Morphological Effect of CeO2 Nanoparticles on Catalysis of CO Oxidation

Nanocrystalline cerium oxide (CeO(2)) particles prepared by the novel two-state precipitation method were used for catalysis of CO oxidation. Firstly, various morphological CeO(2) nanoparticles were formed via proposed temperature-arranged routes. The crystalline structure, morphology, particle size and surface area of the samples were characterized by using XRD, TEM, HRTEM and BET techniques. In this work, the investigation of morphological effect for CeO(2) catalysts on the activity of CO oxidation was emphasized. From the experimental results, it indicated that the prepared samples were all non-porous and fcc structured CeO(2). The morphology and shape of samples could be easily manipulated by the two-stage temperature arrangements. The products, as precipitating at 90 degrees C for 5 minutes and then aging at 90 degrees C, were particulate, whereas they were needle-like by aging at 0 degrees C. For the reaction of CO oxidation, the needle-like CeO(2) nanoparticles demonstrated higher catalytic activity more than the particulate ones, attributing from the major occurrences of higher-activity {110} and {100} facets. Moreover, the calcinated samples with higher degree of crystallinity showed further promotion in catalytic activity. These results were in good agreements with those obtained by TPR analyses.