Stoichiometric methane conversion to ethane using photochemical looping at ambient temperature

Xiang Yu (1) , Vladimir L Zholobenko (2) , Simona Moldovan (3) , Di Hu (1) , Dan Wu (1) , Vitaly Ordomsky (1) , Andrei y Khodakov (1)

1 UCCS - Unité de Catalyse et Chimie du Solide - UMR 8181
2 Keele University [Keele]
3 GPM - Groupe de physique des matériaux

Methane is the main component of natural and shale gas, methane clathrates and biogas, and is a potent greenhouse gas. About 90% of methane is currently burnt in various combustion processes, releasing carbon dioxide into the atmosphere 1-7. Finding ways to efficiently convert methane into fuels and chemicals is important for the rational utilization of fossil and renewable energy feedstocks, as well as for reducing the emission of greenhouse gases. Methane is a highly stable molecule; it has no functional groups and a very high C-H bond enthalpy (439 kJ mol −1). Methane is also inert relative to acid attack and has a very low proton affinity (544 kJ mol −1) and acidity (pK a = 40). Therefore, direct chemical conversion of methane to value-added chemicals and fuels remains a formidable challenge for modern science 8-10. Commercial technologies of methane utilization, other than combustion, are rather limited. They involve methane steam reforming, partial oxidation, autothermal reforming or the Andrussow reaction 11-13. The non-commercial routes for methane conversion can be divided into oxidative and non-oxidative routes 8-21. The non-oxidative routes, such as methane aromatization, result in substantial carbon deposition, while the oxidative routes, such as methane thermocatalytic coupling and methane partial oxidation, usually suffer from insufficient selectivity and abundant production of CO 2. Most of the known methane conversion reactions require very high temperatures (>800 °C). Generally, these thermochemical processes are accompanied by CO 2 emissions arising from the combustion of fossil fuels utilized to maintain the reactor at high temperatures 18-23. Photocatalytic non-oxidative coupling of methane with very low quantum efficiencies and yields was observed over silica, highly dispersed Ga or Ce species 24-26. Activation of methane over Zn 2+ / ZSM-5 and Ga 3+ /EST-10 photocatalysts has been reported, with the photocatalytic activity attributed to the presence of extra-framework zinc cations and Ti-OH groups on titanate wires 27,28. Photocatalytic non-oxidative coupling of methane has been observed when

Domaines: Catalyse; Chimie organique

Xiang Yu, Vladimir L Zholobenko, Simona Moldovan, Di Hu, Dan Wu, et al.. Stoichiometric methane conversion to ethane using photochemical looping at ambient temperature. Nature Energy, 2020, 5 (7), pp.511-519. ⟨10.1038/s41560-020-0616-7⟩. ⟨hal-03052393⟩