GROWTH, SURFACE CHARACTERIZATION, AND REACTIVITY OF TIO2 ANATASE FILMS-EPSCOR

TiO2 is as promising photocatalyst for environmental degradation of organic compounds and solar energy conversion. Commercial titania is a mixture of rutile and anatase phases, and, for as of yet unknown reasons, anatase is the photocatalytically more active form. In contrast to rutile, atomic-scale information on well-characterized anatase surfaces and their chemical properties was virtually absent at the beginning of this project. We have performed surface science investigations of anatase with the goal to understand, and ultimately control, the surface chemistry underlying its diverse applications. We have of (1) characterized all main crystallographic surface orientations of anatase, namely the (101), (100), (001), and (103) surfaces (2) have investigated the influence of surface imperfections such as defects and steps; (3) have investigated the influence of dopants on epitaxial (001) anatase films; and (3) have investigated the chemical and adsorption and reaction processes of simple molecules (water and methanol) on anatase surfaces. The experiments were performed in collaboration with Pacific Northwest National Laboratory (PNNL) using a variety of complementary surface science techniques. They have lead to a thorough characterization of this model system and have provided a more complete understanding of TiO2, which could possibly lead to improved efficiency in of photocatalytic applications.