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X-ray Absorption Fine Structure Combined with X-ray Fluorescence Spectrometry. Part 15. Monitoring of Vanadium Site Transformations on Titania and in Mesoporous Titania by Selective Detection of the Vanadium Kα1 Fluorescence

“…metavanadate) into dispersed tetrahedral monooxo vanadate was suggested. The V site transformation from higher symmetry to tetrahedral was supported by DFT calculations 23,24,44 and ab initio calculations of V K-edge XANES spectra. 7 Spectrum profiles of Figure 4a and 4c were more similar to data for surface V site models of 5-fold and 4-fold coordination, respectively, calculated by ab initio calculations of XANES.…”

“…The XANES was most similar to that for Mn 1-x V 2-2x Mo 2x O 6 (Figure 1g and Table 3, entry g) in which the V sites are 5-fold coordinated (Table 2). 33 The V-OH bond length is reported between 1.75 and 1.85 Å 23,44,47 versus V-O bond lengths for standard V compounds listed in Table 2. Therefore, dispersed vanadate species of 5-fold coordination are proposed for fresh, exposed V/TiO 2 transformed from monooxo V species (Figure 6, b f a).…”

Quantum Mechanical Studies of Large Metal, Metal Oxide, and Metal Chalcogenide Nanoparticles and Clusters

“…It should also be noted that TiO 2 has been studied as a supporting material for VO x . Mikheeva and co-workers reported that vanadium could be stabilized on the anatase surface (001) both in tetrahedral and in octahedral coordination with the formation of monoxo- and dioxovanadyl structures. They used LDA with the VWN exchange correlational functional.…”

“…Some of their results were compared to previous ionic pair potential models by Yu and Freas, 611 an ab initio HF/STO-4G* study by Hagfeldt et al, 612 and a small clusters (n < 4) study with the LSDA approach by Albaret et al 613 It should also be noted that TiO 2 has been studied as a supporting material for VO x . Mikheeva and co-workers 614 reported that vanadium could be stabilized on the anatase surface (001) both in tetrahedral and in octahedral coordination with the formation of monoxo-and dioxovanadyl structures. They used LDA with the VWN exchange correlational functional.…”