Sol–gel synthesis and characterization of Al2O3–CeO2 composite nanopowder

An aqueous sol–gel method has been developed for preparation of an Al2O3–15 wt.% CeO2 composite nanopowder using metal chlorides and aluminum powder. The structural evolutions and morphological characteristics of the nanopowder were investigated by X-ray diffractometry, scanning electron microscopy, thermal analysis, Brunauer–Emmett–Teller surface area measurement and Fourier transform infrared spectroscopy. The results showed that crystallization of nanopowder occurred above 600 °C. The presence of the second phase suppressed the crystallization for both Al2O3 and CeO2. Al2O3–CeO2 nanopowder with a specific surface area of 56.1 m2/g and average particle size of 90 nm was obtained by calcination at 800 °C. The activation energy of Al2O3–15 wt.% CeO2 nanocrystallite growth during calcination was measured to be 28.2 kJ/mol whereas that of Al2O3 was about 17.1 kJ/mol.