Core-shell trimetallic NiFeV disulfides and amorphous high-valance NiFe hydroxide nanosheets enhancing oxygen evolution reaction

Developing highly efficient, stable, and earth-abundant heterogeneous electrocatalysts for the oxygen evolution reaction (OER) is a significant challenge. Herein, we designed and synthesized a novel core–shell trimetallic Ni0.70Fe0.10V0.20S2 @ amorphous NiFe hydroxide for enhancing OER kinetics using thermal sulfidation and in situ electrochemical tuning methods. Electrochemical testing of various as-prepared catalysts at the same mass loading demonstrated that the trimetallic Ni0.70Fe0.10V0.20S2 @ amorphous NiFe hydroxide possessed the highest intrinsic activity for the OER compared to other reference catalysts. Furthermore, the heterostructures are directly grown on a carbon paper with a high surface area and good conductivity to form an integrated 3D electrode with an overpotential of 204 mV at the current density of 10 mA cm-2 and a small Tafel slope of 39 mV dec-1 in 1.0 M KOH electrolyte. This is one of the most effective OER electrocatalysts. X-ray photoelectron spectroscopy and scanning electron microscopy indicated that the material structure and chemical composition of Ni0.70Fe0.10V0.20S2 @ amorphous NiFe hydroxide exhibited good stability under harsh OER conditions. These advantages could be mainly attributed to the synergistic effect between the core and shell, high electronic conductivity of the core, and more active sites on the surface of the amorphous shell. Additionally, this study provides novel insights for designing and synthesizing heterostructure multimetallic disulfides electrocatalysts for OER in the future.