Ag/Pr6O11 catalysts supported by either Pr6O11 nanorods (Pr6O11-NRs) or nanoparticles (Pr6O11-NPs) were prepared by conventio nal incipient wetness impregnation. The nanocomposite of Ag/Pr6O11-NRs demonstrated a higher catalytic activity for CO oxidation than Ag/Pr6O11-NPs at lower temperatures. This improved performance may be ascribed to the mesoporous features and resultant oxygen vacancies of the Pr6O11 nanorods support, as well as the large surface area and homogeneous loading of Ag species. As a result, 98.7 and 100% CO conversions were achieved at 210 and 240 degrees C for Ag/Pr6O11-NRs, while Ag/Pr6O11-NPs require a temperature of 320 degrees C to obtain the 100% CO conversion rate. These findings reveal that Pr6O11-NRs is the preferable support, comparative to Pr6O11-NPs, for Ag/Pr6O11 catalysts, for CO oxidation.