Abstract

Fast, time-resolved pair distribution function (PDF) methods were applied in situ, to probe the mechanism and kinetics of supported gold nanoparticle formation. The PDF provides quantitative details on how the population and structure of different species evolve throughout the reaction. By fitting reaction models to the changes in species concentration, the reaction mechanism can be identified, with measurements at multiple temperatures allowing an estimation of the apparent activation energy. Here, for the formation of Au nanoparticles supported on γ-Al₂O₃, we find that the reaction follows a zeroth-order reaction mechanism with an activation energy of ∼73 kJ mol^–1.