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 (NiS x P y ) as an efficient precatalyst for OER, with one-dimensional (1D) nanowires grown on 1D nanorods. The resulting metallic hybrid NiS x P y catalyst can accelerate the electron transfer process and expose abundant in situ-generated NiOOH species during OER (NiS x P y –O). Therefore, NiS x P y –O exhibits a low overpotential of 192 mV (with 100% iR compensation; this value should be 200 mV without compensation) to achieve an O 2 partial current density ( j O2 ) of 10 mA cm –2 and a robust stability over 135 h without obvious degradation. Moreover, a j O2 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.