Application of quasi-equilibrated thermodesorption of linear and di-branched paraffin molecules for detailed porosity characterization of the mono-layered zeolite MCM-56, in comparison with MCM-22 and ZSM-5

Makowski, Wacław; Mlekodaj, Kinga; Gil, Barbara; Roth, Wiesław J.; Marszałek, Bartosz; Kubů, Martin; Hudec, Pavol; Smiešková, Agáta; Horňáček, Michal

doi:10.1039/c4dt00232f

Cited by 15 publications

(22 citation statements)

References 36 publications

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“…244 By using specially chosen probe molecule (2,2-dimethyloctane) the amount of surface 12-ring cups in hierarchical MWW zeolites could be quantified. 219…”

Section: Non-conventional Pore Characterization Methodsmentioning

confidence: 99%

“…Application of the t-plot method in adsorption data analysis for hierarchical micromesoporous materials: A) simulated isotherm from Figure 9, B) experimental adsorption data for MCM-56 zeolites: parent (P) and modified by swelling with hexadecyltrimethylammonium-OH/Cl and pillaring with TEOS (M). 219 The corresponding adsorption isotherms are shown in Figure 10A.…”

Section: Figure 11mentioning

confidence: 99%

“…218 This procedure almost always results in very good fit, even for microporous materials that do not meet assumption of the BET model, as unlimited multilayer adsorption is not consistent with the mechanism of filling the micropores. This is shown in Figure 12, where N 2 adsorption isotherms observed for two MCM-22 zeolites (P: parent and M: modified by swelling with HDTMA-OH/Cl solution and pillaring with TEOS) 219 are plotted together with the theoretical BET functions, resulting from the calculations. Despite very good linearity of the transformed data ( Figure 12B), values of the BET surface area obtained for both zeolites (686 and 413 m 2 /g for zeolite M and P, respectively) are much higher than the corresponding t-plot values (259 and 160 m 2 /g).…”

Section: Figure 11mentioning

confidence: 99%

“…Application of the BET method for determination of the specific surface area of MCM-56 zeolites: parent (P) and modified by swelling with HDTMA-OH/Cl and pillaring with TEOS (M). 219 Red points denote the data used in calculation, green or red line -the resulting BET functions (A: nonlinear, B: linearized) calculated from the fitting parameters.…”

Section: Figure 12mentioning

confidence: 99%

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Layer like porous materials with hierarchical structure

et al. 2016

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Many chemical compositions produce layered solids consisting of extended sheets with thickness not greater than a few nanometers. The layers are weakly bonded together in a crystal and can be modified into various nanoarchitectures including porous hierarchical structures. Several classes of 2-dimensional (2D) materials have been extensively studied and developed because of their potential usefulness as catalysts and sorbents. They are discussed in this review with focus on clays, layered transition metal oxides, silicates, layered double hydroxides, metal(iv) phosphates and phosphonates, especially zirconium, and zeolites. Pillaring and delamination are the primary methods for structural modification and pore tailoring. The reported approaches are described and compared for the different classes of materials. The methods of characterization include identification by X-ray diffraction and microscopy, pore size analysis and activity assessment by IR spectroscopy and catalytic testing. The discovery of layered zeolites was a fundamental breakthrough that created unprecedented opportunities because of (i) inherent strong acid sites that make them very active catalytically, (ii) porosity through the layers and (iii) bridging of 2D and 3D structures. Approximately 16 different types of layered zeolite structures and modifications have been identified as distinct forms. It is also expected that many among the over 200 recognized zeolite frameworks can produce layered precursors. Additional advances enabled by 2D zeolites include synthesis of layered materials by design, hierarchical structures obtained by direct synthesis and top-down preparation of layered materials from 3D frameworks.

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“…244 By using specially chosen probe molecule (2,2-dimethyloctane) the amount of surface 12-ring cups in hierarchical MWW zeolites could be quantified. 219…”

Section: Non-conventional Pore Characterization Methodsmentioning

confidence: 99%

Section: Figure 11mentioning

confidence: 99%

Section: Figure 11mentioning

confidence: 99%

Section: Figure 12mentioning

confidence: 99%

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Layer like porous materials with hierarchical structure

et al. 2016

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“…Pore size characteristics were also determined by Quasi Equilibrated Temperature-Programmed Desorption and Adsorption (QE-TPDA) 53 with nonane as the probe molecule. 54 The obtained profiles ( Figure 3C), exhibiting strong desorption maxima at 80-120 °C corresponding to small mesopores or large micropores, were consistent with the static nitrogen sorption results.…”

Section: Gas Adsorption and Pore Size Determinationsmentioning

confidence: 99%

Pillaring of layered zeolite precursors with ferrierite topology leading to unusual molecular sieves on the micro/mesoporous border

et al. 2018

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Layered zeolite materials with FER layer topology can produce various condensed and expanded structures including zeolite frameworks, FER and CDO, their interlayer expanded forms (IEZ), and organic-intercalated and pillared derivatives. This work concerns pillaring of the surfactant-swollen derivative with a gallery height of ca. 2.5 nm between layers by treatment with tetraethylorthosilicate (TEOS) at room and elevated temperatures. The materials obtained at 100 °C and higher showed unusual properties including 2 nm pores on the micro/mesoporous border and disordered layer packing indicated by the absence of distinct low angle interlayer peaks at d-spacing >3 nm (∼3° 2θ Cu Kα radiation) in the X-ray diffraction pattern (XRD). TEOS treatment at room temperature produced a pillared molecular sieve with the expected mesoporous characteristics, namely a pore size of around 3 nm and a high intensity low angle (001) peak at 2.3° 2θ, and a d-spacing of 3.8 nm, in the XRD. The characterization aiming to elucidate the nature of the obtained unusual products included gas adsorption isotherms, aberration corrected (C-corrected) Scanning Transmission Electron Microscopy (STEM) studies and Si solid state NMR. BET surface area values decreased with the temperature of TEOS treatment from approximately 1200 m g to ∼900 and 600 m g, at room temperature, 100 °C, and 120 °C, respectively. The Si solid state NMR revealed the presence of both Q ((SiO)SiOX, X = H or minus charge) and Q ((SiO)Si) centers giving separated signals up to the pillaring step. After pillaring at 100 °C and calcination, the nominal intensity ratios Q : Q were 2.17 and 2.61 but the signals were merged into one broad peak indicating the structural heterogeneity of Si-O coordination. The microscopy showed the presence of FER layers in the samples but the overall structure and composition were not well-defined. The observed unusual disorganization and possible partial degradation of layers during pillaring may result from the combination of high temperature, alkalinity (surfactant hydroxide) and siliceous composition of the layers. The obtained pillared products are of interest for the preparation of larger pore catalysts and sorbents or controlled drug delivery.

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