PREPARATION OF NANOSCALE PLATINUM(0) CLUSTERS IN GLASSY-CARBON AND THEIR CATALYTIC ACTIVITY

We have found that the incorporation of platinum at the molecular level in carbon precursors, poly(phenylene-1,3-diacetylene) and poly(1,2,3,5-tetrafluorophenylene-1,3-diacetylene), followed by thermolysis at relatively low temperatures (600-degrees-C), results in the formation of conductive, dimensionally stable carbon matrices containing nanoscale crystalline platinum particles. The size of the clusters generated in the carbon solids can be controlled by the platinum loading level in the carbon precursors. The platinum clusters possess a narrow size distribution with average diameters from 8 to 19 angstrom. The exchange current density of the materials for the hydrogen evolution reaction correlates with the number of vertex sites for the clusters with the highest efficiency found for the smallest clusters. The materials also exhibit excellent catalytic activity for the reduction of dioxygen with a response similar to that found for polycrystalline platinum.