Structure and Morphology of Silver Nanoparticles on the (111) Surface of Cerium Oxide

• Published in: Journal of physical chemistry. C 2015-03, Vol.119 (11), p.6024-6032
• Main Authors: Benedetti, Francesco, Luches, Paola, Spadaro, Maria Chiara, Gasperi, Gabriele, D’Addato, Sergio, Valeri, Sergio, Boscherini, Federico
• Format: Article
• Language: English
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp5120527

The structure of Ag nanoparticles of different size, supported on the cerium oxide (111) surface, was investigated by X-ray absorption fine structure at the Ag K-edge. The results of the data analysis in the near and extended energy range are interpreted with the help of the results obtained by X-ray photoelectron spectroscopy and scanning tunneling microscopy measurements and allow to obtain a detailed atomic scale description of the model system investigated. The Ag nanoparticles have an average size of a few tens of angstroms, which increases with increasing deposited Ag amount. The nanoparticles show a slight tendency to nucleate at the step edges between different cerium oxide layers and they have a face centered cubic structure with an Ag–Ag interatomic distance contracted by 3–4% with respect to the bulk value. The interatomic distance contraction is mainly ascribed to dimensionality induced effects, while epitaxial effects have a minor role. The presence of Ag–O bonds at the interface between the nanoparticles and the supporting oxide is also detected. The Ag–O interatomic distance decreases with decreasing nanoparticle size.