Study On Water Oxidation Kinetics Of Bi Vo4 Photoanode Modified By MnCaCoO_x Catalyst

Learning from natural photosynthesis is a rational and effective way to develop artificial photosynthesis systems,but it is still a big challenge.The decomposition reaction of water involves the electron-hole separation and transfer of four electrons and protons.Among them,water is decomposed by the semiconductor photoelectrode to produce hydrogen and oxygen,but the slow reaction kinetics of the semiconductor surface is still an urgent problem to be solved.Therefore,it is very necessary to find a suitable catalyst to improve the reaction kinetics of the semiconductor electrode surface.In this paper,a photoelectric catalytic system was assembled to simulate various effects of the P680 chromophore.The system uses semiconductor bismuth vanadate prepared by electrodeposition as a substrate,and BiVO₄ absorbs light to generate photogenerated electrons and holes.At the same time,a simple method was used to deposit calcium manganese oxide as a hole transport layer.Co-Pi catalyst was electrodeposited on the layer.The catalytic system between manganese,calcium and cobalt was established for the first time.The electron transfer mechanism on the promoter has completed the simulation of the photosystem II in photocatalytic water oxidation,which has improved the water oxidation capacity of the system.The photocurrent density of the composite electrode reached 2.30 m A cm^-2 at 1.23 V vs RHE.Through electrochemical measurements,the charge transfer behavior of the photoanode was studied,and the potential mechanism of MCoO_x?M = Sr,Ca,Zn,Y?enhancing the PEC performance of BiVO₄ thin films was understood.Inorganic oxide with proper Co / Caratio The electron-withdrawing / electron-donating effect between the Co and Casites can help calcium ions effectively suppress the charge recombination on the semiconductor surface,greatly enhancing the water oxidation kinetics of the photoanode at 1.23 V vs RHE,the photocurrent density of BiVO₄ /CaCoO_x electrode in aqueous solution can reach 2.46 m A cm^-2,and the initial potential shows a large cathode shift.At the same time,this paper proves that the inert redox metal ion with Lewis acid promotes the water oxidation mechanism.The catalytic ability of the composite photoanode increases with the increase of the Lewis acidity of the inert metal ion.