Manganese Defective Clustering: Influence on the Spectroscopic Features of Ceria-Based Nanomaterials

AMARAL, D.C.; ROCHA, L.S.R.; GRANONE, L.I.; LAGE, M.M.; CHURIO, M.S.; SANCHEZ, M.D.; LONGO, E.; NASCIMENTO, H.M.S.; ASSIS, M.; MOURA, F.; PONCE, M.A.

INORGANIC CHEMISTRY

AMER CHEMICAL SOC

Año: 2023 vol. 62 p. 12392 - 12402

0020-1669

The influence of manganese modification on the spectroscopic features of manganese-doped CeO2 systems synthesized by the microwave-assisted hydrothermal route and their correlation with the presence of O defective structures were verified, focusing on their interaction with poisonous atmospheres. Raman and electron paramagnetic resonance studies confirmed the presence of defective clusters formed by dipoles and/or quadrupoles. The number of paramagnetic species was found to be inversely proportional to the doping concentration, resulting in an increase in the Mn2+ signal, likely due to the reduction of Mn3+ species after the interaction with CO. X-ray photoelectron spectroscopy data showed the pure system with 33% of its cerium species in the Ce3+ configuration, with an abrupt decrease to 19%, after the first modification with Mn, suggesting that 14% of the Ce3+ species are donating one electron to the Mn2+ ions, thus becoming nonparamagnetic Ce4+ species. On the contrary, 58% of the manganese species remain in the Mn2+ configuration with five unpaired electrons, corroborating the paramagnetic feature of the samples seen in the electron paramagnetic resonance study.