A new and generic preparation method of mesoporous clay composites containing dispersed metal oxide nanoparticles

Nanosized oxide precursors of various transitional metals, including iron, chromium, cobalt, manganese and cerium, were prepared by dissolving their corresponding hydroxides in acetic acid solutions. These precursors were used to substitute the sodium ions in laponite clay like the way to prepare pillared clays, forming mesoporous solids with high surface areas of ca. 510–640 m2/g. Stabilised by the adsorbed acetic acid molecules, the nanoparticle precursors of the metal oxides were well dispersed on the silicate platelets during the synthesis. The increase in the porosity after the intercalation of nanoparticles is primarily interpreted in terms of further delamination of the laponite clay caused by the reaction between the acidic metal precursor solutions and the silicate platelets. The clay composites containing nanoparticles of cobalt oxide appeared much more active than the impregnated cobalt catalysts in the deep oxidation of volatile organic compounds.