X-ray photoelectron spectroscopy study of electrodeposited nanostructured CeO2 films

Nanostructured CeO2 films are produced by anodic electrodeposition onto a variety of substrates. The crystal structure and oxidation state of the films are studied by x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS), respectively. Calculations from XRD show that crystallite sizes of the electrodeposited films range from 6–10 nm. Sintering of these films to 700 °C increases the grain size to approximately 25 nm. A study of Ce 3d, Ce 4d, O 1s, and the valence-band region indicates that the Ce(IV)/Ce(III) ratio increases with sintering temperature, with features of both Ce4+ and Ce3+ identified by XPS. Ce 3d and O 1s characteristics show that high-temperature sintering of the films facilitates Ce(IV) oxide formation.