Letter | Published:

Visible-light-driven methane formation from CO2 with a molecular iron catalyst

Nature volume 548, pages 7477 (03 August 2017) | Download Citation

Abstract

Converting CO2 into fuel or chemical feedstock compounds could in principle reduce fossil fuel consumption and climate-changing CO2 emissions1,2. One strategy aims for electrochemical conversions powered by electricity from renewable sources3,4,5, but photochemical approaches driven by sunlight are also conceivable6. A considerable challenge in both approaches is the development of efficient and selective catalysts, ideally based on cheap and Earth-abundant elements rather than expensive precious metals7. Of the molecular photo- and electrocatalysts reported, only a few catalysts are stable and selective for CO2 reduction; moreover, these catalysts produce primarily CO or HCOOH, and catalysts capable of generating even low to moderate yields of highly reduced hydrocarbons remain rare8,9,10,11,12,13,14,15,16,17. Here we show that an iron tetraphenylporphyrin complex functionalized with trimethylammonio groups, which is the most efficient and selective molecular electro- catalyst for converting CO2 to CO known18,19,20, can also catalyse the eight-electron reduction of CO2 to methane upon visible light irradiation at ambient temperature and pressure. We find that the catalytic system, operated in an acetonitrile solution containing a photosensitizer and sacrificial electron donor, operates stably over several days. CO is the main product of the direct CO2 photoreduction reaction, but a two-pot procedure that first reduces CO2 and then reduces CO generates methane with a selectivity of up to 82 per cent and a quantum yield (light-to-product efficiency) of 0.18 per cent. However, we anticipate that the operating principles of our system may aid the development of other molecular catalysts for the production of solar fuels from CO2 under mild conditions.

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References

  1. 1.

    , & Electrochemical conversion of CO2 to useful chemicals: current status, remaining challenges, and future opportunities. Curr. Opin. Chem. Eng. 2, 191–199 (2013)

  2. 2.

    , & Catalysis for the valorization of exhaust carbon: from CO2 to chemicals, materials, and fuels. Technological use of CO2. Chem. Rev. 114, 1709–1742 (2014)

  3. 3.

    , , & A review of catalysts for the electroreduction of carbon dioxide to produce low-carbon fuels. Chem. Soc. Rev. 43, 631–675 (2014)

  4. 4.

    et al. Integration of anodic and cathodic catalysts of Earth-abundant materials for efficient, scalable CO2 reduction. Top. Catal. 58, 57–66 (2015)

  5. 5.

    et al. Efficient electrolyzer for CO2 splitting in neutral water using Earth-abundant materials. Proc. Natl Acad. Sci. USA 113, 5526–5529 (2016)

  6. 6.

    & Efficient photocatalysts for CO2 reduction. Inorg. Chem. 54, 5096–5104 (2015)

  7. 7.

    , , & Electrons, photons, protons and Earth-abundant metal complexes for molecular catalysis of CO2 reduction. ACS Catal. 7, 70–88 (2017)

  8. 8.

    et al. Electrocatalytic reduction of carbon dioxide to carbon monoxide and methane at an immobilized cobalt protoporphyrin. Nat. Commun. 6, 8177 (2015)

  9. 9.

    et al. Electrochemical CO2 reduction to hydrocarbons on a heterogeneous molecular Cu catalyst in aqueous solution. J. Am. Chem. Soc. 138, 8076–8079 (2016)

  10. 10.

    , & Enhanced electrochemical methanation of carbon dioxide with a dispersible nanoscale copper catalyst. J. Am. Chem. Soc. 136, 13319–13325 (2014)

  11. 11.

    et al. Amino acid modified copper electrodes for the enhanced selective electroreduction of carbon dioxide towards hydrocarbons. Energy Environ. Sci. 9, 1687–1695 (2016)

  12. 12.

    et al. A carbon-based photocatalyst efficiently converts CO2 to CH4 and C2H2 under visible light. Green Chem. 16, 2142–2146 (2014)

  13. 13.

    , , , & Wafer-level artificial photosynthesis for CO2 reduction into CH4 and CO using GaN nanowires. ACS Catal. 5, 5342–5348 (2015)

  14. 14.

    , & Heterogeneous molecular systems for photocatalytic CO2 reduction with water oxidation. Angew. Chem. Int. Ed. 55, 14924–14950 (2016)

  15. 15.

    . et al. Facile one-step synthesis of hybrid graphitic carbon nitride and carbon composites as high-performance catalysts for CO2 photocatalytic conversion. ACS Appl. Mater. Interf. 8, 17212–17219 (2016)

  16. 16.

    et al. Photocatalytic reduction of CO2 with H2O to CH4 over ultrathin SnNb2O6 2D nanosheets under visible light irradiation. Green Chem. 18, 1355–1363 (2016)

  17. 17.

    et al. Enhanced activity and stability of carbon-decorated cuprous oxide mesoporous nanorods for CO2 reduction in artificial photosynthesis. ACS Catal. 6, 6444–6454 (2016)

  18. 18.

