Ga doping enhances the oxygen evolution reaction performance and stability of NiFe layered double hydroxides

Abstract

NiFe layered double hydroxide (NiFe-LDH), as a promising non-precious metal oxygen evolution reaction (OER) catalyst, suffers from the inherent limitations of poor conductivity and insufficient exposure of active sites, coupled with the phenomenon of activity decline at high current densities, which severely restricts its application in the OER. Here, we propose a structurally defective strategy to prepare a self-assembled ultrathin nanosheet structure by introducing Ga³⁺ ions, and in situ growth of NiFeGa-LDH@NF on nickel foam (NF) to improve its OER performance. The incorporation of Ga³⁺ reduces the average thickness of the nanosheets from 4–5 nm to 1–2 nm, which significantly increases the catalyst activity surface area, and further optimizes its electronic structure causing a significant decrease in the charge transfer resistance. The optimized NiFeGa-LDH@NF provides a high current density of 100 mA cm⁻² at an overpotential of 258 mV, which is 43 mV lower than that of the pure NiFe-LDH@NF. Moreover, the voltage changes by only 1.3% after 72 h at a constant current density of 50 mA cm⁻², showing its excellent stability. This work presents a new perspective to increase structural defects by the introduction of transition metal ions and demonstrates the effect on OER performance, providing a new line of thought for the development of higher performance OER electrocatalysts.