A unique electrospun alpha-Fe2O3 nanofiber catalyst was obtained. The fibers are hollow and built by flat nanocrystals with {001} and {012} facets. The nanocrystals are assembled as a mosaic with all of the facets mainly constituting the total surface area, with a value of 22.1 m(2) g(-1). These peculiar fibers exhibited outstanding photocatalytic efficiency towards the NO gas oxidation compared to nanometric hematite powders.