On the Importance of Fresh Stock Solutions for Surfactant-Free Colloidal Syntheses of Gold Nanoparticles in Alkaline Alcohol and Water Mixtures

A room temperature surfactant-free synthesis of gold nanoparticles in the size range 10–20 nm that only requires HAuCl4 as precursor, NaOH base, water solvent and a mono-alcohol such methanol or ethanol reducing agent, has recently been detailed. This approach is promisingly simple to obtain colloids stable for months. Here, it shown use fresh stock solutions base one key ensure formation small-sized nanoparticles. The need relatively freshly prepared does not appear be crucial syntheses using stabilizers and/or viscous solvents glycerol. possibly overlooked importance age solution might account limited interest date low viscosity mono-alcohols highlighted.