1D/1D Hierarchical Nickel Sulfide/Phosphide Nanostructures for Electrocatalytic Water Oxidation

The sluggish kinetics of the oxygen evolution reaction (OER) limits the efficiencies of solar-powered electrical-conversion applications, such as water splitting and carbon dioxide reduction. Herein, we rationally designed a metallic nanostructured nickel sulfide/phosphide hybrid (NiSxPy) as an efficient precatalyst for OER, with one-dimensional (1D) nanowires grown on 1D nanorods. The resulting metallic hybrid NiSxPy catalyst can accelerate the electron transfer process and expose abundant in situ-generated NiOOH species during OER (NiSxPy–O). Therefore, NiSxPy–O exhibits a low overpotential of 192 mV (with 100% iR compensation; this value should be 200 mV without compensation) to achieve an O2 partial current density (jO2) of 10 mA cm–2 and a robust stability over 135 h without obvious degradation. Moreover, a jO2 of 10 mA cm–2 at an overpotential of 315 mV (with 100% iR compensation; this value should be 365 mV without compensation) is attained in near-neutral conditions. These results may pave a new way to design metallic precatalysts with 1D/1D hierarchical nanostructures to boost the OER.