Kinetic oscillations in the rate of CO oxidation on Pd(110)

Ehsasi, M.; Seidel, Carsten; Ruppender, H.; Drachsel, W.; Block, J.H.; Christmann, K.

doi:10.1016/0167-2584(89)90803-7

Cited by 15 publications

(16 citation statements)

References 24 publications

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“…At higher pressures oxide formation has been postulated as the dominant mechanism [80]. Stable oscillations and period doubling have been observed on Pd( 1 1 0) [81]. They have been tentatively associated with the penetration of chemisorbed oxygen to the Pd bulk, experimentally proven by Ladas et al [82].…”

Section: Comments On Oscillationsmentioning

confidence: 85%

Monte Carlo simulations of surface reactions

Nieminen

Jansen

1997

Applied Catalysis A: General

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Section: Comments On Oscillationsmentioning

confidence: 85%

Monte Carlo simulations of surface reactions

Nieminen

Jansen

1997

Applied Catalysis A: General

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“…For details, we refer to our previous work. 12,18,44 Consequently, an observed hysteresis in the CO 2 formation rate changes its sense of rotation, and an isothermal cross-shaped phase diagram is obtained. In the case of Pt͑111͒ surface a hysteresis is likewise observed, but it does not rotate with the oxygen pressure, i.e., the phase diagram is not of the cross-shaped type.…”

Section: ͑3͒mentioning

confidence: 92%

Macroscopic and mesoscopic characterization of a bistable reaction system: CO oxidation on Pt(111) surface

Berdau

Yelenin

Karpowicz

et al. 1999

The Journal of Chemical Physics

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Influence of extended interactions on the surface dynamics in the catalytic CO oxidation on Pt single crystal substrateThe catalytic oxidation of CO by oxygen on a platinum ͑111͒ single-crystal surface in a gas-flow reactor follows the Langmuir-Hinshelwood reaction mechanism. It exhibits two macroscopic stable steady states ͑low reactivity: CO-covered surface; high reactivity: O-covered surface͒, as determined by mass spectrometry. Unlike other Pt and Pd surface orientations no temporal and spatiotemporal oscillations are formed. Accordingly, COϩO/Pt͑111͒ can be considered as one of the least complicated heterogeneous reaction systems. We measured both the macroscopic and mesoscopic reaction behavior by mass spectrometry and photoelectron emission microscopy ͑PEEM͒, respectively, and explored especially the region of the phase transition between low and high reactivity. We followed the rate-dependent width of an observed hysteresis in the reactivity and the kinetics of nucleation and growth of individual oxygen and CO islands using the PEEM technique. We were able to adjust conditions of the external control parameters which totally inhibited the motion of the reaction/diffusion front. By systematic variation of these conditions we could pinpoint a whole region of external control parameters in which the reaction/diffusion front does not move. Parallel model calculations suggest that the front is actually pinned by surface defects. In summary, our experiments and simulation reveal the existence of an ''experimental'' bistable region inside the ''computed'' bistable region of the reactivity diagram ͑S-shaped curve͒ leading to a novel dollar ͑$͒-shaped curve.

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“…The b 1 -oxygen state has been attributed to subsurface oxygen (O ads + Ã v fi O sub ), as indirectly indicated by work function measurements [30]. For reference, CO adsorption (50 L) at 100 K on the clean Pd(110) surface leads to several molecular CO ads states, with desorption peak temperatures at 230 (a 1 ), 280 (a 2 ), and 330 (a 3 ) K, and higher temperature features at 410 (b 1 ) and 470 (b 2 ) K (data not shown) [31]. The CO desorption spectrum for the Pd(111) for a coverage of h CO = 0.6 ML at 200 K is similar to those on Pd(110), and also shows four peaks at 250, 330, 380 (a) and 470 K (b) (data not shown).…”

Section: Detection Of Surface Intermediatesmentioning

confidence: 94%

Study of the low-temperature reaction between CO and O2 over Pd and Pt surfaces

et al. 2005

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Field electron microscopy (FEM), high-resolution electron energy loss spectroscopy (HREELS), molecular beams (MB) and temperature-programmed reaction (TPR) have been applied to the study of the kinetics of CO oxidation at low temperature, and to determine the roles of subsurface atomic oxygen (O sub ) and surface reconstruction in self-oscillatory phenomena, on Pd(111), Pd(110) and Pt(100) single crystals and on Pd and Pt tip surfaces. It was found that high local concentrations of adsorbed CO during the transition from a Pt(100)-hex reconstructed surface to the unreconstructed 1·1 phase apparently prevents oxygen atoms from occupying hollow sites on the surface, and leads to the appearance of a weakly bound active adsorbed atomic oxygen (O ads ) state in an on-top or bridge position. It was also inferred that subsurface oxygen O sub on the Pd(110) surface may play an important role in the formation of new active sites for the weakly bound O ads atoms. Experiments with 18 O isotope labeling clearly show that the weakly bound atomic oxygen is the active form of oxygen that reacts with CO to form CO 2 at T~140-160 K. Sharp tips of Pd and Pt, several hundreds angstroms in diameter, were used to perform in situ investigations of dynamic surface processes. The principal conclusion from those studies was that non-linear reaction kinetics is not restricted to macroscopic planes since: (i) planes as small as~200 Å in diameter show the same non-linear kinetics as larger flat surfaces; (ii) regular waves appear under conditions leading to reaction rate oscillations; (iii) the propagation of reaction-diffusion waves involves the participation of different crystal nanoplanes via an effective coupling between adjacent planes.

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Kinetic oscillations in the rate of CO oxidation on Pd(110)

Cited by 15 publications

References 24 publications

Monte Carlo simulations of surface reactions

Monte Carlo simulations of surface reactions

Macroscopic and mesoscopic characterization of a bistable reaction system: CO oxidation on Pt(111) surface

Study of the low-temperature reaction between CO and O2 over Pd and Pt surfaces

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