Nanoporous Metal Oxides Synthesized by the Nanoscale Casting Process Using Supercritical Fluids

Abstract

Nanoporous metal oxides (TiO2, Al2O3) have been synthesized using activated carbon templates with supercritical fluid solvents by using the nanoscale casting (NC) process. The precursors were dissolved in supercritical CO2 and attached to activated carbon fibers or powders as templates. After removal of the activated carbon templates by calcination in air at 873 K or by treatment in oxygen plasma, the nanoporous TiO2 or Al2O3 replicating the macroscopic shapes of the activated carbon templates was obtained. The surface area of the titania sample was 387 m2/g. The titania sample crystallized in the anatase form. The alumina samples have mesopores corresponding to the graphene crystallite size of the activated carbon. The alumina samples crystallized in the γ-alumina form.