Preparation of CeO_2 Nano Rods Through a Sonication-Assisted Precipitation

摘要

A CeO_2 nanopowder has been synthesized using sonication-assisted precipitation. The use of ultrasonics during precipitation showed potential morphology control during synthesis. The sonication-assisted precipitation with highly aqueous base (20 M NaOH) successfully induced the formation of a one-dimensional nanostructure of CeO_2 rods with a homogeneous shape and size (TEM: 24 nm diameter and 129 nm long). A conventional precipitation under the same conditions provided the CeO_2 in nonuniform sizes and shapes. Heat treatment (1100℃ for 4 h) was required for CeO_2 formation when (NH_4)_2C_2O_4 was used instead of NaOH. The concentration of the precipitation agent (15-20 M) strongly affected the size and shape of the product. Importantly, according to the temperature-programmed reduction/oxidation study, the CeO_2 prepared using the sonication-assisted route showed a relatively higher level of reversible oxygen storage capacity (2384 μmol/g), compared with the CeO_2 prepared by conventional route (1748 μmol/g).