Banca de QUALIFICAÇÃO: RONIER ALCÂNTARA OLIVEIRA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : RONIER ALCÂNTARA OLIVEIRA
DATE: 05/09/2026
TIME: 14:00
LOCAL: Videoconferência - Google Meet
TITLE:

Bi₂MoO₆/Nb₂O₅ Heterostructures as Multifunctional Platforms for Piezophotocatalysis: Advances in the Degradation of Organic Contaminants Under Visible Light

KEY WORDS:

Bi₂MoO₆; Nb₂O₅; heterostructures; piezophotocatalysis; Congo Red; environmental remediation; visible light.

PAGES: 111
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Cerâmicos
SUMMARY:

The increasing contamination of water resources by persistent and highly toxic organic pollutants has driven the development of sustainable technologies for environmental remediation. In this context, piezophotocatalysis stands out by combining light and mechanical energy to maximize charge carrier separation and enhance the production of reactive oxygen species. In this study, Bi₂MoO₆/Nb₂O₅ heterostructures were synthesized via a microwave-assisted hydrothermal method. Samples were prepared with different molar ratios of Bi₂MoO₆ to Nb₂O₅, designated as B1 (1:1), B2 (1:2), and B3 (2:1). Structural, morphological, surface, optical, piezoelectric, and electrochemical properties were investigated using XRD with Rietveld refinement, Raman spectroscopy, SEM, EDS, XPS, UV-Vis spectroscopy, N₂ adsorption-desorption, photoluminescence, piezoelectric measurements, electrochemical impedance spectroscopy, and Mott-Schottky analysis. The results confirmed the successful formation of the heterostructures and revealed strong interfacial interactions between the phases, promoting improved charge carrier separation and transport. The B2 heterostructure exhibited the best piezophotocatalytic performance, achieving approximately 95% degradation of Congo Red under visible light irradiation and ultrasound, while also demonstrating a high synergy index between the photocatalytic and piezocatalytic processes. This superior performance was attributed to the formation of a type-II heterojunction coupled with the piezophototronic effect, which facilitates energy band bending and intensifies the directional migration of electrons and holes. The results demonstrate that the combination of Bi₂MoO₆ and Nb₂O₅ constitutes a promising strategy for the development of efficient, sustainable, and low-cost piezophotocatalytic materials for applications in environmental remediation and advanced wastewater treatment.

COMMITTEE MEMBERS:
Interna - 1802888 - FABIANA VILLELA DA MOTTA
Interno - 1474380 - MARCIO ASSOLIN CORREA
Interno - 1883170 - MAURICIO ROBERTO BOMIO DELMONTE
Externa à Instituição - FERNANDA DE LOURDES SOUZA - UFSCAR
Externo à Instituição - MÁRIO ANDREAN MACÊDO CASTRO - IPEN