From nanoparticles to nanorods: Insights into the morphology changing mechanism of ceria

It is of significant importance for the applications to controllably and facilely synthesize ceria with tunable morphology and exposed surfaces. A series of nanosized ceria with different morphology have been synthesized by a simple precipitation method under an inert atmosphere with no surfactant or template. nanoparticles and one-dimensional (1D) nanostructures of ceria have been prepared with Ce(NO3)3 and CeCl3 as cerium precursor respectively. With different mole ratio of [Cl-: NO3-], the transition morphologies from nanoparticles to nanorods have been synthesized. The shape-controlling effect of these ions is due to their different roles in the oxidation of Ce(OH)3 to Ce(OH)4. The FT-IR analysis proves that the composite of Ce(OH)3 could be oxidized by NO3- and the NO3- be reduced to NO. However, the existence of Cl- can inhibit the oxidizing capacity of NO3-. The anion-induced controllable synthesis, which is a surfactant- and template-free facile precipitation method, provides a potential route for fabricating ceria nanostructures for its various applications.