Metal-organic frameworks-derived nitrogen-doped carbon with anchored dual-phased phosphides as efficient electrocatalyst for overall water splitting

Green energy utilization depends greatly on the development of highly efficient catalysts for clean electrochemical energy conversion systems, such as green hydrogen production. Through nanostructuring to expose sufficient active sites in non-precious metal-based catalysts, both the catalytic activity and stability can be enhanced. Herein, we synthesize cobalt phosphides nanorods anchoring in N-doped carbon nanosheets (NC) (denoted as Co2P/CoP-NC) via a cation-induced strategy derived from zeolite imidazole frameworks (ZIFs), followed by phosphorization process. Different cations (Ni2+ and Co2+) are explored to reveal the influence of cations on the phase composition, microstructure, and electrochemical performance of Zn/Co-ZIF-derivatives. By controlling the type and mass of introduced cations (Ni2+/Co2+) in the Zn/Co-ZIF precursor, Co2P/CoP-NC and NiP/Co2P/CoP-NC with different morphologies can be obtained after the phosphorization process, respectively. The optimized Co2P/CoP-NC nanomaterial can possess high bi-functional catalytic activity for both the HER and OER with a small overpotential of 91 and 292 mV at a current density of 10 mA cm(-2) in alkaline media, respectively, as well as considerable durability. The competitive HER and OER performances are contributed to the 3D sea-urchin-nanostructure, high conductivity, and hetero-interfaces between CoP and Co2P. Co2P/CoP-NC catalyst as the anode and cathode electrodes, respectively, could achieve high electrocatalytic activity with a low applied voltage of 1.61 V at 10 mA cm-2 in alkaline solution, as well as high durability. This work may offer a cation induction method for the controllable design and synthesis of hierarchical nanocatalysts of metal-organic framework derivatives.