Ceria (CeO2) aerogels with high surface area and high porosity have been prepared. Ce-methoxyethoxide diluted in excess methoxyethanol was slowly hydrolyzed to yield a gel, which was then supercritically dried in CO2. Both as-synthesized and annealed aerogels were examined by X-ray powder diffraction, infrared spectroscopy, scanning electron microscopy, and BET surface area and pore-size analyses. Thermal analysis of the as-synthesized gel showed it to contain only similar to5 wt% residual organics, which were removed by 300 degreesC under oxygen. The unheated ceria aerogel was crystalline and exhibited a specific surface area of 349 m(2)/g with average pore diameter of similar to21.2 nm and 90% porosity. Heat treatment led to a reduction of porosity and pore size, as would be expected, but the extremely narrow pore-size distribution of the aerogel was retained.