Films based on cerium oxide sensitive to carbon monoxide

Vaz, Isabela Cristina Fernandes; Cabral, Ana Cristina Tolentino; Procópio, Alley Michael Silva; Filho, Francisco Moura

doi:10.1016/j.matlet.2021.131174

Cited by 4 publications

(1 citation statement)

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“…One way to control and modulate defects, especially vacancy clusters, is the substitution or doping of transition metals in the CeO 2 structure. This can lead to the formation of defects in the forbidden region of the band gap of CeO 2 , causing the promotion of electrons to the 4f states of Ce, which are responsible for determining the properties of this semiconductor. , The introduction of elements with different oxidation states or ionic radii into the CeO 2 sublattice, e.g., Ca 2+ , Mg 2+ , and Gd 3+ , has already proven to be effective in improving the properties of this semiconductor. − Due to its electronic properties, manganese (Mn) is a dopant that has been extensively used to change the properties of semiconductors, in particular their electronic, optical, and structural properties . Mn can exhibit multivalent oxidation states when MnO y –CeO x solid solutions are formed.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2023

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The influence of manganese modification on the spectroscopic features of manganese-doped CeO 2 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 Mn 2+ signal, likely due to the reduction of Mn 3+ species after the interaction with CO. X-ray photoelectron spectroscopy data showed the pure system with 33% of its cerium species in the Ce 3+ configuration, with an abrupt decrease to 19%, after the first modification with Mn, suggesting that 14% of the Ce 3+ species are donating one electron to the Mn 2+ ions, thus becoming nonparamagnetic Ce 4+ species. On the contrary, 58% of the manganese species remain in the Mn 2+ configuration with five unpaired electrons, corroborating the paramagnetic feature of the samples seen in the electron paramagnetic resonance study.

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