* Corresponding author. E-mail: (Y.S.) ysong@sandia.gov; (J.A.S.) jasheln@unm.edu. Sandia National Laboratories. University of New Mexico. § University of Georgia. 10.1021/nl0719123 CCC: $37.00 Published on Web 11/14/2007 2007 American Chemical Society
templating assemblies such as peptide tubes, surfactant micelles, multilamellar vesicles, unilamellar liposomes, and liposomal aggregates, with/without incorporated molecular photocatalysts, our group has successfully synthesized a series of platinum nanostructures with shape control, which include peptide-nanotube/nanoparticle composites,20 globular nanodendrites,21,22 flat dendritic nanosheets,22,23 foamlike nanospheres composed of convoluted dendritic sheets,22,23 and porous nanocages.24 Herein, we report the synthesis of platinum nanowire networks based on a modified phase-transfer method, similar to that originally developed by Brust et al. in the 1990s.25-27 Our approach is simple, environmentally friendly, and can be scaled up readily. Shape selectivity in this case relies on the formation of a network of wormlike micelles within an organic solvent phase that acts as a soft template for metal growth. On the basis of a templateless method, Ramanath and his co-workers28,29 have prepared Ag and Au nanowire networks via assembly of nanoparticles at water/toluene interface. However, this templateless strategy has not been shown to be capable of producing metallic nanowire networks other than Ag and Au. Using hard templates like the interconnected channels of mesoporous silica, similar platinum nanowire networks have been prepared by chemical30 and electrochemical deposition31,32 of platinum followed by the removal of the silica framework. However, these methods generally produce poor networks because of the
Figure 1. Illustration of the putative soft template with the wormlike micellar network formed inside droplets of chloroform on the left and the developed platinum nanowire networks formed by reduction of Pt complex within the template on the right. The emulsion system aids in providing mass transport of Pt complex and reductant into the wormlike micelles.

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