Electric Properties Change during Morphological Evolution of CeO 2 Nanostructures: Synergy between Bulk and Surface Defects

MACCHI, CARLOS; PROCÓPIO, ALLEY M. S.; ROCHA, LEANDRO S. R.; ORTEGA, PEDRO P.; ALDAO, CELSO M.; GRANONE, LUIS I.; NASCIMENTO, HUGO M. S.; LONGO, ELSON; CASTRO, MIRIAM S.; IVORRA, FERNANDO D.; SOMOZA, ALBERTO; MOURA, FRANCISCO; PONCE, MIGUEL A.

ACS Omega

ACS OMEGA

Año: 2024 vol. 9 p. 42172 - 42182

2470-1343

CeO2 samples were synthesized via the polymeric precursormethod at different calcination temperatures. Electric properties wereinvestigated using positron annihilation lifetime spectroscopy, electron paramagneticresonance spectroscopy, and complex impedance spectroscopy.Reduction in the specific surface area of the particles with increasing calcinationtemperature along with morphological changes were observed. PALS depicteddoubly ionized oxygen vacancies surrounded by two Ce3+ atoms, while the EPRspectroscopy showed a singly ionized oxygen vacancy surrounded by Ce3+ andCe4+ ions. Impedance measurements unraveled the presence of polarons, whilethermal treatments led to a lower electrical conductance, as the calcinationtemperature increased.