The electronic structure of vanadium antimonate. A theoretical study

BEATRIZ IRIGOYEN; ALFREDO JUAN; SUSANA LARRONDO; NORMA AMADEO

CATALYSIS TODAY

Elksevier

Lugar: Amsterdam; Año: 2005 vol. 107 p. 40 - 45

0920-5861

The electronic structure of VSbO4 exhibits similarities with that of other metal transition oxides with rutile-type structure, showing O 2s, O 2p, Sb and V bands well differentiated. Deeper in energy (at –34 eV), there is a band formed by O 2s orbitals with something of Sb 5s (bottom) and Sb 5p (top).  In the –20 eV energy region appear the Sb 5s orbitals, while around –14 eV there are O 2p states (metal-oxygen bonding) and also some Sb 5p orbitals contributions. At the Fermi level it can be observed the contribution of V 3d orbitals, which is in agreement with the metal character that vanadium gives to VO2 en the rutile phase. Higher in energy it can be found the V 4s and V 4p orbitals. On the other hand, the analysis of the electronic populations of the VSbO4 catalyst doped with titanium shows that partial substitution of Sb by Ti provokes V-cations oxidation. This mainly occurs by depopulation of V 3d antibonding states located around the Fermi level and results in the V-O bonds reinforcement. These findings suggest that Ti-doping of V-Sb oxides should give a more selective catalyst.