In situ FTIR study of the NO plus CO reaction on a silica-supported platinum catalyst at atmospheric pressure using a new pulse technique

The CO+NO on the Pt/SiO2 reaction is studied using a new pulse technique. This method allows one to simultaneously follow the surface species and the gas phase composition evolutions at atmospheric pressure and high temperature (498 K in this case) with a time resolution of about 1 s, When CO is pulsed in a NO continuous flow on the Pt/SiO2 catalyst, the NO reduction occurs mainly at the end of the pulse, The N-2 selectivity of the reduction increases with the CO amount in the pulse. We show that these results correspond to a NO dissociation mechanism: CO reduces the platinum surface; NO adsorbs and dissociates on reduced Pt sites with recombination into N-2 and N2O, The NO dissociation itself is a fast step and the N-2 selectivity increases with the availability of dissociation sites. (C) 2001 Academic Press.