Engineering Multifunctional Atomically Dispersed Polynuclear Ag–Co–Mn Sites on CeZrO_xfor Selective NO_xAbatement with CO in O₂-Rich Environments

We report the synthesis of atomically dispersed polynuclear Ag–Co–Mn sites supported on CeZrO_x for the selective catalytic reduction of NO_x 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 NO_x reduction and offers a strategic approach to designing efficient catalysts for complex reactions.