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DOE OSTI · 3374681

Lattice-Nitrogen-Mediated Chemistry Suppresses Hydrogen Evolution for Record Faradaic Efficiency in Ammonia Synthesis

Yesudoss, David Kumar [Texas A & M Univ., College Station, TX (United States)]·Lai, Hao-En [Texas A & M Univ., College Station, TX (United States)]·Johnson, Denis [Texas A & M Univ., College Station, TX (United States)]·Lee, Mark [Texas A & M Univ., College Station, TX (United States)]·Reinhart, Benjamin [Argonne National Laboratory (ANL), Argonne, IL (United States)]·Balbuena, Perla B. [Texas A & M Univ., College Station, TX (United States)] (ORCID:0000000223583910)·Djire, Abdoulaye [Texas A & M Univ., College Station, TX (United States)] (ORCID:0000000307345952)
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Abstract

Ammonia (NH 3 ) production using air, water, and electricity offers a transformative route to carbon-free chemical synthesis, addressing global sustainability challenges. However, the hydrogen evolution reaction (HER) in aqueous systems significantly hinders NH 3 selectivity, limiting Faradaic efficiency (FE) to below ~15%. Here, we report an FE of approximately 48%, the highest recorded for aqueous NH 3 synthesis, using two-dimensional (2D) nitride catalysts. These catalysts enable lattice nitrogen protonation through the Mars-van Krevelen (MvK) mechanism, effectively suppressing HER. Using operando spectroelectrochemistry, we identified active sites and tracked nitrogen vacancy cycles, providing unprecedented insights into the reaction pathways. Our findings, supported by advanced computational techniques and complementary spectroscopic analyses, highlight the stability and efficiency of the MvK cycle, setting a new benchmark for sustainable NH 3 production.

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Yesudoss, David Kumar [Texas A & M Univ., College Station, TX (United States)], Lai, Hao-En [Texas A & M Univ., College Station, TX (United States)], Johnson, Denis [Texas A & M Univ., College Station, TX (United States)], Lee, Mark [Texas A & M Univ., College Station, TX (United States)], Reinhart, Benjamin [Argonne National Laboratory (ANL), Argonne, IL (United States)], Balbuena, Perla B. [Texas A & M Univ., College Station, TX (United States)] (ORCID:0000000223583910), Djire, Abdoulaye [Texas A & M Univ., College Station, TX (United States)] (ORCID:0000000307345952). 2025-08-13. Lattice-Nitrogen-Mediated Chemistry Suppresses Hydrogen Evolution for Record Faradaic Efficiency in Ammonia Synthesis. https://doi.org/10.1021/jacs.5c09104

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