SO_x uptake and release properties of TiO₂/Al₂O₃ and BaO/TiO₂/Al₂O₃ mixed oxide systems as NO_x storage materials

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• 作者：Gö ; ksu S. 艦entü ; rk^a ; Evgeny I. Vovk^a ; ^b ; Vladimir I. Zaikovskii^b ; Zafer Say^a ; Asl谋 M. Soylu^a ; Valerii I. Bukhtiyarov^b ; Emrah Ozensoy^a ; ^{ozensoy@fen.bilkent.edu.tr}
• 关键词：Al2O3 ; BaO ; TiO2 ; Anatase ; Sulfur poisoning ; DeNOx ; NOx ; SOx ; Sulfation ; NSR ; LNT ; HDS ; Claus Process
• 刊名：Catalysis Today
• 出版年：2012
• 期刊代码：13_09205861
• 类别：ce
• 出版时间：30 April, 2012
• 卷：184
• 期：1
• 页码：54-71
• 文件大小：1711 K

摘要

Titania was used as a promoter to obtain novel materials in the form of TiO₂/Al₂O₃ (Ti/Al) and BaO/TiO₂/Al₂O₃ (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 TiO₂ on 纬-Al₂O₃, 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: TiO₂(anatase) 鈮?#xA0;纬-Al₂O₃ < 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 TiO₂ promotion and/or the changes in the surface acidity. Promotion of BaO/Al₂O₃ with TiO₂ 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 鈭?#xA0;20Ba/Ti/Al(P1) < 20Ba/Al < 20Ba/Ti/Al(P2).