Pt−Ru/Carbon Fiber Nanocomposites:  Synthesis, Characterization, and Performance as Anode Catalysts of Direct Methanol Fuel Cells. A Search for Exceptional Performance

Six Pt−Ru/carbon fiber nanocomposites have been prepared by using a bimetallic precursor as a source of metal. Carbon fiber supports include singled-walled nanotubes, multiwalled nanotubes, or graphitic carbon nanofibers having either platelet, wide herringbone, or narrow tubular herringbone atomic structures. Preparative procedures have been optimized to enhance the performance of these nanocomposites as anode electrocatalysts in direct methanol fuel cells. Pt−Ru nanoparticles are the major metal-containing component of these nanocomposites along with variable amounts of Ru metal. A range of direct methanol fuel cell performance is observed with a Pt−Ru/narrow tubular herringbone graphitic carbon nanofiber nanocomposite showing the highest performance. This performance is equivalent to that recorded for an unsupported Pt−Ru colloid at an anode catalyst loading of 2.7 mg total metal/cm2, but 64% greater than that of the unsupported Pt−Ru colloid at a lower catalyst loading of 1.5 mg/cm2.