Search results for " Sol–gel"
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Nanoparticles of AlTiZr mixed oxides as support of hydrodesulfurizaton catalysts: Synthesis and characterisation
2012
Abstract TiAlZr mixed oxides, synthesized using sol–gel 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…
centers induced by γ irradiation in sol–gel synthesized oxygen deficient amorphous silicon dioxide
2007
The effects of room temperature γ-ray irradiation up to a dose of ∼1300 kGy are investigated by Electron paramagnetic resonance (EPR) measurements in amorphous silicon dioxide (a-SiO2) produced by a sol-gel synthesis method that introduces O{triple bond, long}Si{single bond}Si{triple bond, long}O oxygen deficiency. We have found that exposure to radiation generates the Eγ′ center with the same spectral features found in high purity commercial a-SiO2. The maximum concentration of defects induced in this sol-gel material indicates that its resistance to radiation is comparable to that of synthetic fused a-SiO2. The concentration of Eγ′ center increases with irradiation, featuring a sublinear …