Facile Low-Temperature Synthesis of Ceria and Samarium-Doped Ceria Nanoparticles and Catalytic Allylic Oxidation of Cyclohexene

CeO 2 as one of the most promising oxidation catalysts has attracted much attention because of its superior performance. The extent of oxidation properties is controlled by the ratio of Ce 3+ /Ce 4+, particle size, and surface area. Here, a facile low-temperature aqueous solution-based chemical route for the synthesis of CeO 2 and samarium-doped CeO 2 (Sm−CeO 2 ) nanoparticle aggregates, with high content of Ce 3+ and surface area, using aqueous solution of ammonium carbonate complex of cerium is presented. The morphologies and structures of the prepared CeO 2 nanoparticle were characterized by X-ray diffraction (XRD), thermal analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and hydrogen-temperature programmed desorption. The synthesized CeO 2 and Sm−CeO 2 nanoparticle aggregate showed significantly improved catalytic activity toward allylic oxidation to corresponding en-ones compared to bulk CeO 2 . The present method provides a new and facile strategy toward the synthesis of CeO 2 and Sm−CeO 2 nanoparticle aggregates with extensive applications.