(745a) Kinetic Evaluation of N2 Activation in Plasma Catalytic Ammonia Synthesis
AIChE Annual Meeting
2018
2018 AIChE Annual Meeting
Catalysis and Reaction Engineering Division
Fundamentals of Catalysis V
Friday, November 2, 2018 - 12:30pm to 12:48pm
Non-thermal plasma is an emerging technology that has recently gained interest for a wide range of applications. The reactive species generated in the plasma phase make it highly attractive as a way to activate and convert stable molecules. In particular, combining non-thermal plasmas with a solid catalyst has garnered significant attention for promoting reactivity at mild conditions compared to the thermal reaction1. Plasma catalysis has been applied to a number of reactions, mostly focusing on the activation of stable bonds, such as aliphatic C-H bonds2 and CO23. Of particular interest is the activation of N2 at low temperatures and atmospheric pressure4. Catalytic enhancement of plasma ammonia synthesis has been demonstrated repeatedly over a wide range of catalysts5; however, the mechanism for this enhancement remains under-investigated. In this study, we present our recent results on the interaction between reactive species in the plasma phase with metal surfaces. In particular, we are interested in how vibrationally excited N2 species promote ammonia production at mild conditions. Through kinetic experiments of this reaction we evaluate the role of activated N2 in the plasma phase in driving catalytic enhancement6. This is done through 1) characterization of plasma properties, such as N2 vibrational temperature, 2) rate measurements and determination of the rate orders for this reaction with respect to N2 and H2 over Ni, Fe, Ru, and Co catalysts, and 3) the measurement of energy barriers for the plasma catalytic reaction on each catalyst studied.
(1) Neyts, E. C.; Ostrikov, K.; Sunkara, M. K.; Bogaerts, A. Chem. Rev. 2015, 115 (24), 13408–13446.
(2) Kim, J.; Go, D. B.; Hicks, J. C. Phys. Chem. Chem. Phys. 2017, 19 (4), 13010–13021.
(3) Nizio, M.; Benrabbah, R.; Krzak, M.; Debek, R.; Motak, M.; Cavadias, S.; Gálvez, M. E.; Da Costa, P. Catal. Commun. 2016, 83, 14–17.
(4) Patil, B. S.; Wang, Q.; Hessel, V.; Lang, J. Catal. Today 2015, 256, 49–66.
(5) Mizushima, T.; Matsumoto, K.; Ohkita, H.; Kakuta, N. Plasma Chem. Plasma Process. 2007, 27 (1), 1–11.
(6) Mehta, P.; Barboun, P.; Herrera, F. A.; Kim, J.; Rumbach, P.; Go, D. B.; Hicks, J. C.; Schneider, W. F. Nat. Catal. 2018, No. 4.