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

• Create supported Ag-Pd core–shell catalyst on MWNTs using galvanic displacement.
• Oxygen reduction reaction of 3 different galvanic displacement procedures.
• Ag@Pd/MWNTs have greater current density for ORR than standard catalysts.
• Ag@Pd/MWNTs show improved tolerance to alcohols present during ORR.
• Ag@Pd/MWNTs have improved durability compared to standard Pd/C catalysts.

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/cm2, compared to Pt/C (0.97 mA/cm2) and Pd/C (1.09 mA/cm2). In the presence of ethanol, the Ag@Pd/MWNTs current density decreased by 0.12 mA/cm2, compared to Pt/C (0.87 mA/cm2) and Pd/C (2.13 mA/cm2). The Ag@Pd/MWNTs also show improved durability with an increased mass activity of ~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.

Figure optionsDownload as PowerPoint slide