Reaction between N2O and CH4 over Fe ion-exchanged BEA zeolite catalyst: A possible role of nascent oxygen transients from N 2O

Satoshi Kameoka, Takeshi Nobukawa, Shin Ichi Tanaka, Shin Ichi Ito, Keiichi Tomishige, Kimio Kunimori

研究成果: Article査読

60 被引用数 (Scopus)

抄録

The reaction between N2O and CH4 over an Fe ion-exchanged BEA zeolite (Fe-BEA) catalyst was studied by using a pulse reaction technique, temperature-programmed desorption (TPD) and infrared (IR) spectroscopy. N2O readily reacted with CH4 in the presence of an N2O + CH4 mixture above 200°C, while both the O2 + CH4 reaction and the catalytic decomposition of N2O over the Fe-BEA catalyst required higher temperatures (above 400°C). In the O2-TPD studies, a desorption peak of O2 was observed above 600°C after O2 treatment at 250°C, while a new O2 desorption peak appeared at the lower temperatures after N2O treatment at 250°C. However, the new O(a) species resulting from the N2O treatment hardly reacted with CH4 even at 350°C, which was confirmed by the CH 4-pulsed experiments. On the other hand, a new IR band at 3683 cm-1, which can be assigned to the OH group on Fe ion species, was observed after O2 or N2O treatment. The peak intensity at 3683 cm-1 was not changed in the exposure of CH4 only, but decreased in the exposure of N2O + CH4 mixture above 150°C. At the same time, the CHxOy(a) species such as Fe-OCH3 were formed, which were observed by IR measurements. The adsorbed surface species showed a high reactivity with N2O even at low temperatures (∼200°C). A possible mechanism is discussed in terms of active oxygen species such as nascent oxygen transients (O*(a)), which are formed in the exposure of N2O + CH4 mixture, and may play an important role in the activation/oxidation of CH4 at initial steps to form CHxOy(a) species.

本文言語English
ページ(範囲)3328-3333
ページ数6
ジャーナルPhysical Chemistry Chemical Physics
5
15
DOI
出版ステータスPublished - 2003 8月 1
外部発表はい

ASJC Scopus subject areas

  • 物理学および天文学(全般)
  • 物理化学および理論化学

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