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Potassium hydride-intercalated graphite as an efficient heterogeneous catalyst for ammonia synthesis

Author
Abstract

Due to the high energy needed to break the N ≡ N bond (945 kJ mol−1), a key step in ammonia production is the activation of dinitrogen, which in industry requires the use of transition metal catalysts such as iron (Fe) or ruthenium (Ru), in combination with high temperatures and pressures. Here we demonstrate a transition-metal-free catalyst—potassium hydride-intercalated graphite (KH 0.19 C 24)—that can activate dinitrogen at very moderate temperatures and pressures. The catalyst catalyses NH3 synthesis at atmospheric pressure and achieves NH3 productivity (µmolNH3 gcat−1 h−1) comparable to the classical noble metal catalyst Ru/MgO at temperatures of 250–400 °C and 1 MPa. Both experimental and computational calculation results demonstrate that nanoconfinement of potassium hydride between the graphene layers is crucial for the activation and conversion of dinitrogen. Hydride in the catalyst participates in the hydrogenation step to form NH3. This work shows the promise of light metal hydride materials in the catalysis of ammonia synthesis.

Year of Publication
2022
Journal
Nature Catalysis
Volume
5
Issue
3
Number of Pages
222–230
URL
https://research.tue.nl/en/publications/potassium-hydride-intercalated-graphite-as-an-efficient-heterogen
DOI
10.1038/s41929-022-00754-x
Dataset
10.1038/s41929-022-00754-x
PId
93ee2275de0e9ef091eaaa0110d76f32
Alternate Journal
Nat. Catal.
Label
OA
Journal Article
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