XPS and TPD study of NO interaction with Cu(111): Role of different oxygen species

The adsorption and reaction of NO on clean and O-precovered Cu(111) has been studied using X-ray photoelectron spectroscopy and temperature-programmed desorption spectroscopy. By varying NO exposure and annealing temperature, two different types of chemisorbed oxygen species, with O 1s binding energies (BE) of 531.0 (O-531) and 529.7 eV (O-529), were prepared on Cu(111). In the presence of O-531 species, the relative occupation of different NO adsorption states was largely affected, and most of the adsorbed NO(a) underwent dissociative desorption, releasing N2O and N-2 upon heating. In contrast, in the presence of O-529 species, the dissociative desorption of NO(a) was largely suppressed. Furthermore, the O-529 species show a more significant blocking effect on NO adsorption than the chemisorbed O-531 species. Our results reveal that the effect of precovered oxygen species on the adsorption and reaction of NO on Cu(111) is closely related to the type of oxygen species and oxygen coverage. (C) 2013, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.