Luminescent Layered Double Hydroxides Intercalated with an Anionic Photosensitizer via the Memory Effect

Abstract

Layered double hydroxides (LDHs) containing Eu 3+ activators were synthesized by coprecipitation of Zn 2+ , Al 3+ , and Eu 3+ in alkaline NO 3 − -rich aqueous solution. Upon calcination, these materials transform into a crystalline ZnO solid solution containing Al and Eu. For suitably low calcination temperatures, this phase can be restored to LDH by rehydration in water, a feature known as the memory effect. During rehydration of an LDH, new anionic species can be intercalated and functionalized, obtaining desired physicochemical properties. This work explores the memory effect as a route to produce luminescent LDHs intercalated with 1,3,5-benzenetricarboxylic acid (BTC), a known anionic photosensitizer for Eu 3+ . Time-dependent hydration of calcined LDHs in a BTC-rich aqueous solution resulted in the recovery of the lamellar phase and in the intercalation with BTC. The interaction of this photosensitizer with Eu 3+ in the recovered hydroxide layers gave rise to efficient energy transfer from the BTC antennae to the Eu 3+ ions, providing a useful tool to monitor the rehydration process of the calcined LDHs.

Layered Double Hydroxides

“…This Special Issue on "Layered Double Hydroxides" gathers a multidisciplinary collection of original contributions and review articles from authors with diverse scientific backgrounds and who employ LDHs for very different applications, permitting the demonstration of their versatility. Along with LDH-focused papers, this Special Issue also includes some research in which materials different to LDHs resulted in a convenient choice for selected purposes.A study of particular interest is the report from Teixeira et al [1], where the extreme flexibility of LDH matrices in changing both interlayer and metal components to tune their physicochemical properties is explored. The memory effect in thermally treated LDHs, i.e., the restoration of their lamellar structure by rehydration in aqueous solutions containing anions, is leveraged for the synthesis of rare earth Eu 3+ doped luminescent LDHs intercalated with 1,3,5-benzenetricarboxylate anion.…”

Aplicação Do Método God E Estatística Multivariada No Estudo Da Vulnerabilidade De Aquífero À Contaminação Em Aracaju/Se

“…No intervalo de 270 ºC até 430 ºC ocorre o processo mais importante para o efeito memória, relacionado a perda do grupo hidroxila presentes nas camadas do LDH, desidratação química. O intervalo restante trata-se da formação da fase de espinélio (RIVES, 2002;TEIXEIRA et al, 2019). Baseado nesse resultado, a temperatura adequada para o tratamento térmico das amostras seria 350ºC.…”

“…A intercalação do fotossensibilizador BTC é feita utilizando o efeito memória dos HDLs. Al 0.95 Eu 0.05 (OH) 6 ]ˑ(BTC 3-) 0.33 (ZnAlEu-BTC) foram preparados pelo método da hidrólise controlada dos cátions metálicos(TEIXEIRA et al, 2019). Inicialmente é preparada uma solução dos sais referente aos metais que irão compor as camadas do LDH.…”

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

“…LDH minerals exhibit a wide flexibility in composition and a score of polyvalent ions can be introduced into the layers. 1 , 2 The versatile composition of the LDH unlocks large application possibilities in diverse research fields, such as catalysis, electrolysis, drug delivery, and environmental sciences. 3 − 12 …”