.3.In this paper,CoOx/BiVO4 composite photoanode materials were prepared by electrodeposition.The electrode was applied to a photoelectrochemical water decomposition hydrogen production experiment.The experimental results show that the hydrogen production of CoOx/BiVO4 is 3.2 times that of BiVO4 film.This is mainly because the introduction of CoOx nanoparticles not only improves the charge separation efficiency and charge injection efficiency,but also suppresses the recombination of photogenerated electron hole pairs,so the composite material has better PEC performance.At the same time,the possible reaction mechanism of photoelectrochemical water decomposition of composite electrode is proposed. |
