Thin MoS2 nanosheets grafted MOFs-derived porous Co-N-C flakes grown on electrospun carbon nanofibers as self-supported bifunctional catalysts for overall water splitting

Active and stable non-precious metal electrocatalysts are critical for the large-scale production of hydrogen/oxygen. Herein, a facile strategy for the in situ growth of MOFs combined with carbonization and subsequent solvothermal treatment for the rational design of thin MoS2 nanosheets grafted Co-N-C flakes (CoNC@MoS2) and grown on electrospun carbon nanofibers (CNFs) as bifunctional electrocatalysts for both hydrogen and oxygen evolution reactions (HER/OER) is reported. Binder-free CoNC@MoS2/CNF films exhibited unique hierarchical architectures with interconnected vine-like CNFs, which imparted favorable flexibility and satisfactory electrical conductivity to the self-supported electrocatalysts for electrochemical reactions. Due to the synergistic effect of the CoNC@MoS2 hybrid nanostructures and fast mass-transport properties of porous carbons, the resultant CoNC@MoS2/CNFs exhibited high catalytic activities and favorable stabilities for the HER and OER in a basic medium. When acting as electrocatalytic electrodes for overall water splitting, CoNC@MoS2/CNF films displayed a low overpotential of 1.62 V to generate a current density of 10 mA cm(-2) with remarkable stability at different voltages for 200 000 s, and even outperformed Pt/C-RuO2 electrode in high current density water electrolysis. This study highlights the rational design of hybrid nanostructures based on MOFs and CNFs as efficient self-supported electrocatalysts, opening new possibilities for the fabrication of functional free-standing materials in energy chemistry.