Hydrothermal synthesis and automotive exhaust catalytic performance of CeO2 nanotube arrays

Ceria (CeO2) nanotube arrays with precisely defined size and density were directly synthesized on glass and cordierite substrates using a ZnO nanorods-assisted hydrothermal method. Eliminating the procedures of template removal and film coating, the one-step synthesis approach could greatly broaden the applications for materials with tubular structures. The proper concentration of cerium nitrate precursor solution acts a vital role to adjust the instantaneous precipitation of CeO2 and dissolution of ZnO templates. The as-prepared CeO2 tube arrays were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and powder X-ray diffraction (XRD) techniques, which reveal a regular tubular structure with the average diameter of 500 nm and length of 3 μm. The automotive exhaust catalytic performance of CeO2 tube arrays prepared on the cordierite was evaluated. Compared with the ceria nanoparticles film, the target CeO2 tubes exhibit improved catalytic activities at a low start-up temperature for oxycarbide and hydrocarbon. Furthermore, the palladium-decorated CeO2 tubes exhibit a higher catalytic activity for the degradation of oxynitride than that of palladium/ceria particles/cordierite.