Evaluating the Role of Pt and Pd Catalyst Morphology on Electrocatalytic Methanol and Ethanol Oxidation

We have investigated the relative efficiency of Pt and Pd catalysts, in the structural formats of nanoporous solids and planar metallic surfaces, for the electro-oxidation of methanol and ethanol in acidic and basic aqueous solutions. There are two issues of primary concern in this comparison. These are the surface area of the two catalyst structures and the crystalline morphology of the metals. We find that the nanoporous solids of Pt and Pd afford greater electro-oxidation efficiency and increased catalytic stability relative to the corresponding planar metallic surface for methanol and ethanol. The increase in current density for the Pt nanoporous solid was greater for basic conditions than for acidic conditions. Although both metals provided increased catalytic activity relative to that of the corresponding planar metal, the reactivity of Pt was greater for methanol, while Pd exhibited greater reactivity for ethanol. Our data point to the utility of nanoporous solids for use as catalytic media.