Electrochemical Performance and H2S Poisoning Study of Mo-Doped Ceria (CMO) SOFC Anodes

Abstract

Here we compare the electrochemical properties of a porous 10 mol. % Gd-doped CeO2 (GDC) anode with those of the same material, but infiltrated with a new plasma spray synthesized 10 mol. % Mo-doped CeO2 nano material (nCMO), all at 600-800 oC in H2, with and without added 10 ppm H2S. While both of these anode materials exhibit very good H2 oxidation activity, their performance does deteriorate when exposed to H2S. However, the nCMO-infiltrated GDC anode is significantly more stable and shows much better sulfur tolerance than the single-phase GDC anode. Furthermore, the response of both anodes is reversible, at least in early exposures, and the original H2 oxidation activity is regained fully when H2S is removed from the fuel stream. At low temperatures (ca. 500oC), these anode materials, contacted to a gold paste current collector, exhibit a dramatic response to H2S, making them of potential use as a H2S sensor.