High‐yield Synthesis of Branched Gold Nanocrystals by a Sodium Diphenylamine‐4‐Sulfonate Reduction Process in Polyethylene Glycol Aqueous Solution

Abstract

For developing new excellent electrocatalysts toward methanol and oxygen, branched Au nanocrystals have been prepared in high yield by the reaction of HAuCl 4 and sodium diphenylamine-4-sulfonate in the presence of PEG (polyethylene glycol) at room temperature. When the amount of PEG was in the range of 1-3 mL, branched Au nanocrystals were all obtained, and the amounts of sodium diphenylamine-4-sulfonate and HAuCl 4 had no obvious effect on the morphology of gold nanocrystals. PEG molecules play an important role in the formation of branched gold nanocrystals. The nanocrystals were characterized by transmission electron microscopy (TEM), selected area electron diffraction, high-resolution transmission electron microscopy (HRTEM) and UV-Vis absorption spectrum. HRTEM research suggests that the tips of gold nanocrystals grow selectively in the [111] directions. The UV-Vis absorption spectrum displays two-separated surface plasmon resonance peaks.

Effect of Moisture on Mechanical Properties and Thermal Stability of Meta-Aramid Fiber Used in Insulating Paper

“…The free volume of a high molecular mass polymer has an important effect on the diffusion of small molecules. In this work, the Van der Waals radius of H 2 O in the meta-aramid fiber system was calculated using the hard-ball probe model [42], and the free volume of the water molecules was calculated from the Van der Waals radius. The calculated results are shown in Table 1.…”

Shape controlled synthesis of multi-branched gold nanocrystals through a facile one-pot bifunctional biomolecular approach

“…[23][24][25] There have been a few other literature reports on seedless approaches for nanostar synthesis. These include those prepared using stabilizers such as bis(p-sulfonatophenyl)phenylphosphine dihydrate dipotassium (BSPP), 26 polyethylene glycol (PEG), 27 polyvinylpyrrolidone (PVP), 17,28 lyotropic liquid crystal template, 22 hexadecylamine (HDA), 29 and a combination of AgNO 3 as shape directing agent and ascorbic acid as reducing agent. 30 Phenolic compounds having multiple hydroxyl groups (e.g.…”

Voltammetry and Flow Injection Analysis with Amperometric Detection for Sensitive Sodium Metamizole Determination on Glassy Carbon Electrode Modified with SWCNTs/Nafion

“…zole could be determined simply using the glassy carbon electrode. 23 However, obtained analytical signal was very low due to the low sensitivity of this electrode. In order to determine sodium metamizole on the trace level more sensitive method should be applied.…”

“…9 Nowadays various analytical procedures have been proposed to determinate sodium metamizole such as: spectrophotometry, 7,8 capillary electrophoresis, 9,10 UV, 11 chemiluminescence; 12,13 chromatography; 14,15 titrimetry, 16 flow injection analysis with amperometric, [17][18][19] bioamperomteric, 20 spectrophotometric 21,22,30 detection. So far in the literature several voltammetry methods were also described using: GC electrode, 23 carbon nanotube modified graphite-epoxy resin composite (GrEC) electrode, 24 platinum electrode coated with polymeric nickel-salen film, 3 carbon-paste electrode modified with N,N -ethylenebis(salicylideneaminato) oxovanadium(IV), 25 nano-riboflavin-modified glassy carbon electrode. Nevertheless some of these methods are expensive, time-consuming, low sensitive and require sample pretreatments.…”