Titanium-containing metal-organic frameworks (MOFs) are known to perform light-promoted chemical transformations. Formation of these frameworks, accessed either natively or via transmetallation, can instill beneficial photocatalytic properties in previously photo-inert scaffolds. Band edge diagrams coupled with their density of states illustrate the persistent nature of the accessible titanium d-states at the conduction band edge, independent of linker identity. In essentially all of these Ti-containing frameworks, the valence band edge localizes on the organic component, permitting facile modulation of the band gap. In sum, the spatial separation of photogenerated excitons will be observed in both the native and titanium(IV)-substituted MOFs, and this exciton pair is useful in photocatalysis.
Abstract