An efficient oxygen evolution reaction catalyst using Ni–Co layered double hydroxide anchored on reduced graphene oxide

Abstract

An efficient oxygen evolution reaction (OER) catalyst is crucial in various electrochemical applications including renewable energy, electrochemistry, and environmental science. Herein, we report the OER performance and stability of a nonprecious metal electrocatalyst consisting of nickel and cobalt-layered double hydroxides (NiCo-LDH) and reduced graphene oxide (rGO) using hydrothermal methods. The prepared NiCo-LDH@rGO catalyst exhibits a homogeneous distribution of NiCo-LDH on the rGO surface and an excellent OER performance. The OER potential of NiCo-LDH@rGO shows a value of 1.60 V at a current density (η) of 10 mA cm⁻², which is 100 mV lower than that of iridium oxide (IrO₂) (η = 10 mA cm⁻² at 1.70 V). Interestingly, at the current density of 20 mA cm⁻², the observed OER potentials for NiCo-LDH@rGO and IrO₂ are 1.65 and 1.84 V, respectively, indicating that NiCo-LDH@rGO has 190 mV lower overpotential compared to IrO₂. The NiCo-LDH@rGO catalyst also shows a lower value of Tafel slope (74 mV dec⁻¹) indicating faster reaction kinetics. The enhanced performance and stability of the NiCo-LDH@rGO catalyst can be attributed to the exposed active sites and the faster electron transfer, due to the synergistic effect of rGO in the NiCo-LDH, which promotes the OER oxidation process.