2008 NSTI Nanotechnology Conference and Trade Show - Nanotech 2008 - 11th Annual

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TechConnect Summit
Clean Technology 2008

One-Step Flame-Synthesis of Carbon-Embedded and -Supported Platinum Clusters

F.O. Ernst, R. B├╝chel, R. Strobel, S.E. Pratsinis
ETH Zurich, CH

Keywords:
platinum, catalysts, carbon black

Abstract:
Carbon-embedded or -supported Pt-clusters were made by a scalable, single-step flame spray pyrolysis (FSP) process. Pt-containing precursors was dissolved in xylene and sprayed and combusted in a controlled oxidation atmosphere resulting in nanostructured, carbon-embedded Pt-clusters. Combustion of xylene alone and subsequent addition of Pt-precursor downstream of the flame (onto the freshly-made carbon particles) led to carbon-supported Pt-clusters. Both carbon-embedded and -supported Pt-clusters possessed the self-preserving size distribution of aerosols grown by coagulation in the free-molecular regime. This indicates that homogeneous gas-phase formation rather than a heterogeneous pathway is present. These carbon-supported Pt-clusters exhibited catalytic activity comparable to the literature for hydrogenation of cyclohexene, highlighting the potential of flame technology for rapid and scalable synthesis of nanocomposite Pt/C particles. The produced particles had specific surface areas ranged from 25 to 200 m2/g for well dispersed Pt-clusters. Carbon-embedded Pt-clusters (2 - 5 nm) were not accessible and inactive as catalysts for hydrogenation of cyclohexene. In contrast, carbon-supported Pt-clusters (5 - 15 nm) were active hydrogenation catalysts demonstrating the accessibility of their Pt surface.


Nanotech 2008 Conference Program Abstract