The use of hydrogen chemisorption for the determination of Ru dispersion in Ru/γ-alumina catalysts

Okal, Janina; Zawadzki, M.; Kępiński, Leszek; Krajczyk, L.; Tylus, Włodzimierz

doi:10.1016/j.apcata.2006.12.005

Cited by 119 publications

(95 citation statements)

References 49 publications

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“…Since the 1970s, many XPS studies have been performed to examine the chemical state of rhenium catalyst surfaces; however, due to instrumentation limitations, these studies were performed ex-situ. [14,20,23,[31][32][33][34][35] The problem with ex-situ studies is that the rhenium oxidation states that are measured postreaction can differ substantially from the species that are present in-situ.…”

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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“…[29] Among these methods, reduction by chemical agents has been the most extensively studied: the use of polyol as a reducing agent is particularly approached by different groups. [7,[30][31][32][33] Frequently, Ru nanosystems are obtained by reduction of RuCl 3 in glycols, such as ethylene glycol or diethylene glycol, [12,[34][35][36] hydrogen reduction [37] or sodium borohydride reduction. [38] Ru nanoparticles are also prepared by using polymers, [39] ligands like amines, alcohols or thiols, [24,25] cellulose derivatives [40] and organosilane fragments [41] as stabilizers.…”

Section: Introductionmentioning

confidence: 99%

Single‐Step Synthesis of Ruthenium Catalytic Nanocrystallites in a Stable Carbon Support

2011

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Metallic Ru nanoparticles have been prepared and incorporated in a protective carbon support by the decomposition of a single organometallic precursor, Ru III acetylacetonate, under autogenic conditions in a single-step process in the absence of any solvents or stabilizers. The product structure was confirmed by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, scanning transmission electron microscopy, transmission electron microscopy and high resolution transmission electron microscopy. Measurements demonstrated the exclusive presence of hexagonal metallic ruthenium nanoparticles with a homogeneous size of 2-4 nm in a carbon sup-

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“…While both methods give catalytically active materials, IE is generally more reproducible and reliable than IW, which results in relatively non-uniform metal distribution, size and shape [44]. Nevertheless, there are limited reports that investigate optimisation of those methods or how the metal distribution is affected by different parameters.…”

Section: Introductionmentioning

confidence: 99%

Can Ultrasound or pH Influence Pd Distribution on the Surface of HAP to Improve Its Catalytic Properties in the Dry Reforming of Methane?

et al. 2017

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samples were evaluated for their catalytic activity towards dry reforming of methane (DRM) and the reaction was monitored via a thermal conductivity detector, coupled with gas chromatography (GC-TCD). It was found that ultrasound-assisted IE significantly accelerated the process from 3 days to 3 h and with the Pd 0 metal remaining highly distributed upon the HAP with minor changes in catalytic conversions. Moreover, the ultrasound-assisted IW method successfully improved the Pd 0 distribution and catalytic performance. On the other hand, the dispersion of the metal was unaffected after pH treatments in IE with no catalytic improvements observed, in contrast to IW, where considerable increase in metal distribution and subsequently catalytic performance was observed.Abstract The influence of ultrasound and different pH pre-treatments during the metal doping/modification of a hydroxyapatite (HAP) support is investigated. HAP is first synthesised via a hard-template synthetic route using carbon nanorods followed by their full physiochemical characterisation. The HAP was found to be crystalline and comprised a mesoporous structure as observed via XRD and nitrogen adsorption with a BET surface area of 97.57 (±1.16) m 2 g −1. Ultrasound-assisted ion exchange (IE) and incipient wetness impregnation (IW) methodologies were employed to decorate the surface of HAP with Pd 0 and are compared to previous procedures. The influence of pH upon the distribution of Pd 0 throughout the samples during the doping process is also studied. All the prepared Electronic supplementary material The online version of this article

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The use of hydrogen chemisorption for the determination of Ru dispersion in Ru/γ-alumina catalysts

Cited by 119 publications

References 49 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

Single‐Step Synthesis of Ruthenium Catalytic Nanocrystallites in a Stable Carbon Support

Can Ultrasound or pH Influence Pd Distribution on the Surface of HAP to Improve Its Catalytic Properties in the Dry Reforming of Methane?

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