Electrochemical crystalline/amorphous Ni(OH)S@CoFe-LDH/NF for efficient oxygen evolution reaction

Abstract

Developing efficient electrocatalysts for oxygen evolution reaction (OER) to promote catalytic activities is a significant approach for renewable energy conversion. Herein, a novel crystalline/amorphous composite supported on nickel foam (denoted as Ni(OH)S@CoFe-LDH/NF) was successfully designed and synthesized through a facile hydrothermal and cathodic electrodeposition. Notably, Ni3S2 in Ni(OH)S was converted into amorphization due to the coupling effect and restraint effect of surface ion diffusion and controllable ion diffusion rate. The activated crystalline/amorphous structure enhanced the adsorption of reactants because of the highly unsaturated structure. In 1.0 M KOH, the Ni(OH)S@CoFe-LDH/NF exhibited enhanced activity with a low overpotential of 238 mV at 100 mA cm−2 toward OER. Furthermore, small Tafel slope values and excellent durability were also provided for OER process. DFT calculations confirmed that crystalline/amorphous composite could decrease the energy barrier to promote catalytic activity. This study could pave a way to enable the evolution of electrocatalysts by constructing crystalline/amorphous composite via a top-down strategy for OER process.