| AVS 55th International Symposium & Exhibition | |
| Surface Science | Tuesday Sessions |
| Session SS-TuP |
| Session: | Surface Science Poster Session |
| Presenter: | P.J. Riedel, University of Wyoming |
| Authors: | P.J. Riedel, University of Wyoming J. Zhou, University of Wyoming |
| Correspondent: | Click to Email |
Ceria-supported Pt nanoparticles are widely used in many important applications, including three-way automobile emission-control catalysis and fuel cells owing to the peculiar redox properties and oxygen storage capacity of ceria as well as the synergistic effect between the Pt and ceria. Previous chemistry studies using XPS and TPD in the literature have demonstrated that the reactivity of ceria-supported Pt nanoparticles is dependent on the cerium oxidation state. To elucidate the nature of their reactivity, we investigated their structure and morphology using STM. Reducible CeOx(111) thin films were grown in situ on Ru(0001) under ultrahigh vacuum conditions. Our data demonstrate that surface structures of ceria thin films are dependent on the degree of ceria reduction. Fully oxidized CeO2(111) film exhibits a fairly low density of point defects due to the formation of oxygen vacancies. However, the number of surface defects increases as the ceria film is reduced. Pt particles were vapor-deposited onto ceria thin films at 300 K. The growth of Pt particles was investigated by STM as a function of metal coverage, post-deposition annealing temperatures, as well as Ce oxidation state, which were further compared to the growth of Rh and Pd. The research is sponsored by the start-up fund at the University of Wyoming and the Wyoming NASA Space Grant.