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Coordination of Eu3+ Activators in ZnAlEu Layered Double Hydroxides Intercalated by Isophthalate and Nitrilotriacetate

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Autor(es):
Morais, Alysson F. ; Silva, Ivan G. N. ; Lima, Bonifacio C. ; Garcia, Fernando A. ; Mustafa, Danilo
Número total de Autores: 5
Tipo de documento: Artigo Científico
Fonte: ACS OMEGA; v. 5, n. 37, p. 8-pg., 2020-09-22.
Resumo

Luminescent layered double hydroxides (LDH) intercalated by isophthalate (ISO) and nitrilotriacetate (NTA) have been synthesized and characterized by powder X-ray diffraction (PXRD), extended X-ray absorption fine structure (EXAFS), elemental analysis (ICP-OES and CHN), and photoluminescence spectroscopy. While PXRD shows the successful formation of ZnAlEu LDHs, EXAFS reveals that the Eu activators are hosted in the hydroxide layers with an eightfold, oxygen-rich coordination, distinct from the sixfold coordination expected for the octahedral sites of metal cations in LDHs. This kind of coordination should locally distort the brucite-like layers. Additionally, the intercalation of ISO and NTA in the LDHs is shown to change the coordination environment around Eu compared to nitrate-intercalated ZnAlEu LDHs, which suggests that these anions directly interact with the Eu centers and/or strongly affect their coordination geometry. Finally, from the photoluminescence results, analyzed based on the Judd-Ofelt theory, it is determined that Eu is most likely in an environment with no inversion symmetry. (AU)

Processo FAPESP: 15/19210-0 - Hidróxidos duplos lamelares (LDH) nanoestruturados com propriedades de up e down-conversion para aplicações como sensibilizadores em células solares
Beneficiário:Danilo Mustafa
Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores
Processo FAPESP: 18/13837-0 - Espectroscopia de terras raras como uma ferramenta para monitorar a liberação controlada de aditivos alimentares
Beneficiário:Alysson Ferreira Morais
Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado