In situ Study of Au Nanoparticle Growth in a Mechanochemical-Aging-Based Synthesis

As we strive to perform chemical transformations in a more sustainable fashion, inducing reactions through the absorption of mechanical energy has emerged as a highly successful approach. Due to the wide-ranging applications of gold nanoparticles (AuNPs), mechanochemical strategies have already been employed for their synthesis. However, we do not yet fully understand the underlying processes surrounding the gold salt reduction, nucleation and growth of AuNPs in the solid state. Herein, we present a mechanically activated aging synthesis of AuNPs, through a solid-state Turkevich reaction. Solid reactants are only briefly exposed to mechanical energy before being aged statically for a period of six weeks at different temperatures. The aging step grants a greater period of time to analyze the initial reduction and subsequent nanoparticle formation processes. During the aging period the reaction was monitored using a combination of X-ray photoelectron spectroscopy (XPS), diffuse reflectance spectroscopy (DRS), powder X-ray diffraction (PXRD) and transmission electron microscopy (TEM) to gain meaningful insights into the solid-state formation of gold nanoparticles.