11 research outputs found
Mechanical treatment of TiO2 and ZrO2 oxide mixtures
The mixed ZrO2âTiO2 system (5â50 wt% of ZrO2) has been studied to investigate the influence
of the mechanical treatment on its physicochemical properties depending on the composition, time
of milling (5, 10 and 20 min, r.p.m. 82) and temperature (400, 550 and 700 C). Samples were
characterized by Raman spectroscopy, X-ray powder diffraction, Scanning Electron Microscopy coupled
with Energy Dispersion X-ray analyzer, High Resolution-Transmission Electron Microscopy and
nitrogen adsorption porosimetry. Results show that srilankite (TiZrO4) phase has been produced. No
influence of the milling time and temperature on the phase composition is observed. The presence
of zirconia increases the thermal stability of anatase phase up to 700 C hindering the anataseâ
rutile phase transformation
Nanoparticles of AlTiZr mixed oxides as support of hydrodesulfurizaton catalysts: Synthesis and characterisation
TiAlZr mixed oxides, synthesized using solâgel method, were characterized and used as supports
of hydrodesulfurization catalysts (12 wt% Mo) prepared by impregnation either with molybdenum
heteropolyacid H3PMo12O40 or its cobalt salt Co1.5PMo12O40. Structure, morphology and textural
properties of oxides and catalysts were characterized using X-ray powder diffraction (XRD), Raman spectroscopy,
Nitrogen adsorption porosimetry, TEM-EDS, temperature-programmed desorption (TPD) and
temperature-programmed reduction (TPR) techniques. Activity of the catalytic systems was tested in
thiophene hydrodesulfurization (HDS).
No formation of a new oxide phase was revealed in the synthesized mixed materials. However the effect
of separated oxides on the structure of ternary oxides was observed. Maximum in HDS activity of Mo
containing samples was determined by optimum content of alumina in the mixed oxides. Incorporation
of cobalt into the heteropolyacid increased the HDS activity about two times and masked the effect of
the support composition