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Reusable photocatalytic film for efficient water disinfection under low light intensity

Nature Water volume 3, pages 1003–1016 (2025)Cite this article

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Abstract

Access to microbiologically safe water remains a pressing global issue, especially in resource-limited and disaster-affected regions. This study introduces a self-floating photocatalytic film that achieves >4.3-log bacterial inactivation in 10 litres of highly contaminated water within 40 min under low natural sunlight intensity (13–18 mW cm−2), where conventional photocatalysts (for example, TiO2, g-C3N4 and so on) are nearly ineffective. The remarkable performance is attributed to reactive oxygen species, especially oxygen-centred organic radicals, an unconventional active species with ultralong lifetimes—several orders of magnitude longer than typical reactive oxygen species. Their persistence allows accumulation under weak illumination, sustaining disinfection efficiency despite limited photon input. Moreover, oxygen-centred organic radicals can avoid attacking the catalyst, conferring excellent film stability (reusable ≥50 times), thereby ensuring cost-effectiveness and sustainability. With low energy demand, high robustness and operational simplicity, this photocatalytic film is particularly suitable for resource-limited regions and is promising for real-world applications in global water safety.

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Fig. 1: Schematic diagram showing the characteristic features of OCORs and the applications of the photocatalytic film.
Fig. 2: Structural characteristics of photocatalysts.
Fig. 3: Performance of photocatalytic water treatment.
Fig. 4: Formation, stability, utilization and conversion of OCORs.
Fig. 5: Intrinsic mechanisms for promoting the formation of OCORs.
Fig. 6: Water disinfection using a ready-to-use photocatalytic film.

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Data availability

The data supporting the findings of this study are available within this paper and the Supplementary Information. Source data are available from the corresponding authors upon reasonable request.

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Acknowledgements

This work was supported by the National Natural Science Foundation of China (grant numbers 22336007 to G.O., 22422611 and 22206209 to Y.-X.Y.), the Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) via project number SML2023SP220 (Y.-X.Y.) and the Guangdong Basic Research Center of Excellence for Functional Molecular Engineering Project 31000-42080002 (G.O.).

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Authors and Affiliations

  1. Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, LIFM, School of Chemistry, IGCME, Sun Yat-sen University, Guangzhou, China

    Yuyan Huang, Xiaojun Li, Jianqiao Xu, Fang Zhu & Gangfeng Ouyang

  2. School of Chemical Engineering and Technology, IGCME, Sun Yat-sen University, Zhuhai, China

    Huijie Yan, Yu-Xin Ye & Gangfeng Ouyang

  3. Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, Guangdong, China

    Yu-Xin Ye & Gangfeng Ouyang

  4. Guangdong Provincial Key Laboratory of Chemical Measurement and Emergency Test Technology, Institute of Analysis, Guangdong Academy of Sciences (China National Analytical Center, Guangzhou), Guangzhou, China

    Yu-Xin Ye & Gangfeng Ouyang

Authors
  1. Yuyan Huang
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Contributions

Y.H., Y.-X.Y. and G.O. co-proposed the idea and designed the experiments. Y.H. contributed to performing the experiments and the DFT calculations. Y.H., Y.-X.Y., X.L., H.Y., J.X. and F.Z. contributed to performing and analysing the experiments. Y.H., Y.-X.Y. and G.O. participated in writing the manuscript. We thank the PL group of Instrumental Analysis & Research Center, Sun Yat-sen University for their contributions to temperature-dependent PL measurements.

Corresponding authors

Correspondence to Yu-Xin Ye or Gangfeng Ouyang.

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Nature Water thanks Min Sik Kim, Changha Lee and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary Information

Supplementary Texts 1–17, Notes 1–3, Figs. 1–71, Tables 1–7 and References.

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Huang, Y., Li, X., Yan, H. et al. Reusable photocatalytic film for efficient water disinfection under low light intensity. Nat Water 3, 1003–1016 (2025). https://doi.org/10.1038/s44221-025-00500-0

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