Hysteresis and oscillations in the selectivity during the NO-H2 reaction over Rh(533)

Janssen, N.M.H.; Cobden, P.D.; Nieuwenhuys, B.E.; Ikai, Masamichi; Mukai, Kozo; Tanaka, Kenichi

doi:10.1007/bf00807013

Cited by 28 publications

(28 citation statements)

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“…However, the main features of observed oscillations for both catalysts are as follows: [14][15][16] ͑1͒ Oscillatory behavior could be obtained on the cooling branch of the temperature hysteresis. Above a H 2 /NO ratio of about eight some peaks in the N 2 formation rate appear during the cooling period.…”

Section: Experimental Observationsmentioning

confidence: 94%

“…This species can be attributed to either subsurface oxygen or NH x . 13 The first observations of rate oscillations and hysteresis phenomena in the NOϩH 2 reaction over macroscopic Rh single crystal surfaces were reported by Janssen et al 14,15 for Rh͑533͒ and recently by Cobden et al 16 for Rh͑111͒. An interesting feature of the oscillatory kinetics in the NOϩH 2 reaction is that, for Pt͑100͒, N 2 and NH 3 signals oscillate in phase, whereas for Rh͑533͒ and Rh͑111͒, the rate of N 2 formation oscillates out of phase with the rate of NH 3 formation.…”

Section: Modeled the Oscillations Reported Formentioning

confidence: 96%

“…[14][15][16] The shape of the hysteresis loop was demonstrated to vary significantly with the variation of the P NO /P H2 ratio. The results of mathematical modeling for temperature variation using different P NO /P H2 ratios and with P NO kept constant are shown in Fig.…”

Section: Hysteresis During Heating/coolingmentioning

confidence: 97%

“…Macroscopic rate oscillations during the NOϩH 2 reaction over a stepped Rh͑533͒ surface have been observed in the 10 Ϫ6 mbar pressure regime in excess of H 2 at temperatures ranging from 460 to 495 K. 14,15 Three products have been measured under these conditions: N 2 , NH 3 , and H 2 O. N 2 O has not been observed for the NOϩH 2 reaction over Rh͑533͒ and Rh͑111͒. Not only the activity oscillates in time, but also the selectivity towards the N-containing products oscillates.…”

Section: Experimental Observationsmentioning

confidence: 98%

“…H 2 O is also a main reaction product, and the H 2 O formation rate is in phase with the NH 3 formation rate. 15 The oscillations in the NO pressure are a result of consumption of NO during the reaction. The overall timeaverage conversion of NO during rate oscillations is below 10%.…”

Section: Experimental Observationsmentioning

confidence: 99%

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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: Experimental Observationsmentioning

confidence: 94%

Section: Modeled the Oscillations Reported Formentioning

confidence: 96%

Section: Hysteresis During Heating/coolingmentioning

confidence: 97%

Section: Experimental Observationsmentioning

confidence: 98%

Section: Experimental Observationsmentioning

confidence: 99%

See 3 more Smart Citations

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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Activity Hysteresis during Cyclic Temperature‐Programmed Reactions in the Partial Oxidation of Acrolein to Acrylic Acid

et al. 2017

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Dedicated to Professor Rüdiger Lange on the occasion of his 65th birthdayOxidation of acrolein to acrylic acid on a Mo/V/W mixed oxide catalyst was studied by transient (cyclic temperature-programmed (TP)) as well as steady-state methods. TP reactions (TPReactions) exhibit an activity hysteresis of the catalyst with respect to temperature. As a result of the steady-state measurements, the activity hysteresis is not related to multiple steady states and is exclusively a transient phenomenon. Generally, the dynamics of bulk oxygen plays a key role leading to a reversible oxidation/reduction of the catalyst surface which influences the activity. This means the bulk acts as oxygen buffer. In this context, a reaction model, which involves the participation of bulk oxygen, was deduced and verified by modeling.

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The non‐linear behaviour of the NO‐H₂ reaction over Rh surfaces

et al. 1996

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In this paper we describe the non-linearity of the NO-H, reaction over Rh surfaces. Rate oscillations have been observed over a stepped (1 1 1) surface with (100) steps, (Rh(533) at low pressures ( I @ Pa) below 500 K, while no oscillations could be observed under these conditions over a Rh( 100) surface and a stepped (1 00) surface with ( 1 1 I ) steps, Rh(71 I). The thermal stability of the N atoms formed during the reaction explains the observed structure sensitivity. Moreover, the results suggest that diffusion of N atoms is needed to synchronise the rate oscillations, a process that is absent on Rh (100) and Rh(71 I). Dans cet article, nous decrivons la non-linearite de la reaction NO-H, sur des surfaces de Rh. Des oscillations de vitesse ont ete observees sur une surface etagee (1 1 1) avec des etages (IOO), Rh(533) a de faibles pressions ( 1 fl Pa) en dessous de 500 K, tandis qu'aucune oscillation n'a pu &tre observee dans ces mCmes conditions sur une surface Rh( 100) et une surface etagee (100) avec des etages (1 1 I), Rh (711). La stabilite thermique des atomes de N formes lors de la reaction explique la sensibilite des structures observees. En outre, les resultats suggerent que la diffusion des atomes de N est necessaire pour synchroniser les oscillations de vitesse, un processus qui est absent sur le Rh(100) et le Rh (711).

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Hysteresis and oscillations in the selectivity during the NO-H2 reaction over Rh(533)

Cited by 28 publications

References 15 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

Activity Hysteresis during Cyclic Temperature‐Programmed Reactions in the Partial Oxidation of Acrolein to Acrylic Acid

The non‐linear behaviour of the NO‐H₂ reaction over Rh surfaces

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Hysteresis and oscillations in the selectivity during the NO-H2 reaction over Rh(533)

Cited by 28 publications

References 15 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

Activity Hysteresis during Cyclic Temperature‐Programmed Reactions in the Partial Oxidation of Acrolein to Acrylic Acid

The non‐linear behaviour of the NO‐H2 reaction over Rh surfaces

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The non‐linear behaviour of the NO‐H₂ reaction over Rh surfaces