Surface Structure Sensitive Electrocatalytic Activity of Platinum Nanofilm Decorated Gold Microelectrode for Oxygen Reduction Reaction

摘要

The electrocatalytic activity toward oxygen reduction reaction of a Pt nanofilm decorated gold micro- electrode with various of Pt/Au surface ratio has been investigated. The surface ratio of Pt over Au onthe electrode is precisely controlled through Cu under potential deposition followed by the surfacelimited redox replacement reaction with Pt complex ions. Microelectrodes are applied to study theoxygen reduction diffusion-limited current. It turns out that Pt-Au bimetallic catalyst toward oxygenreduction reaction exhibits a surface ratio dependent activity. The variation of reduction kinetic currentdensity as well as the value of onset potential is observed with respect to the Pt/Au surface ratio. Thehighest specific activity and most efficient utilization of Pt for oxygen reduction reaction is observedwith the Pt/Au ratio of 0.62. The resutls demonstarte that microelectrode-based technology is apromising way to determine the electrocatalytic acitivity and also provide an idea to design low Ptcontent electrocatalysts for oxygen reduction reactions.