Chemisorption of CO at strongly basic sites of MgO solid: A theoretical study

Citation
X. Lu et al., Chemisorption of CO at strongly basic sites of MgO solid: A theoretical study, J PHYS CH B, 104(43), 2000, pp. 10024-10031
Citations number
43
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
JOURNAL OF PHYSICAL CHEMISTRY B
ISSN journal
15206106 → ACNP
Volume
104
Issue
43
Year of publication
2000
Pages
10024 - 10031
Database
ISI
SICI code
1520-6106(20001102)104:43<10024:COCASB>2.0.ZU;2-6
Abstract
The hybrid B3LYP density functional method together with cluster models hav e been used to explore the adsorption and adsorption-induced dimerization a nd trimerization of CO over the low-coordinated oxygen anions of MgO solid. The calculations reveal the following: (i) monomeric, dimeric, and trimeri c adsorptions on the low-coordinated anions lead to the formation of anioni c surface species CmOm+12- (m = 1-3); (ii) dioxoketene ion C2O32- Which has a strong C=C bond can be formed at O-3C site, whereas at O-4C site the for mation of tripler trans-C2O32- adspecies is thermodynamically favorable ove r the formation of singlet C2O32- adspecies which has a weak C-C bond; (iii ) The C3O42- surface species does have a ketenic group, i.e., O=C=C <, and shows substantial stability. The calculated energetics suggests that the di meric adspecies are unlikely to be stable adspecies, but may be the interme diates for the formation of higher oligomeric adspecies of CO. The calculat ed IR frequencies of CmOm+12- (m = 1-3) surface complexes have been compare d with the experimental IR spectra.