Large Platinum Structures as Promising Catalysts for the Oxygen-Reduction Reaction

Herein, Pt and Pd catalysts (in the absence and presence of Fe, concomitantly or not with rutin or quercetin), PtPd and PtAu alloys, and Pt under Au are generated on a glassy carbon (GC) surface by using direct electrodeposition. The electrochemical profiles of these materials are investigated by using cyclic voltammetry and microgravimetry (electrochemical quartz crystal microbalance). Their electrocatalytic activity toward the oxygen-reduction reaction (ORR) is studied by using hydrody-namic cyclic voltammetry. Physical characterization of the samples is performed by using SEM and energy-dispersive X-ray microanalysis. Electrodeposited catalysts that contain Pt exhibit high electrocatalytic activity toward the ORR and reproducible response, in particular at low Pt concentrations in the electrodeposition solution, thus suggesting the possibility of applying these catalysts to acid fuel cells. Large nanorock structures are formed on the GC electrode that is modified with Pt(0.50)/Pd( 0.50)+ rutin, whereas the GC electrode that is modified with Pd in the presence or absence of Fe, concomitantly or not with rutin or quercetin, shows poor electrocatalytic activity.