Molecular-level insights on the reactive facet of carbon nitride single crystals photocatalysing overall water splitting

Abstract

Unraveling how reactive facets promote photocatalysis at the molecular level remains a grand challenge, while identification of the reactive facets can provide guidelines for designing highly efficient photocatalysts and unravelling the microscopic mechanisms behind them. Recently, a series of polytriazine imides (PTIs) was reported with highly crystalline structures; all had a relatively low photocatalytic activity for overall water splitting. Here, high-angle annular dark-field scanning transmission electron microscopy, energy dispersive spectroscopy mapping, and aberration-corrected integrated differential phase contrast imaging were used to study PTI/Li+Cl single crystals before and after in situ photodeposition of co-catalysts, showing that the prismatic {10\(\bar 1\)0} planes are more photocatalytically reactive than the basal {0001} planes. Theoretical calculations confirmed that the electrons are energetically favourable to transfer toward the {10\(\bar 1\)0} planes. Upon this discovery, PTI/Li+Cl crystals with different aspect ratios were prepared, and the overall water splitting performance followed a linear correlation with the relative surface areas of the {10\(\bar 1\)0} and {0001} planes. Our controlling of the reactive facets directly instructs the development of highly efficient polymer photocatalysts for overall water splitting.

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Fig. 1: The morphology and atomic structure of PTI/Li+Cl.
Fig. 2: The spatial distribution of the Pt co-catalysts after photodeposition.
Fig. 3: The electronic structure properties.
Fig. 4: Photocatalytic performances.

Data availability

The data that support the findings of this study are available from the corresponding author upon reasonable request.

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Acknowledgements

This work was financially supported by the National Key R&D Program of China (2018YFA0209301), the National Natural Science Foundation of China (U1905214, 21961142019, 21425309, 21761132002, 21861130353, 21802021, 21973014, 51701170 and 51871058), the Chang Jiang Scholars Program of China (T2016147), the project of science and technology plan of Fujian Province (2018J01520) and the 111 Project (D16008). This work made use of the TEM resources at Fuzhou University and the Nanoport Europe of Thermo Fisher Scientific in the Netherlands. Z. Yu thanks A. Carlsson for professional assistance in iDPC imaging.

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Contributions

X.W. conceived and designed the experiment. L.L., Z.L. and J.Z. synthesized the experimental samples and carried out most of the characterization, as well as the photocatalytic reactions. Z.L. and Z.Y. performed the SEM and TEM characterizations. Z.Y. analysed the TEM data. X.C. and W.L. carried out the DFT calculations. X.W. supervised the experiments. All the authors discussed the results and wrote the manuscript.

Corresponding author

Correspondence to Xinchen Wang.

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Supplementary Information

Supplementary Figs. 1–21 and Tables 1–2.

Supplementary Data Atomic coordinates 1

Optimized computational model.

Supplementary Data Atomic coordinates 2

Optimized computational model.

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Lin, L., Lin, Z., Zhang, J. et al. Molecular-level insights on the reactive facet of carbon nitride single crystals photocatalysing overall water splitting. Nat Catal 3, 649–655 (2020). https://doi.org/10.1038/s41929-020-0476-3

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