Oxygen-Stabilized Rh Adatoms: 0D Oxides on a Vicinal Surface

Mittendorfer, Florian; Franz, Thomas; Klikovits, J.; Schmid, Michael; Merte, Lindsay R.; Zaman, Sameena Shah; Варга, П.; Westerström, Rasmus; Resta, Andrea; Andersen, Jesper N; Gustafson, Johan; Lundgren, Edvin

doi:10.1021/jz2011308

Cited by 5 publications

(6 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The reason for the shifted rows now becomes clear, since without the shifted rows some of the oxygen atoms would have occupied unfavorable bridgelike sites. However, it was recently shown that oxygen may stabilize Rh adatoms on a Rh(113) surface, 20 and we cannot exclude such a scenario on the Pd(113) nanofacets. Therefore, we propose a model as shown in Fig.…”

Section: B Low-pressure Regime: Chemisorption On Pd(112)mentioning

confidence: 83%

Oxygen interaction with the Pd(112) surface: From chemisorption to bulk oxide formation

et al. 2012

Self Cite

View full text Add to dashboard Cite

We investigated the interaction of oxygen with the Pd(112) surface from ultrahigh vacuum up to 5 mbars oxygen partial pressure in a temperature range from 523 to 673 K. We combined in situ surface x-ray diffraction with scanning tunneling microscopy, high-resolution core-level spectroscopy, and low-energy electron diffraction. A structural model of the clean Pd (112) is proposed based on the x-ray-diffraction data. The morphology of the Pd(112) surface is strongly influenced by the oxidation conditions: at 673 K, upon exposure to oxygen at pressures from 2 × 10

show abstract

Section: B Low-pressure Regime: Chemisorption On Pd(112)mentioning

confidence: 83%

Oxygen interaction with the Pd(112) surface: From chemisorption to bulk oxide formation

et al. 2012

Self Cite

View full text Add to dashboard Cite

show abstract

“…On ultrathin FeO films, to reach a Pd density somewhere in between that on ZrO 2 /Pt 3 Zr and ZrO 2 /Pd 3 Zr, the deposition temperature has to be decreased to 130 K . The reason becomes clear when studying the bonding geometries: For the late transition metals, bonding to two atoms at opposite sides is favorable. − Assuming typical Me–O bond lengths around 0.2 nm, an O–Me–O geometry requires O–O distances of ≈0.4 nm with space in between for the Me atom. This is possible at open surfaces like the distorted ZrO 2 {111} variants (Figure ), but not on most other oxides with in-plane O–O distances typically around 0.30 nm or less.…”

Section: Discussionmentioning

confidence: 99%

Metal Adatoms and Clusters on Ultrathin Zirconia Films

Choi¹,

Mayr-Schmölzer²,

Valenti

et al. 2016

J. Phys. Chem. C

Self Cite

View full text Add to dashboard Cite

Nucleation and growth of transition metals on zirconia has been studied by scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. Since STM requires electrical conductivity, ultrathin ZrO2 films grown by oxidation of Pt3Zr(0001) and Pd3Zr(0001) were used as model systems. DFT studies were performed for single metal adatoms on supported ZrO2 films as well as the (1̅11) surface of monoclinic ZrO2. STM shows decreasing cluster size, indicative of increasing metal–oxide interaction, in the sequence Ag < Pd ≈ Au < Ni ≈ Fe. Ag and Pd nucleate mostly at steps and domain boundaries of ZrO2/Pt3Zr(0001) and form three-dimensional clusters. Deposition of low coverages of Ni and Fe at room temperature leads to a high density of few-atom clusters on the oxide terraces. Weak bonding of Ag to the oxide is demonstrated by removing Ag clusters with the STM tip. DFT calculations for single adatoms show that the metal–oxide interaction strength increases in the sequence Ag < Au < Pd < Ni on monoclinic ZrO2, and Ag ≈ Au < Pd < Ni on the supported ultrathin ZrO2 film. With the exception of Au, metal nucleation and growth on ultrathin zirconia films follow the usual rules: More reactive (more electropositive) metals result in a higher cluster density and wet the surface more strongly than more noble metals. These bind mainly to the oxygen anions of the oxide. Au is an exception because it can bind strongly to the Zr cations. Au diffusion may be impeded by changing its charge state between −1 and +1. We discuss differences between the supported ultrathin zirconia films and the surfaces of bulk ZrO2, such as the possibility of charge transfer to the substrate of the films. Due to their large in-plane lattice constant and the variety of adsorption sites, ZrO2{111} surfaces are more reactive than many other oxygen-terminated oxide surfaces.

show abstract

“…Platinum is widely used as a catalyst in numerous chemical reactions. It plays an important role as a heterogeneous catalyst in hydrogenation and dehydrogenation reactions, for example, and platinum is a vital component of automotive three-way catalytic converters. − Despite the importance of platinum in catalysis, there have been only a very limited number of spectroscopic studies of its clusters in the gas phase. , It is well-known that the oxidation state of a metal catalyst’s surface strongly affects its catalytic behavior; according to several reports in the literature, oxidized Pt, Pd, Rh, and PtRh surfaces are more efficient during the catalytic oxidation of CO than the pure metal surfaces. The reaction mechanisms of CO and NO oxidation are not well understood at the molecular level, however, and thus more information concerning the reactivity of catalytically active metals such as Pt is clearly needed.…”

Section: Introductionmentioning

confidence: 99%

Reactions of Neutral Platinum Clusters with N₂O and CO

et al. 2013

View full text Add to dashboard Cite

The reduction of N2O in the gas phase by isolated, neutral platinum clusters, Pt(n) (n = 4-12), was investigated using mass spectrometry. The associated oxygen transfer reactions had the general formula Pt(n)O(m-1) + N2O → Pt(n)O(m) + N2 (m = 1 or 2). The rate constants k1 and k2 for the reactions in which m = 1 and 2, respectively, were ascertained and were found to be similar to one another. Unexpectedly, Pt6O was discovered to be completely unreactive with N2O under the applied experimental conditions. The reaction mechanism was elucidated on the basis of density functional theory (DFT) calculations, which indicated a reaction barrier between Pt6O + N2O and Pt6O2 + N2. The possibility of catalyzing either the reduction of N2O or the oxidation of CO using neutral Pt(n) species was also examined and the results showed that Pt(n) does not exhibit significant catalytic properties and that O and CO instead coadsorb to Pt(n). Desorption of CO2 from the coadsorbed clusters was not clearly identifiable from mass spectra. The reactivities of the platinum clusters were discussed and compared with the properties of the highly catalytically active rhodium clusters.

show abstract

Oxygen-Stabilized Rh Adatoms: 0D Oxides on a Vicinal Surface

Cited by 5 publications

References 42 publications

Oxygen interaction with the Pd(112) surface: From chemisorption to bulk oxide formation

Oxygen interaction with the Pd(112) surface: From chemisorption to bulk oxide formation

Metal Adatoms and Clusters on Ultrathin Zirconia Films

Reactions of Neutral Platinum Clusters with N₂O and CO

Contact Info

Product

Resources

About

Oxygen-Stabilized Rh Adatoms: 0D Oxides on a Vicinal Surface

Cited by 5 publications

References 42 publications

Oxygen interaction with the Pd(112) surface: From chemisorption to bulk oxide formation

Oxygen interaction with the Pd(112) surface: From chemisorption to bulk oxide formation

Metal Adatoms and Clusters on Ultrathin Zirconia Films

Reactions of Neutral Platinum Clusters with N2O and CO

Contact Info

Product

Resources

About

Reactions of Neutral Platinum Clusters with N₂O and CO