Isomorphous Substitution in Zeolites

Nagy, J.B.; Aiello, R.; Giordano, G.; Katović, A.; Testa, Flaviano; Kiricsi, Imre

doi:10.1007/3829_006

Cited by 13 publications

(8 citation statements)

References 197 publications

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“…The two-layer ONIOM methodology (ONIOM) [49,50] was used for the calculations. The [(HO) 3 SiO] 4 M fragment and probe molecules were defined as the high-level region and treated with the B3LYP/B1 method. The rest as the low-level region was treated at B3LYP/3-21G level [30,51].…”

Section: Computationalmentioning

confidence: 99%

Lewis and Brönsted acidic sites in M4+-doped zeolites (M=Ti, Zr, Ge, Sn, Pb) as well as interactions with probe molecules: A DFT study

Yang

Zhou

Han

2012

Journal of Molecular Catalysis A: Chemical

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Section: Computationalmentioning

confidence: 99%

Lewis and Brönsted acidic sites in M4+-doped zeolites (M=Ti, Zr, Ge, Sn, Pb) as well as interactions with probe molecules: A DFT study

Yang

Zhou

Han

2012

Journal of Molecular Catalysis A: Chemical

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“…Nowadays, there has been considerable interest in the isomorphous replacement of Al atoms by other trivalent cations due to the increased interest in zeolites. These micro-porous species possess different physical and chemical properties from their aluminium analogues and offer possibilities for new applications of molecular sieves [1][2][3][4][5]. Gallium is directly below aluminium in the periodic table; therefore, it forms chemically similar, analogous tetrahedra to AlO 4 .…”

Section: Introductionmentioning

confidence: 99%

“…Fig 5. Temperature dependences of the spin-lattice relaxation rate of the 71 Ga nuclei in Ga-natrolite.…”

mentioning

confidence: 99%

NMR Study of Synthetic Gallosilicate Natrolite

et al. 2019

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Solid-state 29Si and 71Ga NMR was used to study the synthetic gallosilicate Na16Ga16Si24O80 ·16H2O (Ga–natrolite). It has been shown that Ga–natrolite contains mainly Si(GaO4)3(SiO4) and Si(GaO4)2(SiO4)2-structural units and has sufficiently ordered structure. Temperature dependence of the spin–lattice relaxation time T1 of 71Ga nuclei has also been studied using solid-state NMR. Spin–lattice relaxation of the 71Ga was determined to be governed by the electric quadrupole interaction with the crystal electric field gradients modulated by translational motion of H2O molecules in the Ga–natrolite pores.

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“…New zeolitic materials showing specific catalytic properties can be gained by a partial isomorphous substitution of silicon by other tetrahedrally (T) coordinated heteroatoms such as boron and aluminum. Borosilicates of MFI structure having tunable acidic strength are new shape-selective industrial catalysts in oxidation and hydroxylation reactions. , Boron-containing β ([B]-BEA) zeolites can be used as the precursor of other borosilicates ([B]-SSZ-31, [B]-SSZ-42, etc. ). , Boron can be extracted under extreme mild conditions, leaving thermally stable silanol nests, which can be reoccupied by other elements (e.g., by Al) .…”

Section: Introductionmentioning

confidence: 99%

“…It is possible to distinguish tetrahedrally coordinated boron species located in well-ordered zeolite-like frameworks and in separate, randomly distributed, nonordered amorphous phases as well as trigonal boron. Corrections are necessary in the spectrum for BO 3 line intensities for quantitative determination of trigonal boron due to quadrupolar interactions. , …”

Section: Introductionmentioning

confidence: 99%

Distribution of Aluminum and Boron in the Periodical Building Units of Boron-Containing β Zeolites

Korányi

Nagy

2006

J. Phys. Chem. B

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Various boron only ([B]-BEA) as well as aluminum- and boron-containing beta zeolites ([Al,B]-BEA) have been prepared and modified by ion exchange of ammonium, sodium, and nickel ions. The zeolite samples have been characterized by 11B, 27Al, and 29Si MAS as well as three of them by 11B and 27Al 3Q-MAS NMR spectroscopy. The quantitative contributions of defect-free Si(nX) (n = 2, 1, 0; X = Al, B) and Si(OH)x (x = 2, 1) sites to the NMR signal intensities were calculated from the various Si/(Al + B) ratios and relative 11B, 27Al, and 29Si NMR signal intensities using the special distribution of aluminum and boron in different periodical building units of the zeolite framework. The boron atoms are sitting exclusively in diagonal positions in the four-membered rings of [B]-BEA zeolites, while the aluminum atoms are situated both in diagonal and lone positions in the four-membered rings of [Al,B]-BEA zeolites. A higher part of boron atoms are positioned in framework-related deformed tetrahedral boron species than in lattice positions in the [B]-BEA than in the [Al,B]-BEA zeolites. All extraframework octahedral aluminum species are transformed back to lattice positions due to ion exchange from the protonated form to ammonium-, sodium-, or nickel-ions containing zeolites. Oppositely, trigonal boron leaves the zeolite structure completely during ion exchange.

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Isomorphous Substitution in Zeolites

Cited by 13 publications

References 197 publications

Lewis and Brönsted acidic sites in M4+-doped zeolites (M=Ti, Zr, Ge, Sn, Pb) as well as interactions with probe molecules: A DFT study

Lewis and Brönsted acidic sites in M4+-doped zeolites (M=Ti, Zr, Ge, Sn, Pb) as well as interactions with probe molecules: A DFT study

NMR Study of Synthetic Gallosilicate Natrolite

Distribution of Aluminum and Boron in the Periodical Building Units of Boron-Containing β Zeolites

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