Partial oxidation of CH4 to synthesis gas using an Rh |YSZ|Ag electrochemical membrane reactor

Abstract

Partial oxidation of CH₄ has been carried out using an electrochemical membrane reactor composed of an yttria-stabilized zirconia (YSZ) disc with the faces covered with Ag and Rh films. Synthesis gas was obtained continuously by feeding CH₄ and O₂ over the Rh-and Ag-coated surfaces, respectively, at a low temperature of 773 K. It is likely that the partial oxidation of CH₄ to CO–H₂ as well as the complete oxidation to CO₂–H₂O proceed on the Rh-coated surface. The reaction pathways are independent of each other as judged by the reaction behaviour in terms of the dependence on the applied voltage and the reaction time course. It is considered that the complete oxidation was achieved by the oxygen species appearing at the three-phase boundary of Rh |YSZ| atmosphere through YSZ. Direct partial oxidation was realised by the oxygen species migrating from the three-phase boundary onto the Rh surface.