The use of the heteropoly acids, H5PMo10V2O40, H7[P2W17O61(FeIII·OH2)] or H12[(P2W15O56)2Fe4III(H2O)2], in the anode catalyst layer of a proton exchange membrane fuel cell

The use of heteropoly acids (HPAs) in PEM fuel cell anode catalyst layers was studied. To compare the doped electrodes with a control electrode in a meaningful way membrane electrode assemblies (MEAs) were prepared with two 1/2 anodes, one the undoped control and one the test electrode. This ensured that both the control and test electrode were subject to the same thermal and electrochemical history. After curve fitting the data using a least squares method the error was found to be 1% in E0, 25% in the Tafel slope and 15% in the area specific resistance. The electrodes used were commercial electrodes of the Los Alamos type (ELATs). Doping a fuel cell anode with H5PMo10V2O40 resulted in a fourfold increase in the area specific resistance of the MEA, but the performance was not equivalent to that of an anode incorporating Nafion®. Doping H5PMo10V2O40 in Nafion® painted ELATs resulted in negligible improvements in the performance compared to ELATs incorporating only Nafion®. Much more impressive was the improvement in maximum power from doping the Nafion® painted ELAT with H7[P2W17O61(FeIII·OH2)] or H12[(P2W15O56)2Fe4III(H2O)2]. Eighty-five percent improvements in maximum power and 100% improvements in area specific resistance were observed from this HPA doped ELAT.