A photochromic composite with enhanced carrier separation for the photocatalytic activation of benzylic C–H bonds in toluene

Abstract

Photocatalysis based on the use of semiconducting materials is an emerging alternative to conventional thermochemical catalysis, and it has the potential to promote chemical synthesis under greener and milder conditions. However, heterogeneous photocatalytic organic reactions are still in their infancy, limited by the low-efficiency carrier separation of the currently available photocatalytic materials. Here, we report photochromic Bi2WO6–x/amorphous BiOCl (p-BWO) nanosheets, which, distinct from pristine Bi2WO6, show blue colouration upon visible light irradiation and are bleached by atmospheric oxygen. Studies on the microscopic structure of the material reveal the existence of abundant W(vi)O6–x units, which serve as the sites for the fast and continuous consumption of photogenerated electrons, thereby effectively facilitating the separation of electron–hole pairs. The prepared composite features a remarkable enhancement in performance for the photocatalytic oxidation of toluene with a conversion rate 166-fold higher compared with that of pristine Bi2WO6.

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Fig. 1: Characterization of p-BWO and pristine Bi2WO6.
Fig. 2: Photocatalytic oxidation of toluene.
Fig. 3: Catalytic performance of p-BWO and pristine Bi2WO6.
Fig. 4: Atomic-resolution structure characterization and SAED patterns of the p-BWO.
Fig. 5: Raman and XAFS characterization for Bi2WO6 and the p-BWO sample series.
Fig. 6: Energy band scheme, microscopic structure and working mechanism of p-BWO.

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Acknowledgements

This work was supported by the National Key R&D Program of China (2017YFA0700101 and 2016YFA0202801) and National Natural Science Foundation of China (numbers 21325101, 21231005, 21573119 and 21590792). We thank the 1W1B station for XAFS measurements at the Beijing Synchrotron Radiation Facility.

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X.C., Z.C., R.L., W-C.C., S.L. and J.Z. performed the experimental work and analysed the results. T.H., X.T., Y.W., R.S., D.W. and W.Z. discussed and provided advice on the work. X.C., Z.C., Q.P., C.C. and Y.L. conceived and designed the experiments. All authors co-wrote the manuscript.

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Correspondence to Qing Peng or Chen Chen or Yadong Li.

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Cao, X., Chen, Z., Lin, R. et al. A photochromic composite with enhanced carrier separation for the photocatalytic activation of benzylic C–H bonds in toluene. Nat Catal 1, 704–710 (2018). https://doi.org/10.1038/s41929-018-0128-z

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