A DFT study of the chemisorption of methoxy on clean and low oxygen precovered Ru(0001) surfaces

• Tipo: Artigo em Revista Científica Internacional
• Data: 2007

Autores

Natalia N D S Cordeiro (Autor) FCUP; Ana S S Pinto (Autor) Outra; Jose A N F Gomes (Autor) FCUP

Revista

Título: Surface Science

Vol. 601

Páginas: 2473-2485

ISSN: 0039-6028

Editora: Elsevier

Indexação

ISI Web of Knowledge - 12 Citações

Scopus - 12 Citações

Classificação Científica

FOS: Ciências exactas e naturais > Química

Outras Informações

ID Authenticus: P-004-9CH

DOI: 10.1016/j.susc.2007.04.168

Abstract (EN): Adsorption, of the methoxy radical on clean and on low oxygen precovered Ru(0001) metallic surfaces has been studied by densityfunctional theory cluster calculations. Methoxy is predicted to be preferentially chemisorbed on both hollow sites (hep and fcc) of such surfaces, and adopts an upright orientation (C-3, local symmetry). Such prediction is supported by the good agreement found between the calculated vibrational frequencies and the experimentally observed RAIRS spectra. Regarding the charge transfer process between the adsorbate and the surface, our results suggest that the bonding is dominantly polar covalent which arises from a charge donation from the ruthenium surface to the radical, and the co-adsorbed electronegative oxygens deplete slightly the surface electron density. However, the major difference is not induced through much O-Ru bonding, but indirectly, by lowering the valence d-band center of the system. This results in a lower adsorption energy for methoxy than on the clean Ru(0001) surface, in accordance with experimental data. Further, accordingly to the present calculations, the radical is expected to dissociate or desorb more easily on the modified surface but with no participation from the co-adsorbed oxygen atoms.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 13