| AVS 55th International Symposium & Exhibition | |
| Surface Science | Tuesday Sessions |
| Session SS-TuP |
| Session: | Surface Science Poster Session |
| Presenter: | J.S. Ratliff, University of South Carolina |
| Authors: | J.S. Ratliff, University of South Carolina J.B. Park, University of South Carolina S.A. Tenney, University of South Carolina S.F. Conner, University of South Carolina D.A. Chen, University of South Carolina |
| Correspondent: | Click to Email |
Pure Pt, pure Au, and bimetallic Pt-Au clusters were deposited on TiO2(110) at room temperature and studied with scanning tunneling microscopy, low energy ion scattering, and temperature programmed desorption. Pt forms smaller clusters with higher cluster densities than Au for the same metal coverage. Bimetallic Pt-Au clusters were formed by seeding Au at existing Pt clusters. The growth of Au on Pt seed clusters was confirmed by a decrease in cluster density upon dosing Au onto 0.25 monolayers (ML) of Pt. For the growth of Au on Pt seed clusters, the average cluster size increases and cluster density decreases with increasing Au coverage. Low energy ion scattering spectroscopy confirms that both Pt and Au are at the surface of the clusters, even at 300K. Carbon monoxide was used to probe the activity of the bimetallic clusters. With a constant total metal coverage, CO desorption scales linearly with the Pt percentage. Upon dosing increasing amounts of Au onto 0.25ML of Pt, CO desorption decreases but does not reach zero, even with 3ML of Au, suggesting that CO may be able to pull Pt to the surface of the clusters. CO2 production from bimetallic clusters exposed to O2 prior to CO exposure decreases much more rapidly with increasing Au coverage than does CO desorption due to decreased number of Pt surface sites for O2 dissociation.