| AVS 61st International Symposium & Exhibition | |
| Surface Science | Thursday Sessions |
| Session SS+TF-ThM |
| Session: | Organic Layers on Surfaces |
| Presenter: | Matthew Patterson, Louisiana State University |
| Authors: | M.C. Patterson, Louisiana State University M.F. DiTusa, Louisiana State University C.A. Thibodeaux, Louisiana State University RW. Hall, Dominican University of California O. Kizilkaya, Louisiana State University R.L. Kurtz, Louisiana State University E.D. Poliakoff, Louisiana State University P.T. Sprunger, Louisiana State University |
| Correspondent: | Click to Email |
We have examined the electronic structure of phenol on rutile TiO2(110) using angle resolved photoelectron spectroscopy (ARPES), electron energy loss spectroscopy (EELS), and density functional calculations on model phenoxy/TiO2 clusters. Previous electron paramagnetic resonance studies have shown that exposure of titania powder to phenol at 250°C results in the formation of environmentally persistent free radicals(EPFRs), which have lifetimes on the order of dozens of hours and have been shown to exacerbate negative health effects caused by particulate matter. The proposed chemisorption model of radical formation from aromatic species on metal oxides involves electron transfer from the adsorbed organic to the metal oxide, locally reducing the oxide. Resonant ARPES shows direct evidence of charge transfer from high-temperature adsorbed phenol to electronic states of TiO2 (110) usually associated with the accumulation of charge at surface oxygen vacancies, providing direct evidence of the hypothesized reduction mechanism. Electronic EELS reveals there is an associated decrease of phenol HOMO-LUMO gap. Electronic structure calculations using model phenoxy-TiO2 clusters give insight into the changes induced in the occupied molecular orbitals of the chemisorbed phenoxyl radical. Results will be discussed in light of other metal oxide systems