Boosting the Oxygen Evolution Reaction Performance of Inert ZnO by Incorporating Ni and Trace-Level Ir for Scalable and Industrial-Level Water-Splitting Catalysts

Abstract

Developing efficient and durable electrocatalysts for hydrogen production from water splitting via the oxygen evolution reaction (OER) is a significant challenge. To address this issue, we designed a Ni and trace amount of Ir incorporated ZnO heteroelectrocatalyst on nickel foam (Ir/Ni–ZnO@NF) using a facile and scalable dip-coating method without any binder. The incorporation of Ir and Ni into the ZnO host material enables the formation of an even thin film without surface cracking, facilitates residual stress relaxation, and significantly enhances OER activity. Our systematic study revealed that increased Ir incorporation in the Ir/Ni–ZnO enhances the Ni³⁺ content, leading to improved OER performance. The optimized Ir/Ni–ZnO exhibited excellent OER catalytic performance with an overpotential of 294.4 mV at 100 mA cm^–2 and a Tafel slope of 66.89 mV dec^–1. Additionally, we investigated the optimized Ir/Ni–ZnO@NF as the anode electrode of a practical anion exchange membrane water electrolyzer (AEMWE). The enlarged Ir/Ni–ZnO@NF anode electrode (3 cm × 3 cm) exhibited a cell voltage of 1.975 V at a current density of 8 A cm^–2 and stable operation over 17 h in the AEMWE system. These findings confirm the development of high-performing and durable heterocatalysts, and their promising scalable and practical application for hydrogen production by water-splitting.