Enhanced oxygen evolution reaction activity and stability through Fe and Cr Co-incorporation in cobalt hydroxide

Efficient and durable electrocatalysts are essential for advancing sustainable energy conversion, particularly for the oxygen evolution reaction (OER) in water splitting. However, overcoming the complex, multi-electron OER mechanism remains a significant challenge, with the formation of high-oxidation-state metal–OOH (M–OOH) intermediates acting as the rate-limiting step. Here, we present a high-performance CoFeCr (oxy)hydroxide electrocatalyst, synthesized by strategically incorporating Fe and Cr into a Co matrix. The co-incorporation of Fe and Cr transforms flake-like Co hydroxide into uniform nanospheres, significantly enhancing OER activity through the formation of abundant oxyhydroxide species. This catalyst exhibits exceptional OER performance, with a low overpotential of 203 mV at 10 mA cm⁻² and a Tafel slope of 42.03 mV dec⁻¹ in 1 M KOH. Furthermore, it maintains excellent stability over 100 h of continuous operation at 100 mA cm⁻² in 1 M KOH. The superior performance is attributed to the synergistic effects of Fe, which accelerates OOH intermediate formation, and Cr, which improves electrical conductivity and stabilizes active sites by forming high-valence Cr⁶⁺ species. The CoFeCr (oxy)hydroxide electrocatalyst significantly outperforms state-of-the-art NiFe-based counterparts, establishing itself as a robust and efficient electrocatalyst for large-scale water splitting.