Facile synthesis of catalytically active platinum nanosponges, nanonetworks, and nanodendrites

In this paper, we report a simple approach for the preparation of various porous Pt nanomaterials (NMs) in aqueous solution. Employing different temperatures and concentrations of sodium dodecyl sulfate (SDS), we obtained Pt nanosponges, Pt nanonetworks, and Pt nanodendrites from the reduction of PtCl₆^2- ions via galvanic replacement reactions with Te nano-wires (length: 879 nm; diameter: 19 nm). At ambient temperature, Pt nanosponges and Pt nanodendrites formed selectively in the presence of SDS at concentrations of < 10 mm and>50 mm, respectively. At elevated reaction temperatures, we obtained Pt nanonetworks and Pt nanodendrites in the presence of SDS at concentrations of <10 mm and >50mm, respectively. Transmission electron microscopy images revealed that these Pt NMs were all composed of one dimensional Pt nanostructures having widths of 3.0±1.0nm and lengths of 17.0± 4.8 nm. Cyclic voltammetry data indicated that the as-prepared Pt nanonet- works, nanosponges, and nanodendrites possessed large electrochemically active surface areas (77.0, 70.4, and 41.4 m²g^-1, respectively). For the electrocatalytic oxidation of methanol, the ratio of the forward oxidation peak current (I_f) to the backward peak current (I_b) of the Pt nanodendrites, nanosponges, and nanonetworks were all high (I_f/I_b = 2.88, 2.66, and 2.16, respectively). These three NMs exhibit greater electrocatalytic activities and excellent tolerance toward poisoning species for the oxidation of methanol when compared with the performance of standard Pt NMs.