Banca de QUALIFICAÇÃO: VIVIANE DA SILVA PINHEIRO
Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.STUDENT : VIVIANE DA SILVA PINHEIRO
DATE: 14/08/2023
TIME: 09:00
LOCAL: https://meet.google.com/wvf-ofqi-jxs
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: 81
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Cerâmicos
SUMMARY:
The demand for environmental preservation has been studied in several applications. 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 particles (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, 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 Methyl Orange/AMe (anionic). 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 fluffy and 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. Photocatalysis tests showed that pure BaMoO4 has low efficiency. The heterostructures showed improved efficiency with results above 96% for degradation of methyl orange and 100% for methylene blue. In reuse with 4 consecutive cycles, the samples showed good photocatalysis capacity.
COMMITTEE MEMBERS:
Presidente - 1883170 - MAURICIO ROBERTO BOMIO DELMONTE
Interna - 1802888 - FABIANA VILLELA DA MOTTA
Externa ao Programa - 1718775 - KALINE MELO DE SOUTO VIANA - UFRNExterna à Instituição - MARIA INES BASSO BERNARDI - USP
Externo à Instituição - RICARDO LUÍS TRANQUILIN - UNIAN