A Pt-Ru/graphitic carbon nanofiber nanocomposite exhibiting high relative performance as a direct-methanol fuel cell anode catalyst

Multistep deposition and reactive decomposition of a precursor molecule containing one Pt and one Ru atom on herringbone graphitic carbon nanofibers (GCNFs) affords a Pt-Ru/GCNF nanocomposite containing Pt-Ru alloy nanoclusters widely dispersed on the GCNF support. The nanocomposite has a total metal content of 42 wt % with a bulk Pt/Ru atomic ratio of ca. 1:1, and metal alloy nanoclusters having average particle sizes of 6 nm as calculated from XRD peak widths or 7 nm as measured directly from TEM images. XRD and electrochemical analysis of the nanocomposite as-prepared and stored under ambient conditions reveals the presence of small amounts of Ru metal and oxidized metal species. Comparative testing of this nanocomposite and an unsupported Pt-Ru colloid of similar surface area and catalyst particle size as anode catalysts in a working direct-methanol fuel cell (DMFC) reveals a 50% increase in performance for the Pt-Ru/GCNF nanocomposite. More detailed study of the catalytic performance of metal alloy/GCNF nanocomposites as DMFC anode catalysts appears to be warranted.