Details

Autor(en) / Beteiligte

• Winter, Lea R
• Ashford, Bryony
• Hong, Jungmi
• Murphy, Anthony B
• Chen, Jingguang G

Titel

Identifying Surface Reaction Intermediates in Plasma Catalytic Ammonia Synthesis

Ist Teil von

• ACS catalysis, 2020-12, Vol.10 (24), p.14763-14774

Ort / Verlag

United States: American Chemical Society

Erscheinungsjahr

2020

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Ammonia synthesis by plasma catalysis has emerged as an alternative process for decoupling nitrogen fixation from fossil fuels. Plasma activation can potentially circumvent the limitations of conventional thermocatalytic ammonia synthesis; however, the contribution of different reaction mechanisms to the production of ammonia at the catalyst surface remains unclear. Here, we identify the reaction intermediates adsorbed on γ-Al2O3-supported Ni and Fe catalysts during plasma-activated ammonia synthesis under various temperatures and reactor configurations using FTIR spectroscopy, steady-state flow reactor experiments, and computational kinetic modeling. Ammonia yield can be influenced by plasma-derived intermediates and their interactions with catalyst surfaces, which lead to different reaction pathways: Ni/γ-Al2O3 enhances plasma-promoted NH3 production and favors surface-adsorbed NH x species, while Fe/γ-Al2O3 shows the presence of N2H y and a lower overall concentration of N-containing adsorbates. Plasma–catalyst interactions are probed to reveal that elevated temperature and plasma irradiation of the surfaces promote NH3 desorption. The direct evidence of catalytic surface reactions occurring during a plasma-activated process provides mechanistic insight into plasma-activated ammonia synthesis.