Unraveling the Promotion Effects of Dynamically Constructed CuO_<i>x</i>‑OH Interfacial Sites in the Selective Catalytic Oxidation of Ammonia

The selective catalytic oxidation of ammonia (NH₃-SCO) into N₂ and H₂O is a recognized effective protocol to eliminate excessive NH₃ emission. Nevertheless, it is a great challenge for NH₃-SCO catalysts to balance the NH₃ oxidation activity with N₂ selectivity. Herein, promotion effects of the dynamically constructed CuO_<i>x</i>-OH interfacial sites for NH₃ oxidation activity without the scarification of N₂ selectivity were unraveled. The enrichment of coordination unsaturated Cu sites and Cu-OH acid sites in CuO_<i>x</i>-OH interfacial sites optimized the adsorption and activation for NH₃ and O₂, leading to the over 9-fold increase in NH₃ oxidation rate and the 40 kJ/mol decrease in apparent activation energy compared with the conventional CuO sites. Unexpectedly, the fast internal-selective catalytic reduction (i-SCR) mechanism was identified on CuO_<i>x</i>-OH interfacial sites, which is characterized by the presence of consumable NO₂ adsorbed species. This work paves an innovative way for the development of effective NH₃-SCO catalysts and contributes to the deeper understanding of the reaction mechanism.