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

Abstract

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.