Synthesis of nanocrystalline CeO2 particles by different emulsion methods

Cerium oxide nanoparticles were synthesized using three different methods of emulsion: (1) reversed micelle (RM); (2) emulsion liquid membrane (ELM); and (3) colloidal emulsion aphrons (CEAs). Ammonium cerium nitrate and polyoxyethylene-4-lauryl ether (PE4LE) were used as cerium and surfactant sources in this study. The powder was calcined at 500 °C to obtain CeO2. The effect of the preparation procedure on the particle size, surface area, and the morphology of the prepared powders were investigated. The obtained powders are highly crystalline, and nearly spherical in shape. The average particle size and the specific surface area of the powders from the three methods were in the range of 4–10 nm and 5.32–145.73 m2/g, respectively. The CeO2 powders synthesized by the CEAs are the smallest average particle size, and the highest surface area. Finally, the CeO2 prepared by the CEAs using different cerium sources and surfactant types were studied. It was found that the surface tensions of cerium solution and the type of surfactant affect the particle size of CeO2.