A study of the adsorption of oxygen on silver at high pressure by electron spectroscopy

In situ X-ray photoelectron spectroscopic observation of a silver foil at 473 K exposed to oxygen at pressures up to 0.5 torr has identified three species, characterised by oxygen 1s binding energies of 528.3, 530.3 and 532.5 eV. The first two are identified as due to atomic oxygen, respectively chemisorbed at the surface and incorporated into the bulk. The third species is tentatively assigned to molecular oxygen, probably as a surface peroxidic group; both the UV photoelectron spectra and the O(1s) intensities determined at two different electron take-off angles are consistent with this interpretation.