Banca de DEFESA: VIVIANE DA SILVA PINHEIRO
Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.STUDENT : VIVIANE DA SILVA PINHEIRO
DATE: 29/02/2024
TIME: 09:30
LOCAL: https://meet.google.com/npk-nguo-sxn
TITLE:
STUDY OF THE PROPERTIES OF PHOTOCATALYSIS AND PHOTOLUMINESCENCE OF BaMoO4/g-C3N4 SYNTHESIZED BY THE MICROWAVE-ASSISTED SOLVOTHERMAL METHOD
KEY WORDS:
Barium molybdate; graphitic carbon nitride; coprecipitation; solvothermal method; and photocatalysis.
PAGES: 99
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Cerâmicos
SUMMARY:
The need for environmental preservation has been the subject of study in several areas of application. Heterogeneous photocatalysis has been used for some years for the degradation of effluents. In this approach, the electronic band structure makes semiconductor type materials used as catalysts. However, degradation of organic dyes is damaged by the rapid recombination of charge carriers in semiconductors. One way to solve it is to promote the formation of heterostructures to improve particle properties. Among the various materials, barium molybdate has been highlighted due to its excellent properties and possibility of application in several areas. BaMoO4/xg-C3N4 heterostructures (x= 0.3 and 0.5 grams) were synthesized by the coprecipitation method followed by microwave-assisted solvothermal at 140 °C for 30 minutes. To employ the solvothermal method, 1,4 - butanediol alcohol was used as solvent. Then, analyzes were carried out to characterize the structure by X-ray diffraction (DRX), Raman scattering spectroscopy, morphological analysis by scanning electron microscopy by field emission (FEG-MEV), optical properties by means of the UV-Vis spectrophotometer, and investigation of the photocatalysis activity under UV radiation in the decontamination of simulated organic pollutants with Methylene Blue/AM (cationic) and Crystal Violet/VC (cationic). XRD diffractograms show that the microwave assisted solvothermal method is efficient for obtaining BaMoO4 particles and heterostructures with well defined peaks, showing high crystallinity without a secondary phase. The micrographs showed irregularly shaped BaMoO4 particles with a mean diameter between 168.84 and 240.86 nanometers. g-C3N4 exhibited nanosheet morphology with a porous surface. The gap energy measured by the direct method ranged from 4.63 – 4.70 eV for pure BaMoO4 samples and from 3.33 – 3.50 eV for BaMoO4/xg-C3N4. The heterostructures showed improved efficiency, achieving degradation rates of 95,17% for crystal violet and 95,16% for methylene blue, in contrast to the 25% and 19%, respectively, observed in pure BaMoO4 samples. In reuse tests with 4 consecutive cycles, the samples showed good photocatalytic capacity. Photoluminescence spectra were obtained at room temperature and revealed a blue emission peak for all samples when excited at 355 nm.
COMMITTEE MEMBERS:
Presidente - 1883170 - MAURICIO ROBERTO BOMIO DELMONTE
Interna - 1802888 - FABIANA VILLELA DA MOTTA
Externo à Instituição - ELSON LONGO DA SILVA - UFSCAR
Externo à Instituição - JUAN MANUEL ANDRÉS BORT - UJI
Externo à Instituição - RICARDO LUÍS TRANQUILIN - UNIAN