Ultrasonic-assisted hydrothermal synthesis of ceria nanorods and their catalytic properties for toluene oxidation

Ceria nanorods with relatively high yield were successfully prepared by a convenient hydrothermal reaction method followed by ultrasonication without any templates or surfactants. The cerium precursor, concentration of NaOH solution, and the employment of ultrasonic have been demonstrated to be the crucial factors for the formation of CeO2 nanorods. NO3- ions, excluding Cl-, SO42-, and CH3COO-, were designated to act as the inhibitors in the morphogenetic process forming the rods. Nanorods could only be shaped using relatively high concentrations of alkali solution. Ultrasonication proved to be an effective means of improving the yield of ceria nanorods. Among the different content of nanorods, the catalytic activity of high content of nanorods was obviously the best. Thus, properties of CeO2 could be improved by modifying the morphology. Furthermore, the catalytic pathway for toluene oxidation over the ceria nanorods has been explored by in-situ FTIR.