Synthesis, characterization and photocatalytic activity of α-Fe2O3 nanoparticles

Photo-catalytically active mesoporous alpha-Fe2O3 nanoparticles have been synthesized by a simple thermal decomposition technique at two different annealing temperatures, ca. 500 and 650 degrees C. Characterization of the materials were carried out using powder X-ray diffraction (XRD), scanning electron microscopy (SEM), N-2-sorption isotherm, UV-Vis spectroscopy and FTIR spectroscopy. The N-2-sorption experiment showed type-IV isotherms with average pore diameters 4.4 and 3.5 nm. The Brunauer-Emmett-Teller (BET) surface area of the sample annealed at 500 degrees C (79.2 m(2)/g) was considerably higher than at 650 degrees C (58.5 m(2)/g). The band gap energy was investigated by the UV-Vis absorption study and the presence a-phase of Fe2O3 was confirmed by FTIR spectroscopy. The photo-catalytic activity of the Fe2O3 nanoparticles was tested by the decomposition of aqueous solution of Rose Bengal dye and showed the complete decomposition under light irradiation. The kinetics of the decomposition process was also investigated and found to show the pseudo-first-order reaction kinetics with the rate constants of 2.65 x 10(-2) and 1.57 x 10(-2) min(-1), respectively. (C) 2011 Elsevier Ltd. All rights reserved.