    , , & A study of through-space charge interaction substituent effects in molecular catalysis leading to the design of the most efficient catalyst of CO2-to-CO electrochemical conversion. J. Am. Chem. Soc. 138, 16639–16644 (2016)

  19. 19.

    , & Molecular catalysis of the electrochemical and photochemical reduction of CO2 with Fe and Co metal based complexes. Recent advances. Coord. Chem. Rev. 334, 184–198 (2017)

  20. 20.

    , , & Efficient and selective molecular catalyst for the CO2-to-CO electrochemical conversion in water. Proc. Natl Acad. Sci. USA 112, 6882–6886 (2015)

  21. 21.

    , & Selective and efficient photocatalytic CO2 reduction to CO using visible light and an iron-based homogeneous catalyst. J. Am. Chem. Soc. 136, 16768–16771 (2014)

  22. 22.

    , & Non-sensitized selective photochemical reduction of CO2 to CO under visible light with an iron molecular catalyst. Chem. Commun. 53, 2830–2833 (2017)

  23. 23.

    , & Visible light photoredox catalysis with transition metal complexes: applications in organic synthesis. Chem. Rev. 113, 5322–5363 (2013)

  24. 24.

    , , , & Nitrogen-doped graphenes as efficient electrocatalysts for the selective reduction of carbon dioxide to formate in aqueous solution. Green Chem. 18, 3250–3256 (2016)

  25. 25.

    , , & A local proton source enhances CO2 electroreduction to CO by a molecular Fe catalyst. Science 338, 90–94 (2012)

  26. 26.

    , , & Pendant acid-base groups in molecular catalysts: H-bond promoters or proton relays? Mechanisms of the conversion of CO2 to CO by electrogenerated iron(0)porphyrins bearing prepositioned phenol functionalities. J. Am. Chem. Soc. 136, 11821–11829 (2014)

  27. 27.

    , , & Homogeneous photocatalytic reduction of CO2 to CO using iron(0) porphyrin catalysts: mechanism and intrinsic limitations. ChemCatChem 6, 3200–3207 (2014)

  28. 28.

    , & Homogeneous catalysis of electrochemical hydrogen evolution by iron(0) porphyrins. J. Am. Chem. Soc. 118, 3982–3983 (1996)

  29. 29.

    et al. Frontiers, opportunities, and challenges in biochemical and chemical catalysis of CO2 fixation. Chem. Rev. 113, 6621–6658 (2013)

  30. 30.

    , & Disproportionation of the iron carbonyl hydride (n5-C5H5)Fe(CO)H(Ph2PCH2CH2PPh2) to the iron methyl (n5-C5H5)Fe(Ph2PCH2CH2PPh2)Me. J. Chem. Soc. Chem. Commun. 1404–1405 (1982)

  31. 31.

    , , , & A new synthetic route to the preparation of a series of strong photoreducing agents: fac-tris-ortho-metalated complexes of iridium(III) with substituted 2-phenylpyridines. Inorg. Chem. 30, 1685–1687 (1991)

  32. 32.

    et al. Iron-catalyzed photoreduction of carbon dioxide to synthesis gas. Catal. Sci. Technol. 6, 3623–3630 (2016)

  33. 33.

    ., ., & Handbook of Photochemistry 3rd edn (CRC Press, 2006)

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Acknowledgements

This work was partially supported by the CNRS, Défi Transition énergétique “Emergence CO2” (the PERIODIC project). H.R. thanks the China Scholarship Council for a PhD fellowship (CSC student number 201507040033). We thank D. Clainquart (Université Paris Diderot) for assistance in gas chromatography/mass spectrometry analysis and I. Azcarate for porphyrin synthesis.

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Affiliations

  1. Université Paris Diderot, Sorbonne Paris Cité, Laboratoire d’Electrochimie Moléculaire, UMR 7591 CNRS, 15 rue Jean-Antoine de Baïf, F-75205 Paris Cedex 13, France

    • Heng Rao
    • , Luciana C. Schmidt
    • , Julien Bonin
    •  & Marc Robert
  2. INFIQC-CONICET, Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, 5000 Córdoba, Argentina

    • Luciana C. Schmidt

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Contributions

M.R. conceived the research, J.B. and M.R. directed the project and co-wrote the paper. J.B. conceived the experimental setup. J.B., L.C.S. and H.R. conducted experiments. H.R., J.B. and M.R. analysed results. All the authors contributed to the scientific interpretation and reviewed the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Julien Bonin or Marc Robert.

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https://doi.org/10.1038/nature23016

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