Application of Gold(III) Acetate as a New Precursor for the Synthesis of Gold Nanoparticles in PEG Through Ultrasonic Spray Pyrolysis

The present investigation reports the first-time successful synthesis of AuNPs using a new precursor salt of Au(III) acetate through USP. An aqueous solution of this salt was prepared with very limited solubility with H2O. HCl and HNO3 were then added separately to increase the solubility, resulting in a clear, yellowish solution. This enabled the successful formation of AuNPs with USP. In order to improve AuNPs synthesis, NaOH and Na2CO3 were added into the precursor to increase its pH (6–7). With such approach, it was possible to perform USP synthesis using varying concentrations of [Au] in the precursor. Evaporation and reaction temperatures (100 and 300 °C) of USP were chosen based on detected decomposition temperatures of Au(III) acetate with TGA-DT. TEM confirmed the presence of circular shaped, unagglomerated AuNPs having an Fm-3m space group with diameter range of 15–30 and circularity value range of 0.89–0.92. The UV–Vis spectroscopy showed absorbance peaks at 528 and 532 nm. ICP-MS indicated the highest concentration of AuNPs, 79 ppm, by the precursor with the lower initial concentration of [Au]. This could be due to the smallest sedimentation and turbulent losses of larger AuNPs in transport tubes and reaction USP zones.