resumo
A large number of silicates containing transition metals and rare earth (in particular lanthanide) elements have been reported until recently. Generally, they exhibit a rich structural chemistry with interesting physical and chemical properties, and, in contrast to zeolites, which are built of [SiO4](4-) and [AlO4](5) tetrahedrons, their frameworks embody metals in different coordination. In particular, materials containing rare earth and/or lanthanide elements may combine, in a single and stable solid, microporosity and tuneable optical properties. Such multi-functionality may be explored with interest, being a challenging approach to novel chethical and optical applications. This article aims to review rare earth and lanthanide silicates published to date, namely their relevant structure features and photoluminescent properties, being divided in two sections according to the major approaches used for their preparation, i.e. doping and embedding. The parent materials hosting the rare earth or lanthanide elements, the type and number of such emitters, and the disorder and dimensionality of the solids are some of the addressed topics. Furthermore, this review is also intended to highlight the great challenges that optical centres design offers in the field of material science. Some potential applications are also debated, such as wastewater remediation, nuclear medicine, imaging, and sensors. Notwithstanding the relevance that photoluminescent porous and layered lanthanide silicates may achieve in wastewater treatment, as a result of their stability and high selectivity combined with capacity, their sensing ability towards a specific ion or molecule will be for sure of capital importance in the near future. (C) 2016 Elsevier Inc. All rights reserved.
palavras-chave
PRESSURE HYDROTHERMAL SYNTHESIS; STATE NMR-SPECTROSCOPY; RARE-EARTH SILICATES; MICROPOROUS TITANOSILICATE ETS-10; FRAMEWORK CERIUM SILICATE; ZEOLITE-TYPE MATERIALS; X-RAY-DIFFRACTION; CRYSTAL-STRUCTURE; HIGH-TEMPERATURE; SOLID-STATE
categoria
Chemistry; Science & Technology - Other Topics; Materials Science
autores
Figueiredo, BR; Valente, AA; Lin, Z; Silva, CM
nossos autores
Anabela Tavares Aguiar Valente
Investigador Principal
Bruno Reis Figueiredo
Estudante de doutoramento
Carlos Manuel Silva
Professor associado
Zhi Lin
Investigador Principalagradecimentos
B.R. Figueiredo wishes to acknowledge a Ph.D. grant from Fundacao para a Ciencia e a Tecnologia (SFRH/BD/75457/2010). This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. Authors thank Professor Joao Rocha (CICECO, UA) for his helpful comments and review of this article.