Facile synthesis of single crystalline α-Fe2O3 ellipsoidal nanoparticles and its catalytic performance for removal of carbon monoxide

Single crystalline alpha-Fe2O3 ellipsoidal nanoparticles were prepared by a simple hydrothermal method without any requirement of calcination step at high temperature. X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) have been used to investigate the ellipsoidal structure. The formation and evolution of these ellipsoidal nanoparticles were investigated by SEM, and the results showed that the ellipsoidal structure was achieved through aggregation of nanoparticles while the traditional Ostwald ripening mechanism also played an important role in formation of the initial particles before aggregation and smoothed the morphology of the ellipsoidal nanoparticles after attachment. The as-prepared alpha-FeO3 ellipsoidal nanoparticles could catalyze oxidation of almost 100% CO at a temperature of 330 degrees C. The present work shows that the nanostructures of catalyst are important to their catalytic performance besides the traditionally accepted factors, such as high BET surface area. (c) 2007 Elsevier B.V. All rights reserved.