Article | Published:

Efficient water oxidation catalysts based on readily available iron coordination complexes

Nature Chemistry volume 3, pages 807813 (2011) | Download Citation

Abstract

Water oxidation catalysis constitutes the bottleneck for the development of energy-conversion schemes based on sunlight. To date, state-of-the-art homogeneous water oxidation catalysis is performed efficiently with expensive, toxic and earth-scarce transition metals, but 3d metal-based catalysts are much less established. Here we show that readily available, environmentally benign iron coordination complexes catalyse homogeneous water oxidation to give O2, with high efficiency during a period of hours. Turnover numbers >350 and >1,000 were obtained using cerium ammonium nitrate at pH 1 and sodium periodate at pH 2, respectively. Spectroscopic monitoring of the catalytic reactions, in combination with kinetic studies, show that high valent oxo-iron species are responsible for the O–O forming event. A systematic study of iron complexes that contain a broad family of neutral tetradentate organic ligands identifies first-principle structural features to sustain water oxidation catalysis. Iron-based catalysts described herein open a novel strategy that could eventually enable sustainable artificial photosynthetic schemes.

  • Compound C16H24F6MnN4O6S2

    [Mn(OTf)2(Me2Pytacn)]

  • Compound C16H24F6FeN4O6S2

    [Fe(OTf)2(Me2Pytacn)]

  • Compound C16H24CoF6N4O6S2

    Co(OTf)2(Me2Pytacn)]

  • Compound C16H24F6N4NiO6S2

    Ni(OTf)2(Me2Pytacn)]

  • Compound C22H28F6FeN4O6S2

    [Fe(OTf)2(mcp)]

  • Compound C20H28Cl2FeN4

    [Fe(Cl)2(mcp)]

  • Compound C42H57F6Fe2N8O8S2

    [(Fe(mcp))2(μ-O)(μ-OH)](OTf)2

  • Compound C22H26F6FeN4O6S2

    [Fe(OTf)2(bpbp)]

  • Compound C18H22F6FeN4O6S2

    [Fe(OTf)2(mep)]

  • Compound C20H18F6FeN4O6S2

    [Fe(OTf)2(tpa)]

  • Compound C16H32F6FeN4O6S2

    [Fe(OTf)2(tmc)]

  • Compound C23H30F6FeN6O6S2

    [Fe(NCCH3)(MePy2CH-tacn)](OTf)2

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Acknowledgements

We thank R. Hage, X. Ribas and P. Lahuerta for reading this work and for comments. We thank the European Research Foundation for project FP7-PEOPLE-2010-ERG-268445 (J.Ll.), El Ministerio de Ciencia e Innovación for project CTQ2009-08464 (M.C.), for a Ramon y Cajal contract (J.Ll.) and for a PhD grant (I.G-B.), Generalitat de Catalunya for an ICREA Academia Award and the European Research Council for Project ERC-2009-StG-239910 (M.C.). RahuCat is acknowledged for giving the tritosylTACN.

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  1. Departament de Química, Universitat de Girona, Campus Montilivi, 17071 Girona, Spain

    • Julio Lloret Fillol
    • , Zoel Codolà
    • , Isaac Garcia-Bosch
    • , Laura Gómez
    • , Juan José Pla
    •  & Miquel Costas

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Contributions

J.Ll. and M.C. devised the initial concept for the work and designed the experiments. Z.C., I.G-B., L.G. and J.Ll. carried out the experiments. J.J.P. and J.Ll. designed the differential pressure transducer hardware and software. Z.C., I.G-B. and J.Ll. analysed the data. J.Ll. and M.C. co-wrote the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Julio Lloret Fillol or Miquel Costas.

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DOI

https://doi.org/10.1038/nchem.1140

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