The decomposition of ammonia on the flat (111) and stepped (557) platinum crystal surfaces

Guthrie, W. L.; Sokol, Jason; Somorjai, Gábor A.

doi:10.1016/0039-6028(81)90496-9

Cited by 46 publications

(24 citation statements)

References 20 publications

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“…Pure ammonia does not decompose noteably on Pt surfaces below 600 K, whereas with oxygen the rate of decomposition is considerable [19,45]. On the oxygen covered stepped Pt surfaces studied here a high reactive sticking coefficient of ammonia reaching 0.2 also supports this idea [18].…”

Section: Discussionsupporting

confidence: 63%

Kinetics of ammonia oxidation on stepped platinum surfaces

2005

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Section: Discussionsupporting

confidence: 63%

Kinetics of ammonia oxidation on stepped platinum surfaces

2005

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“…Reactions proposed for the activation of ammonia molecules on Pt surfaces are decomposition [46,54,55], reaction with adsorbed oxygen atoms [56,57], and reaction with adsorbed hydroxyl groups, where OH ads is generated by NH x + O interactions [19,[57][58][59][60]. DFT studies [61] confirmed that stepwise abstraction of hydrogen atoms from NH 3 by reaction with O and OH are fast compared to decomposition of NH x , and that the reaction path of ammonia decomposition can therefore be neglected.…”

Section: Suggested Reaction Mechanismmentioning

confidence: 65%

Kinetics of ammonia oxidation over Pt foil studied in a micro-structured quartz-reactor

Kraehnert

Baerns

2008

Chemical Engineering Journal

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The kinetics of Pt-catalyzed ammonia oxidation on polycrystalline Pt were investigated at partial pressures of ammonia and oxygen up to 6 kPa and temperatures between 286 and 385• C, applying a micro-structured reactor that ascertained temperature control of the exothermic reaction. Using literature-based mechanistic models, a micro-kinetic model was derived based on parameter optimization and a model discrimination procedure. The model described the rates of formation of all nitrogen-containing products, i.e. N 2 , N 2 O and NO. Catalyst characterization of platinum samples by electron microscopy indicated that reaction-induced restructuring of the Pt surface limited the accuracy of derived kinetic parameters already at the low temperature applied in this work. Despite of necessary simplifications, the best-fitting kinetic model predicted reasonable product selectivities for the reaction conditions of an industrial ammonia burner.

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“…investigated [126][127][128][129][130][131][132][133][134][135]. These studies have been undertaken primarily to acquire insights into the industrially important ammonia synthesis process.…”

Section: Molecular Beam Epitaxymentioning

confidence: 99%

Growth of GaN from elemental Gallium and Ammonia via Modified Sandwich Growth Technique

et al. 2004

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Gallium nitride (GaN) films were grown on (0001) sapphire substrates at 1050°C by controlled evaporation of gallium (Ga) metal and reaction with ammonia (NH3) at a total reactor pressure of 800 Torr. Pure nitrogen (N2) was flowed directly above the molten Ga source to prevented direct reaction between the molten Ga and ammonia, which causes Ga spattering and GaN crust formation. At the same time, this substantially enhanced the Ga transport to the substrate. A simple mass-transport model based on total reactor pressure, gas flow rates and source temperature was developed and verified. The theoretical calculations and growth rate measurements at different ammonia flow rates and reactor pressures showed that the maximum growth rate was controlled by transport of both Ga species and reactive ammonia to the substrate surface.

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The decomposition of ammonia on the flat (111) and stepped (557) platinum crystal surfaces

Abstract: Ammonia adsorptions desorption and decomposition to H 2 and N 2 has been studied on the flat (lll) and stepped (557)

Cited by 46 publications

References 20 publications

Kinetics of ammonia oxidation on stepped platinum surfaces

Kinetics of ammonia oxidation on stepped platinum surfaces

Kinetics of ammonia oxidation over Pt foil studied in a micro-structured quartz-reactor

Growth of GaN from elemental Gallium and Ammonia via Modified Sandwich Growth Technique

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