Ultrasmall
ceria (CeO2) and metal-doped CeO2 nanoparticles
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. N2 sorption
studies and porosity analysis confirm that the prepared materials
after thermal treatment at 450 °C possess a very high specific
surface area, up to 240 m2 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 ≈
54 °C and E
a = 39.5 kJ mol–1) followed by the Cu and Sm-doped CeO2 ones.