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Oxidation of CH4 over Pd supported on TiO2-doped SiO2: Effect of Ti(IV) loading and influence of SO2

par Venezia, A.M.;Di Carlo, G.;Pantaleo, G.;Liotta, L.F.;Melaet, Gérôme;Kruse, Norbert
Référence Applied catalysis. B, Environmental, 88, page (430)
Publication Publié, 2008-10-25

Article révisé par les pairs

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Résumé :

Titania-modified silicas with different weight% of TiO2 were prepared by sol–gel method and used as supports for Pd (1 wt%) catalysts. The obtained materials were tested in the oxidation of methane under lean conditions in absence and in presence of SO2. Test reactions were consecutively performed in order to evaluate the thermal stability and poisoning reversibility. Increasing amounts of TiO2 improved the catalytic activity, with an optimum of the performance for 10 wt% TiO2 loading. Moreover, the titaniacontaining catalysts exhibited a superior tolerance towards SO2 by either adding it to the reactants or feeding it as a pure pretreatment atmosphere at 350 8C. Catalysts were characterized by XPS, XRD, FT-IR and BET measurements. According to the structural and surface analyses, the mixed oxides contained Si–O–Ti linkages which were interpreted as being responsible for the enhanced intrinsic activity of supported PdO with respect to PdO on either pure SiO2 or pure TiO2. Moreover, the preferential interaction of the sulfur molecule with TiO2 and the easy SOx desorption from high surface area silica were the determining factors for the superior SO2 tolerance of the TiO2-doped catalysts.