Enhanced electrocatalyticperformance of Pt nanoparticles on triazine-functionalized graphene nanoplateletsfor both oxygen and iodine reduction reactions

Abstract

Platinum (Pt) nanoparticles were stably anchored on triazine-functionalized graphene nanoplatelets (TfGnP), which were prepared by a two-step reaction starting from carboxylic acid- (CGnP), acyl chloride- (AcGnP) and amide-functionalized graphene nanoplatelets (AfGnP). The resulting Pt nanoparticles on TfGnP (Pt/TfGnP) exhibited outstanding electrocatalytic activity with significantly enhanced stability compared with commercial Pt＆ndash;based catalysts for the oxygen reduction reaction (ORR) in fuel cells (FCs) and the iodine reduction reaction (IRR) in dye-sensitized solar cells (DSSCs). For the ORR in FCs, the onset and half-wave potentials of Pt/TfGnP in acidic conditions displayed greater positive shifts to 0.58 and 0.53 V, respectively, than those of the commercial Pt/C catalyst (0.57 and 0.52 V). For the IRR in DSSCs, Pt/TfGnP displayed a reduced charge transfer resistance (Rct) of 0.13 ＆Omega; cm2 at the CE/electrolyte interface. This value was much lower than the Pt CE of 0.52 ＆Omega; cm2. More importantly, Pt/TfGnP exhibited profoundly improved electrochemical stability in both the ORR and IRR compared to the Pt-based catalysts. The combination of extraordinary high electrocatalytic activity with stability could be attributed to the high specific surface area (963.0 m2 g＆ndash;1) and the triazine units of the TfGnP, respectively, which provided more active sites and stably anchored the Pt nanoparticles.