Abstract
Selective catalytic oxidation (SCO) of NH(3) to N(2) is one of the most effective methods used to eliminate NH(3) emissions. However, achieving high conversion over a wide operating temperature range while avoiding over-oxidation to NO(x) remains a significant challenge. Here, we report a bi-metallic surficial catalyst (Pt(S)CuO/Al(2)O(3)) with improved Pt atom efficiency that overcomes the limitations of current catalysts. It achieves full NH(3) conversion at 250 °C with a weight hourly space velocity of 600 ml NH(3)·h(-1)·g(-1), which is 50 °C lower than commercial Pt/Al(2)O(3), and maintains high N(2) selectivity through a wide temperature window. Operando XAFS studies reveal that the surface Pt atoms in Pt(S)CuO/Al(2)O(3) enhance the redox properties of the Cu species, thus accelerating the Cu(2+) reduction rate and improving the rate of the NH(3)-SCO reaction. Moreover, a synergistic effect between Pt and Cu sites in Pt(S)CuO/Al(2)O(3) contributes to the high selectivity by facilitating internal selective catalytic reduction.