Regulating Co–O covalency to manipulate mechanistic transformation for enhancing activity/durability in acidic water oxidation

Abstract

Developing earth-abundant electrocatalysts with high activity and durability for acidic oxygen evolution reaction is essential for H₂ production, yet it remains greatly challenging. Here, guided by theoretical calculations, the challenge of overcoming the balance between catalytic activity and dynamic durability for acidic OER in Co₃O₄ was effectively addressed via the preferential substitution of Ru for the Co²⁺ (T_d) site of Co₃O₄. In situ characterization and DFT calculations show that the enhanced Co–O covalency after the introduction of Ru SAs facilitates the generation of OH* species and mitigates the unstable structure transformation via direct O–O coupling. The designed Ru SAs-CoO_x catalyst (5.16 wt% Ru) exhibits enhanced OER activity (188 mV overpotential at 10 mA cm⁻²) and durability, outperforming most reported Co₃O₄-based and Ru-based electrocatalysts in acidic media.