Investigation About The Interfacial Kinetics Process Of Photoelectrochemical Water Splitting With Sanning Electrochemical Microscope

The energy crisis and environmental problems make the acquisition of new alternative energy become one of the research hotspots.Under the circumstances,solar-driven photoelectrochemical?PEC?water splitting technology obtained fast development.However,the fast transfer and recombination processes of photogenerated charge carriers in the bulk and electrode/electrolyte interface are not clear.As we all know,the dynamic process has important influence on the performance of catalyst,so it is necessary to explore these processes.With thin layer cell and ultramicroelectrode,SECM has the characteristics of high spatial resolution,fast mass transfer rate and can study the interface reaction kinetics process under steady-state conditions.Based on the unique advantages of SECM,we adopt SECM feedback model to study the interfacial charge transfer?catalyst regeneration kinetics?and the back-transfer kinetics?photogenerated electrons and holes recombination kinetics at the surface of photoelectrodes?at the semiconductor/electrolyte interface with different types of photocatalysts.The kinetic parameters obtained from the experiments have important guiding significance for the study of catalytic mechanism and the optimization of catalysts.The specific experimental contents are as follows:At first,we explored the regeneration process of photocatalyst BiVO₄ and the recombination behavior of photogenerated charge carriers at the photoanode/electrolyte interface.Then,we further studied the regeneration and recombination process of BiVO₄/co-catalyst system?co-catalysts included Ni-Fe-LDH,RuOx,CoPi?.It was found that the co-catalyst greatly inhibited the recombination process of photogenerated charge carriers at the interface,and the reason for the co-catalyst to improve the performance of BiVO₄?photoelectric catalyst?was finally clarified.Based on the study of the oxide semiconductor photocatalyst BiVO₄,we systematacially studied the regeneration process and photogenerated charge carriers recombination behavior on a new type of semiconductor material?graphite carbon nitride?g-CN??and illustrated the reason for poor catalysis performance of g-CN from a dynamic perspective.The experimental data provided theoretical basis for further improvement in photoelectrochemical catalysis performance of g-CN.