Oxygen Vacancy Induced Structural Distortions in Black Titania: AUnique Approach using Soft X-ray EXAFS at the O-K Edge

Unknown changes in the crystalline order of regular TiO2 result in the formation of black titania, which has garnered significant interest as a photocatalytic material due to the accompanying electronic changes. Herein, the nature of the lattice distortion caused by an oxygen vacancy was determined that in turn results in the formation of mid-band-gap states found in previous studies of black titania. An innovative technique is introduced using a state-of-the-art silicon drift detector, which can be used in conjunction with extended X-ray absorption fine structure (EXAFS) to measure bulk interatomic distances. Also discussed is how the energy dispersive nature of such a detector can allow for an unimpeded signal, indefinitely in energy space, thereby sidestepping the hurdles of more conventional EXAFS, which is often impeded by other absorption edges.