Banca de QUALIFICAÇÃO: CAROLINE HELENA CLAUDINO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : CAROLINE HELENA CLAUDINO
DATA : 13/06/2025
HORA: 14:00
LOCAL: https://conferenciaweb.rnp.br/sala/juliana-255
TÍTULO:

INTERFACE CONTROL OF HEMATITE–TITANIUM DIOXIDE HETEROJUNCTION VIA MICROWAVE-ASSISTED SYNTHESIS

PÁGINAS: 51
RESUMO:

Titanium dioxide (TiO₂) and hematite (Fe₂O₃) are promising semiconductors for the production of solar fuels, but both have intrinsic limitations, such as rapid charge recombination and low light absorption. The construction of a heterojunction between them can overcome these disadvantages, as long as the interface is properly controlled. In this context, this work proposes to investigate how microwave irradiation can modulate the growth of TiO₂ on Fe₂O₃ in order to obtain more efficient heterojunctions. The materials were synthesized by a hydrothermal conventional route and by a microwave-assisted method, using previously synthesized hematite films as a substrate for TiO₂ deposition. The materials obtained were characterized by SEM, TEM, EDS, XRD, Raman, XPS and UV-Vis/DRS. The application of the photoanodes was evaluated through photoelectrochemical experiments and hydrogen generation tests in a medium containing Triethanolamine (TEOA) as a sacrificial agent, under irradiation with a solar simulator (AM 1.5G) and Xe and Hg lamps. The electrodes prepared by the microwave-assisted route showed superior performance compared to those synthesized conventionally, indicating that the interaction of microwaves with the precursors positively influences the formation of the heterojunction interface, promoting greater charge separation, light absorption and catalytic efficiency in the production of H₂. X-ray diffraction confirmed the presence of the expected hematite and anatase phases in all the samples. However, microwave-assisted synthesis favored the additional formation of rutile and TiO, attributed to the generation of “hot-spots” by the interaction of microwaves with hydroxyl groups on the surface of the hematite, leading to localized heating and phase transformation. The Fe₂O₃-TiO₂MW (via microwave) heterojunction showed a photocurrent density approximately 9.4 times higher and a hydrogen production rate approximately 2 times higher compared to Fe₂O₃-TiO₂C (via conventional), confirming the effectiveness of microwave-assisted synthesis in improving the performance of the materials, the quality of the interface and the feasibility of application in energy conversion systems.

MEMBROS DA BANCA:
Presidente - Interno ao Programa - 2351974 - JULIANA DOS SANTOS DE SOUZA
Membro Titular - Examinador(a) Externo ao Programa - 2605463 - JOSE ANTONIO SOUZA
Membro Titular - Examinador(a) Externo à Instituição - REJANE MARIA PEREIRA DA SILVA - UESPI
Membro Suplente - Examinador(a) Externo ao Programa - 1305186 - SERGIO BROCHSZTAIN
Membro Suplente - Examinador(a) Externo à Instituição - PAOLA CORIO