No abstract

The surface basicity of pure ceria is strongly enhanced by the presence of the supported La 2 O 3 , the effect being very much influenced by the calcination temperature. X-ray diffraction (XRD), Raman spectroscopy, and La 3d 5/2 XPS data for the different samples show a progressive incorporation of La 3+ into the ceria lattice as the calcination temperature is increased. This structural change is considered to be responsible for the modifications that occurred in the basicity of the lanthana-modified ceria samples as revealed by temperature-programmed desorption-mass spectrometry (TPD-MS) of pre-adsorbed CO 2 .