Single-Crystal Nanowires of Platinum Can Be Synthesized by Controlling the Reaction Rate of a Polyol Process

Abstract

Platinum nanowires of approximately 100 nm in length and approximately 5 nm in diameter have been synthesized by reducing H(2)PtCl(6) with ethylene glycol in the presence of poly(vinyl pyrrolidone) (PVP) and a trace amount of Fe(3+) or Fe(2+). The wires were generated at the final stage of the synthesis, which involved the formation of several intermediate species. The Fe(3+) or Fe(2+) ions had dual functions in the synthesis: they induced aggregation of Pt nanoparticles into larger structures that served as the nucleation sites, and they greatly reduced the reaction rate and supersaturation level to induce anisotropic growth. The reaction mechanism was studied by X-ray photoelectron spectroscopy (XPS) and UV-vis spectral analysis. The Pt nanowires could be readily separated from the surfaces of the agglomerates by sonication and obtained as pure samples by centrifugation.

Nanostructured Pt-alloy electrocatalysts for PEM fuel cell oxygen reduction reaction

“…The same approach was also used to affect the growth rate of nucleation along the h100i axis by adding Ag + into the reaction solution. 116 Sea-urchin-shaped Pt nanostructures were obtained by a polyol process in air at 110 1C, 90 with the help of a trace amount of Fe 2+ (or Fe 3+ ) in the solution to control the thermodynamics and kinetics of the reduction reaction. The other examples for such controlling synthesis are the formation of Pt nanotetrapods, 117 Pt nanowires ( Fig.…”

“…The other examples for such controlling synthesis are the formation of Pt nanotetrapods, 117 Pt nanowires ( Fig. 13(a)), 90 and nanoflowers ( Fig. 13(b)), 106 by adding Fe 3+ or gaseous species such as N 2 or H 2 into the reaction solutions.…”

Recent Advances in the Liquid‐Phase Synthesis of Metal Nanostructures with Controlled Shape and Size for Catalysis

“…Single-crystal nanowires of platinum of ,100 nm in length and ,5 nm in diameter have been synthesized by reducing H 2 PtCl 6 with ethylene glycol in the presence of PVP and a trace amount of Fe 3+ or Fe 2+ (104). The iron ions had dual functions in the synthesis: they induced aggregation of Pt nanoparticles into larger structures that served as the nucleation sites, and they greatly reduced the reaction rate and supersaturation level to induce anisotropic growth.…”

Phase diagrams of microemulsions containing reducing agents and metal salts as bases for the synthesis of metallic nanoparticles

“…Different mechanisms were suggested for the role of the added modifying element, namely (a) adsorption of the alcohol molecules on Pt and oxygen derivatives generated from the decomposition of water on the added element (for example Pb, Sn) [11][12][13], (b) "ligand effect" (electronic interaction of the added element with Pt which changes the adsorption energy of the adsorbate on Pt) [14], and (c) homogeneous catalytic reactions which was confirmed by the presence of complexed cations of the added element in the reaction media [12,15]. Hence, because of their expected specific catalytic activities and selectivities, intermetallic (nano)particles synthesized by different techniques [16][17][18][19] are gaining in importance. For example, Abruna and co-workers [20,21] have prepared Pt/Pb intermetallic phases by heating metals to ca.…”