Enhanced Stability of PtRu Supported on N-Doped Carbon for the Anode of a DMFC

The performance and long-term stability of a direct-methanol fuel cell (DMFC) employing PtRu supported on nitrogen-modified carbon is compared with that of PtRu/C (Hi-spec 5000). The long-term stability test is carried by means of accelerated degradation testing (ADT) at an anodic potential of 0.8 V vs. DHE for 640h. The initial DMFC performance of the MEA containing PtRu/C (N-doped) is slightly lower than that of the PtRu/C (Hi-SPEC) because of the lower ECSA of the former. After 640h ADT, the anode ECSA loss is found to be similar to 21% and similar to 26% for the PtRu/C (N-doped) and PtRu/C (Hi-SPEC), respectively. Electrochemical analyzes reveal that cathode of the MEA with PtRu/C (N-doped) is less contaminated with Ru. It is further corroborated by post-mortem analysis done by scanning electron microscopy (SEM) associated with EDS, which indicates 4.8 and 8.2 at.% Ru accumulation, respectively, in the cathodes of the PtRu/C (N-doped) and PtRu/C (Hi-SPEC) MEAs after 640h ADT. Although both MEAs sustain anode and cathode ECSA losses, the performance for the PtRu/C (N-doped) MEA is improved by similar to 28% and similar to 8% after initial and long-term ADT, while the performance for the PtRu/C (Hi-SPEC) MEA is improved by similar to 20% after initial and decreased by similar to 3% after long-term ADT. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.063211jes] All rights reserved.