Surface electronic and structural properties of CeO_2 nanoparticles: A study by core-level photoemission and peak diffraction

摘要

A correlation between the particle size and the lattice parameter has been established in cerium oxide nanoparticles. The variation in the lattice parameter is attributed to the lattice strain induced by the introduction of Ce~(3+) due to the formation of oxygen vacancies. Lattice strain was observed to decrease with an increase in the particle size. The Ce~(4+) to Ce~(3+) ratio in CeO_2 nanoparticles increases with increasing the calcination temperature in air atmosphere. Such anomalous behavior is due to the physical effect of nanoparticle sizes on increasing the oxidation state of Ce ions in CeO_2.