masterThesis
Influência do método de síntese e caracterização de pós compósitos de NiO- Ce1-xEuxO2-δ para anodos catalíticos de células a combustível
Fecha
2013-02-06Registro en:
MEDEIROS, Amanda Lucena de. Influência do método de síntese e caracterização de pós compósitos de NiO- Ce1-xEuxO2-δ para anodos catalíticos de células a combustível. 2013. 90 f. Dissertação (Mestrado em Processamento de Materiais a partir do Pó; Polímeros e Compósitos; Processamento de Materiais a part) - Universidade Federal do Rio Grande do Norte, Natal, 2013.
Autor
Medeiros, Amanda Lucena de
Resumen
Fuel cells are electrochemical devices that convert chemical energy into electricity.
Due to the development of new materials, fuel cells are emerging as generating
clean energy generator. Among the types of fuel cells, categorized according to the
electrode type, the solid oxide fuel cells (SOFC) stand out due to be the only device
entirely made of solid particles. Beyond that, their operation temperature is relatively
high (between 500 and 1000 °C), allowing them to operate with high efficiency.
Another aspect that promotes the use of SOFC over other cells is their ability to
operate with different fuels. The CeO2 based materials doped with rare earth (TR+3)
may be used as alternatives to traditional NiO-YSZ anodes as they have higher ionic
conductivity and smaller ohmic losses compared to YSZ, and can operate at lower
temperatures (500-800°C). In the composition of the anode, the concentration of NiO,
acting as a catalyst in YSZ provides high electrical conductivity and high
electrochemical activity of reactions, providing internal reform in the cell. In this work
compounds of NiO - Ce1-xEuxO2-δ (x = 0.1, 0.2 and 0.3) were synthesized from
polymeric precursor, Pechini, method of combustion and also by microwave-assisted
hydrothermal method. The materials were characterized by the techniques of TG,
TPR, XRD and FEG-SEM. The refinement of data obtained by X-ray diffraction
showed that all powders of NiO - Cex-1EuxO2-δ crystallized in a cubic phase with
fluorite structure, and also the presence of Ni. Through the characterizations can be
proved that all routes of preparation used were effective for producing ceramics with
characteristics suitable for application as SOFC anodes, but the microwave-assisted
hydrothermal method showed a significant reduction in the average grain size and
improved control of the compositions of the phases