Oxygen nonstoichiometry of nanocrystalline ceria

Correlation relations between oxygen nonstoichiometry and particle size in nanocrystalline CeO2 − x are revised. The ceria unit cell parameter is shown to increase from 0.5410 to 0.5453 nm as the particle size decreases from 23 to 2.3 nm. The CeO2 − x critical particle size where cerium(IV) is completely reduced to cerium(III) is calculated as 1.1–1.3 nm.