Diameter-dependent catalytic activity of ceria nanorods with various aspect ratios for toluene oxidation

Ceria nanorods with various aspect ratios were successfully synthesized by a convenient hydrothermal method without any templates or surfactants. The samples were characterized by TEM, HRTEM, XRD, N-2 adsorption/desorption, XPS, Raman and H-2-TPR. The results showed that the diameter and length of the ceria nanorods were determined by the concentration of NaOH solution and the hydrothermal reaction time, respectively. In addition, the diameter-dependent catalytic activity for abatement of toluene had been found over the nanorods with various aspect ratios. The thinner nanorods presented higher catalytic activity owing to the existence of more Ce3+ ions and more oxygen vacancy sites on the surface. Over the thinnest nanorods, the most active catalyst, three consecutive runs in toluene oxidation and a longstanding oxidation test running at 380 degrees C for 100 h were also carried out. (C) 2014 Elsevier B.V. All rights reserved.