ZIF-derived Co nanoparticle/N-doped CNTs composites embedded in N-doped carbon substrate as efficient electrocatalyst for hydrogen and oxygen evolution

Herein, we report a bifunctional electrocatalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) by pyrolysis of zeolitic imidazolate framework-67 (ZIF-67), melamine, and PVP composites solid gel. During the pyrolysis, ZIF-67 formed N and Co co-doped carbon nanotubes on the surface (Co@CNT/NC), melamine and PVP have been converted into N-doped carbon (NC) substrate. Our Co@CNT/NC composites display the overpotential of HER and OER at current density of 10 mA cm−2 only need 136 mV and 280 mV, respectively. The synergistic effect of catalytic active sites such as metallic Co, Co–N bond, and N-doped carbon, and the large specific surface area caused by special morphology of the materials, enabled the catalysts to exhibit superior catalytic performance of HER and OER. The work provides a new idea to construct highly efficient HER and OER dual-functional electrocatalysts.