In situ FTIR studies of the selective catalytic reduction of NO by C3H6 over Pt/Al2O3

The selective catalytic reduction (SCR) of nitric oxide (NO) by propylene (C3H6) over a 0.8 Wt% Pt/Al2O3 catalyst was studied by the use of in situ Fourier transform infrared (FTIR) spectroscopy. Spectra of both the Pt/Al2O3 catalyst as well as the bare Al2O3 support were collected during the course of this study. NO adsorption resulted in the formation of nitrate species associated with the Al2O3 support, as well as surface NO species associated with Pt. Similarly, C3H6 adsorption resulted in the formation of carboxylate species associated with Al2O3, as well as surface CO associated with Pt. Finally, experiments conducted with the reactive NO-C3H6-O-2 mixture resulted in the formation of surface cyanide (-CN) and isocyanate (-NCO) species. The origin and reactivity of these species is discussed in view of their potential involvement as intermediates in the hydrocarbon-SCR reaction. (C) 1999 Academic Press.