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Title: CH{sub 3} and CH{sub 2} oxidation reactions on MoO{sub 3}(100): Analysis of the electronic structure

Journal Article · · Journal of Catalysis

The oxidation reactions of CH{sub 3} and CH{sub 2} fragments on MoO{sub 3}(100) were studied following the changes in the electronic structure and the bonding character of the bonds between the adsorbed fragments and the MoO{sub 3} surface atoms. The adsorption energy for these fragments was computed using a methodology based on the atomic superposition and electron delocalization molecular orbital theory. The electronic structure was analyzed by the local density of states concept. A detailed picture of the bonding between fragments and the surface is given by examining the overlap population. In the homolytic mechanism each C-H bond breakage occurs before the corresponding hydrocarbon fragment reaches the energy barrier and the O-H is formed after surmounting this barrier. A strong C-O chemical bond is established as a consequence of the last H abstraction. On the other hand, in the heterolytic mechanism the C-H breaking is accompanied by a temporarily weakening of a second C-H bond and the formation of an increasingly strong C-Mo bond. In the last H abstraction of methane decomposition the C-H bond is broken only in the final step. while on the layer of MoO{sub 3} exposing mainly O atoms, the interactions between the CH{sub 3} or the CH{sub 2} fragment and the surface O atom are negligible; on the layer of MoO{sub 3} exposing Mo atoms, the molecular orbitals of these fragments show an important hybridization due to the significant C-Mo chemical interaction.

Research Organization:
Univ. Nacional del Sur, Bahia Blanca (AR)
OSTI ID:
20017450
Journal Information:
Journal of Catalysis, Vol. 190, Issue 1; Other Information: PBD: 15 Feb 2000; ISSN 0021-9517
Country of Publication:
United States
Language:
English