Mechanistic Insights into Ammonia Oxidation over Electron Transfer-Induced Pt–O–Cu Dual Sites

The low selectivity for N 2 in the oxidation of NH 3 over commercial Pt/Al 2 O 3 catalysts is primarily due to the overoxidation of NH 3 facilitated by Pt sites, leading to the formation of unwanted byproducts such as N 2 O and NO. In this study, we present a novel strategy to enhance N 2 selectivity while maintaining NH 3 conversion by constructing Pt–O–Cu dual sites. These dual sites exhibit synergistic acid-redox characteristics through surface electron transfer mediated by bridged lattice oxygen. Additionally, the ability of surface-adsorbed oxygen to exchange with lattice oxygen is significantly improved. The electron-deficient Cu sites enhance NH 3 adsorption by providing empty 3d orbitals, while the electron-rich Pt sites promote NH 3 dehydrogenation. Subsequently, the formation of –NH or –N intermediates at the Pt sites can react with adsorbed NH 3 on the Cu sites to produce N 2, predominantly following the integrated selective catalytic reduction mechanism. The optimized dual-site catalyst achieves over 95% NH 3 conversion and N 2 selectivity at 180 °C.