Unravelling the Enigma of Nonoxidative Conversion of Methane on Iron Single-Atom Catalysts |
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| Authors: | Dr Yuan Liu Dr Jin-Cheng Liu Teng-Hao Li Zeng-Hui Duan Dr Tian-Yu Zhang Ming Yan Dr Wan-Lu Li Prof Dr Hai Xiao Prof Dr Yang-Gang Wang Prof Dr Chun-Ran Chang Prof Dr Jun Li |
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| Institution: | 1. Department of chemistry and Key Laboratory of Organic Optoelectronics & Molecular Engineering of Ministry of Education, Tsinghua University, Beijing, 100084 China;2. School of Chemical Engineering and Technology, Shaanxi Key Laboratory of Energy Chemical Process Intensification, Xi'an Jiaotong University, Xi'an, 710049 China;3. Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, IL, 62901 USA;4. Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055 China |
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| Abstract: | The direct, nonoxidative conversion of methane on a silica-confined single-atom iron catalyst is a landmark discovery in catalysis, but the proposed gas-phase reaction mechanism is still open to discussion. Here, we report a surface reaction mechanism by computational modeling and simulations. The activation of methane occurs at the single iron site, whereas the dissociated methyl disfavors desorption into gas phase under the reactive conditions. In contrast, the dissociated methyl prefers transferring to adjacent carbon sites of the active center (Fe1©SiC2), followed by C−C coupling and hydrogen transfer to produce the main product (ethylene) via a key −CH−CH2 intermediate. We find a quasi Mars–van Krevelen (quasi-MvK) surface reaction mechanism involving extracting and refilling the surface carbon atoms for the nonoxidative conversion of methane on Fe1©SiO2 and this surface process is identified to be more plausible than the alternative gas-phase reaction mechanism. |
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| Keywords: | computational simulations methane reaction mechanisms single-atom catalysis |
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