Formation of electron-deficient Ni in a Nb/NiFe-layered double hydroxide nanoarray via electrochemical activation for efficient water oxidation

Abstract

The intrinsically sluggish kinetics of the oxygen evolution reaction (OER) at the anode poses a formidable challenge to the industrial application of water electrolysis, although NiFe-based oxides and hydroxides have emerged as promising anodic candidates. Within this framework, we report the synthesis of Nb-doped NiFe-layered double hydroxides (Nb/NiFe-LDH) via a straightforward one-step hydrothermal approach. Notably, Nb doping maintained the structural integrity of the NiFe-LDH framework and it enhanced the valence state of the active Ni species during the electrochemical activation process, which accelerated the concomitant reconstruction kinetics of the LDH phase. As a result, Nb/NiFe-LDH demonstrated a remarkable overpotential of 198 mV to attain a current density of 10 mA cm⁻² in an alkaline electrolyte. This work proposes a novel doping strategy for enhancing the performance of OER electrocatalysts.