Photoelectron spectroscopic study of X-ray induced reduction of CeO2

XPS technique is used to study the modification induced in CeO2 on exposure to Al K-alpha X-rays. A study of Ce (3d) and O (Is) spectra of sintered and unsintered pellets of ceria with X-ray exposure time is carried out to investigate the effect of hydroxyl species on X-ray induced reduction of CeO2. After prolonged exposure to X-rays, a colour change is observed on the sample surface of the unsintered pellet. Results show that the reduction of ceria to sub-stoichiometric oxides occurs at a faster rate in the unsintered pellet on X-ray irradiation. (C) 1997 Elsevier Science B.V.