Facile Synthesis of Catalytically Active Platinum Nanosponges, Nanonetworks, and Nanodendrites

Abstract

Facile synthesis: Pt nanosponges, nanonetworks, and nanodendrites (see figure) are synthesized through a unique galvanic replacement reaction between Te nanowires and PtCl(6) (2-) ions in the presence of sodium dodecyl sulfate. The three Pt nanomaterials all have large active surface areas and highly electrocatalytic activities for the oxidation of methanol.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 PtCl(6) (2-) ions via galvanic replacement reactions with Te nanowires (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 >50 mM, respectively. Transmission electron microscopy images revealed that these Pt NMs were all composed of one dimensional Pt nanostructures having widths of 3.0+/-1.0 nm and lengths of 17.0+/-4.8 nm. Cyclic voltammetry data indicated that the as-prepared Pt nanonetworks, nanosponges, and nanodendrites possessed large electrochemically active surface areas (77.0, 70.4, and 41.4 m(2) g(-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.