Pd nanoparticles supported on N and P dual-doped graphene as an excellent composite catalyst for methanol electro-oxidation

Abstract

We synthesize a novel composite catalyst of Pd nanoparticles supported on N and P dual-doped graphene (N-P-G) for the methanol electro-oxidation reaction in alkaline medium. It is revealed that the Pd nanoparticles with a particle size of ∼4.59 nm uniformly distribute on the surface of N-P-G with a two-dimensional flake-like structure. The synergistic doping of N and P changes the electronic structure of graphene, increases the electron density of Pd and produces higher proportion of P-C bonds. This increases the metallic Pd content in the composite, enhances the combination of Pd nanoparticles with graphene, and produces more active sites. The Pd/N-P-G catalyst delivers a catalytic current density of 11.9 mA cm−2 in 1 M KOH with 1 M CH3OH at −0.2 V after the test duration for 3600 s, manifesting excellent electrocatalytic performance for methanol oxidation. These results may provide a new opportunity for the design of the Pd-based catalysts in the direct methanol fuel cells (DMFCs) technology.