Developing Cu-Co-Based Catalysts for Enhanced OER in Alkaline Water Electrolysis

Abstract

Copper, Cobalt-based (CuCo-based) catalysts are promising candidates for the anodes of alkaline water electrolyzers due to their high electrical conductivity, variable chemical state, and the potential for cost-effective large-scale production. However, the effective chemical composition and structure of these catalysts are still being explored. In this work, the focus is on the proposal CuCo-based catalysts for the oxygen evolution reaction (OER) in alkaline water electrolysis, with significant advantages for their use in anion exchange membrane (AEM) electrolyzer systems. CuCo-based catalysts with varying Cu:Co ratios were synthesized using a co-precipitation method and heat treatment, resulting in spinel type (oxides), CuCo-O, or brucite type structures (hydroxides), CuCo-OH. The catalysts were characterized using XRD, SEM, EDX, TEM and ICP-OES to confirm their morphology and composition. The OER catalytic performance of the catalysts was evaluated using rotating disk electrode (RDE) measurements with a 3-electrode system and 1 M KOH as the electrolyte.Our results show that CuCo-OH provides lower overpotentials than CuCo-O at a current density of 10 mA/cm2. Nevertheless, CuCo-O exhibits a more consistent performance than CuCo-OH, indicating its superior properties in terms of reproducibility and reliability. Additionally, we propose a promising Cu:Co mol ratio of CuCo-OH and CuCo-O. These findings highlight the importance of the chemical composition and provides insight into the structure design of OER catalysts for alkaline water electrolysis. The results suggest a synergistic effect of Cu and Co in the catalyst composition, which could be further explored in future research.