CeO2 nanocrystals:: Seed-mediated synthesis and size control

This work reports on seed-mediated synthesis and size control of monodispersed CeO2 nanoparticles. CeO2 nanoparticles of mean size smaller than 2 nm were first prepared by a simple mixing of aqueous solution of cerium (IV) sulfate and ammonia solution at ambient conditions. Using these as-prepared fine particles as the tiny seeds, tunable sizes of CeO2 nanoparticles were achieved via a facile hydrothermal treatment. All samples were characterized by X-ray diffraction (XRD), infrared (IR) spectroscopy, UV-vis spectroscopy, and thermogravimetric analysis (TGAL). It is shown that in comparison with other inorganic cerium salts such as cerium (III) nitrates, cerium (IV) sulfate appears more suitable for forming CeO2 nanoparticles at room temperature. Sulfate groups are strongly thermodynamically adsorbed on CeO2 nanoparticle surfaces. The formation mechanism, surface hydration and sulfation characteristics of the resulting CeO2 nanoparticles are also discussed. (C) 2007 Elsevier Ltd. All rights reserved.