Formation of Novel Ordered Mesoporous Silicas with Square Channels and Their Direct Observation by Transmission Electron Microscopy

Abstract

The layered polysilicate kanemite can be used to synthesize the novel mesoporous silica KSW‐2 (see picture), which contains square channels. The individual silicate sheets of kanemite are bent during the gradual leaching of hexadecyltrimethylammonium (C16TMA) surfactants from a layered C16TMA–kanemite complex.

Recent advances of mesoporous materials in sample preparation

“…The structure and phase behavior of these mesostructured inorganic-organic composites depend on the nature of surfactant molecules and silica precursors. By selecting different types of surfactants (neutral block copolymer, cationic surfactants and anionic surfactants), additives (trimethylbenzene, alcohols and salt), synthesis temperatures, and basic or acidic reaction media, various silica mesoporous materials such as MCM-41 with two-dimensional hexagonal (p6mm) [4], SBA-12 with three-dimensional hexagonal (P6 3 /mmc) [5], SBA-16 with three-dimensional cubic (Im3m) [6], lamellar [7], cellular foam [8] can thus be prepared with different pore structures. Besides the adjustment of mesoporous structure, mesoporous materials with different morphologies (thin films [9], fibers [10], particles [11], monoliths [12]) can be obtained by controlling the process conditions or parameters.…”

Templated Synthesis for Nanoarchitectured Porous Materials

“…96 KSW-2-type (c2mm) mesoporous silica can be prepared through the bending of individual silicate sheets with intra-and interlayer condensation. 97 The structural units originating from the silicate sheets (kanemite) are partially retained in the frameworks, showcasing the unique capabilities of layered silicate which cannot be attained by MCM-type mesoporous silica. 98 In the past two decades, many efforts have been made to synthesize nanoporous materials with well-controlled pore size, shape, composition, and spatial arrangement.…”

Synthesis of Mesostructured Materials Using Nb-containing Layered Perovskites and Cationic Surfactants

“…In the case of mesoporous materials synthesized from homogeneous solutions such as mesoporous silica, MCM-41, the mesostructure of the materials mainly depends on synthetic conditions and SDA [4] While KSW-2 which is synthesized using a layered silicate, kanemite as starting material has a unique square shape pore , which is difficult to form from homogeneous solution [5] . This suggests that structure of layered compounds as starting materials is an important factor for controlling the mesostructure of the resultant composites.…”