The electronic structure of vanadium antimonate: A theoretical study
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. At lower energy (at -34 eV), there is a band formed by O 2s orbitals with some Sb 5s (bottom) and Sb 5p (top). The Sb...
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| Autores principales: | , , , |
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| Formato: | JOUR |
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_09205861_v107-108_n_p40_Irigoyen |
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| Sumario: | 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. At lower energy (at -34 eV), there is a band formed by O 2s orbitals with some Sb 5s (bottom) and Sb 5p (top). The Sb 5s orbitals appear in the -20 eV energy region, 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 in the rutile phase. The V 4s and V 4p orbitals can be found higher in energy. On the other hand, the analyses of the electronic populations of the VSbO 4 catalyst doped with titanium show that partial substitution of Sb by Ti provokes V-cations oxidation. This occurs mainly by depopulating V 3d antibonding states located around the Fermi level and results in VO bonds reinforcement. Those vanadium cations in a higher oxidation state improve the catalyst surface reoxidation step, suggesting that Sb partial substitution by Ti gives a more active catalyst. The effect of the Ti-doping on the reaction rate limiting step is also discussed. © 2005 Elsevier B.V. All rights reserved. |
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