Dynamic and Steady-State Methods for Evaluation of CO-Tolerant Electrocatalysts and Membrane-Electrode-Assemblies

The operation of PEMFC stacks with impure hydrogen generated from reforming processes based on hydrocarbon fuels is associated with problems due to poisoning of the Pt based anode catalyst by carbon monoxide (CO) 1-3]. In order to address these problems, advanced CO tolerant PtRu electro-catalysts and MEAs have been developed by OMG over the past years 4-7]. In the course of this work, specific testing and evaluation methods for these products were established and implemented. During operation of PEMFC systems in vehicles and busses, transient exposure of the anode catalyst with high levels of CO can occur. To simulate these conditions in a lab environment, dynamic testing procedures simulating transient CO poisoning conditions were developed. For stationary PEMFC systems running on CO containing natural gas (NG) reformate, besides the production costs, endurance, stability and lifetime of MEAs are of primary importance. For this application field, the “CO-gain” diagnostic method was developed. This in-situ method allows to generate data and information on anode catalyst performance while performing a continuous, non-interrupted lifetime testing of the MEA. This paper describes the dynamic and steady-state testing methods developed and employed at OMG to evaluate CO tolerant electrocatalysts and membrane-electrode-assemblies (MEAs). For illustration, typical performance data obtained with the new testing procedures and methods are presented.