High N2 selectivity of Pt-V-W/TiO2 oxidation catalyst for simultaneous control of NH3 and CO emissions.

[Display omitted] • Pt-V-W supported on TiO 2 catalysts were prepared by co-impregnation method. • Simultaneous oxidations of NH 3 and CO were characterized over Pt-V-W/TiO 2. • Pt-V-W/TiO 2 exhibited improved N 2 selectivity compared to Pt/TiO 2. • Pt-V interaction plays a role in active site of i-SCR and CO-SCR during oxidations. We report a superior N 2 selectivity in the catalytic emission control of NH 3 and CO over PtVW/TiO 2 catalysts synthesized by the co-impregnation method. The PtVW/TiO 2 selective oxidation catalyst (SCO) enabled the following surface reactions over bimetallic Pt-V sites: (1) selective catalytic reduction of internally generated NO x species by NH 3 (i -SCR) and (2) selective catalytic reduction of NO x by the CO (CO-SCR) present in the feed gas. The enhanced N 2 selectivity was characterized in terms of adsorbent behavior and catalyst surface properties as a function of the catalyst formulations. It was found that the strong interaction between the Pt and V metal species increased both the reducibility and the surface acidity of the catalyst, which could be a crucial factor in the enhancement of N 2 selectivity. Surface IR measurement and DFT calculations relates these enhanced catalytic properties to the removal of the generated NO x via reaction with stored imide, amide (–NH x) and isocyanate (–NCO) species on the catalyst surface. These stored species enhance the N 2 selectivity through the i -SCR and CO-SCR mechanisms. A dual-zoned bench-scale monolith reactor has been tested, with a commercial SCR (front) and the developed SCO (rear) in series. This dual-zoned system showed high N 2 selectivity and outstanding CO and NH 3 oxidation. [ABSTRACT FROM AUTHOR]