Plasma chemical synthesis. I. Effect of electrode material on the synthesis of ammonia

Yin, Khin Swe; Venugopalan, M.

doi:10.1007/bf00564632

Cited by 63 publications

(68 citation statements)

References 19 publications

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“…This seems to be in contrast to experiments of various research groups in the world, in which it was shown that the ammonia production is dependent on the type of wall material, e.g., iron, stainless-steel, copper, nickel, silver, aluminum, Pyrex, zinc, or platinum. [9][10][11][12][13] However, a major difference with our experiments is that in those experiments the wall is used to form adsorbed nitrogen atoms by the dissociative adsorption We observed that the ammonia molar fraction is independent of the two wall materials studied, which indicates that the N and H flux to the surface is most likely not changed by an a-SiN x deposited wall. The high N and H flux to the surface leads to a surface covered with N and H radicals and other molecular radicals.…”

Section: Influence Of Surface Materials On Ammonia Productionmentioning

confidence: 72%

“…It was shown by various research groups that ammonia production using plasmas is dependent on the type of wall material ͑up to a factor of 3͒. [10][11][12][13] The wall is namely still used as a catalyst to form adsorbed nitrogen atoms by the dissociative adsorption of excited N 2 molecules or molecular nitrogen ions. In 1989, Uyama and Matsumoto reported that zeolite added to the downstream plasma in high-frequency discharges facilitated the ammonia production.…”

Section: Introductionmentioning

confidence: 99%

“…Plasmas containing nitrogen and hydrogen are also extensively studied because of their widespread applications in research and industrial environments. The plasmas are used for the chemical synthesis of ammonia, 9,11,14 nitriding of materials, 17 the deposition of amorphous silicon nitride ͑a-SiN x :H͒ films for solar cell applications, 19 the plasma-assisted atomic layer deposition of TiN thin films, 20 and the etching of organic low k films. 21 Previously, we have shown that ammonia can be formed efficiently in plasmas generated from mixtures of nitrogen and hydrogen via plasma-activated catalysis.…”

Section: Introductionmentioning

confidence: 99%

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Detailed study of the plasma-activated catalytic generation of ammonia in N2-H2 plasmas

Helden¹,

Wagemans²,

Yagci³

et al. 2007

Journal of Applied Physics

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We investigated the efficiency and formation mechanism of ammonia generation in recombining plasmas generated from mixtures of N 2 and H 2 under various plasma conditions. In contrast to the Haber-Bosch process, in which the molecules are dissociated on a catalytic surface, under these plasma conditions the precursor molecules, N 2 and H 2 , are already dissociated in the gas phase. Surfaces are thus exposed to large fluxes of atomic N and H radicals. The ammonia production turns out to be strongly dependent on the fluxes of atomic N and H radicals to the surface. By optimizing the atomic N and H fluxes to the surface using an atomic nitrogen and hydrogen source ammonia can be formed efficiently, i.e., more than 10% of the total background pressure is measured to be ammonia. The results obtained show a strong similarity with results reported in literature, which were explained by the production of ammonia at the surface by stepwise addition reactions between adsorbed nitrogen and hydrogen containing radicals at the surface and incoming N and H containing radicals. Furthermore, our results indicate that the ammonia production is independent of wall material. The high fluxes of N and H radicals in our experiments result in a passivated surface, and the actual chemistry, leading to the formation of ammonia, takes place in an additional layer on top of this passivated surface.

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Section: Influence Of Surface Materials On Ammonia Productionmentioning

confidence: 72%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Detailed study of the plasma-activated catalytic generation of ammonia in N2-H2 plasmas

Helden¹,

Wagemans²,

Yagci³

et al. 2007

Journal of Applied Physics

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“…The reaction yield is low (15%) but residual gases can be recycled, increasing thus the efficiency up to 98%. Similar methods have been experimented using an iron catalytic electrode, placed within an N 2 -H 2 discharge or in the discharge afterglow to produce NH 3 [23][24][25] or hydrazine [26] or for nitriding treatments of iron [27]. Different discharges have been tested like dc and ac discharge current, rf, and microwave discharge.…”

Section: N X H Y Radicals and Molecules Produced In Ar-n 2 -H 2 Expanmentioning

confidence: 99%

A Thermochemical Process Using Expanding Plasma for Nitriding Thin Molybdenum Films at Low Temperature

Jauberteau¹,

Jauberteau²,

Touimi³

et al. 2012

ENG

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The mechanical and chemical properties of transition metal nitrides are very attractive for numerous industrial applications. Thin nitride films are expected to be good diffusion barrier in microelectronic devices. Nitrogen diffuses into the whole thickness of the molybdenum film heated at low temperature and exposed to expanding plasma of (Ar-N 2 -H 2 ) compared with pure N 2 plasma. NH x species in the plasma are produced by different homogeneous or heterogeneous reactive mechanisms that results in an expansion of the plasma compared with pure N 2 plasma. NH x species and probably H atoms improve the transfer of nitrogen into the metal by preventing the formation of MoO 2 oxides which act as a barrier of diffusion for nitrogen.

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“…A few research groups reported nonbiological catalytic reduction of nitrogen to ammonia at ambient temperature and pressure with catalysts including metal centers [5][6][7][8][9]. On the other hand, some studies have reported the production of NH 3 from nitrogen and hydrogen using non-equilibrium plasmas at low pressure [10][11][12][13][14], or atmospheric pressure [15,16]. Active nitrogen species in plasmas such as N, N 2 + and N 2 * play an important role in ammonia synthesis in which no catalysis is necessary.…”

Section: Synthesis Of Ammonia Through Direct Chemical Reactions Betwementioning

confidence: 99%

Synthesis of Ammonia through Direct Chemical Reactions between an Atmospheric Nitrogen Plasma Jet and a Liquid

Kubota

Koga

Ohno

et al. 2010

Plasma and Fusion Research

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Fundamental chemical reactions between an atmospheric nitrogen plasma jet and water or a water/ethanol solution have been investigated. When the nitrogen plasma jet was injected directly into pure water, active nitrogen species produced nitric acid and ammonia through fatal reactions with H 2 O. The interaction between nitrogen plasma and a liquid mixture of pure water and ethanol produced NH 4 + ions effectively. These experimental results clearly show that the active nitrogen species in the pulsed-discharge atmospheric plasma can interact strongly with materials in solution to extract oxygen or hydrogen from them and add atomic nitrogen to them.

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Plasma chemical synthesis. I. Effect of electrode material on the synthesis of ammonia

Cited by 63 publications

References 19 publications

Detailed study of the plasma-activated catalytic generation of ammonia in N2-H2 plasmas

Detailed study of the plasma-activated catalytic generation of ammonia in N2-H2 plasmas

A Thermochemical Process Using Expanding Plasma for Nitriding Thin Molybdenum Films at Low Temperature

Synthesis of Ammonia through Direct Chemical Reactions between an Atmospheric Nitrogen Plasma Jet and a Liquid

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