Banca de QUALIFICAÇÃO: ROMUALD TEGUIA DOUMBI

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : ROMUALD TEGUIA DOUMBI
DATE: 09/09/2026
TIME: 08:30
LOCAL: Online via Google Meet
TITLE:

Development of AN ANION EXCHANGE MEMBRANE ELECTROLYSIS CELL WORKING UNDER an external magnetic field

KEY WORDS:

 electrocatalyst; graphene; noble metals; oxygen evolution reaction; overpotential; sol-gel

PAGES: 135
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUMMARY:

The development of an efficient oxygen evolution reaction (OER) electrocatalyst is essential for the anion exchange membrane electrolysis cell used to produce green hydrogen energy. While noble-metal-based electrocatalysts have demonstrated excellent OER performance, their high cost limits their large-scale applications. In this context, an effective transition-metal-based electrocatalyst for OER has been prepared via the autocombustion sol-gel technique. The graphene-supported iron nickel alloy (GFeNi) was prepared and characterized using physicochemical characterization techniques to study its structural, morphological, elemental composition, chemical oxidation state, magnetic, and textural properties. Furthermore, the application of an external magnetic during the study of the OER performance of the electrocatalyst was also carried out in this study. Chemical composition showed that the elements were well distributed on the graphene matrix. Analyzing the structural properties of the electrocatalysts revealed that the GFeNi 1:1.0 catalyst, which has the smallest average crystalline size and lowest lattice strain, exhibited superior catalytic activity due to its high density of exposed active sites. This ferromagnetic electrocatalyst GFeNi 1:1.0 demonstrated high OER activity and kinetics, with an oxygen overvoltage of 264 mV at 10 mA cm^-2 and a Tafel slope of 42 mV dec^-1 in 1 M KOH electrolyte. Under an external magnetic field, the electrocatalytic activity of the GFeNi catalyst has been significantly improved. The oxygen overvoltage (0.211 V vs RHE) was reduced by a percentage of 20 %. The charge-transfer and the catalyst's stability were also enhanced. The superior OER performance of the GFeNi catalyst was attributed to the intrinsic synergistic properties, the partial oxidation of graphene, and the high electrical conductivity of graphene and FeNi, which enhances OER kinetics. Under the magnetic field, the presence of the Lorentz force and local magnetic heat further contributes to creating new active sites and thereby enhancing the electrochemical process. These findings advance understanding of ferromagnetic alloy-based materials for electrolysis applications and other electrochemical devices and highlight the potential of graphene-supported FeNi systems synthesised by sol-gel routes as cost-effective alternatives to noble metals.

COMMITTEE MEMBERS:
Presidente - 1474380 - MARCIO ASSOLIN CORREA
Interno - 1674707 - MARCO ANTONIO MORALES TORRES
Interno - 1883170 - MAURICIO ROBERTO BOMIO DELMONTE
Externa à Instituição - MARIA GARDENNIA DA FONSECA - UFPB