Rapid preparation of Pt-Ru/graphitic carbon nanofiber nanocomposites as DMFC anode catalysts using microwave processing.

Pt-Ru/graphitic carbon nanofiber (GCNF) nanocomposites have been prepared on two different GCNF supports, with the use of a bimetallic precursor as a source of metal and microwave processing for thermal treatments. Pt-Ru nanoparticles appear as the major metal-containing component of these nanocomposites along with variable trace amounts of Ru metal. Use of microwave heating permits rapid preparation of these nanocomposites and affords metal nanoclusters of nearly uniform size. The performance of these nanocomposites as anode electrocatalysts in direct-methanol fuel cells (DMFCs) is compared with that of unsupported Pt-Ru colloid at identical total metal loading. The Pt-Ru/narrow tubular herringbone GCNF nanocomposite shows DMFC performance comparable to that recorded for an unsupported Pt-Ru colloid.

Preparation of Pt-Re/Vulcan carbon nanocomposites using a single-source molecular precursor and relative performance as a direct methanol fuel cell electrooxidation catalyst.

Pt-Re/Vulcan carbon powder nanocomposites have been prepared with total metal loadings of 18 wt.% and 40 wt.% using a new non-cluster (1:1)-PtRe bimetallic precursor as the source of metal. Pt-Re nanoparticles having an average diameter of ca. 6 nm and atomic stoichiometry near 1:1 are formed. TEM, on-particle HR-EDS, and powder XRD data are consistent with the formation of Pt-Re alloy nanoparticles having a hexagonal unit cell with cell constants of a = 2.77 A and c = 4.47 A. A nanocomposite prepared at higher total metal loading under more rigorous thermal treatment also contains Pt-Re alloy nanoparticles having a fcc unit cell structure (a = 3.95 A). The precise dependence of Pt-Re nanocrystal structure on the thermal history of the nanocomposite specimen has not been investigated in detail. While these Pt-Re/carbon nanocomposites are active as anode catalysts in operating direct methanol fuel cells, the measured performance is less than that of commercial Pt-Ru/carbon catalysts and has marginal practical importance.