Highly selective oxidation of methane to methanol at ambient conditions by titanium dioxide-supported iron species


Methane activation under moderate conditions and with good selectivity for value-added chemicals still remains a huge challenge. Here, we present a highly selective catalyst for the transformation of methane to methanol composed of highly dispersed iron species on titanium dioxide. The catalyst operates under moderate light irradiation (close to one Sun) and at ambient conditions. The optimized sample shows a 15% conversion rate for methane with an alcohol selectivity of over 97% (methanol selectivity over 90%) and a yield of 18 moles of alcohol per mole of iron active site in just 3 hours. X-ray photoelectron spectroscopy measurements with and without xenon lamp irradiation, light-intensity-modulated spectroscopies, photoelectrochemical measurements, X-ray absorption near-edge structure and extended X-ray absorption fine structure spectra, as well as isotopic analysis confirm the function of the major iron-containing species—namely, FeOOH and Fe2O3, which enhance charge transfer and separation, decrease the overpotential of the reduction reaction and improve selectivity towards methanol over carbon dioxide production.

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Fig. 1: Photocatalytic methane conversion under different conditions.
Fig. 2: Stability of photocatalysts and carbon source identification during CH4 transformation.
Fig. 3: Physical observation of the 0.33 metalwt.% FeOx/TiO2 sample.
Fig. 4: Chemical and physical characterization of the TiO2-based photocatalysts.

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding authors upon reasonable request.


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We are thankful for financial support from the UK EPSRC (EP/N009533/1), Royal Society Newton Advanced Fellowship grant (NA170422), Leverhulme Trust (RPG-2017-122), Natural Science Foundation of China (21725301, 91645115, 21473003, 21821004, 21573264, 21622310, 21603247 and 21703266), National Key R&D Program of China (2017YFB0602200), China Scholarship Council and First UCL-PKU Strategic Partner Funds. The ICP-AES tests were conducted at UCL Earth Sciences by B. Belgrave. We also thank X. Han from Beijing University of Technology for the contributions on STEM observation. The X-ray absorption spectroscopy experiments were carried out at the SSRF and Beijing Synchrotron Radiation Facility. We are also thankful to C. Windle at UCL for valuable discussion and thorough checks.

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J.X. conducted the catalysts preparation, activity tests and sample characterizations by XPS, photoluminescence and scanning electron microscopy. R.J. analysed and discussed the results of TEM, XAFS and XPS with and without xenon lamp irradiation. A.L. carried out the STEM. Y.B. and Y.Z. conducted and analysed the sample by XPS with and without xenon lamp irradiation. Q.R. collected X-ray diffraction patterns, and carried out IMPS and IMVS measurements and H2O2 reduction in a three-electrode cell. Y.D. conducted the EXAFS and XANES experiments. S.Y. and G.S. contributed to the discussion of the XAFS results and reaction mechanism. J.T. and D.M. designed the project. J.T. supervised the progress of the entire project. The manuscript was written through collective contributions from all authors. All authors approved the final version of the manuscript.

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Correspondence to Junwang Tang.

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Supplementary Discussion; Supplementary Figures 1–32; Supplementary Tables 1–2; Supplementary References

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Xie, J., Jin, R., Li, A. et al. Highly selective oxidation of methane to methanol at ambient conditions by titanium dioxide-supported iron species. Nat Catal 1, 889–896 (2018). https://doi.org/10.1038/s41929-018-0170-x

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