Heterogeneous equilibria in the rhenium-oxygen system

Shcheglov, P. A.; Дробот, Д. В.

doi:10.1134/s0036024406110252

Cited by 26 publications

(23 citation statements)

References 11 publications

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“…[22][23][24] The existence of a Re 5+ species in binary oxides is inconclusive; however, in rhenium-oxide bronzes (e.g. rhenium oxides alloyed other cationic elements), rhenium oxidation states of +4, 5,6 and 7 are all possible.…”

Section: -315mentioning

confidence: 99%

The Oxidation of Rhenium and Identification of Rhenium Oxides During Catalytic Partial Oxidation of Ethylene: An In-Situ XPS Study

Greiner

Rocha

Johnson

et al. 2014

Zeitschrift Für Physikalische Chemie

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Rhenium is catalytically active for many valuable chemical reactions, and consequently has been the subject of scientific investigation for several decades. However, little is known about the chemical identity of the species present on rhenium surfaces during catalytic reactions because techniques for investigating catalyst surfaces in-situ -such as near-ambient-pressure X-ray photoemission spectroscopy (NAP-XPS) -have only recently become available. In the current work, we present an in-situ XPS study of rhenium catalysts. We examine the oxidized rhenium species that form on a metallic rhenium foil in an oxidizing atmosphere, a reducing atmosphere, and during a model catalytic reaction (i.e. the partial-oxidation of ethylene). We find that, in an oxidizing environment, a Re 2 O 7 film forms on the metal surface, with buried layers of sub-oxides that contain Re 4+ , Re 2+ and Re

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Section: -315mentioning

confidence: 99%

The Oxidation of Rhenium and Identification of Rhenium Oxides During Catalytic Partial Oxidation of Ethylene: An In-Situ XPS Study

Greiner

Rocha

Johnson

et al. 2014

Zeitschrift Für Physikalische Chemie

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“…The incident photon energy was 545 eV. The vertical scale for the bottom panel is twice that for the top panel.sublimation, given that Re 2 O 7 is known to be highly volatile and reported to desorb at temperatures as low as 423 K-600 K 38,39,…”

mentioning

confidence: 99%

In SituStudies of Carbon Monoxide Oxidation on Platinum and Platinum–Rhenium Alloy Surfaces

et al. 2014

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CO oxidation has been investigated by near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) on Pt(111), Re films on Pt(111) and a Pt-Re alloy surface. The Pt-Re alloy surface was prepared by annealing Re films on Pt(111) to 1000 K; scanning tunneling microscopy, low energy ion scattering and X-ray photoelectron spectroscopy studies indicate that this treatment resulted in the diffusion of Re into the Pt (111) surface. Under CO oxidation conditions of 500 mTorr O 2 /50 mTorr CO, CO remains on the Pt(111) surface at 450 K, whereas CO desorbs from the Pt-Re alloy surface at lower temperatures. Furthermore, the Pt-Re alloy dissociates oxygen more readily than Pt(111) despite the fact that all of the Re atoms are initially in the subsurface region. Mass spectrometer studies show that the Pt-Re alloy, Re film on Pt andPt (111) all have similar activities for CO oxidation, with the Pt-Re alloy producing ~10% more CO 2 than Pt(111). The Re film is not stable under CO oxidation conditions at temperatures > 450 K due to formation and subsequent sublimation of volatile Re 2 O 7 . However, the Pt-Re alloy surface is more resistant to oxidation and therefore also more stable against Re sublimation.

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“…Results of the analysis are shown in Table 3 . A lower rhenium content can be explained by the evaporation of low melting point rhenium oxides that are likely formed during the reduction of ammonium perrhenate [ 29 , 30 ].…”

Section: Resultsmentioning

confidence: 99%

Ni–Cr Powders Modified with Rhenium as a Novel Coating Material—Physical Properties, Microstructure, and Behavior in Plasma Plume

et al. 2022

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The aim of this work was to develop a new coating material based on Ni20Cr alloy modified with up to 50%wt. rhenium. The modification was carried out by the mechanical mixing of the base powder and ammonium perrhenate with the subsequent thermoreduction in an H2 atmosphere. The obtained powder consists of a nickel–chromium core surrounded by a rhenium shell. The characterization of the powders—including their microstructure, phase and chemical composition, density, flowability, particle size distribution, and specific surface area—was performed. The influence of plasma current intensity and hydrogen gas flow on in-flight particle temperature and velocity were investigated. The results indicate that there is interdiffusion between the base Ni20Cr and the rhenium shell, resulting in intermediary solid solution(s). The modified powders have a higher specific surface area and a lower flowability, but this does not prevent them from being used as feedstock in plasma spraying. In-flight measurements reveal that increasing the content of rhenium allows for the higher temperature of particles, though it also reduces their speed.

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Heterogeneous equilibria in the rhenium-oxygen system

Cited by 26 publications

References 11 publications

The Oxidation of Rhenium and Identification of Rhenium Oxides During Catalytic Partial Oxidation of Ethylene: An In-Situ XPS Study

The Oxidation of Rhenium and Identification of Rhenium Oxides During Catalytic Partial Oxidation of Ethylene: An In-Situ XPS Study

In SituStudies of Carbon Monoxide Oxidation on Platinum and Platinum–Rhenium Alloy Surfaces

Ni–Cr Powders Modified with Rhenium as a Novel Coating Material—Physical Properties, Microstructure, and Behavior in Plasma Plume

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