Template-free nanosized faujasite-type zeolites

Abstract

Nanosized faujasite (FAU) crystals have great potential as catalysts or adsorbents to more efficiently process present and forthcoming synthetic and renewable feedstocks in oil refining, petrochemistry and fine chemistry. Here, we report the rational design of template-free nanosized FAU zeolites with exceptional properties, including extremely small crystallites (10-15 nm) with a narrow particle size distribution, high crystalline yields (above 80%), micropore volumes (0.30 cm(3) g(-1)) comparable to their conventional counterparts (micrometre-sized crystals), Si/Al ratios adjustable between 1.1 and 2.1 (zeolites X or Y) and excellent thermal stability leading to superior catalytic performance in the dealkylation of a bulky molecule, 1,3,5-triisopropylbenzene, probing sites mostly located on the external surface of the nanosized crystals. Another important feature is their excellent colloidal stability, which facilitates a uniform dispersion on supports for applications in catalysis, sorption and thin-to-thick coatings.

Synthesis of mesoporous zeolite catalysts by in situ formation of carbon template over nickel nanoparticles

“…Therefore, large efforts have been made in order to improve the catalyst performance. This has been realized by reduction of the intracrystalline diffusion path length in the following possible approaches: synthesis of zeolites with extra-large pores [15][16][17][18][19][20], direct synthesis of zeolite nanocrystals [21][22][23][24][25][26][27], by exfoliating layered zeolites [28,29], and by introducing mesopores in the microporous materials through templating strategies [14,30,31] or demetallation processes [4,[32][33][34][35][36].…”

Synthesis of ultra-small mordenite zeolite nanoparticles

“…Nano-sized zeolites are crucial industrial catalysts and adsorbent because of less diffusion limitations compared to micrometer-sized ones [5]. Synthesis of nanoparticles of ZSM-5, EMT and FAU has been previously reported [6][7][8]. Mordenite (MOR) is a zeolite with 12 MR and 8 MR channels that have c direction elongation and run one-dimensionally along the c-axis; therefore, MOR crystals with ultrashort c-direction can decrease the diffusion limitations [9].…”

“…The crystallization process at low temperature decreases the kinetic polymerization of silicate and aluminate to obtain highly uniform precursor particles and limits Ostwald ripening [8]. In addition, the high concentration of organic template or SDA could provide abundant crystal nuclei, which lead to small crystallites with a narrow particle size distribution.…”

Size‐Selective Binding of Sodium and Potassium Ions in Nanoporous Thin Films of Polymerized Liquid Crystals

“…However, processing of these inorganic materials is difficult and costly. [10,11] Over the last couple of years, much progress has also been made on the development of synthetic organic nanostructured materials with smaller features by using the self-assembly properties of LC behavior. Comparison of the FT-IR spectra of the individual components with the complex showed that a hydrogenbonded complex was formed (Figure 2A).…”