Platinum nanoparticles coated by graphene layers: A low-metal loading catalyst for methanol oxidation in alkaline media

Abstract Platinum catalysts play a major role in the large scale commercialization of direct methanol fuel cells (DMFC). Here, we present a procedure to create a nanostructural graphene-platinum (GrPt) composite containing a small amount (5.3 wt%) of platinum nanoparticles coated with at least four layers of graphene. The composite, as GrPt ink, was deposited on a glassy carbon electrode and its electrocatalytic activity in a methanol oxidation reaction (MOR) was evaluated in a 1 M CH 3 OH/1 M NaOH solution. The results indicated an enhanced catalytic performance of GrPt towards MOR in alkaline media compared with the Pt/C material. Electron energy-loss spectroscopy and X-ray photoelectron spectroscopy (recorded before and after the electrochemical assays) were employed to analyze the changes in the chemical composition of the nanomaterial and to explain the transformations that took place at the electrode surface. Our findings suggest that growing of graphene on platinum nanoparticles improve the catalytic performance of platinum-graphene composites towards MOR in alkaline media.