Effect of lanthanum doping on the ceria fluorite structure and its relationship with transport properties
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2024
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BRAZIL MRS MEETING, 22nd
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Resumo
Doped ceria and its solid solution are popular materials widely investigated in energy
conversion and electrochemical devices. It has a cubic fluorite structure and doping with
La3+ changes to a disordered fluorite and a C-type structure. Moreover, the doping level
offers a path to tune the defect chemistry for applications in several fields.1 In this work, we
investigate solid solutions of La-doped ceria (LaxCe1-xO2-x/2) with x from 0 to 50 at.%
compressed into pellets to investigate the electrical properties and its correlation with
defect chemistry and crystal structure. The transport properties were studied via
electrochemical impedance spectroscopy in air and different pO2. The findings show that
electrical conductivity increases from 0 to 5 at.%, and then remains constant up to 15 at.%.
However, beyond 20 at.%, it starts to decrease. This trend can be explained by the
formation of vacancies formation.2 For lower levels of lanthanum doping, the creation of
vacancies improves conductivity. However, at higher concentrations (>20 at.%), the
increase of oxygen vacancies leads to the formation of dopant-vacancy clusters. This process
arises from the Coulomb interaction between vacancies and local lattice relaxation in the
crystal. The increase in activation energies above 20 at.% indicates higher resistance to
defect migration. X-ray powder diffraction indicated the presence of only one phase with
increased strain and expansion of lattice parameters, as determined through Rietveld
refinement. Raman spectroscopy indicated structural changes in the fluorite structure,
including the emergence of a C-type phase. Additionally, it detected local symmetrical
breaking and vibrational changes in the structure due to the formation of oxygen vacancies.
Como referenciar
DAMASCENO, SERGIO; VILELA, VANESSA B.; OLIVEIRA, RAPHAEL A.M.P. de; TRINDADE, FABIANE J.; FLORIO, DANIEL Z. de; FONSECA, FABIO C.; STEIL, MARLU-CESAR; FERLAUTO, ANDRE S. Effect of lanthanum doping on the ceria fluorite structure and its relationship with transport properties. In: BRAZIL MRS MEETING, 22nd, September 29 - October 3, 2024, Santos, SP. Abstract... São Carlos, SP: Aptor Software, 2024. p. 828-828. Disponível em: https://repositorio.ipen.br/handle/123456789/48941. Acesso em: 30 Dec 2025.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.