Determination of the Electronic Structure of Titania-Supported Metal Clusters*

Metal clusters are groups of metal atoms with sizes ranging between 2 and 100 atoms, possessing unique electronic and catalytic properties. This work aims to measure the valence electron density of states for titania-supported Ru₃ clusters using the complimentary techniques UPS and metastable induced electron spectroscopy (MIES), and XPS will be used to determine the elemental composition. Ru clusters have been shown to be among the most active catalysts for industry-relevant reactions such as CO hydrogenation.

Two approaches to cluster deposition will be compared. The first is vaporisation of ligand-protected Ru₃(CO)₁₂ clusters onto a titania substrate under ultra-high vacuum, and subsequent heat-removal of the CO ligands to leave the bare Ru₃. The second is using a size-selected, laser ablation cluster source to deposit bare Ru₃ directly onto the substrates. It is known that the properties of supported clusters can differ depending on the deposition method, however these two common methods have never been directly compared for these clusters.