An electrochemically engineered layer of γ-NiOOH with FeOOH on nickel foam for durable OER catalysis for anion exchange membrane water electrolysis

• Published in: RSC sustainability 2025
• Main Authors: Narayanaru, Sreekanth, Kuroki, Hidenori, Tamaki, Takanori, Anilkumar, Gopinathan M., Yamaguchi, Takeo
• Format: Article
• Language: English
• ISSN: 2753-8125; 2753-8125
• DOI: 10.1039/D4SU00538D

An efficient and durable oxygen evolution reaction catalyst is essential for the advancement of anion exchange membrane water electrolyzers. Here we report a simple, rapid, and cost-effective two-step electrochemical synthesis of an efficient and durable oxygen evolution reaction catalyst, which can be produced on an industrial scale. In the first step of catalyst preparation, a ≈250 nm thick γ-NiOOH layer was electrochemically developed over nickel foam. Then iron was electrochemically deposited on γ-NiOOH to stabilize the NiOOH species and improve the OER activity. Various material characterization techniques confirmed the presence of a highly OER-active combination of γ-NiOOH and FeOOH at the catalyst surface. The synergism between high valent Ni 3.6+ in γ-NiOOH and Fe 3+ in FeOOH helps the catalyst to attain 10 mA cm −2 at 1.47 V with a very low Tafel slope value of 34 mV per decade. The catalyst attained 1 A cm −2 at 1.65 V in 1 M KOH at 80 °C under real electrolyzer operational conditions. Furthermore, the catalyst exhibits stable OER activity at high current densities under real electrolyzer testing conditions.