An Approach Toward the Synthesis of Platelike Ordered Mesoporous Materials from Layered Zeolite Precursors

Abstract

An ordered silicate mesophase has been synthesized via a hydrothermal treatment of a lamellar cetyltrimethylammonium-intercalated complex. The precursor was obtained by reaction of the layered silicate Na-RUB-18 with the cationic surfactant cetyltrimethylammonium chloride at pH 11.5. Hydrothermal transformation of this lamellar phase into an MCM-41-type mesoporous silicate was studied by powder X-ray diffraction, thermogravimetric analysis, 29 Si magic-angle spinning NMR, Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy. The as-prepared mesoporous product formed after 5 days of hydrothermal treatment retains the platelike morphology and most of the local ordering of the parent material. Removal of template by calcination drastically decreases the crystallinity, although lower temperature treatment with ozone partly preserved the crystalline structure. The final mesoporous material shows very thin platelike morphology, with MCM-41-type of channels perpendicular to the plates.

Design of MFI Zeolite-Based Composites with Hierarchical Pore Structure: A New Generation of Structured Catalysts

“…[28][29][30] Louis et al made an attempt to allow the crystallization of zeolites on porous glass supports under strong alkaline conditions. 14 The glass matrix was partially transformed into zeolite crystals giving birth to a composite material with a bimodal pore system.…”

Synthesis and optical properties of composites based on ternary Zn1–xCdxS nanoparticles enclosed in a layered octosilicate

“…The first one between 25 and 100ºC with mass loss of 9.5% is attributed to the evolution of physically adsorbed water (Ramos et al, 2013). The second one, between 100 and 150ºC, is assigned to the loss of water molecules coordinated to Na + ions (Garca et al, 2006) and the third between 150 and 300ºC is associated with the water derived from condensation of silanol groups (Iozzi et al, 2009;Ramos et al, 2013). The TG curve of H-Oct shows a gradual weight loss terminated at 340ºC.…”

Strongly acidic mesoporous aluminosilicates prepared via hydrothermal restructuring of a crystalline layered silicate

“…This suggests that the solvent extraction process caused dealumination and preferential dissolution of alumina. We performed 27 Al MAS NMR spectroscopy in order to determine the nature of Al in the aluminosilicate samples and to monitor any changes in the Al environment aer various surfactant removal routes. The 27 Al MAS NMR spectra of the samples, before and aer surfactant removal, are shown in Fig.…”

“…27 Al MAS NMR spectra of the as-synthesized (AS) and surfactant free aluminosilicate materials prepared at Si/Al ratios of 10 (A) and 20 (B) after surfactant removal via calcination (CAL), extraction (EXT) and oxidation (OXI).…”