High activity oxide Pr0.3Sr0.7Ti0.3Fe0.7O3-delta as cathode of SOEC for direct high-temperature steam electrolysis

摘要

A high activity ferrite Pr0.3Sr0.7Ti0.3Fe0.7O3-delta (PSTF) has been synthesized and examined as a cathode of solid oxide electrolysis cell (SOEC) for direct high-temperature steam electrolysis. The SOEC with a configuration of PSTF|YSZ|LSM-YSZ was operated under H2O concentrations ranging from 20%H2O/Ar to 60%H2O/Ar and exhibited excellent electrochemical performances. Polarization resistance of the electrolyzes was as small as 0.43 Omega cm(2) in 60%H2O/Ar at 1.85 V at 800 degrees C. According to AC impendence spectra analyzing, gas diffusion process was the rate-determine-step (RDS) under smaller current density, while under larger current density, transport properties in the electrodes and the interfaces of electrode/electrolyte was RDS. The electrochemical properties of PSTF cathodes were systematically investigated and compared when they were exposed to gas atmosphere with and without safe gas (H-2). The obtained results demonstrated that PSTF electrode could conceivably avoid any hydrogen feeding for steam electrolysis. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.