The reversible adsorption and desorption of CO2 was investigated in the temperature range between room temperature and 250 degrees C on the CeO2 powders prepared through different synthetic routes. The adsorption of CO2 was evaluated with respect to theweight change in the thermogravimetric analysis. Each CeO2 powder was composed of well-crystallized nanometer-sized grains independent of the synthetic routes. The specific surface area varied with the synthetic route, while it was not only the parameter determining the CO2 adsorption. It was found that the crystallite size grown to some extent, or crystallinity, was advantageous for the CO2 adsorption. In addition, the CeO2 powders prepared from a Ce(III) source through the pyrolysis of the precursors containing carbonate groups tended to enhance the CO2 adsorption. The highest value of the CO2 adsorption was 0.051 g per 1 g of CeO2. The surface coverage for the sample, evaluated with {adsorbed CO2 molecules} x {adsorption cross section of CO2}/{specific surface area of the CeO2 sample determined with N-2 adsorption}, reached 1.02, which corresponded to a situation that the surface was fully covered with CO2 molecules. (C) 2019 The Electrochemical Society.