Efficient water oxidation catalysts based on readily available iron coordination complexes

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. One of the bottlenecks for the development of sustainable artificial photosynthesis is the water oxidation reaction, which too often relies on expensive and toxic metals. Now, coordination complexes of readily available, environmentally benign iron are found to catalyse homogeneous water oxidation to O2 with high efficiency.

Cite this article

Fillol, J., Codolà, Z., Garcia-Bosch, I. et al. Efficient water oxidation catalysts based on readily available iron coordination complexes. Nature Chem 3, 807–813 (2011). https://doi.org/10.1038/nchem.1140

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