Electrocatalysis in proton exchange membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs) are discussed. This includes first principles quantum mechanical methods that begin to provide reliable descriptions of elementary processes occurring in complex environments such as the surface of real-world fuel cell catalysts. The complexity of the electrocatalytic environment in fuel cells obscures the fundamental surface chemistry and physics. A key to low overpotentials is having weak interactions of the reactants and products with the catalyst sites, as well as low activation energy barriers for all reaction steps. A simple model of catalyst utilization for supported catalysts used in fuel cells was developed. The values obtained for catalytic area losses from the geometric model suggest the existence of optimum structures for fuel cell electrodes.
|Original language||English (US)|
|Number of pages||5|
|Journal||Electrochemical Society Interface|
|State||Published - Jun 1 2007|