Improved electrochemical performances by carbon nanocapsules as an electrocatalyst support for direct methanol fuel cells

The carbon nanocapsules (CNCs) were evaluated as a catalyst support for direct methanol fuel cells (DMFC). The gas diffusion electrodes (GDE) of CNCs exhibited smaller pores, higher electrochemical surface areas, lower charge transfer resistances, and reduced resistivities as compared to those of Vulcan XC72R (VXC72R). The observed superiorities were attributed to their narrow size distributions and graphene layers on the perimeters. In addition, binary PtRu nanoparticles were synthesized and impregnated to the CNCs and VXC72R. The images from the transmission electron microscope indicated that the PtRu nanoparticles were dispersed better in the CNCs, resulting in relatively reduced particle sizes and greater uniformity. In cyclic voltammery, the PtRu/CNCs catalyzed GDEs revealed significantly larger current responses with lower onset potentials as compared to those of PtRu/VXC72R. Our results confirm the superb characteristic of CNCs as an electrocatalyst support for DMFC applications. (c) 2008 Elsevier B.V. All rights reserved.