Adsorption and Reaction of Acetone over CeO x (111) Thin Films

• Published in: Journal of physical chemistry. C 2009-04, Vol.113 (15), p.6208-6214
• Main Authors: Senanayake, S. D, Gordon, W. O, Overbury, S. H, Mullins, D. R
• Format: Article
• Language: English
• Subjects: C: Surfaces, Interfaces, Catalysis
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp810403d

This study reports the interaction of acetone (CH3COCH3), the simplest ketone, with well ordered CeO2(111) thin film surfaces. The fully oxidized CeO2(111) surface shows a weak interaction with acetone with the sole desorption product (TPD) being acetone at 210 K. The chemisorbed molecule binds to the surface as the η1-acetone species rather than through a bridge-bonded dioxy-configuration. Exposure of a CeO2(111) surface to acetone at 600K removes oxygen as CO and results in the conversion of Ce4+ to Ce3+. Acetone chemisorbs strongly on reduced CeO2−x (111) with molecular acetone desorbing near 500 K. Decomposition also occurs with H2 desorbing between 450 and 600 K and C reacting with O in the ceria to desorb above 650 K. A stable species exists from 200 to 500 K on the reduced surface that has three unique types of C. High resolution C 1s XPS spectra indicate these are Ce−CH2, C−CH3 and C−O species. C k-edge NEXAFS indicates the presence of CC and CO bonds. It is postulated that the intermediate is a carbanion bonded through both O and C atoms to Ce cations.