Supported Bimetallic Dendrimer Templated Nanoparticles

2 Catalysis by Supported Bimetallic Dendrimer Templated Nanoparticles 

The ambient temperature catalytic activity of the PtAu catalyst was subsequently attributed to surface Au atoms and higher temperature activity attributed to surface Pt. Further studies with these catalysts supported on other oxides (alumina, titania) 

In contrast to homogeneous hydrogenations (the PdAu system is most similar), incorporation of Cu into Pt nanoparticles had a substantial poisoning effect on toluene hydrogenation catalysis Pt [36], As Table 4.4 shows, catalytic rates, which were normalized per total mole of Pt, drop by more than two orders of magnitude as the Cu content of the particles increases. This also contrasts with heterogeneous CO oxidation studies for the same catalysts, which showed enhanced activily upon Cu incorporation. The disparate catalysis data were interpreted in terms of a surface enrichment in Cu under the hydrogenation reaction conditions, driven by the lower heat of sublimation of Cu [36, 97, 98]. 

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H. Lang, S. Maldonado, K.J. Stevenson, B.D. Chandler, Synthesis and Characterization of Dendrimer-Templated Supported Bimetallic Pt-Au Nanoparticles, Journal of the American Chemical Society 126, 12949, 2004. 

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