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

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 degrees C in H-2, with and without added 10 ppm H2S. While both of these anode materials exhibit very good H-2 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 H-2 oxidation activity is regained fully when H2S is removed from the fuel stream. At low temperatures (ca. 500 degrees C), 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.