On the X-ray induced chemical reduction of CeO2 as seen with X-ray photoemission spectroscopy

A recent X-ray photoemission spectroscopy (XPS) study (M.V. Rama Rao and T. Shripathi, J. Electron Spectrosc. Relat. Phenom., 87 (1997) 121) on X-ray irradiated ceria stated that hydroxyl groups play a meaningful role in enhancing the chemical reduction of this oxide and that chemical damage mainly involves layers lying at depths that are larger than photoelectron attenuation lengths. We comment upon this paper, and show that the experimental evidence therein presented by the authors does not warrant these conclusions. © 1998 Elsevier Science B.V. All rights reserved.