(148c) Effect of Rare-Earth Metal Dopants on Ceria Catalysts for CO Oxidation

 Ceria has been intensively studied in a field of catalysis with a variety of applications, such as automotive emission control, catalytic combustion, and hydrocarbon reforming, and electrocatalytic reactions. Especially, ceria has been used as an active component in three-way catalysis (TWC) where pollutant emission from internal combustion engines is effectively reduced, due to the nature of outstanding redox behavior being amenable for adsorbing and giving off the oxygen from the atmosphere. Although most researchers have investigated transition metals-doped ceria, rare-earth metal-doped ceria nanocatalysts for CO and soot oxidation may be better support materials.

 In this study, we examine CeO₂ (ceria) doped by various rare-earth metals to search for the suitable CO oxidation activity. We synthesized rare-earth metal (RE=Pr, Sm, Nd, and La) doped CeO₂ nanoparticles with two different RE concentrations, Ce_0.9RE_0.1O_2-δ (RE=10%) and Ce_0.8RE_0.2O_2-δ (RE=20%), by EDTA-citrate complexing method which is capable of producing highly pure and homogeneous nano-powders. Then, the nanoparticles were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). The surface area was also evaluated by Brunauer-Emmett-Teller (BET) measurement. The catalytic efficiency of RE-doped CeO₂ for CO oxidation was measured by gas chromatography (GC). Our results will be helpful for effectively exploring the RE dopant candidates of ceria and the optimal concentration for the enhanced catalytic activity.