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Stoichiometric methane conversion to ethane using photochemical looping at ambient temperature


Methane activation and utilization are among the major challenges of modern science. Methane is potentially an important feedstock for manufacturing value-added fuels and chemicals. However, most known processes require excessive operating temperatures and exhibit insufficient selectivity. Here, we demonstrate a photochemical looping strategy for highly selective stoichiometric conversion of methane to ethane at ambient temperature over silver–heteropolyacid–titania nanocomposites. The process involves a stoichiometric reaction of methane with highly dispersed cationic silver under illumination, which results in the formation of methyl radicals. Recombination of the generated methyl radicals leads to the selective, and almost quantitative, formation of ethane. Cationic silver species are simultaneously reduced to metallic silver. The silver–heteropolyacid–titania nanocomposites can be reversibly regenerated in air under illumination at ambient temperature. The photochemical looping process achieves a methane coupling selectivity of over 90%, a quantitative yield of ethane of over 9%, high quantum efficiency (3.5% at 362 nm) and excellent stability.

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Fig. 1: Photochemical coupling of methane on different materials.
Fig. 2: Changes of Ag–HPW/TiO2 after methane photochemical coupling.
Fig. 3: X-ray diffraction patterns of nanocomposites.
Fig. 4: TEM and STEM-EDX mapping images of fresh Ag–HPW/TiO2 sample.
Fig. 5: Photochemical coupling of methane and ethane on Ag–HPW/TiO2.
Fig. 6: Reaction and regeneration of Ag–HPW/TiO2.

Data availability

The authors declare that the data supporting the findings of this study are available within the paper, Supplementary Information and Source Data files.


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We thank L. Burylo, P. Simon and M. Frère for help with X-ray diffraction and XPS measurements. X.Y. and D.H thank the Chinese scholarship council for providing stipends for their PhD studies in France. We thank Chevreul Institute (FR 2638), Ministère de l’Enseignement Supérieur, de la Recherche et de l’Innovation, Hauts-de-France Region and FEDER for supporting and partially funding this work. GENESIS is supported by the Région Haute-Normandie, Métropole Rouen Normandie, CNRS via LABEX EMC3 and French National Research Agency as a part of the programme 'Investissements d'avenir' with the reference ANR-11-EQPX-0020.

Author information




X.Y., V.V.O. and A.Y.K. conceived the idea for this work. All authors contributed to the design of the experimental set-up and experimental procedures. X.Y. prepared the nanocomposite materials, collected the data and performed ex situ characterization. X.Y, D.W., V.L.Z. and V.V.O performed the infrared measurements. S.M. performed nanocomposite characterization using imaging techniques. V.L.Z., A.Y.K and X.Y. designed the capillary photoreactor and performed the high-conversion methane experiments. D.H. synthesized the silver salt of HPW and conducted additional experiments in order to address the reviewer comments. X.Y. and A.Y.K. wrote the draught, and all the authors worked on improving the manuscript.

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Correspondence to Vitaly V. Ordomsky or Andrei Y. Khodakov.

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Yu, X., Zholobenko, V.L., Moldovan, S. et al. Stoichiometric methane conversion to ethane using photochemical looping at ambient temperature. Nat Energy 5, 511–519 (2020).

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