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. T his method allows one to simultaneously follow the surface species and the gas phase composition evolutions at atmospheric pressure and high temperatu re (498 K in this case) with a time resolution of about 1 s, When CO is pul sed in a NO continuous flow on the Pt/SiO2 catalyst, the NO reduction occur s mainly at the end of the pulse, The N-2 selectivity of the reduction incr eases with the CO amount in the pulse. We show that these results correspon d to a NO dissociation mechanism: CO reduces the platinum surface; NO adsor bs 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 increase s with the availability of dissociation sites. (C) 2001 Academic Press.