Co₃O₄ composite imine-type COFs-derived nitrogen-doped carbon materials as efficient hydrogen electrocatalysts

Imine-type covalent organic frameworks (COFs) materials are mostly used in membrane separation technology, gas storage and separation, etc., while they are seldom used in electrocatalytic hydrogen precipitation due to their poor electrical conductivity and low physicochemical stability. In order to obtain highly stable and active electrocatalysts, a simpler solvothermal method was used to synthesize imine-type COFs (TAPA-TFB-COF), and then Co₃O₄ composite N-doped carbon materials with 3D microsphere structure were obtained by high-temperature pyrolysis using Co(OAC)₂·4H₂O as the Co source (Co₃O₄/NC). It is shown that due to the 3D microsphere structure, high temperature pyrolysis promoting graphitization of the material, and the synergistic effect of Co and heteroatom N, Co₃O₄/NC exhibits excellent electrocatalytic hydrogen precipitation activity, with the onset potential decreasing from −0.92 V (vs. RHE) to −0.27 V (vs. RHE), and the current density increasing to 14 times of that of TAPA-TFB-COF, and the Tafel slope being only 151 mV·dec⁻¹ and electrochemical reaction charge transfer resistance (R_ct) as small as 80.8 Ω.