Banca de QUALIFICAÇÃO: ANDREY JOSÉ MORAES DE LIMA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : ANDREY JOSÉ MORAES DE LIMA
DATE: 20/12/2019
TIME: 14:00
LOCAL: Sala de aulas do PPGCEM
TITLE:

Oxygen evolution reaction in calcium cobaltites: effects of Fe ions addition

KEY WORDS:

calcium cobaltite with  Fe doping,  Oxygen Evolution Reaction, Electrochemical characterization,  Mössbauer spectroscopy

PAGES: 95
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Cerâmicos
SUMMARY:

Hydrogen (H2), considered by many researchers to be the fuel of the future, is a promising source of renewable energy to be used in place of fossil fuels. One of the most commonly used forms of hydrogen production is through electrolysis, where water splitting occurs through two half reactions: Hydrogen Evolution Reaction (HER, Cathodic Reaction) and Evolution Reaction. Oxygen (OER, anodic reaction). OER is critical to a variety of electrochemical technologies related to power generation and storage. In recent years, new research to develop low cost electrocatalysts with good electrochemical activity using more abundant elements in the earth has intensified. This study aimed to study the effect of Fe doping on the calcium evolution reaction of calcium cobaltite (Ca₃Co₄O₉, C349). Powders of Ca₃Co₄O₉ and Ca₃Co_3,9Fe_0,10₉ compositions were obtained by the gelatin modified Pechini method, calcined at 900 ° C for 2 h and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Grid parameters were determined by Rietveld refinement of the diffraction data. The chemical states of the surface of the powders were studied by X-ray photoelectron spectroscopy (XPS). Electrochemical characterization was obtained by linear scanning voltammetry (LSV), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). This paper is the first report of the use of Mössbauer spectroscopy (a technique that allows the recognition of chemical species using gamma radiation) to identify the position of Fe in the layered structure of calcium cobaltite.

BANKING MEMBERS:
Presidente - 1350249 - RUBENS MARIBONDO DO NASCIMENTO
Externa à Instituição - AURISTELA CARLA DE MIRANDA - UFPB
Externo à Instituição - DANIEL ARAÚJO DE MACEDO - UFPB