Tailored TiO₂(110) surfaces and their reactivity

Electron bombardment from a filament as well as voltage pulses from a scanning tunnelling microscope tip have been employed to modify the surface of TiO₂(110). Individual H atoms are selectively desorbed with electrical pulses of +3V from the scanning tunnelling microscope tip, whilst leaving the oxygen vacancies intact. This allows us to distinguish between oxygen vacancies and hydroxyl groups, which have a similar appearance in scanning tunnelling microscopy images. This then allows the oxygen vacancy-promoted dissociation of water and O₂ to be followed with the microscope. Electrical pulses between +5 and +10V induce local TiO ₂(110)1 × 2 reconstructions centred around the pulse. As for electron bombardment of the surface, relatively low fluxes increase the density of oxygen vacancies whilst higher fluxes lead to the 1 × 2 and other 1 × n reconstructions.