Ru-catalyzed anode materials for direct hydrocarbon SOFCs

A solid oxide fuel cell using a thin ceria-based electrolyte film with a Ru-catalyzed anode was directly operated on hydrocarbons, including methane, ethane, and propane, at 600 °C. The role of the Ru catalyst in the anode reaction was to promote the reforming reaction of the unreacted hydrocarbons by the produced steam and CO₂, which avoided interference from steam and CO₂ in the gas-phase diffusion of the fuels. The resulting peak power density reached 750 mW cm⁻² with dry methane, which was comparable to the peak power density of 769 mW cm⁻² with wet (2.9 vol.% H₂O) hydrogen. More important was the fact that the cell performance was maintained at a high level regardless of the change in the methane utilization from 12 to 46% but was significantly reduced by increasing the hydrogen utilization from 13 to 42%. While the anodic reaction of hydrogen was controlled by the slow gas diffusion, the anodic reaction of methane was not subject to the onset of such a gas-diffusion process.