Silver palladium core-shell electrocatalyst supported on MWNTs for ORR in alkaline media

We show that silver palladium core-shell catalysts supported on multiwalled carbon nanotubes (Ag@Pd/MWNTs) are highly active and alcohol tolerant for oxygen reduction reactions (ORR) in alkaline media. These electrocatalysts were synthesized by galvanic displacement of Pd on Ag nanoparticles deposited on MWNTs. The Ag@Pd/MWNTs are shown to be tolerant of the presence of methanol and ethanol in the electrolyte. In the presence of methanol, the Ag@Pd/MWNTs current density decreased by 0.18 mA/cm(2), compared to Pt/C (0.97 mA/cm(2)) and Pd/C (1.09 mA/cm(2)). In the presence of ethanol, the Ag@Pd/MWNTs current density decreased by 0.12 mA/cm(2), compared to Pt/C (0.87 mA/cm(2)) and Pd/C (2.13 mA/cm(2)). The Ag@Pd/MWNTs also show improved durability with an increased mass activity of similar to 3.5 times that of standard Pd/C, after durability testing in ethanol. The Ag@Pd/MWNTs are promising platinum free direct alcohol fuel cell cathode catalysts due to their high activities and durability, as well as their improved tolerance to methanol and ethanol from possible fuel crossover. (C) 2013 Elsevier B.V. All rights reserved.