A Novel Solid Oxide Fuel Cell System Using the Partial Oxidation of Methane

Abstract

A novel solid oxide fuel cell (SOFC) system, which does not need to separate the supply of fuel and oxidant gases and generates electric power as well as chemicals, was studied. The fuel cell consisted of , in which two electrodes were exposed to the same mixture of and air. Electromotive forces (EMFs) were about at operating temperatures between 750 and 950°C, and terminal voltages were about 420 mV with discharge a current density of about 400 mA cm−2 (0.17 W cm−2) at 950°C and 350 mV with 75 mA cm−2 (0.03 W cm−2) at 750°C. The working mechanism of the fuel cell was clarified to be based on the difference in catalytic activity for the partial oxidation of methane between two electrode materials: the Pt catalyzes the partial oxidation of methane to form hydrogen and carbon monoxide, while the Au is inactive to this reaction. Therefore, the Pt acts as a fuel electrode, while the Au acts as an oxygen electrode at which electrochemical reduction of oxygen takes place on discharging the cell.