Activity and stability improvement of platinum loaded on reduced graphene oxide and carbon nanotube composites for methanol oxidation

A series of platinum nanoparticle-loaded carbon composites composed of reduced graphene oxide and multi-walled carbon nanotubes (rGO-CNT/Pt) was chemically synthesized at room temperature. The prepared catalysts were characterized using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The results confirm that rGO mixed CNT composites were successfully prepared with small and highly dispersed Pt nanoparticles on the composite supports. The cyclic voltammetry (CV) and chronoamperometry (CA) electrochemical measurements indicated that the composite carbon catalyst increased the intensity and stability for the methanol oxidation reaction (MOR). In addition, fewer carbon intermediate species were observed in the CO stripping experiment. The incorporation of CNTs into rGO decreases the agglomeration between rGO sheets and increases the active surface of dispersed Pt nanoparticles, resulting in the enhanced oxidation activity of the as-prepared electrocatalysts. The combined characteristics of the highly active Pt nanoparticles and potent electron transfer of the rGO-CNTs enable excellent methanol oxidation with high stability. Consequently, this hybrid carbon material is a good candidate for MOR catalysis, which can be applied to direct methanol fuel cells.