Banca de QUALIFICAÇÃO: THERESA BEATRIZ OLIVEIRA NUNES

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : THERESA BEATRIZ OLIVEIRA NUNES
DATE: 10/04/2026
TIME: 08:30
LOCAL: Auditorio do LIME
TITLE:

Titanium-Niobium Oxide-Based Catalysts For Green Hydrogen Production

KEY WORDS:

Green Hydrogen; Water Electrolysis; Oxygen Evolution Reaction; TiNb₂O₇; Electrocatalysts.

PAGES: 137
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Cerâmicos
SUMMARY:

The growing need to reduce greenhouse gas emissions has driven the development of technologies aimed at sustainable hydrogen production, with water electrolysis standing out as one of the most promising routes for green hydrogen generation. However, the efficiency of this process is limited by the kinetic barriers associated with the oxygen evolution reaction (OER), making the development of efficient and stable electrocatalysts a significant scientific challenge. In this context, the present study investigates the influence of different chemical synthesis routes on the preparation of TiNb₂O₇ nanoparticles and evaluates their performance as electrocatalysts for the OER in alkaline medium. TiNb₂O₇ nanoparticles were synthesized via coprecipitation and polymeric precursor (Pechini) methods, followed by thermal treatments at different calcination times. The obtained materials were characterized using structural and morphological techniques, allowing the correlation of parameters such as crystallinity, crystallite size, and morphology with electrochemical performance. Electrocatalytic activity was assessed through polarization curves, Tafel slope analysis, electrochemically active surface area estimation, and stability tests. Among the investigated samples, the material synthesized by coprecipitation and calcined for 2 h (TNOCP2h) exhibited the best electrocatalytic performance, presenting an overpotential of approximately 287 mV to reach a current density of 10 mA cm⁻², a Tafel slope of 42 mV dec⁻¹, and a double-layer capacitance of 2.39 mF cm⁻², indicating favorable kinetics and higher availability of active sites compared to the other evaluated conditions. These results demonstrate that the synthesis route significantly influences the physicochemical properties and catalytic performance of TiNb₂O₇, highlighting its potential as a promising alternative material for electrocatalytic applications related to sustainable hydrogen production.

COMMITTEE MEMBERS:
Presidente - 1298936 - ANTONIO EDUARDO MARTINELLI
Externo à Instituição - RICARDO FRANCISCO ALVES - UFPB
Externo à Instituição - ARMANDO MONTE MENDES - UFRN
Externo à Instituição - DANIEL ARAÚJO DE MACEDO - UFPB