Template Synthesis of Hollow Metal Oxide Fibers with Hierarchical Architecture

Hollow metal oxide fibers (TiO 2 and Fe 2 O 3 ) have been prepared by using activated carbon fibers (ACFs) as the templates, through a simple impregnation and heat treatment. The resulting products, as compared to ACFs, possessed not only a similar morphological feature upward to the micrometer scale but also different surface nanostructures with unique morphology. The TiO 2 fibers displayed overlapped “wormlike” surface and a hierarchical structure with two distinguishable layers, the inner layer and the outer layer, which were composed of the particles of 7 and 15 nm, respectively. It was also found that the reaction temperature had a significant effect on the TiO 2 surface morphology. The Fe 2 O 3 fibers exhibited a rough and crinkle-like surface and were also composed of hierarchical particles. Both TiO 2 and Fe 2 O 3 fibers possessed the hierarchical pore structure with mesopores in the walls of the large hollow channel. Such porous architecture favored the resultant TiO 2 with better apparent photoactivity than P25 titania for degradation of gaseous acetone and would also make the materials useful for further application in other fields.