title: Adsorption-site-dependent electronic structure of catechol on the anatase TiO2(101) surface.
abstract: The adsorption of catechol (1,2-benzendiol) on the anatase TiO(2)(101) surface was studied with synchrotron-based ultraviolet photoemission spectroscopy (UPS), X-ray photoemission spectroscopy (XPS), and scanning tunneling microscopy (STM). Catechol adsorbs with a unity sticking coefficient and the phenyl ring intact. STM reveals preferred nucleation at step edges and subsurface point defects, followed by 1D growth and the formation of a 2 × 1 superstructure at full coverage. A gap state of ∼1 eV above the valence band maximum is observed for dosages in excess of ∼0.4 Langmuir, but such a state is absent for lower coverages. The formation of the band gap states thus correlates with the adsorption at regular lattice sites and the onset of self-assembled superstructures.
authors.affiliation: Department of Physics and Engineering Physics, Tulane University , New Orleans, Louisiana 70118, United States.
authors.forename: Shao-Chun
authors.initials: SC
authors.lastname: Li
authors.forename: Yaroslav
authors.initials: Y
authors.lastname: Losovyj
authors.forename: Ulrike
authors.initials: U
authors.lastname: Diebold