Banca de QUALIFICAÇÃO: MÁRIO ANDREAN MACEDO CASTRO

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : MÁRIO ANDREAN MACEDO CASTRO
DATE: 10/03/2023
TIME: 09:00
LOCAL: https://meet.google.com/zmr-phwk-xes
TITLE:

Synthesis of CaMoO₄/g-C₃N₄ Z-Type Heterojunctions and Photocatalytic Evaluation of the Degradation of Methylene Blue and Crystal Violet Dyes

KEY WORDS:

Carbon Nitride, Calcium Molybdate, Heterojunction, Methylene Blue, Crystal Violet

PAGES: 108
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Cerâmicos
SUMMARY:

The development of efficient photocatalysts for environmental depollution caused by textile dyes remains a challenge to be solved. In this sense, the combination of two materials forming composites in order to improve the characteristics of both, and its photocatalytic application appears as something promising. In this work, we report the hidrotermic synthesis of CaMoO₄/g-C₃N₄ heterojunctions (CMO/CN) by microwave irradiation, varying the synthesis time (between 15 and 60 minutes) and the CN molar percentage (between 40 and 70 %). The samples were characterized by the techniques of X-Ray Diffraction, Diffuse Reflectance Spectroscopy in the UV-Visible region, Raman Spectroscopy, Photoluminescence, Field Emission Scanning Electron Microscopy, X-Ray Photoelectron Spectroscopy, Nitrogen Adsorption-Desorption Isotherms and Resonance Spectroscopy Electronic Paramagnetics. The photocatalytic activity of CMO/CN composites was evaluated in the degradation of methylene blue and crystal violet dyes under ultraviolet light irradiation. The heterojunction with 70% CN obtained better results than the other samples, reaching 99% degradation of methylene blue in 120 minutes and more than 95% degradation of crystal violet after 180 minutes. After four cycles of reuse, the structural and photocatalytic stability of the best samples was maintained. Tests with scavengers indicated that the superoxide and hole radicals are the main active species, and the formation of the direct Z-scheme heterojunction could be confirmed. Tests under simulated visible light and sunlight showed that the degradation efficiency of methylene blue was improved and that of crystal violet was at least maintained. With all the results, it is believed that the material obtained in this work can be another alternative for photocatalytic application aiming at environmental decontamination.

COMMITTEE MEMBERS:
Presidente - 1883170 - MAURICIO ROBERTO BOMIO DELMONTE
Interna - 1802888 - FABIANA VILLELA DA MOTTA
Interno - 1474380 - MARCIO ASSOLIN CORREA
Externo à Instituição - ANTÔNIO ERNANDES MACEDO PAIVA
Externo à Instituição - RICARDO LUÍS TRANQUILIN