Oxygen reduction reaction at binary and ternary nanocatalysts based on Pt, Pd and Au

Carbon-supported monometallic, binary and ternary nanocatalysts based on Pt, Pd and Au were synthesized by a water in oil microemulsion method and characterized by atomic absorption spectrometry, thermogravimetry, transmission electron microscopy, X-ray diffraction, and electrochemical methods. A comparative study of the oxygen reduction reaction on monometallic, alloyed binary and ternary nanocatalysts has been performed. The catalytic activity and the selectivity of the nanocatalysts towards the ORR have been determined by rotating disc electrode and rotating ring disc electrode in O-2-saturated 0.1 M HClO4 electrolyte. It was shown that the addition of palladium to platinum led to a constant decrease of the activity with the Pd ratio. The modification of platinum by gold allows improving the activity of the catalyst towards ORR for gold ratio up to 50 at%. Ternary Pt70Pd15Au15/C and Pt50Pd25Au25/C were synthesized. These catalysts showed improved catalytic activities towards ORR. Aging tests have been carried out, showing that a part of the loss in the activity of gold containing catalysts is due to gold segregation from the bulk to the surface of nanoparticles. (C) 2015 Elsevier Ltd. All rights reserved.