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Title: Electride support boosts nitrogen dissociation over ruthenium catalyst and shifts the bottleneck in ammonia synthesis

We actively sough novel approaches to efficient ammonia synthesis at an ambient pressure so as to reduce the cost of ammonia production and to allow for compact production facilities. It is accepted that the key is the development of a high-performance catalyst that significantly enhances dissociation of the nitrogen-nitrogen triple bond, which is generally considered a rate-determining step. Here we examine the kinetics of nitrogen and hydrogen isotope exchange and hydrogen adsorption/desorption reactions for a recently discovered efficient catalyst for ammonia synthesis --ruthenium-loaded 12CaO∙7AI2O3 electride (Ru/C12A7:$$\bar{e}$$ )--and find that the rate controlling step of ammonia synthesis over Ru/C12A7:$$\bar{e}$$ is not dissociation of the nitrogen-nitrogen triple bond but the subsequent formation of N-Hn species. A mechanism of ammonia synthesis involving reversible storage and release of hydrogen atoms on the Ru/C12A7:$$\bar{e}$$ surface is proposed on the basis of observed hydrogen adsorption/desorption kinetics.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8]
  1. Tokyo Inst. of Technology (Japan). Materials Research Center for Element Strategy
  2. Tokyo Inst. of Technology (Japan). Materials and Structures Lab.
  3. Tokyo Inst. of Technology (Japan). Materials and Structures Lab.
  4. Univ. College London (UCL), London (United Kingdom). Dept. of Physics and Astronomy
  5. Pacific Northwest National Lab. (PNNL), Richland, WA (United States); ACCEL, Japan Science and Technology Agency, Kawaguchi (Japan)
  6. Tokyo Inst. of Technology (Japan). Materials Research Center for Element Strategy; ACCEL, Japan Science and Technology Agency, Kawaguchi (Japan)
  7. Tokyo Inst. of Technology (Japan). Materials and Structures Lab.; ACCEL, Japan Science and Technology Agency, Kawaguchi (Japan); Tokyo Inst. of Technology (Japan). Frontier Research Center
  8. Tokyo Inst. of Technology (Japan). Materials Research Center for Element Strategy; Tokyo Inst. of Technology (Japan). Materials and Structures Lab.; ACCEL, Japan Science and Technology Agency, Kawaguchi (Japan); Tokyo Inst. of Technology (Japan). Frontier Research Center
Publication Date:
OSTI Identifier:
1260712
Grant/Contract Number:
EP/ L000202
Type:
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 6; Journal ID: ISSN 2041-1723
Publisher:
Nature Publishing Group
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY