Kinetics Investigation of Oxygen Storage Capacity in La(2)O(3)-CeO(2) Solid Solution

La(2)O(3)-CeO(2) nanopowders with different La(2)O(3) (0-20 mol%) were prepared by the sol-gel method. The modification of the cubic structure of ceria by substituting La(3+) for Ce(4+) into the lattice of CeO(2) has been investigated. The crystal structure of La(2)O(3)-CeO(2) nanomaterials has been examined by X-ray powder diffraction and analyzed by the Rietveld refinement method. The introduction of La(3+) enlarges the octahedral void of unit cell in the cubic CeO(2), which favors the oxygen migration in the crystal lattice. Raman characterization results show that the wavenumber of the La(2)O(3)-CeO(2) solid solution shifted to red and the oxygen vacancy increased with lanthana content in Ce(1-x)La(x)O(2-x/2). The oxygen vacancy, generated by La(3+) substituting for Ce(4+), could supply more channels for oxygen migration through the lattice. The changes of lattice structure and the oxygen vacancy with La(2)O(3) are correspondence with the results of oxygen storage capacity (OSC) measurement, which indicate that the changes of macro-performance are connected with the microstructure deformation of La(2)O(3)-CeO(2). The kinetics of Ce(0.8)La(0.2)O(1.9) nanomaterials with the highest OSC value was studied and the apparent activation energy (E(a)) of reduction and oxidation process was calculated to be 5.6 and 6.0 kJ/mol, respectively. The low E(a) value might be one of the reasons for Ce(0.8)La(0.2)O(1.9) nanomaterials with the high OSC value.Chemistry, MultidisciplinaryNanoscience & NanotechnologyMaterials Science, MultidisciplinaryPhysics, AppliedPhysics, Condensed MatterSCI(E)EIPubMed8ARTICLE32155-21621