Nickel(II)-Induced Strategy toward Rice Grain-Like CoFeP Hollow Nanorods for the Enhanced Electrocatalytic Oxygen Evolution Reaction

Water electrolysis for hydrogen production is considered to be a sustainable technology that can effectively alleviate the world's energy crisis. The development of efficient electrocatalysts for the oxygen evolution reaction (OER) is particularly important for electrocatalytic water splitting. Herein, we report a unique nickel(II)-induced strategy to synthesize rice grain-like CoFe bimetallic phosphide (CoFeP RG) hollow nanorods for promoting the OER by coordination self-assembly, etch-regrowth, and low-temperature phosphorization. The presence of nickel(II) at the initial stage of the process is the determinant for the final morphology of CoFeP RG, and the intact contours endow CoFeP RG with super structural stability. Due to the advantages of its peculiar structure and multicomponent synergy, CoFeP RG exhibits an overpotential for the OER of only 281 mV at a current density of 10 mA cm^-2 in 1.0 M KOH, with a low Tafel slope of 64.40 mV dec^-1 and long-term durability of up to 120 h. This study provides a novel idea and a facile method for preparing hollow bimetallic phosphide electrocatalysts.