Study On Hole Interface Engineering To Enhance The Photoelectric Water Decomposition Performance Of Bismuth Vanadate

Since the beginning of the 21st century,the rapid development of the world economy has been accompanied by the rapid consumption of fossil fuels.The burning of fossil fuels has led to the’greenhouse effect’.People are aware that oil and natural gas will become scarce and expensive,so developing renewable energy is already urgent for us.There are abundant solar energy reserves.It is a promising strategy to build a photoelectrochemical（PEC）cell to split water to produce hydrogen and convert natural solar energy into chemical energy to solve the energy crisis.To produce clean hydrogen energy,this paper introduces a hole transport layer and modifies the interface of cobalt phthalocyanine and Fe OOH oxygen evolution catalyst onto the surface of Bi VO₄ photoanode,assembling a multi-layer composite photoanode.This paper uses SEM,TEM,XRD,and XPS methods to characterize and test the electrode,proving the successful synthesis of the composite electrode.The photoelectrochemical performance test results of composite photoanodes show that the interface modification of the photoanode is carried out by loading cobalt phthalocyanine and Fe OOH thin films.Cobalt phthalocyanine serves as a hole transport layer,which improves hole mobility.Fe OOH modification in the outermost layer can accelerate water oxidation kinetics.Linear voltammetry testing shows that the constructed three-component electrode has significantly improved its photocatalytic performance for water decomposition compared to the unmodified electrode.At a voltage of 1.23 V vs.RHE,the photocurrent density of Bi VO₄/Co Pc/Fe OOH composite electrodes can reach 4.2 m A/cm².The photocurrent density of the Bi VO₄/Co F16Pc/Fe OOH electrode with cobalt Hexafluorophthalocyanine as the hole transport layer was further improved,reaching5.1 m A/cm²,significantly improving the photocatalytic activity and water oxidation ability of the Bi VO₄ photoanode.In addition,this paper synthesized Bi VO₄/Ni MOF/Co-Pi multi-component photoanodes by modifying metal organic frameworks and Co-Pi co-catalysts onto Bi VO₄ using a simple dropwise addition method and electrodeposition.Ni MOF can separate and transfer holes,and the polyhedral skeleton structure can also improve conductivity.The interaction between the shell and internal particles leads to the accumulation of free charges,and the successful loading of Co-Pi can better utilize holes for water decomposition reactions.The results of photoelectrochemical testing show that the composite electrode has a significant increase in photocurrent density compared to the individual Bi VO₄ photoelectrode.At 1.23 V vs.RHE,the photocurrent density is 5.0 m A/cm²,which is 3.3 times higher than the individual Bi VO₄ electrode.The assembly of Ni MOF and Co-Pi on the surface provides a pathway for hole transport,improves the charge transfer efficiency of the Bi VO₄substrate,and has a significant effect on suppressing electron-hole recombination.