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Effect of thermal treatment on the 4f-hopping conductivity of CeO2 exposed to CO(g) atmosphere

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Autor(es):
Procopio, Alley Michael da Silva ; Rocha, Leandro Silva Rosa ; Desimone, Paula Mariela ; Giulietti, Giuliana ; Aldao, Celso Manuel ; Longo, Elson ; Moura, Francisco ; Ponce, Miguel Adolfo
Número total de Autores: 8
Tipo de documento: Artigo Científico
Fonte: MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS; v. 292, p. 9-pg., 2023-06-01.
Resumo

The thermal treatment of CeO2 at 600 and 900 degrees C on the film response against CO is analyzed. A fluorite-type crystalline structure was observed, with the later presenting a well-defined morphology formed by the set of (100), (110) and (111) surfaces. The band-gap was 3.35 and 3.37 eV, for the 600 and 900 degrees C samples. We have proposed an equation based on the mass action law that shows the dependence of the carriers density as a function of the grain size, demonstrating that the area-volume relation can affect the number of charge carriers, which reflects in the pre-exponential A factor of conductivity. Reducing gases generate a greater number of carriers available for conduction, reflected on the A factor. When vacancies are annihilated by exposing to an oxygen atmosphere, the Ce (III) amount reduces. The activation energy and pre-factor A in air, vacuum and CO were calculated for correlating with the sample morphologies. (AU)

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: 18/20590-0 - Novos nanomateriais híbridos à base de elementos terras-rara renováveis para aplicações multifuncionais energéticas e de sensoriamento ambiental
Beneficiário:Leandro Silva Rosa Rocha
Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
Processo FAPESP: 20/02352-5 - Investigações espectroscópicas aprofundadas de quantum-dots híbridos de óxido de cério para mitigação da pandemia de COVID-19
Beneficiário:Leandro Silva Rosa Rocha
Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Pós-Doutorado