Monitoring the preparation of (Co)Mo/Al2O3 extrudates using spatially resolved spectroscopic techniques

Bergwerff, Jaap A.; Water, Leon G. A. van de; Lysova, Anna A.; Koptyug, Igor V.; Visser, Taco D.; Jong, Krijn P. de; Weckhuysen, Bert M.

doi:10.1016/s0167-2991(06)80905-5

Cited by 9 publications

(4 citation statements)

References 20 publications

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“…As a proof of principle, a sequence of images was detected using the 31 P NMR signal after a g-Al 2 O 3 pellet saturated with water was immersed in an aqueous solution of H 3 PO 4 . [18][19][20] The images demonstrated that transport of H x PO 4 (3Àx)À into the pellet was slow, and the uniform distribution was obtained only after about 14 h because of the strong interaction of phosphates with alumina surface at low solution pH. A direct confirmation of the existence of this strong interaction was obtained in another experiment in which a dry g-Al 2 O 3 pellet was immersed in an aqueous solution of H 3 PO 4 .…”

Section: Preparation Of Supported Catalystsmentioning

confidence: 78%

“…More reactant vapour and its faster diffusive transport as compared to the liquid phase accelerate the reaction and lead to the fast catalyst temperature rise and the substantial emptying of the pellet. At some point, however, the mass transport and/or phase transition processes become the bottleneck, the reaction subsides and the liquid front advances again (images [15][16][17][18][19][20][21][22][23]. The results seem to indicate that the ignition starts in the subsurface region of the catalyst pellet.…”

Section: Imaging Of Single-catalyst-pellet Reactorsmentioning

confidence: 99%

“…Depending on the sample, the technique used and the image dimensionality, image acquisition times can vary from less than a second to hours. The best sensitivity and resolution are often achieved when magnetic resonance (MR) images are detected by acquiring the 1 H NMR signal, but at the same time other magnetic nuclei (e.g., 31 P, 19 F, 2 H, 13 C) can be used for image detection as well.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic resonance imaging methods for in situ studies in heterogeneous catalysis

2010

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Magnetic resonance imaging (MRI) is a very powerful instrument used extensively in modern medical diagnostics because of its ability to look inside a body in a non-invasive and non-destructive way. Furthermore, MRI is more than just a single tool for extracting structural information. It is more of a sophisticated and versatile toolkit able to provide all sorts of useful information about the internal properties of an object under study and various processes within it, including heat and mass transport, composition and chemical transformations, in a spatially resolved mode. While a living body is different from a catalyst body or a reactor, the in situ and Operando studies in catalysis can clearly benefit from the use of this non-destructive toolkit as a powerful complement to other available spectroscopic tools. This tutorial review gives an introduction to the field and describes the examples of the applications of MRI to the studies of the preparation, deactivation and regeneration of solid catalysts and to the spectroscopy, thermometry and imaging studies of heterogeneous catalysts and model catalytic reactors performed during actual catalytic processes.

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Section: Preparation Of Supported Catalystsmentioning

confidence: 78%

Section: Imaging Of Single-catalyst-pellet Reactorsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Magnetic resonance imaging methods for in situ studies in heterogeneous catalysis

2010

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“…Nevertheless, since several years, numerous studies reported about the role of organic additives as complexing agents, in particularly citric acid. When introduced with the metallic precursors in the impregnation solution, citric acid can increase the active phase active dispersion, improve the solubility of the species and contribute to the formation of heteropolyanions [5][6][7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Impact of Citric Acid on the Impregnation of CoMoP/γ-Al2O3 Catalysts: Time and Spatially Resolved MRI and Raman Imaging Study

et al. 2018

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Chemische Bildgebung von räumlichen Heterogenitäten in katalytischen Festkörpern auf unterschiedlichen Längen‐ und Zeitskalen

Weckhuysen

2009

Angewandte Chemie

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Katalytische Festkörper im Rampenlicht: Die gezielte Entwicklung von neuen oder verbesserten heterogenen Katalysatoren erfordert genaue Einblicke in ihre Struktur und Funktionsweise. Hierfür stehen Techniken der chemischen Bildgebung zur Verfügung, die räumlich und zeitlich aufgelöste Informationen über katalytische Festkörper auf unterschiedlichen Längenskalen liefern – d. h. auf der Stufe der Reaktoren, der Katalysatorkörper, der Katalysatorkörner und der Nanopartikel. Die Kenntnis räumlich‐zeitlicher Gradienten in heterogenen Katalysatoren ist von allergrößter Bedeutung für den gezielten Entwurf von neuen und nachhaltigeren katalytischen Prozessen. Heterogenitäten, die zu raum‐ und zeitabhängigen Phänomenen führen, kommen auf unterschiedlichen Längenskalen vor, beginnend auf der Stufe der Katalysereaktoren (mm bis m), über die Katalysatorkörper (µm bis mm) und Katalysatorkörner (nm bis µm) bis hin zu den aktiven Zentren und Nanopartikeln (Å bis nm). Dieser Aufsatz fasst die jüngsten Fortschritte bei der Entwicklung von raum‐ und zeitauflösenden Spektroskopiemethoden für die Bildgebung räumlicher Heterogenitäten in katalytischen Prozessen auf diesen vier Längenskalen zusammen. Ein Schwerpunkt liegt auf der Anwendung von Kernresonanz‐, optischen und Synchrotronmethoden, die vor allem auf ihre Fähigkeit zur räumlichen Auflösung (1D‐ und 2D‐Bildgebung) und Tiefenprofilierung (3D‐Bildgebung) untersucht werden. Darüber hinaus werden zeitaufgelöste Anwendungen dieser Techniken diskutiert, ebenso wie ihr Potenzial für die Einzelmolekül‐ und Nanopartikeldetektion und ihr Einsatz unter Reaktionsbedingungen. Der Aufsatz endet mit einem Ausblick auf spektroskopische Aktivitätsmarker, markerfreie Spektroskopie, Tomographie auf der Nanoskala und korrelative mikroskopische Ansätze.

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Monitoring the preparation of (Co)Mo/Al2O3 extrudates using spatially resolved spectroscopic techniques

Cited by 9 publications

References 20 publications

Magnetic resonance imaging methods for in situ studies in heterogeneous catalysis

Magnetic resonance imaging methods for in situ studies in heterogeneous catalysis

Impact of Citric Acid on the Impregnation of CoMoP/γ-Al2O3 Catalysts: Time and Spatially Resolved MRI and Raman Imaging Study

Chemische Bildgebung von räumlichen Heterogenitäten in katalytischen Festkörpern auf unterschiedlichen Längen‐ und Zeitskalen

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