High temperature growth of Pt on the Rh(111) surface

Duisberg, M.; Dräger, Marco; Wandelt, K.; Gruber, Elisabeth; Schmid, Michael; Варга, П.

doi:10.1016/s0039-6028(99)00037-0

Cited by 11 publications

(13 citation statements)

References 14 publications

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“…For the case where the substrate is Rh(1 1 1), we are aware of studies only with overlayers of Pt and Co. In the former case, there has been a report [16] that there is some surface alloying between Pt and Rh (though the two elements are immiscible in the bulk). For the latter case, Co atoms have been reported [18] to occupy fcc sites.…”

Section: Resultsmentioning

confidence: 99%

“…While there are a few experiments [14][15][16][17][18] and calculations [19,20] of monolayers of M or N on Ru(0 0 0 1) and Rh(1 1 1), we are not aware of any experiments or calculations on surface alloys of the type MN/S among the twenty such combinations that we have examined in this paper, with the exception of Co-Ag/Ru and Fe-Ag/ Ru [7,9], in both of which it was found that atomic-level mixing was disfavored.…”

Section: Introductionmentioning

confidence: 99%

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Mixing and magnetic properties of surface alloys: The role of the substrate

Marathe

Imam

Narasimhan

2009

Applied Surface Science

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mixing and magnetic properties of surface alloys: The role of the substrate

Marathe

Imam

Narasimhan

2009

Applied Surface Science

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“…A home-built evaporator with resistive heating was used to deposit the Pt film while the sample temperature was held at ∼ 600 K. The Pt coverage was monitored using the changes in CO thermal desorption spectra from the Pt/Rh(111) surface. It has been previously shown 18 that, during the deposition, Pt atoms are incorporated into the topmost Rh layer to form a surface alloy with increasing Pt content and, eventually, a two-dimensional Pt overlayer.…”

Section: Experimental and Computational Methodsmentioning

confidence: 99%

In situ X-ray probing reveals fingerprints of surface platinum oxide

Friebel

Miller

O’Grady

et al. 2011

Phys. Chem. Chem. Phys.

115

109

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In situ x-ray absorption spectroscopy (XAS) at the Pt L 3 edge is a useful probe for Pt-O interactions at polymer electrolyte membrane fuel cell (PEMFC) cathodes. We show that XAS using the high energy resolution fluorescence detection (HERFD) mode, applied to a well-defined monolayer Pt/Rh(111) sample where the bulk penetrating hard x-rays probe only surface Pt atoms, provides a unique sensitivity to structure and chemical bonding at the Pt-electrolyte interface. Ab initio multiple-scattering calculations using the FEFF8 code and complementary extended x-ray absorption fine structure (EXAFS) results indicate that the commonly observed large increase of the white-line at high electrochemical potentials on PEMFC cathodes originates from platinum oxide formation, whereas previously proposed chemisorbed oxygen-containing species merely give rise to subtle spectral changes.

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“…Indeed, 3D island growth has been confirmed with in situ scanning tunneling microscopy for electrochemically deposited Pt/Au(111). [22,23] On Rh(111), a 2D Pt layer can be grown by ultra-high-vacuum evaporation onto a heated substrate, [24] and we recently studied electrochemical surface oxide formation on such a 2D Pt/Rh(111) sample with in situ HERFD XAS and extended X-ray absorption fine structure (EXAFS) analysis. [25] In contrast, the redox-displacement technique also results in small 3D islands for Pt/ Rh(111); this is evident from in situ EXAFS studies (see the Supporting Information).…”

mentioning

confidence: 99%

Degradation of Bimetallic Model Electrocatalysts: An In Situ X‐Ray Absorption Spectroscopy Study

et al. 2011

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One of the major challenges in the development of clean energy fuel cells is the performance degradation of the electrocatalyst, which, apart from poisoning effects, can suffer from corrosion due to its exposure to a harsh environment under high potentials. In this communication, we demonstrate how interactions of Pt with a transition metal support affect not only, as commonly intended, the catalytic activity, but also the reactivity of Pt towards oxide formation or dissolution. We use two well-defined single-crystal model systems, Pt/Rh(111) and Pt/Au(111) and a unique x-ray spectroscopy technique with enhanced energy resolution to monitor the potential-dependent oxidation state of Pt, and find two markedly different oxidation mechanisms on the two different substrates. This information can be of great significance for future design of more active and more stable catalysts. AbstractWe have studied the potential-induced degradation of Pt monolayer model electrocatalysts on Rh(111) and Au(111) singlecrystal substrates. The anodic formation of Pt oxides was monitored using in situ high energy resolution fluorescence detection x-ray absorption spectroscopy (HERFD XAS). Although Pt was deposited on both substrates in a three-dimensional island growth mode, we observed remarkable differences during oxide formation that can only be understood in terms of strong Ptsubstrate interactions throughout the Pt islands. Anodic polarization of Pt/Rh(111) up to +1.6 V vs. RHE (reversible hydrogen electrode) leads to formation an incompletely oxidized passive layer, whereas formation of PtO 2 and partial Pt dissolution is observed for Pt/Au(111).

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High temperature growth of Pt on the Rh(111) surface

Cited by 11 publications

References 14 publications

Mixing and magnetic properties of surface alloys: The role of the substrate

Mixing and magnetic properties of surface alloys: The role of the substrate

In situ X-ray probing reveals fingerprints of surface platinum oxide

Degradation of Bimetallic Model Electrocatalysts: An In Situ X‐Ray Absorption Spectroscopy Study

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