An investigation of the effect of pre-dosed O atoms on the adsorption of NO on Pt{211}

Reflection absorption infrared spectroscopy (RAIRS) and temperature programmed desorption (TPD) have been used to investigate the effect of pre-dosed O atoms on the adsorption of NO on Pt {211} at room temperature. RAIRS experiments show that no new species are formed when NO is adsorbed onto a Pt{2 11} surface that has been pre-dosed with oxygen and no species are lost from the spectra, compared to spectra recorded for NO adsorption on the clean Pt{211} surface. However pre-dosed oxygen atoms do influence the frequency and intensity of several of the observed infrared bands. In stark contrast, pre-dosed O has a large effect on the TPD spectra. In particular N-2 and N2O desorption, seen following NO adsorption on the clean Pt{211} surface, is completely inhibited. This effect has been assigned to the blocking of NO dissociation by the pre-adsorbed O atoms. A new NO desorption peak, not seen for NO adsorption on the clean Pt{211} surface, is also observed in TPD spectra recorded following NO adsorption on an oxygen pre-dosed Pt {211} surface. (C) 2003 Elsevier B.V. All rights reserved.