Banca de QUALIFICAÇÃO: MARIA KUZNETSOVA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : MARIA KUZNETSOVA
DATE: 24/11/2022
TIME: 09:00
LOCAL: https://conferenciaweb.rnp.br/webconf/juliana-255
TITLE:

Microwave-assisted synthesis of bismuth niobate nanostructures with application in water splitting

PAGES: 20
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Inorgânica
SPECIALTY: Foto-Química Inorgânica
SUMMARY:

Bismuth niobate (BiNbO4) is a semiconductor oxide that is sensitive to visible light and possesses properties that qualify it for photoelectrocatalytic applications. However, it is still poorly investigated for this purpose. Tungsten trioxide, on the other hand, is a semiconductor oxide widely applied in the photoelectrochemical disproportionation of water. However, it has inadequate potential for this process.
Aiming to develop a strategy to overcome the limitations of these two materials, in this work, a microwave-assisted synthesis protocol of heterojunctions based on bismuth niobate (BiNbO4) and tungsten trioxide (WO3) was developed. These photocatalysts were applied as photoanodes for photoelectrochemical disproportionation of water using simulated sunlight irradiation. It was observed that temperature and irradiation power influence the crystal structure of BiNbO4 nanoparticles and, as a consequence, the photocatalytic activity for the heterojunctions formed. Analysis of the XRD patterns showed that higher temperatures and irradiation powers favor the formation of the orthorhombic arrangement of BiNbO4. Furthermore, it was observed that the morphology of the WO3 films is directly controlled by the addition of weak acids in the reaction medium that allowed the formation of the particles in the form of wrinkled rods and cubic particles. It was observed that the use of orthorhombic BiNbO4 - of lower band-gap energy - associated with WO3 films formed by wrinkled nanotods - of higher surface area - increased interaction between the semiconductors. This strategy led to the formation of a heterojunction capable of producing current densities more than one magnitude higher than that of the pure WO3 film. These findings demonstrated that microwave-assisted synthesis is a very attractive alternative to directly control the crystal structure and photocatalytic activity of tungsten trioxide and bismuth niobate heterojunctions.

BANKING MEMBERS:
Presidente - Interno ao Programa - 2351974 - JULIANA DOS SANTOS DE SOUZA
Membro Titular - Examinador(a) Interno ao Programa - 1601156 - WAGNER ALVES CARVALHO
Membro Titular - Examinador(a) Externo ao Programa - 058.612.078-52 - LUCI ROCHA AVEIRO - IFSP
Membro Suplente - Examinador(a) Interno ao Programa - 3047441 - MONICA BENICIA MAMIAN LOPEZ