LAUSR

TiO2 anatase nanoparticles have shown interesting properties as ultraviolet (UV) light photocatalysts for water and air remediation as well as for solar water splitting. Understanding the structural changes that take place during photocatalysis is critical to developing structure-reactivity relations for these applications. Oxygen vacancies are believed to play an important role in surface reactivity. The structure of TiO2 nanoparticles has been investigated with in situ atomic resolution transmission electron microscopy (TEM) [1,2]. In these experiments, a low electron flux was used to prevent structural damage, however, this results in a poor signal-to-noise ratio. Differentiating intensity fluctuations due to shot noise from fluctuations associated with defect-induced structural changes is crucial and challenging, and the interpretation of the point defect structure can only be accomplished through a detailed comparison with theory. Here, computational methods based on molecular dynamics (MD) and density functional theory (DFT) are employed to construct defect models of TiO2, which are employed in image simulations to interpret experimental observations.