In search of the bottlenecks of ammonia synthesis over Ru/Vulcan under ambient conditions

ASLAN M. Y., Mete E., ÜNER D.

FARADAY DISCUSSIONS, cilt.243, sa.0, ss.164-178, 2023 (SCI-Expanded) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 243 Sayı: 0
  • Basım Tarihi: 2023
  • Doi Numarası: 10.1039/d2fd00173j
  • Dergi Adı: FARADAY DISCUSSIONS
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Biotechnology Research Abstracts, Chemical Abstracts Core, Compendex, EMBASE, INSPEC, MEDLINE, Metadex
  • Sayfa Sayıları: ss.164-178
  • Uşak Üniversitesi Adresli: Evet

Özet

Hydrogenation of the N-N bond under ambient conditions over 1 wt% Ru/Vulcan was monitored through operando Diffuse Reflectance Infrared Spectroscopy (DRIFTS) and DFT. IR signals centered at 3017 cm−1 and 1302 cm−1 were visible with attributes similar to the asymmetric stretching and bending vibrations of gas phase ammonia at 3381 cm−1 and 1650 cm−1. The intensities of the signals increased with consecutive H2 : Ar and N2 flow cycles at room temperature and atmospheric pressure due to accumulation of the formed NHX on the catalyst surface. DFT estimations revealed that a compound with a molecular stoichiometry of N-NH3 can give rise to an IR signal centered at 3051.9 cm−1. The results of this study, combined with the known vapor liquid phase behavior of ammonia, suggest that under subcritical conditions, the bottlenecks of ammonia synthesis are both N-N bond dissociation and ammonia desorption from the pores of the catalyst.