Microwave‐Assisted Nonaqueous Synthesis of Doped Ceria Nanoparticles Assembled into Flakes

Undoped and doped CeO2nanoparticles were synthesized through a combination of microwave‐assisted nonaqueous sol‐gel route and thermal treatment at 300 °C. Nanocrystals of 3 nm were obtained and characterized in detail by Rietveld refinement analysis of the X‐ray diffraction data and by electron microscopy. The refinement indicated that the doping with 3d transition metals (Co, Cu, Fe, and Ni) was successfully achieved and this result was additionally confirmed by EDX measurements. Investigation of the particle morphology by electron microscopy revealed that the nanocrystals were generally not present as primary particles, but self‐assembled into often intergrown flakes with uniform diameters of about 150 nm. In selected cases, the ceria nanocrystals are crystallographically oriented with respect to each other within one flake. BET measurements revealed a high surface area of 126 m2·g–1.