Synthesis of Gold Nanoparticles by Sonogalvanic Replacement in Sodium Polyacrylate Solutions

Synthesis of gold nanoparticles (AuNPs) by galvanic replacement with magnesium scrap in tetrachloroauric(III) acid and sodium polyacrylate solutions in an ultrasonic field (20 kHz) was studied. It was established that at concentrations of (0.1-0.4) mM H[AuCl4], stabilized AuNPs colloidal solutions with a red hue and an absorption maximum of 530…540 nm are formed. Studies have revealed that the formation of AuNPs occurs primarily through sonogalvanic substitution by magnesium and sonochemical reduction of gold from complex ions [AuCl4]-. The formation of spherical nanoparticles with a size range of 5…10 nm was established by TEM studies. In addition, the shape of the nanoparticles remains relatively consistent regardless of the gold precursor amount used or the sonogalvanic synthesis process duration. However, when the temperature is raised from 20 to 40 °C, the rate at which AuNPs are synthesized increases. At the same time, aggregation takes place with the formation of nanoparticles with sizes of 20…40 nm.