On the adsorption sites for CO on the Rh(111) single crystal surface

Beutler, Andreas S.; Lundgren, Edvin; Nyholm, R.; Andersen, Jesper N; Setlik, B.; Heskett, David R.

doi:10.1016/s0039-6028(96)01014-x

Cited by 95 publications

(76 citation statements)

References 16 publications

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“…It is worth mentioning that O 1s line is also detected, supporting our assignment to the aforementioned component at BE > 286 eV. Thus, the C 1s component with higher BE is in agreement with data reported by various authors for the adsorption of CO on a series of TM(hkl) surfaces [32][33][34][35] .…”

Section: Resultssupporting

confidence: 92%

Promotion Effect of Platinum on Gold’s Reactivity: A High-Resolution Photoelectron Spectroscopy Study

et al. 2016

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The reactivity of the Pt/Au(332) surface was studied using high resolution photoelectron spectroscopy and carbon monoxide adsorption at 3.5 x 10 -3 mbar. The characterization of Pt/Au (332) indicates the formation of a Au-Pt surface alloy at the top most atomic layer of the (332) crystal due to an atomic exchange mechanism at both terrace and step edge. The amount of alloyed Au atoms has proven to be dependent on the amount of Pt deposited in the coverage range investigated. The activation of Au atoms by alloying is detected by comparing the ability of the surface to adsorb CO at high pressures. By analyzing the C 1s and O 1s photoemission lines it is possible to conclude that CO adsorption is both dissociative and molecular on the PtAu/Au(332) surface, differently from the behavior observed for Au and Pt single crystals. Also, by rising the temperature of the COads-PtAu/Au(332) surface, a dissociative reaction path is followed with the accumulation of graphitic carbon on the surface and the oxygen desorption. Thus, our results shows, not only the differential catalytic behavior of Pt@Au/Au(hkl) model surfaces but also that Au atoms have an active role on the reaction mechanism.

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Section: Resultssupporting

confidence: 92%

Promotion Effect of Platinum on Gold’s Reactivity: A High-Resolution Photoelectron Spectroscopy Study

et al. 2016

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“…The HREELS peaks shift to 470 cm Ϫ1 ͑58.3 meV͒ and 2041 cm Ϫ1 ͑253.1 meV͒. These values are still characteristic of linear CO, in agreement with HRCLS 21,25 and tensor-LEED; 22 the resulting structure model is depicted in Fig. 1.…”

Section: A Leed Experiments and Site Assignmentsupporting

confidence: 76%

“…In addition, a second major vibrational state is observed in both frequency regions at 1861 cm Ϫ1 ͑230.7 meV͒ and 390 cm Ϫ1 ͑48.3 meV͒, indicating the occupation of a second site. Recent HRCLS, 21 tensor-LEED, 22 and SXRD 23 studies have identified this site as a threefold hollow site. The corresponding structure has been included in Fig.…”

Section: A Leed Experiments and Site Assignmentmentioning

confidence: 96%

CO/Rh(111): Vibrational frequency shifts and lateral interactions in adsorbate layers

Linke

Curulla

Hopstaken

et al. 2001

The Journal of Chemical Physics

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High resolution electron energy loss spectroscopy ͑HREELS͒, low-energy electron diffraction ͑LEED͒, and thermal desorption spectroscopy ͑TDS͒ were used to study lateral interactions in the adsorbate layer of the CO/Rh͑111͒ system. The vibrational spectra show that CO adsorbs exclusively on top at low coverage. At about half a monolayer a second adsorption site, the threefold hollow site, becomes occupied as well. A steady shift to higher frequencies of the internal C-O vibrations is observed over the whole coverage range. The frequency of the metal CO ͑M-CO͒ vibration in the on-top mode hardly shifts at low coverage. However, upon the emergence of the second adsorption site the M-CO vibrations experience a shift to lower frequencies. The population of the second site is also accompanied by the development of a low temperature shoulder in the TD spectra, indicating an increasingly repulsive interaction in the adsorbed CO layer. Vibrational spectra of isotopic mixtures of 12 CO and 13 CO were used to assess the origin of the observed frequency shifts. They confirm that frequency shifts of the C-O stretching vibration at total CO coverage of 0.33 ML in the (ͱ3ϫͱ3)R30°structure arise purely from dipole-dipole coupling. Dilution of an isotopic species effectively suppresses frequency shifts arising from dipole-dipole coupling. Therefore, experiments with a small amount of 13 CO as a tracer to monitor the frequency shifts in the 12 CO adlayer were carried out over the entire coverage range of 12 CO. The results demonstrate that dipole-dipole coupling causes the frequency shifts at low coverage ͑Ͻ0.5 ML͒, whereas chemical effects set in at higher coverage ͑0.5-0.75 ML͒, connected with the population of the threefold sites. The results illustrate that HREELS in combination with isotopic dilution is a powerful tool in the assessment of lateral interactions between adsorbed molecules.

