Metal Organic Framework–Derived Co and Co-Nx Embedded Mesoporous Carbon Sheets as an Efficient Electrocatalyst Toward the Oxygen Reduction Reaction for Air-Breath Cathode Microbial Fuel Cells

The Co/Co-Nx-embedded mesoporous 3D flower-like carbon sheet (Co/Co-N-MC-800) catalyst is successfully prepared from high N content H-1,2,4-Triazol-3-amine organic-ligand at different pyrolysis temperatures based on in situ pyrolysis Co-metal organic frame (MOF) (Co-PTA-MOF) precursor under nitrogen. The metal active center of the mesoporous Co/Co-N-MC-800 catalyst with more defect sites is situated in the positively charged 0 ~  + 2, and the bond spacing is consistent with the Co-N₄ plane structure of the co-porphyrin. The obtained Co/Co-N-MC-800 possesses an excellent oxygen reduction reaction performance with a higher onset potential (0.92 V vs RHE) and half-wave potential (0.76 V vs RHE), which is closer to Pt/C and outstanding long-term stability with 89.1% current retention after 89 h and displays an optional power density of 1079.3 ± 22.5mW·m⁻² in air-breath cathode microbial fuel cell (MFC). The improved catalytic performance maybe attributes to combination of the special 3D nanostructure, embedded cobalt nanoparticles (forming Co-N_x) and N-doped mesoporous carbon sheet material. The present study provides the technical and theoretical basis for the ORR through the cathode modification of MOF prepared from non-precious metal and N content organic-ligand.