- Title
- A proposed reaction mechanism for the selective oxidation of methane with nitrous oxide over Co-ZSM-5 catalyst forming synthesis gas (CO + H₂)
- Creator
- Khan, Naseer A.; Kennedy, Eric M.; Dlugogorski, Bogdan Z.; Adesina, Adesoji A.; Stockenhuber, Michael
- Relation
- International Journal of Hydrogen Energy Vol. 43, Issue 29, p. 13133-13144
- Publisher Link
- http://dx.doi.org/10.1016/j.ijhydene.2018.05.026
- Publisher
- Elsevier
- Resource Type
- journal article
- Date
- 2018
- Description
- Probable reaction intermediates and mechanistic steps involved for the selective oxidation of methane (CH₄) with nitrous oxide (N₂O) forming synthesis gas (CO + H₂) over Co-ZSM-5 was examined. To assess the reaction kinetics reactions were conducted within a temperature range of 300°C - 550°C and at atmospheric pressure, and the composition of reactant feed (N₂O/CH₄) was varied between three fixed ratios (5, 3, and 1). TPD, XRD, TEM and FT-IR techniques were used for catalyst characterization and mechanistic studies. It was found, that H₂ selectivity is higher for feeds with lower N₂O concentration. Furthermore, CO formation commences at lower temperatures in comparison to H2 gas which is a result of the formation of methanol (CH₃OH) and carbon oxides (CO and CO₂) at low CH₄ conversions. Based on the reaction conditions, the literature proposes direct and an indirect mechanistic route for synthesis gas formation. Our catalytic study suggests a direct route for the synthesis gas formation; i.e. H₂ gas is formed by the decomposition of intermediate species (methoxy and CH₂O). This is supported by spectroscopic investigation. Under favourable reaction conditions and over the Co-ZSM-5 catalyst, N₂O first oxidizes CH₄ to CH₃OH, an active reaction intermediate, which then subsequently is converted into (formaldehyde) CH₂O and H₂. CH₂O is highly reactive and decomposes into CO and H₂.
- Subject
- selective oxidation; CH4; N2O; Co-ZSM-5
- Identifier
- http://hdl.handle.net/1959.13/1412326
- Identifier
- uon:36460
- Identifier
- ISSN:0360-3199
- Language
- eng
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