DFT Study On Metal/metal Oxide Heterogeneous

The interface of metal/metal oxide nano-heterojunction plays an very important role.Due to the interface between substrate and strengthen the body,the strong interaction between the main performance for composite yuan charge transfer and transfer between regional group,makes the interface of the heterostructure materials physical and chemical properties change significantly.Using the discrete Fourier transform DFT program VASP,systematically studied the metal/metal oxide(NiO/Ni,Bilayer Ru/Ti02,Pt1/TiO2,0-v/Ti02)heterojunction nanomaterials structure characteristics,electrical properties and the effects of interface of HER,Description of the root cause of material modification,enhance the efficiency of the light,the electric catalytic and thus puts forward the approach of developing new optical,electric catalyst.Firstly,the structural characteristics of NiO/Ni nanoheterostructure(NHSs)and the effect of interface effect on the hydrogenation reaction were studied through the calculation of the first principle.The mechanism of enhancing hydrogen reaction performance was discussed on the micro.In this study,the reaction activity sites of two exposed Ni surfaces were determined.One of them is the hcp-hollow bit of the nearest neighbor near the interface,which is better than that of platinum(Pt).The other is the fcc-hollow bit at the distance,which has a catalytic performance similar to Pt.The charge transfer between NiO and Ni surfaces is enhanced by reducing the energy of the surface atoms(i.e.,the d-band center),thus increasing the catalytic reaction rate on the nickel surface.On this basis,we studied the effect of adding Au on the reaction of cah.The mechanism of Ni-Au HDs to improve the activity of HER reaction was attributed to the special role of NiO and Au in HDs,and we became"double-acting mechanism".Because O and Au are more electronegative than Ni,Au at the NiO boundary and Au at the sheath of nuclear shell take electrons from the Ni(111)substrate.This leads to the Fermi level of Ni or d-down,with center orbit occupied state decreases,can weaken the keys of Ni-H,can reduce the adsorption of Ni base slabs H,prompted the gibbs free energy ? GH*heat tend to be neutral.However,because the number of NiO and the number of active sites are much larger than the ni-au interface,NiO/Ni's HER reaction is still dominant.In addition,Chemical synthesized with Ti02 as the basal nano heterostructure:Bilayer Ru/Ti02,Pt1/TiO2,O-v/TiO2 as the prerequisite,The electrical properties are studied by us,explained the material modification to improve the light,the efficiency of catalytic mechanism.The calculation results of the optimization of the atomic structure show that the relaxation caused a serious dislocation of atoms in the interface,which destroyed the periodic arrangement of the lattice.The O and metal atoms in the interface area have a tendency to get close to each other in order to achieve a stable structure,which indicates that the structural relaxation of the interface is a way to reduce energy in the material system.Interface area electron density of states(LDOS)analysis shows that the failure to form a metal/metal oxide interface structure of metal x/Oy compounds,and interface will lead to uneven distribution of electric charge,the formation of micro electric field for the whole material system.This suggests that the heterojunction interface effect can significantly broaden the scope of visible light absorption,prolonged survival of e--h+,and therefore to higher photocatalytic efficiency to lay a solid foundation.