One-pot synthesis of hierarchical porous layered hybrid materials based on aluminosilicate sheets and organic functional pillars

Abstract

Layered hybrid materials (LHMs) based on ordered silicoaluminate sheets linked with organic fragments, perpendicularly located and stabilized in the interlayer space, were synthesized by a one-pot direct hydrothermal process in the absence of structural directing agents (SDAs) and using bridged silsesquioxanes as organosilicon precursors. By following the synthesis described here, the preliminary preparation of inorganic layered precursors, post-synthesis swelling and/or pillaring treatments can be avoided. The physico-chemical and structural characteristics of the materials were studied by chemical and thermogravimetrical analyses, X-ray diffraction, TEM microscopy, spectroscopic techniques (NMR and FTIR) and textural measurements. The complete exchange of intracrystalline sodium cations by protons, without substantial structural alteration of the hybrid materials, facilitated the generation of hybrid materials, which contained acid and base sites located in the inorganic (silicoaluminate layers) and in the organic interlayer linkers, respectively, with the resultant acid base materials showing promise as active and selective catalysts.