The role of co-adsorbed O 2 on the catalytic reduction of NO with 13C 2H 5OH on the surface of Pt(3 3 2)

Abstract

The influence of pre-dosed O 2 on the catalytic reduction of NO with 13C 2H 5OH on the surface of stepped Pt(3 3 2) was investigated using Fourier transform infra red reflection–absorption spectroscopy (FTIR-RAS) and thermal desorption spectroscopy (TDS). We show that the oxidation of 13C 2H 5OH with O 2 is a very effective reaction, occurring at 150 K and giving rise to acetate. The presence of NO does not lead to any evident oxidation of 13C 2H 5OH irrespective of the annealing temperature. For the case of O 2 + 13C 2H 5OH + NO co-adlayers, oxidation of 13C 2H 5OH also takes place at 150 K. However, no new surface species that are supposed to be an intermediate for the production of N 2 are detected. The influence of O 2 on the production and desorption of N 2 is intimately related to both O 2 and 13C 2H 5OH coverage. The presence of pre-dosed O 2 does not greatly promote N 2 desorption. In fact, N 2 desorption is suppressed quantitatively with increasing O 2 coverage, after which unreacted, or left-over O atoms appear and remain on steps. It is concluded that the presence of pre-dosed O 2 does not play a role of activating reactants in the catalytic reduction of NO with 13C 2H 5OH on the surface of Pt(3 3 2).