Unraveling the Promotion Effects of Dynamically Constructed CuO<sub><i>x</i></sub>-OH Interfacial Sites in the Selective Catalytic Oxidation of Ammonia
Tianwei Lan, Jiang Deng, Xiaoyu Zhang, Fuli Wang, Xiangyu Liu, Danhong Cheng, Dengsong Zhang
Abstract
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 CuOx-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 CuOx-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 CuOx-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.