Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10269625 | Electrochimica Acta | 2005 | 11 Pages |
Abstract
We report on the use of the polyoxometalate acids of the series [PMo(12 â n)VnO40](3 + n)â (n = 0-3) as electrocatalysts in both the anode and the cathode of polymer-electrolyte membrane (PEM) fuel cells. The heteropolyacids were incorporated as catalysts in a commercial gas diffusion electrode based on Vulcan XC-72 carbon which strongly adsorbed a low loading of the catalyst, ca. 0.1 mg/cm2. The moderate activity observed was independent of the number of vanadium atoms in the polyoxometalate. In the anode the electrochemistry is dominated by the V3+/4+ couple. With a platinum reference wire in contact with the anode, polarization curves are obtained withVOC of 650 mV and current densities of 10 mA cmâ2 at 100 mV at 80 °C. These catalysts showed an order of magnitude more activity on the cathode after moderate heat treatment than on the anode,VOC = 750 mV, current densities of 140 mA cmâ2 at 100 mV. The temperature dependence of the catalysts was also investigated and showed increasing current densities could be achieved on the anode up to 139 °C and the cathode to 100 °C showing the potential for these materials to work at elevated temperatures.
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Authors
Bradford R. Limoges, Ronald J. Stanis, John A. Turner, Andrew M. Herring,