IR Microimaging of Direction‐Dependent Uptake in MFI‐Type Crystals

Hwang, Seungtaik; Parditka, Bence; Cserháti, Csaba; Erdélyi, Zoltán; Gläser, Roger; Haase, Jürgen; Kärger, Jörg; Schmidt, Wolfgang; Chmelik, Christian

doi:10.1002/cite.201700128

Cited by 6 publications

(3 citation statements)

References 72 publications

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“…This, how-ever, does not mean any limitation in significance if mass transfer may be implied to occur in only the plane perpendicular to the observation direction. This may be easily ensured with 1d and 2d pore spaces and may quite generally be cared for by an appropriate (partial) sealing of the particle/crystal under study [31,32]. Bottom right shows a typical example of the transient concentration profiles (in this case obtained during molecular uptake) as attainable by either technique.…”

Section: Monitoring Diffusion and Catalytic Conversionmentioning

confidence: 99%

Jens Weitkamp – in Memoriam

Kärger

2021

Chemie Ingenieur Technik

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This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.In Memory of Prof. Dr.-Ing. Jens Weitkamp Prof. Jens Weitkamp was a pioneer in the field of zeolite catalysis, especially for applications such as hydrocracking, isomerization, alkylation, but also selective ring opening of polynuclear aromatics. This is an extended version of the closing remarks delivered at the Symposium in honor of Professor Jens Weitkamp on February 11th, 2020, at the DECHEMA house,

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Section: Monitoring Diffusion and Catalytic Conversionmentioning

confidence: 99%

Jens Weitkamp – in Memoriam

Kärger

2021

Chemie Ingenieur Technik

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“…Summing up, the techniques of microimaging are seen to nicely complement each other, with the option of monitoring simultaneously different molecular species by IRM and with the notably higher spatial resolution (up to 0.5 𝜇𝜇m) of IFM. The fact that both techniques record the concentration integral ∫ 𝑐𝑐(𝑔𝑔, 𝑦𝑦, 𝑧𝑧)𝑑𝑑𝑧𝑧 𝐿𝐿 0 in observation direction (with L denoting the crystal thickness) rather than the local concentration 𝑐𝑐(𝑔𝑔, 𝑦𝑦, 𝑧𝑧) does not mean any restriction, if one is interested in materials with pore systems allowing mass transfer in only one or two dimensions (extending perpendicular to observation direction) [72][73][74] or if the upper and lower faces of the crystal/particle under study are sealed [71,75,76].…”

Section: Microimaging By Ir and Interference Microscopymentioning

confidence: 99%

Transport-Optimized Nanoporous Materials for Mass Separation and Conversion as Designed by Microscopic Diffusion Measurement

Kärger

Valiullin

2018

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Nanoporous materials find widespread application in material upgrading by separation (“molecular sieving”) and catalytic conversion. Mass transfer in these materials is a key phenomenon deciding about their technological performance. This chapter deals with the application of measurement techniques which are able to follow the diffusive fluxes of the guest molecules in such materials over “microscopic” distances, including the pulsed field gradient (PFG) technique of Nuclear Magnetic Resonance (NMR) and the techniques of microimaging by interference microscopy (IFM) and by IR microscopy (IRM). Microscopic measurement is a prerequisite for attaining unbiased information about the elementary steps of mass transfer and about their role within the overall process of technological exploitation. We dedicate this treatise to the memory of our dear and highly esteemed colleague Nicolaas Augustinus Stolwijk, notably in recognition of his manifold activities in the field of diffusion, distinguished by their impressively high standard in connecting the message of various techniques of measurement and in combining them to comprehensive views on quite intricate subjects.

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“…Hwang et al. covered MFI‐type zeolite crystals by Al‐ALD with a growth rate of 1.33–1.46 Å cycle −1 to make the external zeolite crystal impermeable for guest molecules [110] . The coverage of external surface allowed the propagation of guest molecules along the longitudinal extension of the MFI‐type zeolite, which may provide the possibility for the fluxes of reactant and product molecules within single zeolite crystals during catalytic reactions.…”

Section: Introducing Metals On Zeolites By Aldmentioning

confidence: 99%

Atomic‐Scale Designing of Zeolite Based Catalysts by Atomic Layer Deposition

Yin

Gao

et al. 2021

ChemPhysChem

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Zeolite‐supported catalysts have been widely used in the field of heterogeneous catalysis. Atomic‐scale governing the metal or acid sites on zeolites still encounters great challenge in controllable synthesis and developing of novel catalysts. Atomic layer deposition (ALD), owing to its unique character of self‐limiting surface reactions, becomes one of the most promising and controllable strategies to tailor the metallic deposition sites in atomic scale precisely. In this review, we present a comprehensive summary and viewpoint of recent research in designing and engineering the structural of zeolite‐based catalysts via ALD method. A prior focus is laid on the deposition of metals on the zeolites with emphasis on the isolated states of metals, followed by introducing the selected metals into channels of zeolites associates with identifying the location of metals in and/or out of the channels. Subsequently, detailed analysis of tailoring the acid sites of different zeolites is provided. Assisted synthesis of zeolite and the regioselective deposition of metal on special sites to modify the structures of zeolites are also critically discussed. We further summarize the challenges of ALD with respect to engineering the active sites in heterogeneous zeolite‐based catalysts and provide the perspectives on the development in this field.

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IR Microimaging of Direction‐Dependent Uptake in MFI‐Type Crystals

Cited by 6 publications

References 72 publications

Jens Weitkamp – in Memoriam

Jens Weitkamp – in Memoriam

Transport-Optimized Nanoporous Materials for Mass Separation and Conversion as Designed by Microscopic Diffusion Measurement

Atomic‐Scale Designing of Zeolite Based Catalysts by Atomic Layer Deposition

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