Tuning the selectivity of NH3 oxidation via cooperative electronic interactions between platinum and copper sites

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.