Synthesis and Characterization of Alkoxide-Derived Pt Nanoparticles

Abstract

Identification of the species formed during the in situ reduction of hexachloroplatinic acid by sodium ethoxide, forming a Pt sol, is made. The solution phase is shown to consist of suspended metallic Pt nanoparticles (1-3 nm in diameter), acetaldehyde, and a Pt(II) species, identified by NMR and X-ray adsorption near-edge spectroscopy (XANES) to be NaPtCl3(C2H4), a sodium analogue of Zeise's salt [KPtCl3(C2H4)]. The NaPtCl3(C2H4) product exhibits greater stability in both ethanol and air than the conventional Zeise's salt, providing a means of storing the useful Zeise's anion [PtCl3(C2H4)-]. Electrochemistry, X-ray diffraction (XRD), and transmission electron microscopy (TEM) analyses have shown that the precipitate phase formed during the synthesis is composed solely of Pt particles approximately 6 nm in diameter and NaCl. Thermal gravimetric analysis/differential scanning calorimetry (TGA/DSC) showed that the color of the precipitate is an accurate gauge of the ratio of Pt to NaCl, with the lightest to darkest precipitates containing from 1% to 40% nanoparticulate Pt by mass, respectively. A comprehensive characterization of both phases formed has allowed us to propose a mechanism for the conversion of hexachloroplatinic acid to Pt nanoparticles.

Determination of Platinum in Plant Samples by Voltammetric Analysis

“…After applying more positive potential than À 0.200 V, the subsequent oxidation of the hydrogen atoms occurs during the anodic scan and the catalytic current of hydrogen -proportional to the concentration of platinum in the bulk solution can be observed (E p1 ). Such reactions were previously observed for different systems and other electrodes [42,55,56]. According to the data shown in Figure 1, the oxidation process which is proportional to Pt concentration can be seen at a potential about À 0.100 V. The further oxidation of Pt to oxides takes place at a potential about 0.900 V (E p2 ).…”

Optimization of Synthesis Parameters Employed during Pt Nanoparticle Formation by in situ Reduction

“…As can be seen in Table 1, contrary to the Type A synthesis, neither the Type B or C syntheses yielded a PPT. This latter observation is unsurprising, considering the absence of Na + in the Type B and C reactants and the proposed coprecipitation 14,15 of Pt with NaCl.…”

“…14,15 It was shown 14 that this alkoxide synthesis route results in the formation of metallic Pt nanoparticles (ca. 1-3 nm in diameter), which undergo sintering at higher temperatures.…”

Preparation of highly crystalline graphitic nanocarbon for the electro-oxidation of methanol

“…The Pt catalysts were prepared by a chemical reduction method using sodium ethoxide as the reducing agent [11,30]. The Pt precursor (H 2 PtCl 6 , Acros) and sodium ethoxide (Aldrich, NaOCH 2 CH 3 ) were dissolved in ethanol.…”

“…Because of the need for a high intrinsic electrocatalytic activity, Pt basedcatalysts are generally used as state-of-the-art catalysts on both anodes and cathodes [4,5]. A number of attempts have been made to improve fuel cell performance by increasing the surface area of the Pt particles, which can be achieved via the use of highly dispersed Pt [4][5][6][7][8][9][10][11].…”