Synthesis of porous carbons having surface functional groups and their application to direct-methanol fuel cells

Pitch-based porous carbons having -SO₃H groups on their surfaces were synthesized by carbonization of mesophase pitch and then sulfonation of the resulting compounds. As-synthesized carbons were characterized by BET surface area analysis, pore volume analysis and XRD. The concentration of -SO₃H groups present on the carbons was measured by neutralization titration. PtRu nano-clusters were supported on the pitch-based porous carbons, and these electrocatalysts were used as anodic materials in a DMFC. Membrane-electrode assemblies prepared using these electrode materials showed an improved power density compared with a commercial 60% PtRu/Vulcan XC-72. This performance is ascribed to the higher ionic conductivity of the anode layer and the well exposed catalytic active sites.