Ag nanoparticles activating lattice oxygen in reconstructed N-modified Co catalysts for efficient oxygen evolution...

The deliberate fabrication of high-activity oxygen evolution reaction (OER) catalysts is of critical importance for efficient hydrogen production through electrocatalytic water splitting. However, the enhancement of activity in transition metal-based catalysts is limited by scaling relations governing the adsorption energies of reaction intermediates. Herein, we develop a strategy involving the introduction of metal nanoparticles to increase the covalency of metal‑oxygen bonds during catalyst reconstruction, thereby activating lattice oxygen. We synthesized silver nanoparticle-decorated nitrogen-modified cobalt nanosheet arrays (Ag/N-Co) as an electrocatalyst and demonstrate that the incorporation of Ag promotes charge redistribution in N-Co and enhances the covalent hybridization of Co-O bonds during OER. This effect facilitates a transition from the adsorbate evolution mechanism (AEM) to the lattice oxygen-mediated mechanism (LOM) in N-CoOOH (derived from N-Co), while lowering the energy barriers associated with the formation of oxygenated intermediates. Attributed to the Ag-induced activation of lattice oxygen, the Ag/N-Co catalyst displays excellent OER performance in alkaline electrolyte, requiring an overpotential of merely 162 mV to achieve 10 mA cm^-2 along with remarkable stability for 200 h of continuous operation.