Diborane Interactions with Pt7/Alumina: Preparation of Size-Controlled Borated Pt Model Catalysts

Bimetallic catalysts provide the ability to tune catalytic activity, selectivity, and stability. Model catalysts with size-selected bimetallic clusters on well-defined supports offer a useful platform for studying catalytic mechanisms; however, producing size-selected bimetallic clusters can be challenging. In this study, we present a way to prepare bimetallic model (PtnBm/alumina) cluster catalysts by depositing size-selected Pt7 clusters on an alumina thin film, then selectively adding boron by exposure to diborane, and heating. The interactions between Pt7/alumina and diborane were probed using temperature-programmed desorption/reaction (TPD/R), X-ray photoelectron spectroscopy (XPS), low-energy ion scattering (ISS), plane wave density functional theory (PW-DFT), and molecular dynamic (MD) simulations. It was found that the diborane exposure/heating process does result in preferential binding of B in association with the Pt clusters. Borated Pt clusters are of interest because they are known to exhibit...