Catalytic Behavior of Pd–Ni/Composite Anode for Direct Oxidation of Methane in SOFCs

Abstract

Electrocatalysis of a Pd–Ni/composite anode (small amounts of Pd–Ni catalyst on a lanthanum chromite-based porous composite anode) for direct oxidation of dry methane in solid oxide fuel cells (SOFCs) was studied at . Synergy of Pd and Ni catalysts was observed for the direct oxidation of dry methane. Maximum power densities with the Pd–Ni/composite anode were 150 and at 1073 and , respectively. Carbon deposition on the Pd–Ni/composite anode was quite low under both open- and closed-circuit conditions. Therefore, stable power generation was performed under the closed-circuit condition, and no physical damage was observed for the cell under the open-circuit condition with dry methane. XRD analysis suggested the formation of Pd–Ni alloy on the composite anode. A suitable reaction scheme for the direct oxidation of dry methane over the Pd–Ni/composite anode was proposed on the basis of the kinetic experiment, the gasification experiment of the deposited carbon by steam, and impedance spectra. The decomposition of to and C, and the gasification of C by to and CO, are key reactions for the effective direct oxidation of dry over the Pd–Ni/composite anode.