Banca de DEFESA: GABRIELA DA COSTA CARVALHO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : GABRIELA DA COSTA CARVALHO
DATE: 28/02/2024
TIME: 10:00
LOCAL: Programa de Pós-Graduação em Ciência de Materiais
TITLE:

DESIGN OF LANTANIDE-BASED METALORGANIC NETWORKS USING LASER ABLATION IN A LIQUID ENVIRONMENT

KEY WORDS:

Laser Ablation in a Liquid Environment; Metal-Organic Networks; Niobium

PAGES: 75
BIG AREA: Outra
AREA: Multidisciplinar
SUMMARY:

Metal-organic networks (MOFs) are hybrid materials that have high potential for application in several areas of research. It is possible to obtain these materials through different synthetic routes, which in a way directly influence their properties, such as porosity, crystallinity and structure. In general, these methodologies are well established, however, they have disadvantages, such as long synthesis times, the need to supply high energy and/or generation of byproducts. Therefore, the unconventional technique of laser ablation synthesis in liquid media (ALAL) is seen as a promising methodology for obtaining nanostructured materials, as this is a chemically clean and fast process. Among the different types of MOFs, luminescent metalorganic networks stand out, composed of photoactive components, such as lanthanide ions (Ln3+). Another promising material is niobium, a metal that is widely available in Brazilian soil, which has high stability characteristics and excellent superconductivity properties at low temperatures. Therefore, this work aims to prepare and characterize niobium, terbium and europium MOFs with carboxylated ligands using ultrashort pulse ALAL. Thus, coordination networks were obtained from the ligands 1,3,5-benzenetricarboxylic acid (H3BTC) and benzenehexacarboxylic acid (H6Mell) and the oxides of terbium (Tb2O3) and europium (Eu2O3), with the solvent mixture DMF:H2O, through the liquid laser ablation synthesis technique (ALAL). These products were characterized by powder X-ray diffraction, FTIR spectroscopy, thermogravimetric analysis, scanning electron microscopy and photoluminescence spectroscopy. The products obtained in the syntheses of Eu2O3 with the BTC ligand showed good correspondence with the MOFs reported in the literature; With the Mell ligand, a coordination network with an unprecedented morphological structure was obtained. In the synthesis with Tb2O3, a mixed material of terbium oxide with traces of MOF-76 was obtained in the process with BTC and for Mell the coordination of the metal with the ligand was observed. Finally, no products were obtained from the ablation of niobium oxide, possibly due to the presence of oxygen in the medium that reacted with the Nb in the medium, favoring the formation of oxide, preventing the formation of networks. The results of the syntheses, as well as their characterizations, allow us to conclude that ALAL is a promising synthetic route, which by making the correct adjustments to the laser parameters makes it possible to obtain nanostructured materials.

COMMITTEE MEMBERS:
Externo à Instituição - LEONIS LOURENÇO DA LUZ - UFPE
Externa à Instituição - OHANNA MARIA MENEZES MADEIRO DA COSTA
Presidente - 1131289 - WALTER MENDES DE AZEVEDO