Theoretical studies were made of the influence of Sb and V cation vacancies, in the electronic structure and reactivity of vanadium antimonate, using molecular orbital methods. From the analysis of the electronic properties of the VSbO4 crystal structure, it could be deduced that both Sb and V vacancies increased the oxidation state of closer V cations. This indicated that, in the rutile-type VSbO4 phase, the Sb and V cations defects stabilized the V in a higher oxidation state (V4+). Calculations of the adsorption energy for different toluene adsorption geometries on the VSbO4(110) surface have also been performed. The oxidation state of Sb, V and O atoms and the overlap population of metal–O bonds were evaluated. The results indicated that the cation defects influence on toluene adsorption reactions was slight. Various alternatives were computed for re-oxidation of the VSbO4(110) surface active sites which were reduced during oxygenated product formation. These calculations indicated that the V cations in a higher oxidation state (V4+) were the species which preferentially incorporated lattice O into the reduced Sb cations. Thus, the cation defects could stabilize the V4+ species in the VSbO4 structure; governing its ability to provide lattice O as a reactant.

Theoretical Study of the Influence of Cation Vacancies on the Catalytic Properties of Vanadium Antimonite. S.Messina, A.Juan, S.Larrondo, B.Irigoyen, N.Amadeo: Applied Surface Science, 2008, 254[18], 5837-43