Direct Conversion of Methane to Ethylene and Acetylene over an Iron-Based Metal-Organic Framework

Yujie Ma, Xue Han, Shaojun Xu, Wanpeng Lu, Bing An, Daniel Lee, Sarayute Chansai, Alena M. Sheveleva, Zi Wang, Yinlin Chen, Jiangnan Li, Weiyao Li, Floriana Tuna, Eric J. L. Mcinnes, Christopher Hardacre, Martin Schroder, Sihai Yang, et al

Research output: Contribution to journalArticlepeer-review

Abstract

Conversion of methane (CH4) to ethylene (C2H4) and/or acetylene (C2H2) enables routes to a wide range of products directly from natural gas. However, high reaction temperatures and pressures are often required to activate and convert CH4 controllably, and separating C2+ products from unreacted CH4 can be challenging. Here, we report the direct conversion of CH4 to C2H4 and C2H2 driven by non-thermal plasma under ambient (25 °C and 1 atm) and flow conditions over a metal-organic framework material, MFM-300(Fe). The selectivity for the formation of C2H4 and C2H2 reaches 96% with a high time yield of 334 μmol∙gcat−1∙h−1. At a conversion of 10%, the selectivity to C2+ hydrocarbons and time yield exceed 98% and 2056 μmol∙gcat−1∙h−1, respectively, representing a new benchmark for conversion of CH4. In situ neutron powder diffraction (NPD), inelastic neutron scattering (INS) and solid-state nuclear magnetic resonance (ssNMR), electron paramagnetic resonance (EPR) and diffuse reflectance infrared Fourier transform (DRIFT) spectroscopies, coupled with modelling studies, reveal the crucial role of Fe−O(H)−Fe sites in activating CH4 and stabilising reaction intermediates via the formation of Fe−O(CH3)−Fe adduct. In addition, a cascade fixed-bed system has been developed to achieve online separation of C2H4 and C2H2 from unreacted CH4 for direct use. Integrating the processes of CH4 activation, conversion and product separation within one system opens a new avenue for natural gas utility, bridging the gap between fundamental studies and practical applications in this area.
Original languageEnglish
JournalAmerican Chemical Society. Journal
DOIs
Publication statusPublished - 18 Sept 2023

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