The dual-functional role of carboxylate in a nickel–iron catalyst towards efficient oxygen evolution

Abstract

The efficiency of the oxygen evolution reaction (OER) is severely limited by the sluggish proton-coupled electron transfer processes and inadequate long-term stability. Herein, we introduce a carboxylate group (TPA) to modify NiFe layered double hydroxide (NiFe LDH@TPA), resulting in notable improvements in both activity and stability. A combination of spectroscopic and theoretical investigations reveals the dual-functional role of incorporated TPA. It facilitates the deprotonation of OER intermediates while strengthening the Fe–O bond and acting as a molecular fence, ensuring superior OER kinetics and anti-dissolution properties. NiFe LDH@TPA delivers a low overpotential of 200 mV at 10 mA cm⁻² and an impressive long-term stability of 500 h at 150 mA cm⁻², significantly outperforming its unmodified counterpart. Furthermore, operating in an anion exchange membrane water electrolyzer, it affords prolonged stability at an industrial-scale current density of 1 A cm⁻², sustaining performance for over 120 hours. This strategy offers a promising avenue for the development of durable and efficient OER catalysts.