Role of active oxygen and NO_x species in N₂O decomposition over Fe-ferrierite

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• 作者：Zden臎k Sobalí ; k^a ; Edyta Tabor^a ; ^{edyta.tabor@jh-inst.cas.cz} ; Jana Nová ; ková ; ^a ; Naveen K. Sathu^a ; Karel Zá ; v臎ta^b
• 关键词：N2O decomposition ; Iron ferrierite ; Active oxygen ; Mö ; ssbauer spectroscopy ; Fe&ndash ; NOx species
• 刊名：Journal of Catalysis
• 出版年：2012
• 期刊代码：97_00219517
• 类别：ce
• 出版时间：May, 2012
• 卷：289
• 期：Complete
• 页码：164-170
• 文件大小：548 K

摘要

Direct evidence for the formation of surface Fe-NO_x species over iron ferrierites during decomposition of N₂O was found with a combination of temperature-programmed desorption of adsorbed surface species and infrared and M枚ssbauer spectroscopies. Surface NO_x species were produced via the conversion of a transiently formed Fe(III)-O by exposing iron ferrierites (Si/Al = 8.7, Fe/Al = 0.07-0.1) to N₂O. The transformation of Fe(III)-O into Fe-NO_x was time- and temperature- dependent. Below 280 掳C, predominantly Fe(III)-O species were formed; these species are known to be highly active in oxidations at low temperatures. A transformation of Fe(III)-O into Fe-NO_x species occurred when the reaction temperature was increased or when the reaction time was increased at low temperatures. This resulted in the disappearance of the oxidation activity of iron ferrierite. In contrast, the formation of Fe-NO_x species enhanced the rate of N₂O decomposition. Once formed, NO_x species were stable during the subsequent N₂O decomposition.