Abstract
The electrocatalytic reduction of nitrate (NO3−) and nitrite (NO2−) to ammonia (NH3), herein NOxRA, has recently attracted much attention in the broader field of NOx− electroreduction (NOxER), particularly in catalyst development. Many promising NOxRA catalysts have been reported, though translation of these catalysts into devices and processes remains limited. This appears to be partially correlated to the catalyst testing conditions employed. Herein, the electrolytes reported in 411 papers published from January 2023 to June 2024 were compared to the compositions of NOx−-laden water sources. Approximately 60% of these papers employed pH and NO3−/NO2− concentration ([NOx−]) combinations matching water sources with very limited potential as NOxRA feedstocks. This suggests a large proportion of NOxRA catalyst research targets scenarios where NOxRA will be inherently ineffective. To aid translation of research to application, this perspective suggests criteria by which suitable NOxRA, and more broadly, NOxER, feedstocks might be identified, to mimic relevant conditions for catalyst testing through: (i) appropriate matching of pH and [NOx−], (ii) explicit selection of the substrate (i.e. NO3− and/or NO2−), and (iii) inclusion of other expected species. Using this approach, recommended conditions are provided for two examples of viable NOx−-laden feedstocks.
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Acknowledgements
A.M.L.F. acknowledges the Westpac Future Leaders Scholarship and Australian Government RTP stipend. This work was supported by the Australian Research Council (grant Nos. CE230100032 and DP220101511). Certain data included herein are derived from Clarivate™ (Web of Science™). © Clarivate 2025. All rights reserved.
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A.M.L.F. performed the literature search and extracted the electrolyte composition data from the papers. A.M.L.F. drafted the initial manuscript. A.M.L.F., C.B., A.K.L.Y., A.F.M., and T.M. contributed to refining and editing the manuscript. A.F.M. and T.M. jointly supervised the work.
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Frisina, A.M.L., Barnett, C., Yuen, A.K.L. et al. A systematic critique of electrolyte choices in recent literature on the electrochemical reduction of NOx−. Commun Chem (2025). https://doi.org/10.1038/s42004-025-01824-4
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DOI: https://doi.org/10.1038/s42004-025-01824-4
