Synergistic promotion of the oxygen evolution reaction by Co and Fe dual-doping of NiS2

Abstract

Hydrogen production via electrocatalytic water splitting is an efficient strategy to achieve carbon neutrality. However, the slow reaction kinetics of the oxygen evolution reaction (OER) hinders its large-scale industrial application. Therefore, it is crucial to construct efficient, stable, and scalable OER electrocatalysts. This work used a two-step hydrothermal method to prepare cobalt and iron dual-doped NiS₂ nanosheet arrays (Co,Fe–NiS₂) on nickel foam. Theoretical and experimental studies demonstrate that the introduction of Co and Fe can modify the space charge redistribution of NiS₂, optimizing the Gibbs free energy of the OER intermediate and accelerating water splitting kinetics. The catalyst Co,Fe–NiS₂ exhibits excellent OER performance in alkaline media, achieving a large current density of 500 mA cm⁻² at an overpotential of only 242 mV due to the synergistic effect of the two dopants. It can maintain its durability for 100 hours at 700 mA cm⁻² without significant degradation. This study offers valuable insights into the impact of cation dual-doping modulation on catalytic activity and presents a possible pathway for effective industrial water splitting.