Hematite nanorods with tunable porous structure: Facile hydrothermal-calcination route synthesis, optical and photocatalytic properties

One-dimensional hematite (alpha-Fe2O3) nanostructures have attracted much concern due to their distinguished utilizations in nanomagnetism, photoanodes, and gas sensors. In order to extend the applications of hematite, a facile fast nontoxic method to synthesize 1D hematite nanostructures is highly required. In this contribution, alpha-Fe2O3 nanorods with tunable porous structure and optical absorbance properties were successfully synthesized via a facile hydrothermal-calcination route. Uniform high aspect ratio alpha-FeOOH nanorods with a length of ca. 600 nm, diameter of ca. 30 nm, and aspect ratio of ca. 20 were synthesized via a mild hydrothermal treatment (150 degrees C, 6.0 h) of the co-precipitation of FeCl3 and NaOH solutions followed by a subsequent calcination (400 or 700 degrees C in the presence of NaCl). The presence of the CTAB with a mass ratio of 5.0% favored the preferential growth of the alpha-FeOOH nanorods with larger aspect ratio, while the thermal decomposition of alpha-FeOOH at 400 or 700 degrees C in the presence of NaCl led to the high aspect ratio (ca. 15) porous or low aspect ratio (ca. 5) nonporous alpha-Fe2O3 nanorods, respectively. The UV-vis spectra showed that the optical absorbance properties of the calcined porous/nonporous alpha-Fe2O3 nanorods were well tuned, and the photocatalytic evaluation revealed that the nonporous alpha-Fe2O3 nanorods exhibited higher degradation efficiency for RhB than porous alpha-Fe2O3 nanorods. The as-obtained alpha-Fe2O3 nanorods with tunable porous structure as well as the tunable optical and photocatalytic properties suggested their great potential applications in the near future. (C) 2014 Elsevier B.V. All rights reserved.