2008 Spring Symposium
Raymond J. Gorte
Chemical & Biomolecular Engineering
University of Pennsylvania
Philadelphia, PA
Abstract — Electrodes are being developed for Solid Oxide Electrolyzers (SOE), especiallythose that could be used for Natural-Gas Assisted Steam Electrolysis (NGASE). NGASErequires electrodes that exhibit stable performance in dry methane, with lowoverpotentials, and allow operation at high temperatures. A variety of novel air and fuelelectrodes have been developed and tested for SOE and NGASE devices.
In all cases, theelectrodes are made by addition of the active, electrode components into porous yttriastabilizedzirconia (YSZ) layers that had been pre-sintered with the YSZ electrolyte. Airelectrodes based on Sr-doped LaFeO3 (LSF) have been shown to exhibit superiorperformance to more traditional LSM-based electrodes but can deactivate after long timesor high temperatures, apparently due to sintering of the LSF. Cu-based electrodes werefound to exhibit poor thermal stability above 1073 K due to sintering of Cu, but Cu-Coelectrodes prepared by Co electrodeposition onto the Cu composite had significantlyimproved performance. It was shown that a Cu monolayer forms at the Co surface afterheating in H2 due to free-energy considerations, so that the Cu-Co electrodes exhibit thethermal stability of Co and the chemical stability of Cu. Finally, a novel, all-ceramicelectrode was developed for use in fuel environments. The ceramic electrode consists of athin functional layer optimized for catalytic activity with a thicker conduction layer.
Speaker’s Biography — Dr. Gorte is the Russell Pearce and Elizabeth Crimian Heuer Professorof Chemical & Biomolecular Engineering, with a secondary appointment in MaterialsScience & Engineering, at University of Pennsylvania. His current research interests arein ceria-based catalysts and solid-oxide fuel cells.