Formation Of Ni Particles Research Articles

Hydrogenation of toluene over nickel nanoparticles supported on SBA-3 and AlSBA-3 materials

Pure siliceous and aluminosilicate mesoporous molecular sieves of SBA-3 type were used as supports for nickel catalysts obtained via wet impregnation (1 wt.%). Characterization of obtained materials was performed by means of X-ray diffraction (XRD), X-ray fluorescence (XRF), low-temperature nitrogen adsorption/desorption (BET), temperature-programmed desorption of ammonia (TPD-NH3), hydrogen chemisorption measurements and temperature-programmed reduction with hydrogen (TPR-H2). The effect of nickel precursor (nickel nitrate or nickel acetate) and chemical composition of support (SBA-3 and AlSBA-3) on catalytic activity of prepared materials in toluene hydrogenation was studied. It was found that the catalysts obtained using nickel nitrate showed better preserved mesoporous structure with higher dispersion of Ni particles than catalysts obtained from nickel acetate. The use of AlSBA-3 as a support causes the formation of Ni particles with lower dispersion in comparison to the catalysts supported on SBA-3. The activity of nickel catalysts supported on the AlSBA-3 (especially the catalyst obtained using nickel nitrate) for toluene hydrogenation was higher than that of the catalyst supported on SBA-3 despite the lower Ni dispersion. The obtained results bring to conclusion that catalytic activity for toluene hydrogenation is significantly influenced by textural and chemical properties of the support.