(666b) Ammonia Yields during Plasma-Assisted Catalysis Boosted By Hydrogen Sink Effect

Ammonia yields during plasma-assisted catalysis boosted by hydrogen sink effect

Javishk R. Shah,¹ Peter Psarras,² Bomsaerah Seong,² Diego A. Gómez-Gualdrón,² Maria L. Carreon*^,3

¹Russell School of Chemical Engineering, The University of Tulsa, 800 S. Tucker Dr, Tulsa, Oklahoma – 74104, US.

²Chemical and Biochemical Engineering Department, Colorado School of Mines, 1500 Illinois St, Golden, Colorado – 80401, US.

³Chemical and Biological Engineering Department, South Dakota School of Mines & Technology, 501 E. Saint Joseph St. Rapid City, SD, 57701, US

*corresponding author: mariacarreong@gmail.com

KEYWORDS: Plasma-Catalysis, Ammonia, Transition Metals, Molten Alloys, Gallium-rich alloys, Atomic H Catalysis, Synergistic Catalysis, Plasma-Catalyst Synergy

ABSTRACT

Plasma-catalytic ammonia synthesis is known since early 1900s but the possible reaction pathways are currently under investigation. In this article, we present the use of various transition metals and gallium-rich alloys for plasma-catalytic ammonia synthesis. The best three metallic catalysts were identified to be Ni, Sn and Au with the highest ammonia yield of 34%. Furthermore, as compared to its constituent metals some alloys presented about 25-50% better yields. The metals employed were classified in two different categories according to their behavior during ammonia plasma-catalysis. Category I metals are nitrophobic and the measured concentration of Hα in the gas phase inversely correlates with ammonia yield and directly correlates with the binding strength of H on the catalyst surface. Whereas for metals in Category II, the concentration of Hα tend to be lower than for category I metals, consistent with their theoretical predicted behavior as hydrogen sinks. For these metals, the concentration of Hα correlates with ammonia yield.