Mesoporous CeO₂ nanoparticles synthesized by an inverse miniemulsion technique and their catalytic properties in methane oxidation.

Cerium(IV) oxide nanoparticles were synthesized using an inverse miniemulsion technique with cerium nitrate hexahydrate as precursor. The resulting nanocrystallites are as small as 5 nm with a specific surface area of 158 m² g⁻¹ after calcination at 400 °C. With the addition of cetyltrimethylammonium bromide (CTAB) or (poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide)) triblock copolymers (PEO-PPO-PEO) as template in the miniemulsion droplets, the specific surface area can be increased up to 255 m² g⁻¹. The miniemulsions were characterized by dynamic light scattering (DLS) and the obtained oxides were examined by x-ray diffraction (XRD), nitrogen sorption (BET and BJH), and transmission electron microscopy (TEM). The catalytic activity of the resulting ceria was investigated for the temperature-programmed oxidation (TPO) of methane.