Synthesis, Characterization And Electrocatalytic Properties Of Composites Derived From Co-MOFs

At present,noble metal catalysts of Pt-based and Ir/Ru-based have excellent catalytic performance for hydrogen evolution reaction（HER）and oxygen evolution reaction（OER）.However,prohibitive cost of the Pt-based and Ir/Ru-based materials cause a serious limitation for large scale commercial applications.In order to reduce the cost of catalysts,people focus on non-noble metal materials.Metal-organic frameworks（MOFs）have been utilized as precursors or self-sacrificed templates to manufacture porous carbon materials and related nanostructured functional materials for their adjustable pore size,high surface area,and tunable structure.In recently years,researchs have shown that the heteroatom-codoped carbon materials encapsulating transition metal or transition metal sulfide nanomaterials are expected to replace noble metal catalysts.This paper makes the following research:（1）In{[Co₂（DBIBA）₃]·Cl·9H₂O}_n（Co-MOF-1）,the Co²⁺nodes were connected by the linker 3,5-di（1H-benzo[d]imidazol-1-yl）benzoate（DBIBA）.The DBIBA was synthesized by the DBIBN ligand（3,5-di（1H-benzo[d]imidazol-1-yl）benzonitrile）in situ acidic hydrolysis of cyanide functional group.Co-MOF-1 mixed with the thiomolybdate[Mo₃S₁₃]^2-nanoclusters to prepare the N-,O-,and S-tri-doped carbon encapsulating Co₉S₈ and MoS₂（Co₉S₈/MoS₂@NSOC-T）nanocomposite by one-step pyrolysis.The Co₉S₈/MoS₂@NSOC-900 hybrid material exhibited remarkable catalytic performance for hydrogen evolution reaction（HER）in both alkaline and acidic solution(an overpotential of 194 mV and 233 mV at 10 mA cm^-2,respectively),which compared to Co₉S₈、MoS₂、Co₉S₈-MoS₂.（2）We adjust the ligands in the metal-organic framework.A new compound[Co（DBIBN）（BDC）]_n（Co-MOF-2）was obtained by hydrothermal method,the Co²⁺nodes were connected by the linker DBIBN and H₂BDC.The structure was determined by X-ray single crystal diffraction.Co-MOF-2 as a precursor to prepare the N-,O-,doped carbon encapsulating Co（Co@NOC-T）nanocomposite by one-step pyrolysis.The electrocatalytic properties of Co@NOC materials were studied.The Co@NOC-800 hybrid materials exhibited remarkable catalytic performance for hydrogen evolution reaction（HER）,when the current density was 10 mA cm^-2,the overpotential was 303 mV.However,the Co@NOC-700 hybrid materials exhibited remarkable catalytic performance for oxygen evolution reaction（OER）,when the current density is 10 mA cm^-2,the overpotential is 380 mV.