Pd/Cu bimetallic nanoparticles supported on graphene nanosheets: Facile synthesis and application as novel electrocatalyst for ethanol oxidation in alkaline media

Abstract

Well distributed Pd/Cu bimetallic nanoparticles supported on graphene nanosheets as novel electrocatalyst has been prepared via a facile synthetic method: started with an electroless deposition route to anchor Cu nanoseeds on graphene nanosheets, followed by a latter displacement reaction to achieve Pd/Cu overlaying nanostructure. The loading density and morphology of bimetallic nanoparticles on graphene are varied by adjusting the initial amount of Cu precursor and reducing agent proportionally. Scanning transmission electron microscopy (STEM) images combining energy dispersive X-ray spectroscopy (EDX) mapping results confirm the existance and distribution of Pd and Cu in the bimetallic nanoparticles, while transmission electron microscopy (TEM) reveals the nanoparticle size and overlaying nanostructure. Cyclic voltammograms tests for the hybrid electrocatalysts in 1.0 M KOH solution show a gradual increase of electrochemically active surface area (EASA) against the increment of nanoparticle loading. Meanwhile, a significantly enhanced tolerance to poisoning of electrocatalyst is observed by cyclic voltammograms curves for ethanol electrooxidation in alkaline media with high If/Ib ratios compared to previous research. The large enhancement on If/Ib ratios of the hybrid electrocatalysts can be ascribed to the well distributed overlaying bimetallic nanostructure supported on graphene nanosheets. The facilely prepared Pd/Cu/graphene hybrid materials demonstrate vastly superior electrocatalytic properties compared to the commercial Pd/C catalyst, indicating a great potential in fuel cells application.