Banca de QUALIFICAÇÃO: JOYCE MARINA PAIVA DA SILVA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : JOYCE MARINA PAIVA DA SILVA
DATE: 16/05/2025
TIME: 14:00
LOCAL: Videoconferência - Google Meet
TITLE:

Optimization of ZnO-based photocatalysts for the water treatment: doping and heterostructure approaches.

KEY WORDS:

ZnO, doping, heterostructure, microwave-assisted hydrothermal, Nb, Ag3PO4.

PAGES: 84
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Cerâmicos
SUMMARY:

Water pollution is a growing environmental challenge, requiring efficient and sustainable methods for its purification. Heterogeneous photocatalysis, based on the activation of semiconductors such as ZnO by radiation, stands out for its ability to degrade contaminants through the generation of reactive species. To optimize the use of ZnO as a photocatalyst, strategies such as doping and heterostructure formation have been investigated. In this thesis, ZnO was initially optimized through doping with Niobium (Nb), where the increased disorder and distortion due to the insertion of Nb ions created defects that reduced particle growth and influenced the material’s photocatalytic and photoluminescent properties. Regarding photocatalysis under solar radiation, all doped samples exhibited better efficiency than pure ZnO, with 1% doping considered the best photocatalyst, achieving 93.8% (methylene blue) and 88% (crystal violet) degradation after 25 minutes for the dye mixture. Furthermore, the study investigated the effect of ZnO/Ag₃PO₄ heterostructure formation on photocatalytic properties under visible and solar radiation, targeting cationic dyes as well as methyl orange. The photocatalytic results indicate that the heterostructures exhibit responsiveness to both cationic and anionic dyes, with greater efficiency for cationic dyes, where 30 minutes under sunlight were sufficient for 99% degradation of the mixture (methylene blue and crystal violet). Thus, doping and heterostructure techniques proved to be efficient, as they enable ZnO activation under sunlight and significantly contribute to enhancing photocatalytic efficiency.

COMMITTEE MEMBERS:
Presidente - 1802888 - FABIANA VILLELA DA MOTTA
Interno - 1883170 - MAURICIO ROBERTO BOMIO DELMONTE
Externo à Instituição - MARCIO DALDIN TEODORO - UFSCAR
Externa à Instituição - RENATA CRISTINA DE LIMA - UFU
Externa à Instituição - VIVIANE DA SILVA PINHEIRO - IFRN