Dual‐ion engineering of Fe‐doped Ni <sub>3</sub> ( <scp>OH</scp> ) <sub>4</sub> ( <scp> NO <sub>3</sub> </scp> ) <sub>2</sub> for Cl <sup>−</sup> ‐resistant oxygen evolution reaction in alkaline medium
Jefferson Zhe Liu, Guoxin Ma, Xun Cao, Ruhai Gao, Li Xu, Jia Liu, Xiaoqian Ren, Lili Lin, Siwei Li
Abstract
Abstract Seawater electrolysis offers a sustainable pathway for green hydrogen production, yet the development of oxygen evolution reaction (OER) catalysts with robust Cl¯ resistance remains a critical challenge. Here, we propose a dual‐ion modification strategy, incorporating NO 3 ¯ and Fe 3+ cations into Ni(OH) 2 (denoted as Fe‐NiNH/NF), to synergistically enhance Cl¯ resistance and OER activity in alkaline simulated seawater. The Fe‐NiNH/NF catalyst demonstrates exceptional performance, requiring only 320 mV overpotential at 100 mA cm −2 in KOH and NaCl solution, with a negligible 10 mV increase compared to pure KOH. When implemented in an alkaline anion exchange membrane water electrolyzer, the catalyst achieves 1.76 V cell voltage at 1 A cm −2 with 350‐h stability. Post‐reaction characterizations confirm the transformation of Fe‐NiNH/NF into Fe‐NiOOH with adsorbed NO 3 ¯. Theoretical calculations reveal that NO 3 ¯ forms an exclusionary layer via strong polarity and steric hindrance, electrostatically repelling Cl¯, and NO 3 ¯ and Fe 3+ collectively downshift the Ni d‐band center, weakening Cl¯ adsorption while optimizing intermediate binding.