Improving OER performance in alkaline water electrolysis with a Zn-doped NiFe LDH electrode developed via self-growth precipitation

Abstract

Developing cost-effective, scalable non-noble-metal electrocatalysts for the oxygen evolution reaction (OER) is essential for alkaline water electrolysis (AWE). Zn-doped NiFe layered double hydroxide (LDH) was synthesized via self-growth precipitation. Zn-incorporated NiFe LDH exhibited superior OER activity over pristine NiFe LDH due to increased surface area and electronic modulation. The optimized Z1N25 (Ni 2+ :Zn 2+ = 25:1) achieved an overpotential of 225 mV at 10 mA cm −2 , lower than NiFe LDH (277 mV), while Tafel slope decreased from 57.8 to 45.2 mV dec −1 . During cyclic voltammetry (CV) activation, partial Zn elution increased electrochemically active surface area while preserving the LDH framework, decreasing overpotential to 190.8 and 180.6 mV after 1000 and 2000 cycles, respectively. The catalyst remained stable over 140 h. Spectroscopic analysis revealed higher Ni oxidation state, enhanced M − OH formation, and Fe 2p red shift. This work demonstrates that Zn incorporation improves OER activity and long-term stability in self-grown NiFe LDH electrodes.