In Situ FTIR Study of the NO+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 N2 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 N2 and N2O. The NO dissociation itself is a fast step and the N2 selectivity increases with the availability of dissociation sites.