Solid oxide fuel cells operated by internal partial oxidation reforming of iso-octane

Abstract

Two types of solid oxide fuel cells (SOFCs), with thin Ce 0.85Sm 0.15O 1.925 (SDC) or 8 mol% Y 2O 3-stabilized ZrO 2 (YSZ) electrolytes, were fabricated and tested with iso-octane/air fuel mixtures. An additional Ru–CeO 2 catalyst layer, placed between the fuel stream and the anode, was needed to obtain a stable output power density without anode coking. Thermodynamic analysis and catalysis experiments showed that H 2 and CO were primary reaction products at ≈750 °C, but that these decreased and H 2O and CO 2 increased as the operating temperature dropped below ≈600 °C. Power densities for YSZ cells were 0.7 W cm −2 at 0.7 V and 790 °C, and for SDC cells were 0.6 W cm −2 at 0.6 V and 590 °C. Limiting current behavior was observed due to the relatively low (≈20%) H 2 content in the reformed fuel.