Banca de DEFESA: WELLINGTON DE SOUZA FERREIRA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : WELLINGTON DE SOUZA FERREIRA
DATE: 29/08/2024
TIME: 13:00
LOCAL: Programa de Pós-Graduação em Ciência de Materiais
TITLE:

Photocatalytic systems for green hydrogen production from nanotubular structures

KEY WORDS:

Titanium dioxide, Hydrogen production, CuBi2O4, Photoelectrocatalysis, Semiconductors.

PAGES: 74
BIG AREA: Outra
AREA: Multidisciplinar
SUMMARY:

Currently, the search for less environmentally impactful energy sources has become a major challenge. Among alternative energy sources, hydrogen produced through solar energy stands out. The formation of heterojunctions between titanium dioxide (TiO₂) nanotubes (NTs) and semiconductors is a promising strategy for utilizing solar energy in the green production of hydrogen. In this work, titanium dioxide (TiO₂) nanotubes (NTs), the ternary oxide CuBi₂O₄, and the binary oxides CuO and Bi₂O₃ were studied as photoelectrocatalysts for hydrogen generation. TiO₂ NTs were synthesized by the electrochemical anodization method (45 V for 110 minutes) and thermally treated at 500°C for 3 h to achieve the anatase crystalline phase. The ternary oxides CuO-Bi₂O₃ were synthesized through an electrochemical process in a corrosion cell, subsequently thermally treated at 500°C for 2 h, using charges in the range of 50mC, 100mC, and 250mC for all heterojunctions (TiO₂/CBO, TiO₂/Bi₂O₃, and TiO₂/CuO). Structurally, the studied heterojunctions were evaluated using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The photocatalytic activity of the systems was evaluated through photoelectrochemical measurements using a three-electrode cell (PEC) and under solar irradiation. An increase in photocurrent density of 2 times was observed for the TiO₂/CBO 50mC system, increasing from 0.21 mA cm⁻² for TiO₂ to 0.51 mA cm⁻² for TiO₂/CBO 50mC. In addition to decreasing electron transfer resistance compared to TiO₂ NTs, the TiO₂/CBO and TiO₂/Bi₂O₃ heterojunctions showed hydrogen production, using a sodium sulfate and glycerol solution as a hole scavenger as the electrolyte to reduce photocorrosion effects. There was a 2-fold increase in the hydrogen production rate (TiO₂/CBO, 0.98 mL H₂ h⁻¹) compared to TiO₂ NTs (0.45 mL H₂ h⁻¹) after a 2-hour production period. Based on the presented results, it is concluded that the heterojunction of the ternary oxide on the surface of TiO₂ NTs enabled an efficient system for hydrogen generation. By expanding the absorption region and improving the photocatalytic performance, the initial hypothesis was confirmed, proving its potential for photoelectrochemical photocatalytic applications.

COMMITTEE MEMBERS:
Externo à Instituição - ENIO PONTES DE DEUS - UFC
Presidente - ***.487.700-** - GIOVANNA MACHADO - UFRGS
Interno - 1301548 - MARCELO NAVARRO