ABSTRACT
The proton exchange membrane fuel cell (PEMFC) is considered a very promising system able to provide energywith high efficiency by using pure hydrogen as fuel. However, the performance and durability of the key components, such as membrane electrode assemblies (MEAs), membranes, electrodes, gaskets, or bipolar plates, remain the focus of international research and development (R&D) (Gasteiger and Markovic, 2009; Kunze and Stimming, 2009; Millet et al., 2011; Zhong et al., 2008). At the heart of a PEMFC is the MEA, which is comprised of two catalytic and two diffu-
sion layers. These layers play a critical role in defining the performance of the MEA. To play its essential function, an electro-catalyst needs to provide high intrinsic activities for the electrochemical oxidation of a fuel at the anode, whether this is hydrogen or alcohol (methanol, ethanol), and for the electrochemical reduction of oxygen at the cathode. Other requirements include high electrical conductivity, appropriate physical and electrical contact with the ionomer, suitable reactant/product gas access/exit, and high stability in the highly corrosive working medium (Thompsett, 2003; Vielstich et al., 2003). To ensure that a fuel cell delivers maximum efficiency, both electrode reactions need to take place as close to their thermodynamic potential as possible.
