N + N → N2 Reaction Rates on Rh(111)

Belton, David N.; DiMaggio, Craig L.; Ng, Koon‐Kwan

doi:10.1006/jcat.1993.1329

Cited by 77 publications

(48 citation statements)

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“…At relatively low initial ⍜ NO ͑curve 2͒ all NO ads molecules dissociate completely at TϽ400 K. In this case, NO desorption is not observed and N 2 desorption starts only at TϾ500 K. Figure 2͑d͒ demonstrates the results of simulation of the N 2 TPD spectra from N/Rh͑111͒ adlayer. These data describe rather well the results of Belton et al, 32 who studied N 2 desorption from a N adlayer on Rh͑111͒ obtained by electron beam dissociation. The experimental results demonstrate, that the kinetics of N ads ϩN ads reaction without complications due to NO ads dissociation were quite different from the kinetics of this reaction in the presence of NO and O adsorbates.…”

Section: N 2 Desorption From No and N Adlayerssupporting

confidence: 83%

“…32 The value of this shift is significantly greater, than the shift corresponding to the usual case of second order desorption kinetics and this may be due to the N ads -N ads repulsive interactions. The parameter for N ads -N ads interaction ⑀ 6,N , presented in the Table I, was obtained by fitting the shift of the N 2 TPD peak, observed in the experiments.…”

Section: N 2 Desorption From No and N Adlayersmentioning

confidence: 94%

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Kinetic oscillations and hysteresis phenomena in the NO+H2 reaction on Rh(111) and Rh(533): Experiments and mathematical modeling

Makeev

Slinko

Janssen

et al. 1996

The Journal of Chemical Physics

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Interesting kinetic phenomena, such as multiple steady states and kinetic oscillations recently found in the NOϩH 2 reaction over Rh͑533͒ and Rh͑111͒ single crystal surfaces in the 10 Ϫ6 mbar pressure range have been studied by means of experiments and computer modeling. A mathematical model, consisting of five ordinary differential equations and taking into account the lateral interactions in the adlayer, has been developed for simulating the NOϩH 2 /Rh͑533͒ and NOϩH 2 /Rh͑111͒ reactions. The simulation results make it possible to explain in detail the underlying reasons for the experimentally observed complex dynamic behavior. In particular, the kinetic oscillations and their properties have been reproduced. It was found that accumulation of NH ads species, which serves as an intermediate in the pathway of NH 3 production, is an important step in the oscillatory mechanism. In addition, the same mathematical model is able to successfully reproduce the experimental data concerning temperature programmed desorption ͑TPD͒ spectra, hysteresis phenomena, and the dependence of selectivity upon temperature and reactant partial pressures. Lateral interactions in the adlayer are shown to play a crucial role in the adequate simulation of the experimental observations.

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Section: N 2 Desorption From No and N Adlayerssupporting

confidence: 83%

Section: N 2 Desorption From No and N Adlayersmentioning

confidence: 94%

Kinetic oscillations and hysteresis phenomena in the NO+H2 reaction on Rh(111) and Rh(533): Experiments and mathematical modeling

Makeev

Slinko

Janssen

et al. 1996

The Journal of Chemical Physics

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“…On this surface, the dissociation of NO(a) and the reaction of NO(a)+N(a) proceed with comparable rates since a mixture of 15 N(a) and 14 NO(a) can be simply prepared just below the temperature of NO dissociation and desorption [6]. On the other hand, the recombination of N(a) is relatively enhanced at higher temperatures because of the high activation energy [1,5,49,50] and depleted NO(a) by increased desorption and dissociation [36]. Surface nitrogen atoms are also removed as ammonia, especially above the critical D 2 pressure.…”

