Morphology Control of Cerium Oxide Particles Synthesized via a Supercritical Solvothermal Method

Rod and sphere-like CeO2 particles were obtained via a supercritical solvothermal method using CeCl3 center dot 7H(2)O and Ce(NO3)(3) center dot 6H(2)O as cerium sources in ethanol and methanol at 400 degrees C for 15 min followed by calcination in air. The rodlike particles were 200-400 nm in diameter and 1-2 mu m in length: The spherical particles-were 300-500 nm in diameter. The as-prepared rodlike particles using CeCl3 center dot 7H(2)O consisted of mixtures of Ce(OH)(3) and Ce(CH3COO)(3) and were converted to rodlike CeO2 by calcination in air at 500 degrees C. In contrast, the spherical particles prepared using Ce(NO3)(3) center dot 6H(2)O consisted of fluorite-structured CeO2 The possible formation mechanism was discussed on the basis of the effect of reaction time on the morphology at 400 degrees C. The cod and spherelike CeO2 particles exhibited strong UV absorption below 400 nm, and the absorbance edges extend to nearly 500 nm. The rod and spherelike CeO2 particles exhibited near-UV emission at 360 nm and blue emission at 465 nm with higher emission intensity compared.. to the commercial CeO2 sample.