Platinum nanodendrites

Nanoscale globular platinum dendrites were synthesized by chemical reduction of platinum complexes with ascorbic acid in aqueous micellar solutions. The dendritic platinum nanostructures can be reproducibly prepared on a gram scale, allowing their characterization by N-2 adsorption as well as transmission electron microscopy (TEM), cross-section TEM, scanning TEM (STEM), scanning electron microscopy (SEM), and x-ray diffraction (XRD). Because of the high surface area, these nanoporous Pt dendrites have potential applications as catalysts and electrocatalysts. Control over the size of these platinum dendrites was realized by seeding their autocatalytic growth at the beginning of the reaction either by addition of platinum nanoparticles or by growing the seed particles using a porphyrin photocatalyst. The results support a mechanism based on dendritic growth from the seeds by an autocatalytic metal-reduction reaction occurring at the surface of the platinum dendrites rather than a mechanism based on formation of nanoparticles that subsequently aggregate.