Ru-doping modulated electronic structure of bimetallic phosphide toward efficient overall water splitting

Efficient water splitting electrocatalysts with low cost is essential for the development of sustainable hydrogen energy . Ni foam supported Ru-doped NiCoP nanowire arrays (Ru–NiCoP@NF) are synthesized via a hydrothermal reaction followed by low-temperature phosphorization. The as-obtained Ru–NiCoP@NF exhibits outstanding bifunctional catalytic activity , achieving 100 mA cm −2 at the overpotentials of 108 and 264 mV for HER and OER , respectively, with a tiny loading of Ru (≈61.8 μg cm −2 ). The electrolyzer assembled using Ru–NiCoP@NF as the bifunctional electrode requires 1.62 V (with no iR correction) for 50 mA cm −2 , 50 mV lower than RuO 2 –Pt/C based electrolyzer . The enhancement of Ru–NiCoP@NF is ascribed to Ru dopants , which contribute to formation of 3D nanowire arrays with the advantages of exposing sufficient active sites, accelerating charge transfer and outstanding mechanical strength . More importantly, the Ru atoms in NiCoP successfully modulate the charge densities around Ni, Co and P through strong electronic interaction, thus elevating the sluggish Volmer step for HER and promoting the adsorption capacity of oxygen-containing intermediates for OER .