Confined Pyrolysis Synthesis of Well-dispersed Cobalt Copper Bimetallic Three-dimensional N-Doped Carbon Framework as Efficient Water Splitting Electrocatalyst

Hydrogen is one of the most desirable alternatives to fossil fuels due to its renewability and large energy density. Electrochemical water splitting, as an environmental-friendly way to produce H 2 of high-purity, is drawing more and more attention. Conductive nitrogen-doped carbon frameworks derived from metal-organic frameworks(MOFs) have been applied as promising electrocatalysts thanks to their superior conductivity, numerous active sites and hierarchical porous structures. However, traditional uncontrolled pyrolysis will lead to aggregation or fusion of the metal sites in MOFs or even cause collapse of the three-dimensional structures. Herein, we provide a confinement pyrolysis strategy to fabricate a CoCu bimetallic N-doped carbon framework derived from MOFs, which exhibits satisfactory catalytic performance with overpotentials of 199 mV towards hydrogen evolution reaction and 301 mV towards oxygen evolution reaction to reach 10 mA/cm 2 in an alkaline solution. This work presents further inspirations for preserving the original skeleton of MOFs during high temperature pyrolysis in order to obtain more stable and efficient electrocatalyst.