Electrochemical Characterization of Various Carbon-Supported Pt-Pd Bimetallic Electrocatalysts Prepared by Electroless Deposition

Various Pt-Pd/C bimetallic compositions have been prepared by electroless deposition (ED) methods. The morphology has been identified as Pd cores partially encapsulated by Pt shells by various spectroscopic techniques. No monometallic Pt or Pd particles have been detected. The ratio of Pt to Pd was also well controlled. Although the electrochemical activity of the Pt-Pd/C catalyst for oxygen reduction reaction (ORR) was equal to or less than that for commercially available Pt/C catalysts, the amount of hydrogen peroxide detected as ring current was reduced by the exposed Pd component, suggesting that such a catalyst has the potential to decrease ionomer degradation in certain applications. The Pt on Pd/C catalysts also show much higher resistance to agglomeration induced by potential cycling. Analysis by high resolution scanning transmission electron microscopy following potential cycling reveals no changes in both particle sizes and electrochemical active areas.