Effect of K, Cs and Ba on the kinetics of NH3 synthesis over carbon-based ruthenium catalysts
Wioletta Raróg-Pilecka , Zbigniew Kowalczyk , Jan Sentek , Dominik Składanowski , Jerzy Zieliński
AbstractThe kinetics of NH3 synthesis over carbon-based ruthenium catalysts promoted with barium or alkali was studied. Both the ammonia partial pressure dependencies of the reaction rates (T = 400°C, p = 63 bar, H2 : N2 = 3 : 1) and the pressure variations of the activity (T = 370°C, p= 4–63 bar, H2 : NN2 = 3 : 1) were found to be different for Ba and for the alkali (K, Cs). Ba–Ru/C proved to be more sensitive to the NH3 content and to the total pressure. The rate of synthesis over the alkali-promoted catalysts is, in turn, much stronger influenced by the ruthenium dispersion. TOFs of NH3 synthesis for the promoted samples at 370°C and 4 bar (Ba 0.085 1/s, Cs 0.05 1/s, K 0.035 1/s) are significantly higher than that for the Ru(0001) basal plane (0.0085 1/s results from the literature data at 370°C, 2 bar). The most active Ru/C samples (Ba or Cs) exceed significantly the fused iron catalyst, especially at high conversions.
|Journal series||Catalysis Letters, ISSN 1011-372X, 1572-879X|
|Keywords in English||Ammonia synthesis, Catalysis, Industrial Chemistry/Chemical Engineering, Kinetics, Pharmacy, Physical Chemistry, promotional effect, Ruthenium catalysts|
|Publication indicators||= 70; = 69.0|
|Citation count*||69 (2015-04-16)|
* presented citation count is obtained through Internet information analysis and it is close to the number calculated by the Publish or Perish system.