SO x uptake and release properties of TiO 2/Al 2O 3 and BaO/TiO 2/Al 2O 3 mixed oxide systems as NO x storage materials
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Please cite this item using this persistent URLhttp://hdl.handle.net/11693/28221
Titania was used as a promoter to obtain novel materials in the form of TiO 2/Al 2O 3 (Ti/Al) and BaO/TiO 2/Al 2O 3 (Ba/Ti/Al, containing 8 wt% or 20 wt% BaO) that are relevant to NO x storage reduction (NSR) catalysis. Two different protocols (P1, P2) were utilized in the synthesis. Ti/Al(P1) manifests itself as crystallites of TiO 2 on γ-Al 2O 3, while Ti/Al(P2) reveals an amorphous Al xTi yO z mixed oxide. The structures of the synthesized materials were investigated via TEM, EDX, BET analysis and XPS while the catalytic functionality/performance of these support materials upon SO x and subsequent NO x adsorption were investigated with TPD and in situ FTIR spectroscopy. Ti/Al(P1, P2) revealed a high affinity towards SO x. Overall thermal stabilities of the adsorbed SO x species and the total SO x uptake of the Ba-free samples increase in the following order: TiO 2(anatase) ≪ γ-Al 2O 3 < Ti/Al(P1) < Ti/Al(P2). The superior SO x uptake of Ti/Al(P1, P2) support materials can be tentatively attributed to the increasing specific surface area upon TiO 2 promotion and/or the changes in the surface acidity. Promotion of BaO/Al 2O 3 with TiO 2 leads to the attenuation of the SO x uptake and a significant decrease in the thermal stability of the adsorbed SO x species. The relative SO x adsorption capacities of the investigated materials can be ranked as follows: 8Ba/Ti/Al(P1) < 8Ba/Ti/Al(P2) < 8Ba/Al ∼ 20Ba/Ti/Al(P1) < 20Ba/Al < 20Ba/Ti/Al(P2). © 2011 Elsevier B.V.
- Conference Paper 2294