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

Abstract

Nanoporous metal oxides (TiO 2, Al 2 O 3 ) have been synthesized using activated carbon templates with supercritical fluid solvents by using the nanoscale casting (NC) process. The precursors were dissolved in supercritical CO 2 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 TiO 2 or Al 2 O 3 replicating the macroscopic shapes of the activated carbon templates was obtained. The surface area of the titania sample was 387 m 2 /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.