Morphology and crystal structure of CeO_2-modified mesoporous ZrO_2 powders prepared by sol-gel method

摘要

Mesoporous ZrO_2 powder modified by CeO_2 has been prepared by sol-gel method combined with novel heat-treatment without any templates. The morphology and crystal structure were characterized by Fourier transform infrared spectrophotometer (FT-IR), thermal gravimetry/differential thermal analysis (TG/DTA), X-ray diffraction (XRD), Raman spectroscope, N_2 absorption-desorption, scanning electron microscope (SEM) and high-resolution transmission electron microscope (HRTEM). It was demonstrated that the morphologies and crystal structures were varied with the CeO_2 content and calcination temperatures. Some circular grooves with diameter about 300-500 nm and thickness of 150-200 nm were observed for 30mol% CeO_2 modified samples. Tetragonal ZrO_2 and cubic (Ce.Zr)O_2 solid solution were in turn observed with CeO_2 content increasing. The oxygen storage capacity (OSC) of the mesoporous powders was determined by thermalgravimetry (TG) under cyclic thermal treatments.