Synthesis and characterization of hierarchical porous materials incorporating a cubic mesoporous phase

Abstract

Hierarchical silica porous materials have been successfully synthesized using polystyrene nanospheres as macropore template, triblock copolymer Pluronic F127 as mesopore template, tetramethyl orthosilicate as silica source and ethanol as cosurfactant. The obtained materials were characterized by XRD, TG-DTA, N 2 adsorption, SEM, TEM and AFM. These materials consist of a system of macropores with diameters of ca. 300 nm whose walls are filled with mesoporous material with average pore diameter 10 nm. The materials are also integrated with non-crystalline micropores. The XRD pattern indicates one sample with structure Fm 3m, which consists of the mesopores organized in a face-centred cubic arrangement. The hierarchical porous material created after template extraction by solvent washing exhibited a BET surface area of 277 m 2 g À1 . Following calcination the material has a BET surface area of 469 m 2 g À1 . Such properties give these materials potential for a wide range of applications in which high surface area combined with a well-defined system of pores at different length scales are required, such as adsorption, catalysis and enzyme immobilization.

The removal of caesium ions using supported clinoptilolite

“…However, due to the microporous characteristics of zeolites, sorption performance is limited because of low diffusion rates [11]. The production of hierarchical materials has been demonstrated to over-come these problems and also to enhance sorption rates [12,13]. Some methods of the production of hierarchical materials include chemical treatment and the use of environmentally harmful chemical reagents.…”

Hierarchically porous materials: synthesis strategies and structure design

“…Short chain alcohols are weak amphiphiles that act as co-solvents to alter the properties of micellar surfactant aggregates. 372,[805][806][807] For example, Sen et al used n-pentanol and n-butanol to obtain disordered, columnar, spherical or cubic mesopores in the calcined 3DOM/m silica materials. 805,806 Brij 56 surfactant (C 16 H 34 (OCH 2 CH 2 ) 10 ) has been used to create hierarchical 3DOM/m silica.…”

“…372,[805][806][807] For example, Sen et al used n-pentanol and n-butanol to obtain disordered, columnar, spherical or cubic mesopores in the calcined 3DOM/m silica materials. 805,806 Brij 56 surfactant (C 16 H 34 (OCH 2 CH 2 ) 10 ) has been used to create hierarchical 3DOM/m silica. 257,[678][679][680] This surfactant is capable of forming a true lyotropic liquid crystal phase when placed in a sol-gel silica precursor.…”

Analytical Understanding of the Materials Design with Well‐Described Shrinkages on Multiscale

“…However, if condensation of the original frameworks is not enough, the matrix will be also shrunk during solvent extraction with reduction of the pore size. In a case of bimodal porous silica, PS spheres can be extracted by THF with a certain decrease of the BET surface area owing to densification of silicate frameworks with condensation.…”