Photoemission study of the subsequential oxidation of dissociatively adsorbed methane on an SnO2 thin film
✍ Scribed by Takasahi Kawabe; Kenji Tabata; Eiji Suzuki; Yoichi Yamaguchi; Yosuke Nagasawa
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 143 KB
- Volume
- 29
- Category
- Article
- ISSN
- 0142-2421
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✦ Synopsis
The subsequent oxidation steps for direct methane selective oxidation with oxygen were examined with xray photoelectron spectroscopy (XPS). The intermediate hydrocarbon species, i.e. methoxide, methanol and dioxymethylene species, were observed in the C 1s level spectrum after CH 4 exposure at 473 K onto an SnO 2 thin film. These chemical species were not oxidized with oxygen even after additional O 2 exposure at 473 K, but molecularly adsorbed methane and its carbonaceous intermediates were oxidized mainly to dioxymethylene species. This result agreed with the expectation from the values of theoretically calculated transition barriers of their oxidation reactions. The dioxymethylene species produced seemed to be partly decomposed to methoxide and formate species during heat treatment up to 773 K.