Banca de DEFESA: THERESA BEATRIZ OLIVEIRA NUNES

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : THERESA BEATRIZ OLIVEIRA NUNES
DATE: 29/06/2026
TIME: 08:30
LOCAL: Remoto
TITLE:

TITANIUM-NIOBIUM-BASED CATALYSTS FOR THE OXYGEN EVOLUTION REACTION APPLIED TO GREEN HYDROGEN PRODUCTION

KEY WORDS:

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

PAGES: 117
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, highlighting water electrolysis 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, this work investigates the influence of different chemical synthesis routes on the production of TiNb₂O₇ nanoparticles and evaluates their electrocatalytic activity toward the oxygen evolution reaction (OER) in alkaline medium, aiming at applications in water electrolysis, in addition to exploring strategies to optimize catalytic performance through defect engineering. TiNb₂O₇ nanoparticles were synthesized by 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. Among all investigated syntheses, the material produced via the coprecipitation route and calcined for 2 h (TNOCP2h) exhibited the best electrocatalytic performance, with an overpotential of approximately 287 mV to achieve 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 greater availability of active sites compared to the other evaluated conditions. The results demonstrate that the synthesis route significantly influences the physicochemical properties and electrocatalytic activity of TiNb₂O₇, highlighting the potential of the TNOCP2h sample for applications in alkaline water electrolysis aimed at sustainable hydrogen production.

COMMITTEE MEMBERS:
Presidente - 1298936 - ANTONIO EDUARDO MARTINELLI
Interno - 1300987 - CARLOS ALBERTO PASKOCIMAS
Externo à Instituição - ARMANDO MONTE MENDES - UFRN
Externo à Instituição - DANIEL ARAÚJO DE MACEDO - UFPB
Externo à Instituição - RICARDO FRANCISCO ALVES - UFPB