Highly Active Multimetallic Palladium Nanoalloys Embedded in Conducting Polymer as Anode Catalyst for Electrooxidation of Ethanol

Fabrication of multimetallic nanocatalysts with controllable composition remains a challenge for the development of low-cost electrocatalysts, and incorporating metal-based catalysts into active carbon nanoarchitectures represents an emerging strategy to improve the catalytic performance of electrocatalysts. Herein, a facile method developed for Pd nanoparticle (NP)-based multimetallic alloys incorporated on polypyrrole (Ppy) nanofibers by in situ nucleation and growth of NPs using colloidal radiolytic technique is described. Electrochemical measurement suggests that the as-prepared catalysts demonstrate dramatically enhanced electrocatalytic activity for ethanol oxidation in alkaline medium. The ultrasmall Pd 30 Pt 29 Au 41 /Ppy nanohybrids (∼8 nm) exhibit excellent electrocatalytic activity, which is ∼5.5 times higher than that of its monometallic counterparts (12 A/mg Pd, 5 times higher activity compared to that of Pd/C catalyst). Most importantly, the ternary nanocatalyst shows no obvious change in chemical structure and long-term stability, reflected in the 2% loss in forward current density during 1000 cycles. The superior catalytic activity and durability of the nanohybrids have been achieved due to the formation of Pt–Pd–Au heterojunctions with cooperative action of the three metals in the alloy composition, and the strong interactions between the Ppy nanofiber support with the metal NPs. The facile synthetic approach provides a new generation of polymer-supported metal alloy hybrid nanostructures as potential electrocatalysts with superior catalytic activity for fuel cell applications.