Solid-state NMR for the analysis of interface excesses in Li-doped MgAl₂O₄ nanocrystals

Autor(es)

Bernardes, Andre A. ; da Silva, Andre L. ; Bettini, Jefferson ; Freitas, Jair C. C. ; Castro, Ricardo H. R. ; Gouvea, Douglas

• Tipo de documento: Artigo Científico
• Fonte: Journal of the American Ceramic Society; v. 107, n. 2, p. 14-pg., 2023-10-24.

Resumo

Interface segregation plays a governing role in nanocrystalline ceramics properties due to the relative increase in the interfacial volume fraction. However, due to the complexity of the detection and quantification of interfacial excesses at the nanoscale, the role of ionic dopants or additives on microstructural evolution and thermodynamics can be easily underestimated. In this work, we address the spatial distribution of Li+ as a dopant in magnesium aluminate spinel nanoparticles. This is achieved through a novel method for the detection and quantification of Li+ across the surface, grain boundary, and bulk (crystal lattice). Based on selective lixiviation combined with chemical analysis, we were able to quantify the amount of Li+ forming surface excess, whereas the quantitative solid-state nuclear magnetic resonance technique enabled the quantification of Li+ segregated in the grain boundaries and dissolved in the lattice. This comprehensive understanding of the Li+ distribution across the nanoparticles makes possible an unprecedented interpretation of coarsening and sintering, with a clear correlation between the microstructure and the Li+ distribution. Although the work focuses on MgAl2O4, the proposed combination of techniques is expected to have a positive impact on the understanding of other multicomponent nanoscale systems. (AU)

• Processo FAPESP: 14/50279-4 - Brasil Research Centre for Gas Innovation
• Beneficiário: Julio Romano Meneghini
• Modalidade de apoio: Auxílio à Pesquisa - Programa Centros de Pesquisa em Engenharia
• Processo FAPESP: 20/15230-5 - Centro de Pesquisa e Inovação de Gases de Efeito Estufa - RCG2I
• Beneficiário: Julio Romano Meneghini
• Modalidade de apoio: Auxílio à Pesquisa - Programa Centros de Pesquisa em Engenharia