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 nanopartide 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.