Low temperature catalytic NO oxidation over microporous materials

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• 作者：Jason A. Loil ; Raul F. Lobo
• 关键词：NO oxidation ; SSZ-13 ; NH3 SCR ; NO2 ; Chabazite ; Environmental catalysis
• 刊名：Journal of Catalysis
• 出版年：March, 2014
• 年：2014
• 卷：311
• 期：Complete
• 页码：412-423
• 全文大小：747 K

文摘

It is shown that NO oxidation is catalyzed by chabazite zeolites in the proton (H⁺), sodium (Na⁺) and siliceous forms, by microporous carbons and by the metal-organic framework (MOF) material Basolite A100庐 at temperatures between 298 K and 423 K. Reaction orders at low conversion for NO and O₂ are 2 and 1, as observed for the gas-phase reaction. At higher conversion and low temperatures, the rate decreases because of the presence of various N_xO_y species within the pores of the materials. Catalytic rates decrease with increasing temperature and yield negative apparent activation energies (鈭?4.9 to 鈭?7.5 kJ mol^鈭?). The catalytic properties of the samples are attributed to their ability to stabilize a [N₂O₄]^{鈥?/sup> transition state within the micropores through van der Waals forces. Na-SSZ-13 samples exhibit faster catalytic rates than siliceous chabazite due to the additional presence of electrostatic forces stabilizing the transition state. An enhancement of catalytic rates on H-SSZ-13 is also observed but is the result of more complex interactions due to the formation of NO+ and in the zeolite pores that can also stabilize the [N₂O₄]鈥?/sup>.}