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

• Ceria nanorods with various aspect ratios were synthesized controllably.
• The relationship between diameter of nanorod and alkali concentration was found.
• The influence factors on the length of nanorods were also discovered.
• A high correlation between removal of toluene and diameter of nanorod was verified.
• The most active nanorods proved to be very stable during the 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, N2 adsorption/desorption, XPS, Raman and H2-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 °C for 100 h were also carried out.

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