Section: No+co Reactionmentioning

confidence: 99%

N2 emission-channel change in NO reduction over stepped Pd(211) by angle-resolved desorption

et al. 2012

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A sharp change in the N 2 emission channel from N 2 O(a)→N 2 (g) +O(a) to N(a)+N(a)→N 2 (g) has been found at around 500 K in a steady-state NO+D 2 reaction over stepped Pd(211)= [(S)3(111)×(100)] by means of angle-resolved desorption. The desorbing N 2 is highly collimated at around 30° off normal toward the step-down direction below about 500 K due to the intermediate N 2 O decomposition, whereas, above 500 K, the near normally directed desorption due to the recombination of N(a) is relatively enhanced. The N 2 O decomposition channel is promoted when the reaction is carried out with hydrogen (deuterium) and the channel change is accelerated by quick changes of the amounts of surface hydrogen and oxygen (or NO(a)) into the opposite directions, and enhanced nitrogen removal as ammonia on the resultant hydrogen-rich surface. In the steady-state NO+CO reaction, the N 2 emission channel gradually changes above 500 K toward recombination. A model for the off-normal N 2 emission is briefly described.

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“…The literature reports a number of methods for the preparation of atomic nitrogen layers. Belton et al 13 prepared N ads layers by dissociation of NO with an electron beam and a subsequent removal of O ads by reaction with CO. Bugyi et al 12 used a discharge tube to atomize nitrogen before adsorption. Another alternative to preparing N ads layers is exposure of the surface to NH 3 at temperatures above ∼400 K. [32][33][34] All the abovementioned preparation methods have the disadvantage that it is difficult to deposit a well-defined amount of atomic nitrogen.…”

Section: Introductionmentioning

confidence: 99%

Kinetics and Mechanism of NH₃ Formation by the Hydrogenation of Atomic Nitrogen on Rh(111)

1997

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The reaction between atomic nitrogen and H 2 has been studied in order to elucidate the mechanism of NH 3 formation on Rh(111). Atomic nitrogen layers of 0.10 monolayer (ML) coverage were obtained by adsorbing NO at 120 K and selectively removing the atomic oxygen from dissociated NO by reaction with H 2 at 375 K. The rate of NH 3 formation is first order in the atomic nitrogen coverage and linearly proportional to the H 2 pressure below 5 × 10 -7 mbar. Static secondary ion mass spectrometry (SSIMS) indicates that N and NH 2 are the predominant reaction intermediates, while small amounts of NH 3 are also detected. The NH 2 surface coverage increases with increasing H 2 pressure. The presence of NH 2 is also indicated by the appearance of a reaction-limited H 2 desorption state in temperature-programmed desorption (TPD) spectra. The hydrogenation of NH 2 to NH 3 is expected to be the rate-determining step in the NH 3 formation. From the temperature dependence of the NH 3 formation rate an effective activation energy of 40 kJ/mol was determined, which could be translated into an activation energy of 76 kJ/mol for the hydrogenation from NH 2 to NH 3 .

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N + N → N2 Reaction Rates on Rh(111)

Cited by 77 publications

References 0 publications

Kinetic oscillations and hysteresis phenomena in the NO+H2 reaction on Rh(111) and Rh(533): Experiments and mathematical modeling

Kinetic oscillations and hysteresis phenomena in the NO+H2 reaction on Rh(111) and Rh(533): Experiments and mathematical modeling

N2 emission-channel change in NO reduction over stepped Pd(211) by angle-resolved desorption

Kinetics and Mechanism of NH₃ Formation by the Hydrogenation of Atomic Nitrogen on Rh(111)

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N + N → N2 Reaction Rates on Rh(111)

Cited by 77 publications

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Kinetic oscillations and hysteresis phenomena in the NO+H2 reaction on Rh(111) and Rh(533): Experiments and mathematical modeling

Kinetic oscillations and hysteresis phenomena in the NO+H2 reaction on Rh(111) and Rh(533): Experiments and mathematical modeling

N2 emission-channel change in NO reduction over stepped Pd(211) by angle-resolved desorption

Kinetics and Mechanism of NH3 Formation by the Hydrogenation of Atomic Nitrogen on Rh(111)

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Kinetics and Mechanism of NH₃ Formation by the Hydrogenation of Atomic Nitrogen on Rh(111)