Characterization and Theory of Electrocatalysts Based on Scanning Electrochemical Microscopy Screening Methods

A strategy for finding new electrocatalysts for the oxygen reduction reaction (ORR) in acidic solutions is outlined and illustrated with results for Pd-Co catalysts. This is based on establishing guidelines for selecting test systems, rapid preparation of arrays, and rapid screening by scanning electrochemical microscopy. Promising candidates are furthertestedassupportedelectrocatalystsbylargerscaleelectrochemicalmethodsandinfuelcells,withoptimization of the composition and structure. Those that emerge are characterized by a variety of methods, including X-ray diffraction, scanning electron microscopy, and X-ray photoemission spectroscopy. Finally, density functional theory is used for detailed calculations of oxygen adsorption and dissociation on the material and provides better guidelines for further testing. The ultimate adoption of fuel cells as power sources depends strongly on their cost and efficiency. A key factor in both of these issues is the fuel cell cathode where the oxygen reduction reaction (ORR) occurs and important questions about whether the currently favored electrocatalyst for polymer electrolyte membrane fuel cells (PEMFC), Pt supported on C, is a viable