Banca de DEFESA: PATRICIA MARIA GONCALVES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : PATRICIA MARIA GONCALVES
DATE: 05/02/2024
TIME: 08:00
LOCAL: https://meet.google.com/nph-ptpj-yxe.
TITLE:

Synthesis, structural and electrochemical characterization of WO3, GO and WO3/GO composite

KEY WORDS:

Tungsten oxide, graphene oxide, WO3/GO, composite WO3/GO

PAGES: 1
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Inorgânica
SUMMARY:

Due to the high energy demand and search for clean, efficient and safe energy, new materials have been tested and improved for direct use in lithium-ion batteries (LIBs). Tungsten oxide (WO3) and graphene oxide (GO) are two materials that, separately, have good applicability in LIBs and, therefore, it becomes interesting to obtain and study the WO3/GO composite, to study the electrochemical stability in LIBs. Using the hydrothermal method, different crystalline structures were obtained for WO3, through variation in pH and, citric acid, and oxalic acid as chelating agents. For the synthesis of GO, the modified Hummer’s method was used. X-ray diffraction analyzes confirmed the presence of two distinct crystalline phases for WO3, the hexagonal phase (h-WO3) at pH 1.5 and 2.0 and the monoclinic phase (m-WO3) at pH 1 ,0. XDR also confirmed the formation of GO, due to the presence of the diffraction peak at 2θ = 10.49°. The FTIR spectra and RAMAN spectra showed the presence of groups related to the materials of interest. Thermogravimetric analyzes showed the mass losses for the samples before and after combining the materials. Cyclic voltammetry tests showed that the WO3/CA/GO composites, synthesized at pHs 1.0 and 1.5, and the WO3/OA/GO composite, synthesized at pH 1.5, exhibited the best electrochemical performances, being promising candidates for use in Li+ ion batteries.

BANKING MEMBERS:
Interno - 1444161 - DANE TADEU CESTAROLLI
Presidente - 1742429 - ELIDIA MARIA GUERRA
Externo à Instituição - ROGERIO DE OLIVEIRA - IFMG