Ceria catalyst for the internal reforming of biogas in a small tubular solid oxide fuel cell system

A perennial problem with carbon based fuels such as methane in SOFC's is that of carbon deposition or 'coking up'. Biogas; a complex and variable mixture of methane, carbon dioxide and other gases; is a high carbon content fuel and so is no exception to this general rule. In this paper, ceria is shown to be an effective catalyst preventing carbon deposition within a solid oxide fuel cell system powered by air reformed biogas. Analysis of the exhaust gases was performed by gas chromatography. This showed that addition of ceria to the anode increased reforming activity at the operating temperatures of the cells with a higher conversion rate of methane to hydrogen and carbon monoxide than for an undoped anode. The addition of ceria to the anode lessens power fluctuations and greatly increases the length of time that a cell can run before coking up Further experiments are testing the longer term performance.