Abstract
The electrocatalytic nitrate reduction reaction (NO3-RR) offers a promising route to sustainable ammonia synthesis, potentially replacing the energy-intensive Haber-Bosch process. While often studied in neutral or alkaline media, NO3-RR in acidic conditions is particularly relevant due to widespread industrial acidic nitrate wastewater, yet it remains challenging due to corrosion and dominant hydrogen evolution. To address this, we designed a corrosion-resistant Ru/WO3-x heterostructure that spatially separates proton and nitrate adsorption sites. Here, we show that a reverse hydrogen spillover effect, where the WO3-x support stores and transports protons to surface Ru active sites, dramatically enhances hydrogenation kinetics and suppresses parasitic hydrogen evolution. This catalyst achieves an ammonia Faradaic efficiency of 94.09% at a high current density of 500 mA cm−2 and a working potential of 0.026 V vs. reversible hydrogen electrode. Furthermore, we demonstrate a sulfide-nitrate “batterolyzer” with a discharge power density of 43.4 mW cm−2. This work reveals an effective proton-management strategy for efficient acidic NO3-RR, advancing its potential for coupled ammonia synthesis and wastewater treatment.
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Acknowledgements
This work was funded by National Key Research and Development Program of China (Grant No.: 2023YFB4004700, H. L.), Natural Science Foundation of Xiamen, China (Grant No.: 3502Z202473021, H. L.), Fundamental Research Funds for the Central Universities of China (Grant No.: 20720240066, H. L.), Basic Research Program of Jiangsu (Grant No.: BK20251079, W. Z.), Natural Science Research Project of Higher Education Institutions in Jiangsu Province (Grant No.: 25KJB150032, W. Z.), National Science and Technology Council in Taiwan (Grant No.: NSTC 114-2112-M-213-026-MY3; 114-2221-E-213-001-MY3, Y-G. L.), National Synchrotron Radiation Research Center in Taiwan(Y-G. L.), National Natural Science Foundation of China (Grant No.: 52501281, F. Y.), Natural Science Foundation of Jilin Province (Grant No.: YDZJ202301ZYTS296, F. Y.) and the Research Program on Science and Technology from the Education Department of Jilin Province (Grant No.: JJKH20240558KJ, F. Y.).
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W. Z. and H. L. conceived the project and wrote the paper. W. Z. and J. L. conducted the physical characterizations and electrochemical tests. Y-C. L. and Y.-G. L. conducted and analyzed the XAS experiments. M. Z. synthesized the catalysts. J. C., C. H., J. J. and F. Y. conducted and analyzed the AIMD and DFT calculations. X. W., Y. H., and G. Y. helped the material characterization and analysis. All authors contributed to the general discussion. W. Z., Y.-C. L., J. C., and M. Z. contributed equally to this work.
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Zhu, W., Lin, YC., Cong, J. et al. Reverse hydrogen spillover accelerates electrocatalytic nitrate reduction to ammonia on Ru/WO3-x in acidic media. Nat Commun (2026). https://doi.org/10.1038/s41467-026-69335-x
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DOI: https://doi.org/10.1038/s41467-026-69335-x
