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Anion vacancies on metal oxide surfaces have been studied as either active sites or promoting sites in various chemical reactions involving oxidation/reduction processes. However, oxide materials rarely work effectively as catalysts in the absence of transition metal sites. Here we report a Ba–Si orthosilicate oxynitride–hydride as a transition-metal-free catalyst for efficient ammonia synthesis via an anion-vacancy-mediated mechanism. The facile desorption of H− and N3− anions plus the flexibility of the crystal structure can accommodate a high density of electrons at vacancy sites, where N2 can be captured and directly activated to ammonia through hydrogenation processes. The ammonia synthesis rates reach 40.1 mmol g−1 h−1 at 300 °C by loading ruthenium nanoparticles. Although not found to dissociate N2, Ru instead facilitates the formation of anion vacancies at the Ru–support interface. This demonstrates a new route for anion-vacancy-mediated heterogeneous catalysis.

Rights:

• Creative Commons BY-NC-ND Attribution-NonCommercial-NoDerivs 4.0 International
  

Keyword: catalyst, ammonia synthesis, hydride

Date published: 2025-02-17

Publisher: Springer Science and Business Media LLC

Journal:

• Nature Chemistry (ISSN: 17554349) vol. 17 p. 679-687

Funding:

• Japan Science and Technology Agency JPMJFR203A (FOREST Program)
• JSPS JP22H00272 (Kakenhi Grants-in-Aid)
• JSPS JP24H02203 (Kakenhi Grants-in-Aid)
• JSPS JPH02204 (Kakenhi Grants-in-Aid)
• Japan Science and Technology Agency JPMJMI21E9 (JST-Mirai Program)
• NEDO JPNP21012
• JSPS JP21F21032 (JSPS fellowship for International Research Fellows)

Manuscript type: Publisher's version (Version of record)

MDR DOI:

First published URL: https://doi.org/10.1038/s41557-025-01737-8

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Updated at: 2025-11-10 16:30:48 +0900

Published on MDR: 2025-11-10 16:25:02 +0900