CeO2 nanocrystals: Seed-mediated synthesis and size control

This work reports on seed-mediated synthesis and size control of monodispersed CeO{sub 2} nanoparticles. CeO{sub 2} 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 CeO{sub 2} 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 (TGA). It is shown that in comparison with other inorganic cerium salts such as cerium (III) nitrates, cerium (IV) sulfate appears more suitable for forming CeO{sub 2} nanoparticles at room temperature. Sulfate groups are strongly thermodynamically adsorbed on CeO{sub 2} nanoparticle surfaces. The formation mechanism, surface hydration and sulfation characteristics of the resulting CeO{sub 2} nanoparticles are also discussed.