Trivalent Ce2O3 and CeO2−x intermediate oxides induced by laser irradiation of CeO2 powders

A strong non-stoichiometry of pure fcc CeO₂ was induced by laser irradiation. The increase of laser power and/or energy density had a saturable effect on particle size growth. The possibility of CeO₂ reduction to A-Ce₂O₃ by laser irradiation was demonstrated. Particles of stable Ce₇O₁₂ phase were observed in all specimens irradiated at low laser-power densities. An epitaxial relationship between triclinic Ce₁₁O₂₀ and cubic Ce₁₂O₂₂ phases was found. The controversial C-Ce₂O₃ phase was detected at the limits of a bcc particle. An unknown bcc phase of acicular morphology, strongly related to C-Ce₂O₃, was also registered. The dose dependence of CeO₂ structural modifications obtained by laser irradiation as a function of laser energy density variation could be explained by a simple defect aggregation model implying lattice defects (oxygen vacancies and Ce³⁺ ions).