Real-time STM observations of atomic equilibrium fluctuations in an adsorbate system: O/Ru(0001)

Wintterlin, Joost; Trost, Johannes; Renisch, Steffen; Schuster, Rolf; Zambelli, Tomaso; Ertl, G.

doi:10.1016/s0039-6028(97)00604-3

Cited by 160 publications

(133 citation statements)

References 30 publications

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“…A previous Monte Carlo simulation of ordering phenomena of NO on Rh͑111͒ indicated that diffusion of molecules such as NO and CO started to become detectable at much lower temperatures of 200 K already, and that diffusion of these molecules was by far the fastest surface process at temperatures above 250 K. 52 Adsorbed atoms diffuse much more slowly, although mobility of O-atoms on ruthenium at room temperature has been demonstrated. 53 Considering reaction around 450 K as the reference case for the limit of low reactant coverage, we see that increasing the precoverage of O-atoms but keeping the CO coverage low ͑below about 0.10 ML͒ leads to an intrinsically faster reaction, characterized by a lower activation energy, and a preexponential factor that changes only insignificantly ͑Fig. 5͒.…”

Section: B Different Co 2 Formation Channels On Rh"110…mentioning

confidence: 85%

Structure sensitivity in the CO oxidation on rhodium: Effect of adsorbate coverages on oxidation kinetics on Rh(100) and Rh(111)

Hopstaken

Niemantsverdriet

2000

The Journal of Chemical Physics

112

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Temperature-programmed reaction spectroscopy has been used to study the surface reaction between CO and O-atoms on Rh͑100͒ and Rh͑111͒ at a range of different adsorbate coverages. Comparison of the reaction on both surfaces in the low coverage regime, where the kinetics can be described by a straightforward Langmuir-Hinshelwood mechanism reveals that the CO oxidation is structure sensitive, with the rate constant being an order of magnitude higher on the Rh͑100͒ than on the Rh͑111͒ surface. As a consequence, the selectivity of the COϩO reaction to CO 2 is about 100% on Rh͑100͒, whereas on Rh͑111͒ the oxidation reaction competes with CO desorption. At low CO coverage, CO oxidation is an elementary step on Rh͑100͒ for a broad range of oxygen coverages. We report kinetic parameters E a ϭ103Ϯ5 kJ/mol and ϭ10 12.7Ϯ0.7 for O ϭ CO →0 on Rh͑100͒. The activation energy for CO oxidation on Rh͑100͒ decreases continuously with increasing O-coverage. At low coverage ( O Ͻ0.25 ML͒ we attribute this to destabilization of CO, leading to an increase in the CO 2 formation rate. At higher coverage ( O Ͼ0.25 ML͒ O-atoms become destabilized as well, as lateral interactions between O-atoms come into play at these coverages. The interactions result in a greatly enhanced rate of reaction at higher coverages.

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Section: B Different Co 2 Formation Channels On Rh"110…mentioning

confidence: 85%

Structure sensitivity in the CO oxidation on rhodium: Effect of adsorbate coverages on oxidation kinetics on Rh(100) and Rh(111)

Hopstaken

Niemantsverdriet

2000

The Journal of Chemical Physics

112

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“…Several research groups have shown that, with an optimized mechanical construction and electronics, STM images can be recorded sequentially at approximately 1-100 frames per second ͑Linderoth et al Wintterlin et al, 1997;Laegsgaard et al, 2001;Besenbacher et al, 2005;Rost et al, 2005͒. These video STMs have a rigid and compact design in order to achieve the required high mechanical resonance frequency.…”

Section: High-speed Scanning Tunneling Microscopymentioning

confidence: 99%

Colloquium: Time-resolved scanning tunneling microscopy

Houselt

2010

Rev. Mod. Phys.

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Scanning tunneling microscopy has revolutionized our ability to image, study, and manipulate solid surfaces on the size scale of atoms. One important limitation of the scanning tunneling microscope ͑STM͒ is, however, its poor time resolution. Recording a standard image with a STM typically takes about a fraction of a second for a fast scanning STM to several tens of seconds for a standard STM. The time resolution of a STM can, however, be significantly enhanced by at least several orders of magnitude. Here various methods are reviewed that are applied in order to significantly improve the time resolution of STM. These methods include high-speed or video STM, atom-tracking STM, and monitoring of the open feedback loop current or closed feedback loop z-piezo-voltage signals as a function of time. An analysis of the time-resolved STM data allows one to map out the potential landscape of the system under study.

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“…They are due to oxygen atoms, as deduced from examination of many images of Ru(001) that show that their number correlates with the O-signal in the AES. Oxygen appears as a depression in the STM images on most metals [26,27,28,29].…”

Section: Near Saturation Coverage (≤ 1 Ml)mentioning

confidence: 99%