10.1021/cm702010k.s001
M.A. Cortes-Jácome
M.A.
Cortes-Jácome
M. Morales
M.
Morales
C. Angeles Chavez
C. Angeles
Chavez
L.F. Ramírez-Verduzco
L.F.
Ramírez-Verduzco
E. López-Salinas
E.
López-Salinas
J.A. Toledo-Antonio
J.A.
Toledo-Antonio
WO<sub><i>x</i></sub>/TiO<sub>2</sub> Catalysts via Titania Nanotubes for the Oxidation of Dibenzothiophene
American Chemical Society
2007
XPS
6.9
HRTEM
surface density concentration
DBT oxidation
XRD
NH
anatase TiO 2.
transmission electron microscopy
nanotube
spectroscopy
TiO 2 oversaturated
nm
tungsten nanoparticles
W surface density
2007-12-25 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/WO_sub_i_x_i_sub_TiO_sub_2_sub_Catalysts_via_Titania_Nanotubes_for_the_Oxidation_of_Dibenzothiophene/2966728
WO<sub><i>x</i></sub>/TiO<sub>2</sub> catalysts were synthesized by impregnating aqueous (NH<sub>4</sub>)<sub>2</sub>WO<sub>4</sub> on hydrous titania nanotubes. The materials were annealed in air at 500 °C and characterized by X-ray diffraction (XRD), Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), and X-ray photoelectron spectroscopy (XPS); their catalytic activity was evaluated in the oxidation reaction of dibenzothiophene (DBT). After annealing at 500 °C, the structure of the support transformed from orthorhombic, with nanotubular morphology, to tetragonal, yielding anatase nanoparticles decorated by tungsten nanoparticles on its surface. During this transformation, the nanotubes released residual Na<sup>+</sup> ions from the interlayer space, which reacted with tungstate species to change the W coordination from octahedral to tetrahedral, yielding ≤1 nm Na<sub><i>x</i></sub>(WO<sub>4</sub>) nanoparticles on the surface of anatase TiO<sub>2</sub>. These nanoparticles were highly active for the DBT oxidation, showing a linear dependence on the W surface density at concentrations below 6.9 W/nm<sup>2</sup>. In TiO<sub>2</sub> oversaturated with tungsten nanoparticles, the intrinsic kinetic velocity (<i>r<sub>DBT</sub></i>) of the DBT oxidation reached its maximum value; 6.9 W /nm<sup>2</sup> is then the optimum surface density concentration to attain a high catalytic activity in the DBT oxidation.