Electrocatalyst materials for PEM fuel cells based on substituted heteropoly acids

FUEL 222

Andrew M. Herring, aherring@mines.edu1, Ronald J. Stanis, rstanis@mines.edu1, Jack R. Ferrell III, jferrell@mines.edu1, Bradford R. Limoges1, Mei Chen Kuo, mkuo@mines.edu1, and John A. Turner, john_turner@nrel.gov2. (1) Department of Chemical Engineering, Colorado School of Mines, Golden, CO 80401, (2) National Renewable Energy Laboratory, Golden, CO 80401
The Heteropoly acids (HPAs) a large and diverse class of the polyoxometallates that can act as redox catalysts when substituted by a transition metal, are proton conductors, and can be reduced to form electronically conducting materials. This makes the HPAs ideal candidates for an electrode material in a PEM fuel cell as the catalyst would ideally enable fast transfer of protons and electrons as well as be a selective catalyst. Some heteropolyoxometalates have been explored as possible electrocatalysts for PEM fuel cell relevant reactions in solution, but few studies have been performed in the solid state. Here we present data for HPA as non-Pt catalysts for the oxygen reduction reaction. The HPA are also known to catalyze the water gas shift reaction at low temperatures and so we have also shown that certain HPA can be used to mitigate the effects of CO impurities on Pt anodes.