Abstract
Photocatalytic reduction of nitrate to ammonia is a promising route for sustainable nitrogen recycling, but its efficiency is often limited by disordered charge migration, interlayer charge depletion, and insufficient reactant activation, especially under dilute conditions. To address these challenges, an asymmetric spatial polarity strategy is applied to regulate polar distribution in donor-acceptor covalent organic frameworks at both molecular and layered levels. Strong intramolecular polarity confines charge transfer pathways, while convergent interlayer polarity enhances the internal electric field and promotes directional charge migration. Differentiated polar active sites facilitate nitrogen-oxygen bond cleavage, hydrogen intermediate formation, and nitrate activation in water. Here, we show that the optimized photocatalyst achieves an ammonium production rate of 0.758 mmol g-1 h-1 and an areal activity of 20.363 mmol cm-2 under natural sunlight, demonstrating competitive performance for nitrate reduction under dilute conditions.
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Data supporting the findings of this study are available within the article and supplementary information. Source data are provided with this paper.
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Acknowledgements
This project was financially supported by the National Natural Science Foundation of China (No. 22268015). Guizhou Science and Technology Platform foundation (No. ZSYS [2025]−033). The authors would like to thank Scientific Compass (www.shiyanjia.com) for materials characterizations and the computing support of the State Key Laboratory of Public Big Data, Guizhou University.
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Y.S. (Data curation, Formal analysis, Investigation, Writing –original draft), Z.W. (Formal analysis), X.D. (Data curation, Software, Writing – original draft), S.-F.Y. (Data curation, Project administration, Supervision), P.C. (Conceptualization, Formal analysis, Funding acquisition, Supervision, Writing – review & editing).
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Su, Y., Wang, Z., Deng, X. et al. Unlocking carrier confluence in covalent organic frameworks for efficient photoreduction of dilute nitrate to ammonia. Nat Commun (2026). https://doi.org/10.1038/s41467-026-69439-4
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DOI: https://doi.org/10.1038/s41467-026-69439-4
