Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9594590 | Surface Science | 2005 | 20 Pages |
Abstract
The reactivity of low-coordinated anions of MgO towards CO has been studied by means of ab initio cluster model DFT calculations. Differently from MgO terraces, where the O2â anions are totally unreactive, oxide anions at step, edge and corner sites exhibit a very high basicity and reactivity towards CO. The reaction: [OLC(CO)nâ1]2â (s) + CO (g) â [OLC(CO)n]2â (s) leads to the formation of polymeric (CnOn+1)2â species, where n goes from 1 to 5. The reaction is non-activated and exothermic; only the formation of the tetramer appears to be nearly thermoneutral. The formation of the hexamer (n = 6) is thermodynamically unfavorable. For each value of n, several isomers have been considered. The vibrational properties of the [OLC(CO)n]2â surface complexes have been computed and used to interpret the low-temperature infrared spectra obtained in the group of Zecchina [G. Spoto, E.N. Gribov, G. Ricchiardi, A. Damin, D. Scarano, S. Bordiga, C. Lamberti, A. Zecchina, Prog. Surf. Sci. 76 (2004) 71].
Related Topics
Physical Sciences and Engineering
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Authors
Cristiana Di Valentin, Emanuele Finazzi, Gianfranco Pacchioni,