Publications

Energetics and Structure of Ag-Water Clusters Formed in Mordenite

Rimsza, Jessica R.; Chapman, Karena W.; Nenoff, T.M.

Zeolite-supported Ag0 clusters have broad applications from catalysis to medicine, necessitating a mechanistic understanding of the formation of Ag0 clusters in situ. Density functional theory (DFT) simulations have been performed on silver, water, and silver-water clusters in silica mordenite (Si-MOR), to identify the role of the confinement on the structure and energetics of Ag0 cluster formation. The most favorable binding energy in the 12-membered ring (MR) pore of the Si-MOR is a 10-15-atom Ag0 cluster. Computational pair distribution function (PDF) data indicates that the Ag0 and Ag0-H2O clusters formed in vacuum versus in Si-MOR exhibit structural differences. Additionally, when the Ag0 cluster is confined, the density decreases and the surface area increases, hypothesized to be due to the limiting geometry of the 12-MR main channel. An energetic drive toward formation of larger Ag0 clusters was also identified, with hydrated silver atoms generating higher energy structures. Overall, this work identifies mechanistic and structural insight into the role of nanoconfinement on formation of Ag0 clusters in mordenite.