Ceria-based anodes with cobalt and copper additions for the direct utilisation of methane in solid oxide fuel cells

Abstract

The utilisation of hydrocarbons as fuels in solid oxide fuel cells presents as an ingenious alternative for boosting the market widespread of such technology. The main advantage is the lower need of infrastructure investments. Therefore, the objective of this thesis was to develop a ceria-based material with cobalt and copper additions to serve as anode for the electrochemical oxidation of methane. The electrocatalysts powders were synthesised with different proportion of cerium, cobalt and copper and were then tested and characterised. The characterisation was done by X-ray diffractometry, X-ray fluorescence, thermogravimetric analysis, temperature-programmed reduction, DC-conductivity tests and particle size distribution. The tests consisted in electrochemical performance and impedance, gas cromatography. Post-mortem characterisation was done by scanning electron microscopy and was focused in assessing eventual carbon deposition by Raman spectroscopy and temperature-programmed oxidation. The produced cells and compositions have shown to be suitable for operating with both hydrogen or methane as fuels in the range of 700-850C. The post-mortem showed the anode integrity and besides that, no significant carbon was found in the anode post-mortem bulk. Therefore, the anode material has presented itself as a promising alternative for real solid oxide fuel cells applications.