The synthesis of nanoparticles is generally carried out by chemical reduction, which is effective but uses a number of toxic substances, making the process potentially harmful to the environment. Thus, as part of the search for environmentally friendly or green synthetic methods, this chapter aimed to present the synthesis of gold nanoparticles (AuNPs) using only HAuCl4, Milli-Q water, white light from a xenon lamp, and amino acids. A total of 21 amino acids were studied, and the shapes and sizes of the resultant nanoparticles were evaluated. The products were characterized by ultraviolet-visible (UV-Vis) and fluorescence spectroscopy, zeta potential measurements, and transmission electron microscopy. The synthesis of the AuNPs was successful with 18 amino acids, and the best results were obtained with aspartic acid, arginine, threonine, tryptophan, and valine. The nanoparticles were spherical and their sizes ranged from 5 to 100 nm. Changes in pH were required to improve the stability of the colloidal suspensions.
Part of the book: Catalytic Application of Nano-Gold Catalysts