Density Functional Theory Calculation Aided Development Of 2D OER Electrocatalytic Materials And Their Performance

Electrocatalytic materials have become indispensable key materials for electrochemical energy storage and conversion equipment because they can effectively reduce overpotential and improve energy conversion efficiency.However,at present,electrocatalytic materials still have shortcomings such as low catalytic activity,poor electrical conductivity,and unsatisfactory cycle stability,which limit their wide application in industrial production.Therefore,the development of electrocatalytic materials with high catalytic activity and high stability has become a focus and hot spot in the field of electrochemical energy storage.In this paper,based on two-dimensional materials such as Metal-Organic Frameworks(MOFs)nanosheets and transition metal disulfides,combined with high-throughput calculations,a series of basic issues such as the influence of metal ions in two-dimensional NiFe bimetal organic framework nanosheets(NiFe-UMNs)on the catalytic activity of oxygen evolution reaction(OER),the structural advantages of NiFe-UMNs over three-dimensional MOFs,the structure-activity relationship between the structural parameters of single-atom supported MoS2 nanosheets(M-UMONs)and OER activity and the method of improving the electrocatalytic OER activity by adjusting the interface orbital coupling between the graphene and the Ni-MOFs nanosheets,were systemtically investigated.Moreover,a series of high-performance electrocatalytic material for OER have been developed.The specific research content is as follows:(1)Two MOFs nanosheets,NiFe-UMNs and CoFe-UMNs,were prepared and the effects of different metal central ions on the electrocatalytic activity of OER were studied.Through density functional theory(DFT)calculation combined with experimental verification,the difference in activity of metal sites on surfaces was explored,the cooperative coupling mechanism between bimetals was clarified,and the influence of the introduction of Fe on the electronic structure of the material was clarified.The optimization effect,that is,the introduction of Fe element can optimize the electron filling number of the eg orbital of NiFe-UMNs,thereby greatly improving the catalytic activity.(2)The supported configurations and theoretical overpotentials of 11 kinds of M-UMONs were predicted by DFT calculations.The 11 kinds of single-atom loaded MoS2 nano sheets were prepared by hydrothermal synthesis,and the experimental measurement results of these samples were used to verify the reliability of DFT calculation.On this basis,the theoretical overpotential and structural parameters of nearly 30 M-UMONs were obtained through high-throughput calculations.The theoretical overpotential was used as the "performance index" and the structural parameters(such as Fermi level,d orbital center,eg orbital electron number,etc.)are used as "structural indicators",and the relationship between the two indicators is deeply explored.The study found that there is a linear functional relationship between the difference between the M-S and M-O bond order and the theoretical overpotential,which can be used as a descriptor of OER activity.(3)The feasibility of anchoring 1584 candidate anchor primers on the surface of graphene is predicted by high-throughput density functional theory calculations,followed that,the spontaneity of side reactions and the degree of delocalization of the unoccupied orbital is also predicted by calculation,and finally screen out the primer molecule with the best comprehensive performance through this three-step screening process step by step.Based on this,the two-dimensional metal-organic framework nanosheets are anchored on graphene by covalently anchoring to build a composite catalytic material with excellent catalytic activity for oxygen evolution reaction with the two-dimensional metal organic framework material as the main body and the graphene as the conductive carrier through the bridging of primer molecule,providing a series of high-performance two-dimensional hybrid materials and the theoretical support.