Influence of Synthesis Time on the Morphology and Properties of CeO2 Nanoparticles: An Experimental-Theoretical Study

Autor(es)

de Oliveira, Regiane Cristina ^{[1, 2]} ; Ciola Amoresi, Rafael Aparecido ^[1] ; Marana, Naiara Leticia ^[3] ; Zaghete, Maria Aparecida ^[4] ; Ponce, Miguel ^[5] ; Chiquito, Adenilson Jose ^[6] ; Sambrano, Julio Ricardo ^[3] ; Longo, Elson ^[7] ; Simoes, Alexandre Zirpoli ^[1]

Afiliação do(s) autor(es)

^[1] Sao Paulo State Univ UNESP, Fac Engn Guaratingueta, Guaratingueta, SP - Brazil

^[2] Sao Paulo State Univ UNESP, Modeling & Mol Simulat Grp, Guaratingueta, SP - Brazil

^[3] Sao Paulo State Univ UNESP, Modeling & Mol Simulat Grp, Bauru, SP - Brazil

^[4] Sao Paulo State Univ UNESP, Chem Inst, LIEC, Interdisciplinary Lab Electrochem & Ceram, Araraquara, SP - Brazil

^[5] INTEMA Natl Univ Mar del Plata, Res Inst Mat Sci & Technol, Mar Del Plata - Argentina

^[6] Univ Fed Sao Carlos, UFSCar, Dept Phys, NanOLaB, Sao Carlos, SP - Brazil

^[7] Univ Fed Sao Carlos, UFSCar, LIEC, Interdisciplinary Lab Electrochem & Ceram, Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Crystal Growth & Design; v. 20, n. 8, p. 5031-5042, AUG 5 2020.
• Citações Web of Science: 0

Resumo

Here we combined experimental and theoretical results to correlate the morphological, optical, and electronic properties of cerium oxide (CeO2) prepared by a microwave-assisted hydrothermal method with varying synthesis times. X-ray diffraction confirmed a cubic structure without deleterious phases. Density functional theory simulations confirmed an indirect (K-L) bandgap energy of 2.80 eV, with an electron transition between O-2p and Ce-4f orbitals, which agrees with the value obtained using diffuse reflectance. Raman spectroscopy shows that changing the synthesis times results in samples with different defect densities at a short range. Theoretical calculations confirmed that the deformations and changes in the experimental Raman spectra area result in oxygen displacement; as the displacement decreases, the crystallinity increases, and only one peak was observed. Scanning electron microscopy and high-resolution transmission electron microscopy show changes in the morphologies as the synthesis time varies. For shorter times, sheet and polyhedral morphologies were noted. With time increases, the sheets turn into nanorods and nanowires until the nanowires decrease and cubes are observed. In addition, an initial study regarding the influence of the surface on the electric response of CeO2 was completed. It was observed that the presence of different surface defects ({[}CeO6 center dot 2V(o)(x)] or {[}CeO7 center dot V-o(x)]) can alter the material resistance. (AU)

• Processo FAPESP: 08/57872-1 - Instituto Nacional de Ciências dos Materiais em Nanotecnologia
• Beneficiário: Elson Longo da Silva
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 17/19143-7 - Uma abordagem teórico-experimental dos mecanismos de condução e defeitos de interface em heteroestruturas sensoras baseados em semicondutores P-N e N-N a partir de matrizes de CeO2
• Beneficiário: Rafael Aparecido Ciola Amoresi
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 13/07296-2 - CDMF - Centro de Desenvolvimento de Materiais Funcionais
• Beneficiário: Elson Longo da Silva
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
• Processo FAPESP: 16/07476-9 - Nanotubos porosos de carbono e de semicondutores inorgânicos: uma abordagem computacional
• Beneficiário: Julio Ricardo Sambrano
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 16/25500-4 - Funcionalização de nanotubos semicondutores via interface e adsorção de gases: uma abordagem computacional
• Beneficiário: Naiara Letícia Marana
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado