Study On The Activity Of Oxygen Vacancy For Overall Water-splitting Of Bismuth Vanadate

With the rapid development of modern scientific and technologic as well as forge ahead in industrialization,people come to grips with the following problems:energy crisis and environmental pollution.Green economy will be a broad for recent years.The group’s main focus is on hydrogen which is considered as an outstanding representative of clean energy.The production of hydrogen through renewable energy such as solar energy is one of the ideal solutions.Watersplitting of semiconductor materials photoelectrocatalysis because of its’ simple reactants and easy collection of products are developing quickly.Hoerver,efficient reactions require high standards for semiconductor catalyst which should own suitable band gap and matched band edge et al.Bismuth vanadium oxide（BiVO4）attract widely attention recently because it owns 2.4 eV suitable band gap which favors for light absorption and strong oxidizing for struggle oxidation reactions.Polyhedra-Bi VO4 demonstrate anisotropic for each different exposed facet.Such as highly exposed[110]facets,because of the selective aggregation of holes is the surface of oxidation reaction.High index planes including[121]facets have advantages in the adsorption and dissociation of water molecules,which is conducive to the overall water-splitting.The reasons why it couldn’t be widely used are following:low carrier mobility,unmatched band edge position of CBM（can’t stand across the reduction potential fot hydrogen production）and so on.In this paper,we mainly used oxygen vacancy to perfect BiVO4 so that achieve its’aim that hydrogen production through photocatalytic and photoelectrocatalysis water-spliting.The preconceived and detailed works are summarized as following:1.Based on Density Functional Theory calculation,using oxygen vacancy（Ovac）to improve photocatalysis electronic property of BiVO4[110]facets.The unmatched CBM position of BiVO4[110]limits its’ ability of hydrogen production.After constructing the Ovac,lacking of atoms result uncoordinated charges can induce internal electric fields.It plays an important role on changing the band structure and band edge position.Furthermore,it can lead local electtonic states to improve the transfer probability of photon-induced charges and adsorption of visible light.It can effectively improve the photocatalytic activity.2.Achieved photoelectrocatalysis overall water-splitting of BiVO4[110]facets by construction of Ovac.We proposed a simple BiVO4-based bifunctional structure as electrode material with the Ovac.The indeced of Ovac leading to unsaturated coordination and charges rearrangement,it minish the hydrogen absorption free energy（ΔGH*）for hydrogen evolution reaction（HER）and relevant overpotential for oxygen evolution reaction（OER）.Enhancing the charge transfer and oxidation property at the same time,improving the efficiency of watet-splitting.Thus,the feasibility of Ovac and the bright future of BiVO4 application are verified.3.The water oxidation reaction（WOR）of BiVO4[121]facets enhanced significantly by using Ovac.The sluggish catalytic reactivity on the surface affects its efficiency.Ovac enable surface activation favoring the adsorption of water molecular and transfer towards WOR.Furthermore,it decreased the overpotential of OER,meaning that high-index planes also play a very important role in research.