Engineering Multifunctional Atomically Dispersed Polynuclear Ag–Co–Mn Sites on CeZrOx for Selective NOx Abatement with CO in O2-Rich Environments

We report the synthesis of atomically dispersed polynuclear Ag–Co–Mn sites supported on CeZrOx for the selective catalytic reduction of NOx by CO (CO-SCR) under O2-rich conditions, overcoming the typical activity-selectivity trade-off of this reaction. This catalytic system achieves >95% NO conversion with 100% N2 selectivity at 250–400 °C under 5 vol % O2. Mechanistic studies reveal that Mn serves as an “electron relay” that facilitates electron flow from Ag to Mn to Co, generating electron-rich Co sites and electron-deficient Ag sites. This charge redistribution effectively enhances the coadsorption of two NO molecules on adjacent Co and Ag sites, where electron transfer from Co and Mn to NO activates the adsorbed NO molecules to form a N2O2 intermediate. This simultaneously weakens O2 adsorption, promoting the reduction of N2O2 to N2O by CO and subsequent N2O dissociation to produce N2. This work demonstrates the synergistic role of multinuclear centers in NOx reduction and offers a strategic approach to designing efficient catalysts for complex reactions.