An X-ray photoelectron spectroscopy study of oxides of arsenic supported on TiO2

XPS binding energies for the 3d levels of As5+ and As3+ have been determined to be 46.0 ± 0.17 eV and 44.6 ± 0.13 eV respectively, for oxides of arsenic being adsorbed on titania. When As2O3 is deposited on titania from the vapour phase it is oxidized to form As5+ species, probably orthoarsenate (V) species which replace OH groups on the titania surface. An X-ray induced reduction of these pentavalent As surface species during XPS data acquisition was observed.