Microporous crystals have emerged as highly
appealing catalytic materials for the plasma catalytic synthesis of
ammonia. Herein, we demonstrate that zeolitic imidazolate
frameworks (ZIFs) can be employed as efficient catalysts for the
cold plasma ammonia synthesis using an atmospheric dielectric
barrier discharge reactor. We studied two prototypical ZIFs
denoted as ZIF-8 and ZIF-67, with a uniform window pore
aperture of 3.4 Å. The resultant ZIFs displayed ammonia synthesis
rates as high as 42.16 μmol NH3/min gcat. ZIF-8 displayed
remarkable stability upon recycling. The dipole−dipole inter-
actions between the polar ammonia molecules and the polar walls
of the studied ZIFs led to relatively low ammonia uptakes, low
storage capacity, and high observed ammonia synthesis rates. Both
ZIFs outperform other microporous crystals including zeolites and
conventional oxides in terms of ammonia production. Furthermore, we demonstrate that the addition of argon to the reactor chamber can be an effective strategy to improve the plasma environment. Specifically, the presence of argon helped to improve the plasma uniformity, making the reaction system more energy efficient by operating at a low specific energy input range allowing abundant formation of nitrogen vibrational species.
KEYWORDS: nonthermal plasma, plasma catalysis, ammonia synthesis, zeolitic imidazolate frameworks, ammonia adsorption effect
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Plasma-Induced Catalytic Conversion of Nitrogen and Hydrogen to Ammonia over Zeolitic Imidazolate Frameworks ZIF-8 and ZIF-67
Microporous crystals have emerged as highly appealing catalytic materials for the plasma catalytic synthesis of ammonia. Herein, we demonstrate that zeolitic imidazolate frameworks (ZIFs) can be employed as efficient catalysts for the cold plasma ammonia synthesis using an atmospheric dielectric barrier discharge reactor. We studied two prototypical ZIFs denoted as ZIF-8 and ZIF-67, with a uniform window pore aperture of 3.4 Å. The resultant ZIFs displayed ammonia synthesis rates as high as 42.16 μmol NH3/min gcat. ZIF-8 displayed remarkable stability upon recycling. The dipole–dipole interactions between the polar ammonia molecules and the polar walls of the studied ZIFs led to relatively low ammonia uptakes, low storage capacity, and high observed ammonia synthesis rates. Both ZIFs outperform other microporous crystals including zeolites and conventional oxides in terms of ammonia production. Furthermore, we demonstrate that the addition of argon to the reactor chamber can be an effective strategy to improve the plasma environment. Specifically, the presence of argon helped to improve the plasma uniformity, making the reaction system more energy efficient by operating at a low specific energy input range allowing abundant formation of nitrogen vibrational species.
more »
« less
- Award ID(s):
- 1947303
- NSF-PAR ID:
- 10229117
- Date Published:
- Journal Name:
- ACS applied materials interfaces
- ISSN:
- 1944-8252
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/doi.org/10.1021/acsami.1c03115.s001
