Banca de DEFESA: ANDREY JOSÉ MORAES DE LIMA
Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.STUDENT : ANDREY JOSÉ MORAES DE LIMA
DATE: 21/06/2021
TIME: 08:00
LOCAL: https://conferenciaweb.rnp.br/webconf/rubens-18
TITLE:
Fe-doped calcium cobaltites as electrocatalysts for oxygen evolution reaction
KEY WORDS:
Calcium cobaltite, oxygen evolution reaction, Mössbauer Spectroscopy, electrochemical characterization.
PAGES: 95
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Cerâmicos
SUMMARY:
The electrolysis of alkaline solutions is one of the most used strategies for producing hydrogen (H2). This process distinguishes itself by breaking the water molecule (water splitting) through two semi-reactions: Hydrogen Evolution Reaction (HER, cathodic reaction) and Oxygen Evolution Reaction (OER, anodic reaction). The OER is fundamental for several electrochemical technologies related to generate and storage energy. New research for developing low-cost electrocatalysts with a good electrochemical activity using more earth abundant elements has intensified in recent years. The current work aims to study the effect of Fe doping on the OER of calcium cobaltites, Ca3Co4-xFexO9 (x = 0, 0.1, 0.4, and 0.8). Powders were obtained by a proteic sol-gel method using gelatin with calcination at 900 °C for 2 h. The resultant samples were characterized by X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM). X-ray photoelectron spectroscopy (XPS) provided information on the surface chemical states, while Mössbauer spectroscopy indicated that Fe has a strong preference for octahedral sites in the CoO2 layer rather than in the Ca2CoO3 layer in the calcium cobaltite misfit-type structure. Linear sweep voltammetry (LSV), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) were used to analyze the electrochemical performance. The results indicate that Ca3Co3.2Fe0.8O9 needs the lowest overpotential of 320 mV to generate a current density of 10 mA cm-2.
BANKING MEMBERS:
Presidente - 1350249 - RUBENS MARIBONDO DO NASCIMENTO
Externo ao Programa - 1674707 - MARCO ANTONIO MORALES TORRES
Externo à Instituição - DANIEL ARAÚJO DE MACEDO - UFPB
Externo à Instituição - RODOLFO BEZERRA DA SILVA - UFRN
Externo à Instituição - THIAGO ARAUJO SIMÕES - UFRB