Crystalline Ce(III)−La(III) Double Basic Carbonates: A Chemical Shortcut To Obtain Nanometric La(III)-Doped Ceria

The controlled decomposition of crystalline Ce1−x La x (OH)CO3 samples to give nanocrystalline Ce1−x La x O2−δ solid solutions is studied as a function of temperature and La(III) content. The hexagonal basic carbonates, related to the mineral bastnaesite, are shown to be suitable precursors for the obtainment of Ce(IV-III), La(III) oxides when exposed to O2 at mild temperatures (250 °C). The oxidation of Ce(III) centers triggers the massive decomposition of the whole precursor, acting as a chemical shortcut to achieve the domain of ceria phases, at temperatures 200 °C lower than the traditional procedures. The mixed oxides exhibit higher surface areas than those obtained for traditional coprecipitation−thermal decomposition procedures, achieving values in the range of those oxides prepared by costly surfactant-assisted methods.