Positron Emission Profiling: a Study of Hydrocarbon Diffusivity in MFI Zeolites

Hensen, Ejm Emiel; Jong, de Am Arthur; Santen, van Ra Rutger

doi:10.1007/3829_2007_014

Cited by 5 publications

(5 citation statements)

References 77 publications

(139 reference statements)

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“…This mechanistic regime is dominated by strong interaction of the sorbate with the pore wall. Intracrystalline diffusion is also referred to as surface, configurational, zeolitic, or micropore diffusion Molecular sieving: When a potential sorbate is larger than the available pores, diffusion of the sorbate into the pore does not proceed .…”

Section: Diffusion In Porous Solidsmentioning

confidence: 99%

Section: Diffusion In Porous Solidsmentioning

confidence: 99%

“…The effective diffusion rate of a sorbate arises from contributions of all diffusion processes that are available to the sorbate within a given porous material, and depends on factors such as pore size, substrate size, adsorption enthalpy, material flexibility, and the presence of defects. In addition to the barriers to diffusion within a porous material, surface barriers, which inhibit diffusion of a sorbate from the bulk phase into a porous material, must be considered . For example, collapse of the crystallographically‐determined pore structure at crystallite interfaces or strong multi‐layer sorption, which leads to either the narrowing or blockage of the accessible pore windows, both contribute to barriers that sorbates must confront at particle boundaries .…”

Section: Diffusion In Porous Solidsmentioning

confidence: 99%

See 2 more Smart Citations

In Operando Analysis of Diffusion in Porous Metal‐Organic Framework Catalysts

Gao

Cardenal

Wang

et al. 2018

Chemistry A European J

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The potential to exert atomistic control over the structure of site‐isolated catalyst sites, as well as the topology and chemical environment of interstitial pore spaces, has inspired efforts to apply porous metal‐organic frameworks (MOFs) as catalysts for fine chemical synthesis. In analogy to enzyme‐catalyzed reactions, MOF catalysts have been proposed as platforms in which substrate confinement could be used to achieve chemo‐ and stereoselectivities that are orthogonal to solution‐phase catalysts. In order to leverage the tunable pore topology of MOFs to impact catalyst selectivity, catalysis must proceed at interstitial catalyst sites, rather than at solvent‐exposed interfacial sites. This Minireview addresses challenges inherent to interstitial MOF catalysis by 1) describing the diffusional processes available to sorbates in porous materials, 2) discussing critical factors that impact the diffusion rate of substrates in porous materials, and 3) presenting in operando experimental strategies to assess the relative rates of substrate diffusion and catalyst turnover in MOF catalysis. It is anticipated that the continued development of in operando tools to evaluate substrate diffusion in porous catalysts will advance the application of these materials in fine chemical synthesis.

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Section: Diffusion In Porous Solidsmentioning

confidence: 99%

Section: Diffusion In Porous Solidsmentioning

confidence: 99%

Section: Diffusion In Porous Solidsmentioning

confidence: 99%

See 1 more Smart Citation

In Operando Analysis of Diffusion in Porous Metal‐Organic Framework Catalysts

Gao

Cardenal

Wang

et al. 2018

Chemistry A European J

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“…Here D 0 is the frequency factor, and E s is the surface diffusion activation energy. [14] iv. 1D diffusion and single-file diffusion: If the molecules in a given channel can pass through each other, this corresponds to normal 1D diffusion.…”

Section: Fundamental Theory Of Molecular Diffusion In Nanoreactors' P...mentioning

confidence: 98%

“…Surface diffusion coefficient: When the diffusing molecular size is similar to the pore diameter, diffusion proceeds by a hopping mechanism in which the diffusing molecular moves along the pore wall. [14] This mechanism is dominated by strong molecule-pore interactions. Under high pressure conditions, the contribution of this mechanism to the total flux is considerable.…”

Section: Fundamental Theory Of Molecular Diffusion In Nanoreactors' P...mentioning

confidence: 99%

Molecular Diffusion in Nanoreactors’ Pore Channel System: Measurement Techniques, Structural Regulation, and Catalytic Effects

Yan,

Lu,

Zhang

et al. 2023

Small

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Nanoreactors, as a new class of materials with highly enriched and ordered pore channel structures, can achieve special catalytic effects by precisely identifying and controlling the molecular diffusion behavior within the ordered pore channel system. Nanoreactors‐driven molecular diffusion within the ordered pore channels can be highly dependent on the local microenvironment in the nanoreactors’ pore channel system. Although the diffusion process of molecules within the ordered pore channels of nanoreactors is crucial for the regulation of catalytic behaviors, it has not yet been as clearly elucidated as it deserves to be in this study. In this review, fundamental theory and measurement techniques for molecular diffusion in the pore channel system of nanoreactors are presented, structural regulation strategies of pore channel parameters for controlling molecular diffusion are discussed, and the effects of molecular diffusion in the pore channel system on catalytic reactivity and selectivity are further analyzed. This article attempts to further develop the underlying theory of molecular diffusion within the theoretical framework of nanoreactor‐driven catalysis, and the proposed perspectives may contribute to the rational design of advanced catalytic materials and the precise control of complex catalytic kinetics.

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Imaging of Transient Concentration Profiles

2012

Diffusion in Nanoporous Materials

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Positron Emission Profiling: a Study of Hydrocarbon Diffusivity in MFI Zeolites

Cited by 5 publications

References 77 publications

In Operando Analysis of Diffusion in Porous Metal‐Organic Framework Catalysts

In Operando Analysis of Diffusion in Porous Metal‐Organic Framework Catalysts

Molecular Diffusion in Nanoreactors’ Pore Channel System: Measurement Techniques, Structural Regulation, and Catalytic Effects

Imaging of Transient Concentration Profiles

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