Direct ethanol PEM fuel cells: The case of platinum based anodes

PtSn/C catalysts were prepared by the direct decoration of Pt/C with Sn through a modified poly process. XRD results showed there existed obvious SnO2 in this catalyst, different from the PtSn/C prepared by co-precipitation, Sn presenting in different valence. The techniques of cyclic voltammetry, anode polarization curve and single direct ethanol fuel cell (DEFC) tests were used to evaluate and compare the electrocatalytic activities to ethanol oxidation over PtSn/C prepared by different preparation procedure and over the commercial PtRu/C catalyst. The experimental results showed that PtSn/C presents higher electrocatalytic activity than PtRu/C. The results also showed that, compared to the PtSn/C prepared by co-precipitation, PtSn/C in this investigation exhibits a similar initial activity but a lower activity along with the current density increment, probably due to its poor electronic conductivity and part coverage of platinum active sites resulting from SnO2. It was found from the GC analysis results that PtSn/C can oxidize ethanol molecules to a deeper extent than PtRu/C, leading to both a higher fuel utilization coefficient and a higher fuel cell efficiency. (c) 2005 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.