Ultrasmall Metal-Doped CeO2 Nanoparticles for Low-Temperature CO Oxidation

Ultrasmall ceria (CeO2) and metal-doped CeO2 nano-particles in the sub-3 nm size regime were synthesized via a facile, single-step, liquid-phase thermal decomposition reaction in a monosurfactant medium, which plays the role of a solvent and coordination molecule. The nanoparticles were characterized by a combination of techniques including powder X-Ray diffraction, Raman spectroscopy, and high-resolution transmission electron microscopy, and their catalytic activity was tested for the CO oxidation reaction. The results show that all the materials are highly crystalline in the as-synthesized form and monodispersed with a near-spherical shape. N-2 sorption studies and porosity analysis confirm that the prepared materials after thermal treatment at 450 degrees C possess a very high specific surface area, up to 240 m(2) g(-1), and additionally a hierarchical mesoporous structure. The CeO2 and doped-CeO2 particles demonstrate superior catalytic activity for the low-temperature CO oxidation. Among the different kinds of doping, the Cu-Co co-doped CeO2 nanoparticles are the most active for the CO oxidation (T-50 approximate to 54 degrees C and E-a = 39.5 kJ mol(-1)) followed by the Cu and Sm-doped CeO2 ones.