A promising plasma-catalytic approach towards single-step methane conversion to oxygenates at room temperature

Chawdhury, Piu, Wang, Yaolin ORCID: 0000-0003-1932-9810, Ray, Debjyoti, Mathieu, Stephanie, Wang, Ni, Harding, Jonathan ORCID: 0000-0002-9920-7831, Bin, Feng, Tu, Xin ORCID: 0000-0002-6376-0897 and Subrahmanyam, Ch (2021) A promising plasma-catalytic approach towards single-step methane conversion to oxygenates at room temperature. APPLIED CATALYSIS B-ENVIRONMENTAL, 284. p. 119735.

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Official URL: http://dx.doi.org/10.1016/j.apcatb.2020.119735

Abstract

Direct conversion of methane into chemicals and fuels under mild conditions has been considered as a ‘holy grail’ of chemistry and catalysis in the 21st century. Plasma-catalytic partial oxidation of methane (POM) to higher-value liquid fuels and chemicals over supported transition metal catalysts (Ni/γ-Al2O3, Cu/γ-Al2O3 and Fe/γ-Al2O3) has been investigated in a co-axial dielectric barrier discharge (DBD) reactor at room temperature and atmospheric pressure. The selectivity of oxygenates was 58.3% in the plasma POM reaction without a catalyst, while the combination of DBD with the catalysts enhanced the selectivity of oxygenates up to 71.5%. Of the three catalysts, Fe/γ-Al2O3 showed the highest methanol selectivity of 36.0% and a significant methanol yield of 4.7%, while the use of Cu/γ-Al2O3 improved the selectivity of C2 oxygenates to 9.4%, which can be attributed to the presence of more acid sites on the surfaces of the Cu catalyst. The possible reaction pathways in the plasma-catalytic POM reaction have been explored by combined means of plasma electrical and optical diagnostics, analysis of gas and liquid products, as well as comprehensive catalyst characterization. The plausible reaction routes for the production of major oxygenate (methanol) on the Fe/γ-Al2O3 surfaces have been proposed. The surface CHx species are found to be critical for methanol synthesis; they can be formed through the direct adsorption of CHx radicals generated in the plasma gas-phase reactions or through the dissociation of adsorbed CH4 on the catalyst surface.

Item Type:	Article
Uncontrolled Keywords:	Partial oxidation of methane, Non-thermal plasma, Plasma-catalysis, Methanol synthesis, Oxygenates
Depositing User:	Symplectic Admin
Date Deposited:	05 Nov 2020 09:24
Last Modified:	18 Jan 2023 23:23
DOI:	10.1016/j.apcatb.2020.119735
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3106080