Toluene Adsoprtion on VSbO4(110): A study of an electronic Structure

B.L. IRIGOYEN ; A. JUAN; S. A. LARRONDO; N. E. AMADEO

BRAZILIAN JOURNAL OF CHEMICAL ENGINEERING

BRAZILIAN SOC CHEMICAL ENG

Lugar: Brasil; Año: 2003 vol. 20 p. 39 - 44

0104-6632

The objective of this work is to electronically analyze toluene adsorption reactions on VSbO4(110). Thus, perpendicular and parallel toluene interactions on the different active sites of the oxide surface (O, Sb and V ions) were studied. Adsorption energy was calculated using the ASED-MO theory, while the electronic analysis was performed with the YAEHMOP code. The electronic density of states (DOS) of the VSbO4 cluster, modeled with a trirutile-type tetragonal supercell, resembles that of 3D solids with a rutile structure. However, due to the presence of vanadium, small peaks appear above the Fermi level. The DOS of toluene has several peaks resulting from the interaction of the aromatic ring with the methyl fragment, which changes when the adsorbate interacts with oxide surface. The C-H bonds in the methyl fragments as well as the Cmethyl-Cphenyl bond weaken when some electronic density is removed. Also, hydrocarbon oxidation could weaken the pi system of the aromatic ring. For toluene perpendicular adsorption (on the Vsite) the calculations show a hybridization of those orbitals coming from the methyl fragment and an important broadening of some of the methyl and phenyl fragment orbitals. In addition, a study of the overlap population suggests that one of the H atoms of the methyl group can be abstracted with the participation of the Sb cation.