Plasma Synthesis of Ammonia in Presence of an Iron Catalyst

Abstract

Plasma chemistry / Catalysis j Ammonia synthesisIn an alternating current glow discharge with internal aluminum electrodes the reaction of nitrogen and hydrogen at~10 Torr was characterized by ammonia formation and a bright emission which was analyzed for excited states of N2, N2, H, NH and NH2. A significant amount of ammonia was formed only when the plasma gas was passed through a cold trap at temperatures below 110 K. When an iron catalyst in the form of a mesh was placed in the plasma zone more ammonia was formed in the cold trap than when the plasma gas was passed over the catalyst placed downstream from the plasma. Increasing the catalyst temperature increased ammonia formation suggesting that more ammonia precursors such as NH and NH2 were formed on the catalyst surface.In einer Wechselstrom-Glimmentladung zwischen inneren Aluminiumelektroden war die Reaktion zwischen Stickstoff und Sauerstoff bei etwa 10 Torr gekennzeichnet durch Ammoniakbildung und eine helle Lichtemission, die auf angeregte Zustände von N2, N2 , H, NH und NH2 analysiert wurde. Merkliche Mengen von Ammoniak wurden nur gebildet, wenn das Plasmagas durch eine Kühlfalle bei Temperaturen unter 110 strömte. Wenn ein netzförmiger Eisenkatalysator in die Plasmazone gebracht worden war, wurde in der Kühlfalle mehr Ammoniak gebildet als wenn das Plasmagas über den Katalysator erst stromabwärts vom Plasma strömte.Steigende Katalysator-Temperatur steigerte die Ammoniakbildung und deutete daraufhin, daß an der Katalysator-Oberfläche mehr Ammoniak-Vorläufer wie NH und NH2 gebildet wurden.

Synthesis of ammonia using microwave discharge at atmospheric pressure

“…We adopted ammonia synthesis for the following reasons: (1) ammonia synthesis is a simple reaction system that produces no solid products; (2) stable discharge can be generated continually during the experiment; and (3) ammonia can be measured accurately using an established analytical technique in the case of very low concentrations of ammonia. Moreover, studies of the synthesis of ammonia using non-equilibrium plasmas have already been reported at reduced pressures [2][3][4][5][6][7][8] as well as at atmospheric pressure using only a few low-frequency discharges [9,10]. Therefore, we can utilize the previous data for comparison with those of the present study in an attempt to more fully understand the plasma chemistry of ammonia synthesis.…”

“…According to a report on ammonia production utilizing discharges, ammonia is considered to be produced via NH radicals as an intermediate [2]:…”

Mass Spectrometry Study of Ammonia Formed During Plasma Nitrocarburizing and Nitriding Processes

“…The lack of points above 450ºC makes it difficult to establish it. However, this maximum value is considerably higher than that measured by Botchway 24 for the stoichiometric ammonia formed by heterogeneous catalysis when using Fe surface as catalyst in N 2 -H 2 glow discharges in similar conditions of pressure, and which was found to be around 600K (327ºC). The curve profiles also are different in the two cases.…”

Plasma-driven catalysis: green ammonia synthesis with intermittent electricity

“…224,225 An afterglow normally describes the effluent of a plasma reactor. However, the term is sometimes used more broadly to indicate that ( plasma) species are no longer exposed to The listed plasma reactors are dielectric barrier discharge (DBD), 96,131,142,[143][144][145][146][147][148][149][150][151][152][153][154][155][156][157][158][159][160][161][162][163][164][165][166][167][168][169] (low pressure) glow discharge (GD), 170,171,[172][173][174][175][176][177][178][179]180 microwave plasma (MW), [181][182][183][184][185]…”

“…262,265,266 Between 1980 and 2000, low pressure glow discharges (LPGDs) received a lot of attention. 170,171,[173][174][175][176][177][178][179][180][181][182][183][267][268][269][270][271][272] In these publications, the surface (both catalytic and non-catalytic) was often related to the ammonia formation. Ions, more specifically N 2 + and N 2 H + , were often mentioned to play an important role in the formation of ammonia.…”