Abstract

Background: To realize the high performance of direct methanol fuel cells (DMFCs), controlled construction of well-dispersed Pt-based bimetallic nanoparticles either of free standing or supported on carbon-based materials is highly sought. This work demonstrates the feasibility of reduced graphene oxide (RGO)-supported Pt-Pd bimetallic nanodendrites as electrocatalysts for enhanced methanol oxidation.

Methods: RGO-supported Pt-Pd bimetallic nanodendrites were conveniently synthesized by simultaneously reducing chloroplatinic acid and potassium tetrachloro palladate with ascorbic acid on RGO supports. X-ray diffraction and transmission electron microscopy were utilized for the physical characterization of Pt-Pd/RGO nanodendrites. Electrocatalytic activity of synthesized catalysts was evaluated in 0.5 M HClO₄ + 1 M CH₃OH solution.

Results: Experimental results on the electrocatalytic activity of methanol oxidation demonstrate that Pt-Pd/RGO bimetallic nanodendrites synthesized using poly(diallydimethylammonium chloride) (PDDA) surfactant exhibits higher methanol electro-oxidation activity compared to Pt-Pd bimetallic nanodendrites synthesized using polyvinylpyrrolidone (PVP) as a surfactant.

Conclusions: This work offers a convenient synthesis strategy to fabricate Pt-Pd nanodendrites (NDs) with improved dispersivity on RGO support with the aid of PDDA and PVP surfactants. Further, these findings suggest that utilization of PDDA as a surfactant yields Pt-Pd NDs with high dispersion on RGO.

Keywords: Bimetallic nanoparticles, electrocatalysts, methanol electrooxidation, reduced graphene oxide.

Graphical Abstract