Oxidation state and lattice expansion of CeO2-x nanoparticles as a function of particle size -: art. no. 125415

Cerium oxide nanoparticles CeO2-x (similar to3-20 nm in diameter) made by a vapor phase condensation method, have been studied by several methods of transmission electron microscopy (TEM): electron energy loss spectroscopy (EELS), high resolution imaging, and electron diffraction. The white-line ratios M-5/M-4 of the EELS spectra were used to determine the relative amounts of cerium ions Ce3+. and Ce4+ as a function of particle size. The fraction of Ce3+ ions in the particles rapidly increased with decreasing particle size below similar to15 nm in diameter. The particles were completely reduced to CeO1.5 at the diameter of