Banca de QUALIFICAÇÃO: LAURA LETÍCIA FREITAS FERREIRA DA SILVA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : LAURA LETÍCIA FREITAS FERREIRA DA SILVA
DATE: 31/08/2026
TIME: 14:00
LOCAL: Plataforma RNP
TITLE:

DEVELOPMENT AND CHARACTERIZATION OF HETEROGENEOUS CATALYSTS FOR APPLICATION IN EPOXIDATION REACTIONS

KEY WORDS:

 nanomaterials; metal oxides; sol-gel; green chemistry

PAGES: 35
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUMMARY:

The growing demand for sustainable chemical processes aligned with the principles of Green Chemistry drives the search for efficient heterogeneous catalysts for biomass valorization. In this context, the present study developed and evaluated heterogeneous catalysts based on transition metal oxides (TiO2, MoO3, WO3, Nb2O5 e SnO2) synthesized via the polyvinylpyrrolidone (PVP)- assisted sol-gel method as a structure-directing agent. Fourier-transform infrared spectroscopy (FTIR) and energy-dispersive X-ray spectroscopy (EDX) analyses confirmed the efficiency of the calcination process in the total removal of organic residues and surfactant, ensuring the production  of inorganic materials with high elemental purity. From a microstructural perspective, SnO2 exhibited a high dislocation density and lattice strain, resulting in the smallest crystallite size among the samples. In contrast, MoO3 displayed the lowest defect density, which favored preferential growth along its crystallographic planes. Despite these dimensional variations, all oxides exhibited a strong negative surface charge, with a zeta potential below -39 mV, guaranteeing high colloidal stability and dispersibility in the reaction medium. The set of physicochemical, structural, and electronic properties obtained confirms the synthesis of highly crystalline and purified nanomaterials, consolidating these metal oxides as promising systems suitable for application as heterogeneous catalysts in epoxidation reactions.

COMMITTEE MEMBERS:
Interno(a) - 426640 - FABIANE CAXICO DE ABREU GALDINO
Externo(a) à Instituição - PAULO ANSELMO ZIANI SUAREZ - UnB
Presidente - 1515173 - SIMONI MARGARETI PLENTZ MENEGHETTI