Determining Quantitative Kinetics and the Structural Mechanism for Particle Growth in Porous Templates

Understanding the formation of nanoparticles and how they are influenced by a support is critically important for optimizing their activity. In situ pair distribution function (PDF) methods were used to probe the kinetics, mechanism, and energetics for Ag nanoparticle formation in a porous zeolite. The nanoscale structure detail and fast time resolution possible using the PDF method allows the separate processes of cation reduction, cluster formation, and nanoparticle growth to be distinguished, a multistep mechanism delineated, and rate constants and activation energies estimated for reduction and surface diffusion steps. Importantly, these insights are derived for the gas–solid phase reactions directly relevant to industrial processes.