Details
| Original language | English |
|---|---|
| Pages (from-to) | 2429-2433 |
| Number of pages | 5 |
| Journal | ChemPhysChem |
| Volume | 10 |
| Issue number | 14 |
| Early online date | 28 Sept 2009 |
| Publication status | Published - 2009 |
Abstract
By applying pulsed-field gradient nuclear magnetic resonance (PFG NMR) in comparison to quasi-elastic neutron scattering (QENS), we sense by measurement of the diffusion of n-octane on different length scales, transport resistances in faujasite type X (which is isostructural with type Y and differs by the lower Si/AI ratio only) with mutual distances of less than 300 nm. Direct observation of the real structure of zeolite X by transmission electron microscopy identifies them as stacking faults of mirror-twin type on (111)- type planes of the cubic framework. Thus, direct experimental proof is given that, in general, nanoporous host systems such as zeolite crystals cannot be considered as a mere arrangement of cavities. It is rather the presence of structural defects that dominates their properties as soon as transport phenomena with practical relevance, including chemical conversion by heterogeneous catalysis and chemical separation by molecular sieving and selective adsorption, become relevant.
Keywords
- Diffusion, Electron microscopy, Neutron scattering, NMR spectrocopy, Zeolites
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Atomic and Molecular Physics, and Optics
- Chemistry(all)
- Physical and Theoretical Chemistry
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In: ChemPhysChem, Vol. 10, No. 14, 2009, p. 2429-2433.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Intracrystalline transport resistances in nanoporous zeolite X
AU - Feldhoff, Armin
AU - Caro, Jürgen
AU - Jobic, Hervé
AU - Ollivier, Jacques
AU - Krause, Cordula B.
AU - Galvosas, Petrik
AU - Kärger, Jörg
PY - 2009
Y1 - 2009
N2 - By applying pulsed-field gradient nuclear magnetic resonance (PFG NMR) in comparison to quasi-elastic neutron scattering (QENS), we sense by measurement of the diffusion of n-octane on different length scales, transport resistances in faujasite type X (which is isostructural with type Y and differs by the lower Si/AI ratio only) with mutual distances of less than 300 nm. Direct observation of the real structure of zeolite X by transmission electron microscopy identifies them as stacking faults of mirror-twin type on (111)- type planes of the cubic framework. Thus, direct experimental proof is given that, in general, nanoporous host systems such as zeolite crystals cannot be considered as a mere arrangement of cavities. It is rather the presence of structural defects that dominates their properties as soon as transport phenomena with practical relevance, including chemical conversion by heterogeneous catalysis and chemical separation by molecular sieving and selective adsorption, become relevant.
AB - By applying pulsed-field gradient nuclear magnetic resonance (PFG NMR) in comparison to quasi-elastic neutron scattering (QENS), we sense by measurement of the diffusion of n-octane on different length scales, transport resistances in faujasite type X (which is isostructural with type Y and differs by the lower Si/AI ratio only) with mutual distances of less than 300 nm. Direct observation of the real structure of zeolite X by transmission electron microscopy identifies them as stacking faults of mirror-twin type on (111)- type planes of the cubic framework. Thus, direct experimental proof is given that, in general, nanoporous host systems such as zeolite crystals cannot be considered as a mere arrangement of cavities. It is rather the presence of structural defects that dominates their properties as soon as transport phenomena with practical relevance, including chemical conversion by heterogeneous catalysis and chemical separation by molecular sieving and selective adsorption, become relevant.
KW - Diffusion
KW - Electron microscopy
KW - Neutron scattering
KW - NMR spectrocopy
KW - Zeolites
UR - http://www.scopus.com/inward/record.url?scp=70349761394&partnerID=8YFLogxK
U2 - 10.1002/cphc.200900279
DO - 10.1002/cphc.200900279
M3 - Article
AN - SCOPUS:70349761394
VL - 10
SP - 2429
EP - 2433
JO - ChemPhysChem
JF - ChemPhysChem
SN - 1439-4235
IS - 14
ER -