Platinum nanoparticles (PtNPs) are prepared from an aqueous
H2PtCl6 solution using the sodium citrate method
and supported on single-heteroatom-doped (S, N, and P) and dual-heteroatom-doped
(N–S and N–P) graphene. The influence of the support
of the electrocatalytic activity of PtNPs toward the oxygen reduction
reaction (ORR) is investigated to assess their suitability as cathode
materials for proton exchange membrane fuel cells (PEMFCs). Physical
characterization of the catalysts proves that the PtNPs are evenly
dispersed onto the heteroatom-doped graphene supports and maintain
a size of 3–5 nm. The electrochemical results are obtained
in a 0.1 M HClO4 electrolyte solution. The results show
that the PtNPs supported on nitrogen and sulfur dual-heteroatom-doped
graphene possess the highest specific activity (SA) of 2.44 mA cm–2 at 0.9 V vs RHE, while the PtNPs supported on S-doped
graphene show the lowest SA of 0.91 mA cm–2. However,
both SA values are well beyond that of PtNPs supported on Vulcan carbon
(0.55 mA cm–2). Thus, the results obtained in this
work confirm that doping the support that the PtNPs are attached to
has a beneficial effect on the electrocatalytic activity toward ORR
in acidic media.