Effects of Sample Preparation Technique on Quantitative Analysis of Automotive Fuel Cell Catalyst Layers

Environmental concerns about carbon emissions are motivating development of Proton-Exchange Membrane Fuel Cell (PEM-FC) technology for automotive propulsion. Catalyst Coated Membranes (CCM), which are the electrochemical „heart‟ of PEM-FC, consist of a proton-conductive polymer membrane embedded between two porous, electron conductive electrodes. The catalyst in the cathode consists of Pt nanoparticles on a carbon support which are coated with a proton-conductive perfluorosulfonic acid (PFSA) ionomer [1]. The oxygen reduction reaction occurs at the triple junction of these three components. One aspect needing improvement to achieve successful commercialization is a reduction of the rate of degradation of catalyst components with electrochemical cycling. Different microscopy techniques are helping optimize the system to improve durability of PEM-FC. However, sample preparation can affect the results of the microanalysis. In order to fully understand each component and how it degrades, it is important to understand and eliminate sample preparation artifacts.