Banca de DEFESA: CAMYLA REGINA DANTAS FERREIRA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : CAMYLA REGINA DANTAS FERREIRA
DATE: 16/06/2023
TIME: 14:00
LOCAL: https://meet.google.com/awg-tdah-gxa
TITLE:

Optimization of synthesis processes to obtain the compound α-MoO3/Ag/C3N4 and study of its photocatalytic activity

KEY WORDS:

Simple oxides, hybrid material, molybdenum, carbon nitride, spray pyrolysis, photocatalysis, photoluminescence.

 

 

PAGES: 124
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Cerâmicos
SUMMARY:

MoO₃ is an n-type semiconductor with unique properties such as photocatalytic efficiency and different morphologies, thus attracting considerable attention and being studied both alone and in association with other semiconductors with the aim of further improving its properties. C₃N₄ is another photocatalyst that has attracted attention due to its low bandgap (2.7 eV), allowing absorption of visible light to generate more electron-hole pairs. of the α-MoO₃/C₃N₄ hybrid material. The work was divided into three stages. In the first stage, using the spray-pyrolysis synthesis method, syntheses were performed at different precursor concentrations (0.1M, 0.2M and 0.3M), temperatures (600 °C to 1000 °C) and atomizer power (70% and 100%), the flow rate, in turn, was fixed at 3 L/min, the different parameters were used in order to obtain a-MoO₃ in a single step. Once MoO₃ synthesis was optimized, the next step was to use the ultrasonic method (step 2) at different times (5 min, 10 min and 15 min) on the selected sample and analyze the results obtained. With the time for the synthesis with the best results, stage 3 was started, in which the coupling of MoO₃ and C₃N₄ was performed using sonochemical method, obtaining the hybrid material composite MoO₃/C₃N₄. The materials were characterized by the techniques of X-Ray Diffraction (DRX), Spectroscopy in the UV-Visible region (Uv-Vis), Scanning Electron Microscopy by Field Emission (MEV-FEG), Photoluminescence and evaluated their photocatalytic efficiency against to organic dyes. The diffractogram showed the attainment of the α-MoO3 orthorhombic phase with a space group of 62 Pbnm as well as the presence of the hydrated phase in the analyzed samples. The composite samples analyzed showed gap energy values of 3.09 eV. Sample MOCN 1 showed the best photocatalytic activity. Through the micrographs, it was possible to observe the influence of the synthesis parameters and the ultrasonic process itself on the morphology of the samples, variations that influenced the photocatalytic activity and photoluminescence of the samples.

 

COMMITTEE MEMBERS:
Interna - 1802888 - FABIANA VILLELA DA MOTTA
Interno - 1883170 - MAURICIO ROBERTO BOMIO DELMONTE
Externo ao Programa - 3304576 - RODOLFO LUIZ BEZERRA DE ARAÚJO MEDEIROS - UFRNExterno à Instituição - NEFTALÍ LENIN VILLARREAL CARREÑO - UFPel
Externo à Instituição - RICARDO LUÍS TRANQUILIN - UNIAN