| AVS 61st International Symposium & Exhibition | |
| Surface Science | Tuesday Sessions |
| Session SS+NS-TuA |
| Session: | Nanostructures: Growth, Reactivity and Catalysis |
| Presenter: | Phillip Sprunger, Louisiana State University |
| Authors: | M.C. Patterson, Louisiana State University P.T. Sprunger, Louisiana State University J.R. Frick, Louisiana State University Y. Xu, Louisiana State University B.F. Habenicht, University of California Merced R.L. Kurtz, Louisiana State University L. Liu, Texas A&M University |
| Correspondent: | Click to Email |
We have studied the nucleation and growth of Au clusters at sub-monolayer and greater coverages on the h-BN nanomesh grown on Rh(111) by means of scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT). STM reveals that sub-monolayer Au deposited at 115 K nucleates within the nanomesh pores and remains confined to the pores even after warming to room temperature. Whereas there is a propensity of mono-atomic high islands at low temperature, upon annealing, bi- and multilayer Au clusters emerge. Deposition of higher coverages of Au similarly results in Au confined to the nanomesh pores at both 115K and room temperature. XPS analysis of core-level electronic states in the deposited Au shows strong final-state effects induced by restricted particle size dominating for low Au coverage, with indications that larger Au clusters are negatively charged by interaction through the h-BN monolayer. DFT calculations suggest that the structure of the Au clusters transitions from monolayer to bilayer at a size between 30 and 37 atoms per cluster, in line with our experiment. Bader charge analysis supports the negative charge state of deposited Au. Using vibrational EELS, CO and O2 are used to probe the activity of these gold model catalysts.