Sulfur Tolerance and Hydrocarbon Stability of La[sub 0.75]Sr[sub 0.25]Cr[sub 0.5]Mn[sub 0.5]O[sub 3]∕Gd[sub 0.2]Ce[sub 0.8]O[sub 1.9] Composite Anode under Anodic Polarization

A (LSCM/GDC) composite electrode was developed and applied as a solid oxide fuel cell (SOFC) anode for the direct oxidation of sulfur-containing methane. The anode was fully activated in wet at and a constant potential of with respect to a Pt/air reference before the fuel was shifted to wet . In the sulfur-containing methane fuel, the anodic current dropped from to in a period, showing a performance degradation rate of ca. 1.4%/hr possibly due to sulfur poisoning. In the subsequent period, the anodic current tended to be relatively stable with a very small degradation rate of 0.017%/h, which is most likely attributed to the coarsening of the electrode microstructure. Though some impurities, such as , , and , were detected in the X-ray diffraction analysis of the anode after of stability test, the scanning electron microscopy micrographs and energy-dispersive X-ray analysis showed that no carbon and sulfur deposition was found on the cross-sectional surface of the anode. The results suggest that the LSCM/GDC composite is a promising candidate material for an anode and has much better hydrocarbon stability and sulfur tolerance under the anodic polarization than Ni-based cermets.