Characterization of nano-cerias synthesized in microemulsions by N2 sorptiometry and electron microscopy

A surfactant-stabilized microemulsion method was used to prepare nano-sized particles (<10 nm) of cubic-CeO2 exposing surfaces of not only highest specific areas (142–201 m2/g) ever reported for polycrystalline ceria, but also high thermal stability at 800 °C. Three different surfactants, a non-ionic, an anionic and a cationic, were used to form the microemulsions. Then, N2 sorptiometry and pore volume distribution calculations, were used to reveal microporous and mesoporous structures of these cerias as a function of surfactant type. Transmission electron microscopy was used to visualize consequent particle behaviors. Suggestions have been made as to the textural attributes of the high surface area and thermal stability. Accordingly, cationic surfactants, in the presence or absence of added non-ionic surfactant, are seen to assist in producing cerias of promising surface textural properties for the chemical makeup of combustion catalysts.

Nano-CeO2 particles (size ⩽6 nm) synthesized near ambient conditions in microemulsions stabilized by mixed non-ionic (Brij) and cationic (DDAB) surfactants were found to suffer considerable loss of surface accessibility (201→29 m2/g201→29 m2/g) due to sintering (⩽6→∼40 nm⩽6→∼40 nm) at 800 °C, whereas those synthesized in the sole presence of the cationic surfactant only suffered mild agglomeration (⩽10→∼15 nm⩽10→∼15 nm), thus retaining a higher surface accessibility (142→45 m2/g142→45 m2/g) at 800 °C.Figure optionsDownload as PowerPoint slide