Phase controllable synthesis of Ni2+ post-modified CoP nanowire for enhanced oxygen evolution

Abstract Recently, tailor-made NiCo bimetallic phosphides hold a promising platform material in many fields such as catalysis and electrochemical energy storage and conversion. Typically, the traditional one-step phosphorization route offers limited phase control, with hexagonal phosphide phase structure (Ni 2 P type). Moreover, the phase component sensitively depends on the metal ratio to a great degree, posing great challenges to synthesize NiCo bimetallic phosphides with tuned composition and phase structure. Herein, we report a carbon encapsulated Ni 2+ post-modified CoP nanowire (denoted as Ni CoP@C) with single orthorhombic CoP phase structure and tuned Ni doping content via a facile & novel in-situ isomorphous-substitution method. More importantly, no any phase separation occurs, also further achieving a high Ni doping content (57 at%) that is less realized previously. As an example application, the as-made Ni CoP@C nanowire exhibits excellent oxygen evolution reaction (OER) activity and stability, showing promising potential in the field of water splitting. The present novel strategy will pave the way for further phase controllable fabrication of bi/multi-metal-based materials in catalysis and energy storage & conversion fields.