Controlled Synthesis of Monodisperse CeO2 Nanoplates Developed from Assembled Nanoparticles

Surfactant-mediated synthesis of monodisperse CeO2 nanoplates (15 nm x 50 nm, 2 nm thick) was conducted by the thermal decomposition of cerium acetate in 1-octadecene. X-ray diffraction patterns indicated selective (200) plane growth of fluorite cubic CeO2 in the CeO2 nanoplates, and transmission electron microscopy revealed that most of the side surfaces exhibited {200} lattice fringes. Smaller amounts of surfactants resulted in larger nanoplates composed of assemblies of small CeO2 nanoparticles (NPs). The formation of this polycrystalline structure of assembled NPs is preferable to induce stability by decreasing the surface energy and positive charge of the NPs. The bandgap energy of CeO2 nanoplates for direct transitions was larger than that for polyhedral CeO2 NPs.