Size-dependent Surface Basicity of Nano-CeO2 and the Desorption Kinetics of CO2 on its Surface

The desorption kinetics of nanocatalysts which is significantly influenced by particle size has crucial effects on catalytic performances. Herein, the desorption activation energy (E-d) and the desorption pre-exponential factor (A) for CO2 on nano-CeO2 with different particle sizes were obtained by temperature-programmed desorption. Meanwhile, we found that the particle size has a significant effect on surface basicity. The effects of particle size on E-d, A, and surface basicity were discussed, as well as the relations between desorption kinetics and surface basicity. The results indicate that with the particle size decreasing, E-d, A, the strength, and the amount of basic sites increase, and E-d, In A, and the amount of basic sites are linearly related with the diameter. Meanwhile, the strength and the amount of basic sites increase with the surface area increasing. The influence of particle size on desorption kinetics can be attributed to the effect of particle size on surface basicity.