Radiolysis-Driven Evolution of Gold Nanostructures – Model Verification by Scale Bridging in situ Liquid-Phase Transmission Electron Microscopy and X-ray Diffraction

Formation and degradation of gold nanostructures in tetrachloroauric acid (HAuCl4) is comprehensively investigated via in situ liquid-phase transmission electron microscopy (LP-TEM). By introducing a novel technique to simulate arbitrary kinetic models for radiochemistry, we provide a holistic understanding of reaction mechanisms in irradiated HAuCl4 solutions, allowing for quantitative prediction and tailoring of redox processes in LP-TEM experiments. It is demonstrated that no experimentally relevant threshold for gold reduction during LP-TEM exists and that radiation-induced metal-ion reduction is relevant even for experiments utilizing X-rays such as X-ray diffraction (XRD). Furthermore, we unveil that oxidative etching of gold nanoparticles depends on both, precursor concentration, and dose rate. This dependency is harnessed to probe the electron beam-induced shift in the Gibbs free energy landscape by analyzing the critical radius of gold nanoparticles.