Synthesis of ceria-praseodimia nanotubes with high catalytic activity for CO oxidation

Ceria-praseodimia nanotubes (Ce0.8Pr0.2O2−δ–NT) have been synthesized for the first time employing a template-based electrodeposition method inside the pores of anodic aluminum oxide (AAO) membranes. Various electron microscopy techniques such as Field Emission Gun Scanning Electron Microscopy (FEG-SEM), Scanning Transmission Electron Microscopy working in High Angle Annular Dark-Field mode (STEM-HAADF), High Resolution Transmision Electron Microscopy (HRTEM), Energy-dispersive X-ray Spectroscopy (X-EDS), Electron Energy Loss Spectroscopy (EELS) and Energy Filtered Transmision Electron Microscopy (EFTEM) have been used to characterise the morphology, structure and chemical composition of the nanotubes. The results indicate that nanotubes are formed by nanocrystals of cerium and praseodymium mixed oxide. Furthermore, the system Ce0.8Pr0.2O2−δ–NT/AAO shows a better performance in the CO oxidation reaction than both powdered Ce0.8Pr0.2O2−δ prepared by conventional methods and CeO2–NT/AAO. These results have been discussed and related to the synergistic effect of doping and nanostructuration of CeO2.