Electrochemical impedance and x-ray absorption spectroscopy (EXAFS) as in-situ methods to study the PEMFC anode

The effect of alloy formation on the performance of carbonsupported Pt and Ru fuel cell catalysts has been investigated by electrochemical impedance spectroscopy (EIS), X-ray absorption spectroscopy (EXAFS) and fuel cell tests. The CO tolerance of the respective anode electrocatalysts has been tested in both reformate and methanol operation. This paper describes results for mixtures of carbon-supported Pt and carbon-supported Ru catalysts. The particle sizes of the active metals have been modified by heat-treatment in nitrogen. It has been observed that the size of Pt and Ru particles has a significant influence on the electrochemical performance, the activity improving for smaller Ru particles. The performance of certain Pt-Ru mixtures in a single cell fuel cell is comparable with an alloy catalyst