Dodecanethiol-Stabilized Platinum Nanoparticles Obtained by a Two-Phase Method: Synthesis, Characterization, Mechanism of Formation, and Electrocatalytic Properties

Abstract

Dodecanethiol-stabilized platinum nanoparticles of less than 3 nm have been synthesized for the first time through a modified two-phase liquid-liquid route. The H 2 PtCl 6 precursor was transferred from water to toluene using tetra-n-octylammonium bromide, followed by the addition of dodecanethiol. Results obtained by Raman spectroscopy, X-ray absorption near edge structure (XANES), and extended X-ray absorption fine structure (EXAFS) indicate a reaction between the platinum precursor and the thiol, resulting in a Pt(II)-stable complex that cannot be reduced by sodium borohydride. The Pt nanoparticles were obtained by the reduction of the platinum precursor before the introduction of dodecanethiol. The time interval at which the dodecanethiol was added to the reaction was used to control the size of the nanoparticles. The formation of dodecanethiol-stabilized Pt nanoparticles with fcc structure and average diameter of 1.7, 2.2 and 2.4 nm was confirmed by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffractometry, transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), XANES, and EXAFS. All of the obtained nanoparticles were electrocatalytically active for methanol oxidation, and the differences in catalytic activity between different samples were related to the size and morphology of the nanoparticles.

Synthesis, Characterization and Catalytic Activity of Binary PtMn/C Alloy Catalysts towards Ethanol Oxidation

“…The signal at 71 eV is due to zero-valent Pt 4f5/2 32 and the signal at 74.5 eV is ascribed to zerovalent Pt4f7/2. 33 Fig. 2 also depicts that the peak intensities decreases as the Pt content in the PtMn/C catalysts increases, consistent with the alloys composition determined by ICP and EDX.…”

Ferromagnetism Exhibited by Nanoparticles of Noble Metals

“…[20] The Brust method was also used to prepare dodecanethiol-capped Pt and Ag nanoparticles. [21,22] Au nanoparticles without any strong capping agent were obtained by photochemical reduction without using any reducing agent. [23] For this purpose, HAuCl 4 ·3 H 2 O solution (10 À4 m) in water (10 mL) containing 5 mL of acetone and isopropyl alcohol was exposed to UV irradiation for 30 min and particles were allowed to settle.…”

Functionalized platinum nanoparticles with surface charge trigged by pH: synthesis, characterization and stability studies

“…However, an efficient separation of the colloid from solution could be difficult to reach [19]. Among the synthetic approaches, wet chemical synthesis offers the opportunity to introduce a selected functionalization onto the NP surface and generally give rise to monodisperse nanoparticles [20–21]. …”