Nonaqueous synthesis, characterization and catalytic activity of ceria nanorods

Large-scale ceria nanorods with high surface area and good crystallization were prepared via a facile nonaqueous process without any surfactants. The results of N2 adsorption/desorption showed that CeO2 nanorods possessed large pore volume, which was about 7-fold of that in conventionally synthesized CeO2 nanoparticles. TEM images revealed the exposure of more reactive {200} and {220} planes, consistent with the favorable formation of more oxygen vacancies on the surface, as confirmed by XPS and O2-TPD. TPR results demonstrated that low temperature reducibility (max. at 334 °C) maintained after reduction–oxidation cycles and even after heat treatment at 900 °C, indicating the strong stability of surface active oxygen species. Based on time-dependent morphology evolution of as-prepared precursor, the formation mechanism of nanorod structure was proposed. Furthermore, catalytic performance of CeO2 nanorods in methane combustion was investigated and compared with that of CeO2 nanoparticles.