Edge Sites with Unsaturated Coordination on Core–Shell Mn3O4@MnxCo3−xO4 Nanostructures for Electrocatalytic Water Oxidation

Transition-metal oxides are extensively investigated as efficient electrocatalysts for the oxygen evolution reaction (OER). However, large-scale applications remain challenging due to their moderate catalytic activity. Optimized regulation of surface states can lead to improvement of catalytic properties. Here, the design of Mn@Co_xMn_3−xO₄ nanoparticles with abundant edge sites via a simple seed-mediated growth strategy is described. The unsaturated coordination generated on the edge sites of Co_xMn_3−xO₄ shells makes a positive contribution to the surface-structure tailoring. Density functional theory calculations indicate that the edge sites with unsaturated coordination exhibit intense affinity for OH⁻ in the alkaline electrolyte, which greatly enhances the electrochemical OER performance of the catalysts. The resulting Mn@Co_xMn_3−xO₄ catalysts yield a current density of 10 mA cm⁻² at an overpotential of 246 mV and a relatively low Tafel slope of 46 mV dec⁻¹. The successful synthesis of these metal oxides nanoparticles with edge sites may pave a new path for rationally fabricating efficient OER catalysts.

Mn@Co_xMn_3−xO₄ nanoparticles with abundant edge sites are designed and synthesized via a simple seed-mediated growth strategy. The edge sites with unsaturated coordination exhibit intense affinity for OH⁻ in the alkaline electrolyte, which greatly enhances the electrochemical oxygen evolution reaction performance.

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