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“…LEED experiments have been used to determine site preferences for CO on Rh͑111͒ at both low and high coverages. [15][16][17] Numerous overlayer structures for CO on Rh͑111͒ have also been observed with LEED, 12,15 a͒ Author to whom correspondence should be addressed. Electronic mail: manos@engr.wisc.edu; Phone: ͑608͒ 262-9053; Fax: ͑608͒ 262-5434.…”

Section: Introductionmentioning

confidence: 85%

“…energy for the hcp site is only 0.05 ͓0.14͔ eV smaller than that of the top site. 17 The desorption energy for CO was determined using TPRS and TPD. In both cases the estimated experimental value was Ϫ1.65 eV for CO coverages below 0.15 ML, 22,23 which is in excellent agreement with our RPBE value ͑Ϫ1.68 eV͒.…”

Section: B Adsorption Of Molecules and Radicalsmentioning

confidence: 99%

Atomic and molecular adsorption on Rh(111)

Mavrikakis¹,

Rempel

Greeley³

et al. 2002

The Journal of Chemical Physics

200

161

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A systematic study of the chemisorption of both atomic ͑H, O, N, S, C͒, molecular (N 2 , CO, NO), and radical (CH 3 , OH) species on Rh͑111͒ has been performed. Self-consistent, periodic, density functional theory ͑DFT-GGA͒ calculations, using both PW91 and RPBE functionals, have been employed to determine preferred binding sites, detailed chemisorption structures, binding energies, and the effects of surface relaxation for each one of the considered species at a surface coverage of 0.25 ML. The thermochemical results indicate the following order in the binding energies from the least to the most strongly bound: N 2 ϽCH 3 ϽCOϽNOϽHϽOHϽOϽNϽSϽC. A preference for threefold sites for the atomic adsorbates is observed. Molecular adsorbates, in contrast, favor top sites with the exceptions of NO ͑hcp͒ and OH ͑fcc or bridge tilted͒. Surface relaxation leads to insignificant changes in binding energies but to considerable changes in the spacing between surface rhodium atoms, particularly for on-top adsorption where the rhodium atom directly below the adsorbate is lifted above the plane of the surface. RPBE binding energies are found to be in remarkable agreement with the available experimental values. All atomic adsorbates, except for H, have a significant diffusion barrier ͓between 0.4 and 0.6 eV ͑RPBE͔͒ on Rh͑111͒. Atomic H and molecular/radical adsorbates appear to be much more mobile on Rh͑111͒, with an estimated diffusion barrier between 0.1 and 0.2 eV ͑RPBE͒. Finally, the thermochemistry for dissociation of CO, NO, and N 2 on Rh͑111͒ has been examined. In all three cases, decomposition is found to be thermodynamically preferable to desorption.

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On the adsorption sites for CO on the Rh(111) single crystal surface

Cited by 95 publications

References 16 publications

Promotion Effect of Platinum on Gold’s Reactivity: A High-Resolution Photoelectron Spectroscopy Study

Promotion Effect of Platinum on Gold’s Reactivity: A High-Resolution Photoelectron Spectroscopy Study

CO/Rh(111): Vibrational frequency shifts and lateral interactions in adsorbate layers

Atomic and molecular adsorption on Rh(111)

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