Molecular Engineered Porous Nanocomposites of Metal Oxide and Clay Using Surfactants

Abstract

A novel synthesis route of metal oxide nanoparticles dispersed in a silicate framework is reported here. This composite nanostructure is highly thermally stable and porous, rendering large surface area and rich surface chemistry promising for catalytic applications. Aqueous solutions of metal salts were used as the precursors of the nanoparticles, and added in an aqueous dispersion of synthetic clay, laponite, in which the clay exists in exfoliated silicate sheets. Acid leaching of the clay sheets occurs in the reaction due to the strong acidity of the metal salt solution. Meanwhile, the metal hydrate ions polymerise because of the high pH of the clay dispersion and condense on the leached silicates. This mechanism is distinctly different from conventional pillaring process. The nanocomposites of various oxides and binary oxides were synthesised. By introducing polyethylene oxide surfactants, we obtained mesoporous nanocomposites with very large surface areas (400-900 m2/g) and porosity. These nanocomposites are superior catalysts or catalyst supports over of microporous pillared clays [1-3] due to their structure and surface properties.

Facile Synthesis of g-C3N4/TiO2/Hectorite Z-Scheme Composite and Its Visible Photocatalytic Degradation of Rhodamine B

“…The molecular formula of synthetic hectorite is M x [Li x Mg 6-x Si 8 O 20 (OH) y F z ] (M=Na, Li). It is known that hectorite can form a house of cards structure in water with exfoliated discrete plates of 20–30 nm, which is suitable for the synthesis of catalyst composites [ 8 , 9 , 10 , 11 ]. Titanium incorporated into hectorite has small crystal sizes, large porosity and high specific surface area [ 12 , 13 , 14 ].…”