Engineering Multifunctional Atomically Dispersed Polynuclear Ag–Co–Mn Sites on CeZrO x for Selective NO x Abatement with CO in O 2 -Rich Environments

Résumé fourni par la source

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 O 2 -rich conditions, overcoming the typical activity-selectivity trade-off of this reaction. This catalytic system achieves >95% NO conversion with 100% N 2 selectivity at 250–400 °C under 5 vol % O 2 . 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 N 2 O 2 intermediate. This simultaneously weakens O 2 adsorption, promoting the reduction of N 2 O 2 to N 2 O by CO and subsequent N 2 O dissociation to produce N 2 . 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.

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