Two V-SBA-15 and V-MCF materials (containing about 2.5 wt.% vanadium) were prepared by direct synthesis and tested as catalysts in the decomposition of the most stable chlorinated-alkane, dichloromethane (a total oxidation reaction) and in the oxidative dehydrogenation (ODH) of propane (a partial oxidation reaction). Comparison was made with: (i) two V-SBA-15 and V-MCF materials prepared by "traditional" impregnation method and (ii) a non-porous V-SiO 2 catalyst prepared by flame pyrolysis. All catalysts tested had a vanadium content of about 2.5 wt.%. Samples properties were investigated by means of complementary techniques (TEM, IR and DR UV-vis spectroscopies, N 2 sorption at -196°C) in order to find possible correlations between catalytic properties of the studied materials and their different physico-chemical features. It is shown that direct synthesis allows a better vanadium dispersion to be achieved, a feature that positively affects catalytic performances in both total and partial oxidations. The different porous networks of the SBA-15 and MCF supports also play an important role on catalytic activity: both V-SBA-15 samples gave better results in dichloromethane decomposition, whereas both V-MCF samples were more selective in propane ODH. The latter findings are ascribed to different molecules diffusion and residence time inside the channels of either SBA-15 or MCF networks.
Effect of vanadium dispersion and of support properties on the catalytic activity of V-containing silicas / M. Piumetti, B. Bonelli, P. Massiani, S. Dzwigaj, I. Rossetti, S. Casale, M. Armandi, C. Thomas, E. Garrone. - In: CATALYSIS TODAY. - ISSN 0920-5861. - 179:1(2012), pp. 140-148.
Effect of vanadium dispersion and of support properties on the catalytic activity of V-containing silicas
I. Rossetti;
2012
Abstract
Two V-SBA-15 and V-MCF materials (containing about 2.5 wt.% vanadium) were prepared by direct synthesis and tested as catalysts in the decomposition of the most stable chlorinated-alkane, dichloromethane (a total oxidation reaction) and in the oxidative dehydrogenation (ODH) of propane (a partial oxidation reaction). Comparison was made with: (i) two V-SBA-15 and V-MCF materials prepared by "traditional" impregnation method and (ii) a non-porous V-SiO 2 catalyst prepared by flame pyrolysis. All catalysts tested had a vanadium content of about 2.5 wt.%. Samples properties were investigated by means of complementary techniques (TEM, IR and DR UV-vis spectroscopies, N 2 sorption at -196°C) in order to find possible correlations between catalytic properties of the studied materials and their different physico-chemical features. It is shown that direct synthesis allows a better vanadium dispersion to be achieved, a feature that positively affects catalytic performances in both total and partial oxidations. The different porous networks of the SBA-15 and MCF supports also play an important role on catalytic activity: both V-SBA-15 samples gave better results in dichloromethane decomposition, whereas both V-MCF samples were more selective in propane ODH. The latter findings are ascribed to different molecules diffusion and residence time inside the channels of either SBA-15 or MCF networks.Pubblicazioni consigliate
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