Theoretical Study On The OER/ORR Electro-Catalytic Property Of Metal Diatoms Doped Transition-metal Dichalcogenides

With the progress of technology since the 21st century,the progress of science and technology and the change of environment have put forward higher requirements for energy,it is imperative to develop new green energy.Due to the high cost and poor stability,the existing precious metal based electrocatalysts（such as Pt based materials,Ru/Ir oxides）restrict the commercial application of fuel cell and water electrolysis technology.Therefore,developing low-cost,high-performance non-noble metal catalysts has become the focus of current researchers.Owing to the unique geometric-electronic structure and physicochemical properties,2D-transition metal dichalcogenides（2D-TMDs）are promising altermatives.Here,based on density functional theory,the electrocatalytic performance of oxygen reduction reaction（ORR）and oxygen evolution reaction（OER）of Co single atom doped MoTe₂（Co/MoTe₂）,heteronuclear double transition metal atom doped MoTe₂（Co M/MoTe₂）and homonuclear double transition metal atom doped Mo S₂（MM/Mo S₂）have been systematically studied.The intrinsic mechanism of its property was discussed by geometric structure,electronic structure and thermodynamic analysis.Detailed contents and conclusions include:（1）Theoretical study on the OER/ORR catalysis activity of Co doped MoTe₂:Electronic structure calculation shows that the conductivity of MoTe₂ is improved by Co single atom doping,and the interaction between Co atom and substrate helps to enhance the stability of doping structure,too.In addition,as an intrinsic inert two-dimensional material to OER/ORR,the catalytic activity of MoTe₂ is activated by CO atom doping.However,the reaction energy barrier is over increased due to the strong adsorption strength of O intermediates,that is to say,there is room for catalytic performance improvement.The emergence of dual atomic catalysts（DACs）provides a new strategy to solve this problem:the adsorption strength of intermediates could be moderated by the local synergistic effect caused by the transition metal dual atom doping,which is an attractive topic worth exploring.（2）Theoretical study on the OER/ORR catalysis activity of Co and M doped MoTe₂:Co M/MoTe₂ is divided into two different doping configurations due to the type of the second doped atom.Co Zn/MoTe₂,Co Pd/MoTe₂and Co Pt/MoTe₂ show better OER/ORR catalytic activity than Co Fe/MoTe₂,Co Ni/MoTe₂ and Co Cu/MoTe₂.Further adsorption energy calculation and structural analysis of intermediates indicated that the synergistic effect between two metal atoms in Co Zn/MoTe₂,Co Pd/MoTe₂and Co Pt/MoTe₂ could moderate the adsorption strength between O atom and substrate,and further boosting the catalytic activity.On the contrary,owing to the"bridge"bonding form of O atom bonds on Co Fe/MoTe₂,Co Ni/MoTe₂ and Co Cu/MoTe₂,the adsorption strength of O intermediates is significantly enhanced,therefore their performance are even worse than that of Co/MoTe₂.Moreover,additional electronic structure calculation shown that the special electronic structure property（such as moderate spin density value）could also provide a positive influence on adsorption strength controling,which is consistent with the study of other two-dimensional materials.These results hint that such mechanism could be widely applied to different systems.（3）Theoretical study on the ORR/OER activity of dual M doping Mo S₂:In order to further understanding the mechanism of catalytic performance on dual-metal-atoms doped TMD,here,the ORR/OER activities of dual M doped Mo S₂（MM/Mo S₂）are studied by first-principle calculations.The results indicate that the dual Pd doped Mo S₂（Pd Pd Mo S₂）presents low OER/ORR overpotential and Pt Pt/Mo S₂ exhibit high OER activity,while other structures show poor catalytic activity.The electronic structure analysis shows that the doped dual metal atoms can enhance the conductivity of Mo S₂and moderate the adsorption strength of intermediates,thus boosting the catalytic performance of Mo S₂.The above results indicate that compared with traditional single atom doping,dual metal atoms doping is an effective strategy to enhance the catalytic performance of TMDs owing to the internal interaction between doped diatoms.Through theoretical calculation,the suitable doping elements can be selected and the catalytic performance can be predicted,thereby providing an convenient reference and guidance for laboratory experimental before experimental process is mature enough.