Work-Function-Modulated Ag Single-Atom Catalysts for Amino Alcohol Oxidation

We report Ag single-atom catalysts for amino alcohol oxidation into amino acids. Using a surface defect trapping strategy, we fabricate a series of Ag₁/MO_x catalysts (M = Ce, Fe, Ti, Zn, Nb) featuring atomic dispersion and tunable electronic states of Ag. Oxygen vacancies on coordinatively unsaturated MO_x act as high-affinity trapping sites to anchor isolated Ag atoms. The electron density of Ag₁ is regulated by the work function of the reducible oxide: low-work-function supports induce stronger electron transfer to Ag, generating electron-enriched Ag^δ+ species (0 < δ < 1), while high-work-function supports suppress charge transfer and stabilize more electron-deficient Ag sites. Together with adjacent oxygen vacancies, these tunable Ag^δ+ sites enable O₂ activation and subsequent amino alcohol oxidation, delivering an initial rate of 0.81 mol h^-1 g_metal ^-1 and 95.1% glycine selectivity in monoethanolamine oxidation. This work establishes a work-function-modulated strategy for designing Ag-based single-atom oxidation catalysts, demonstrating that amino alcohol oxidation can be efficiently achieved beyond the conventional reliance on Au-based systems.