Oxygen Vacancies Inhibiting Photoactivity on TiO2
In a recent scanning tunneling microscopy (STM) study, out of two active sites on trimethyl-acetic-acid-dosed Ti02, the reaction readily occurs at regular Ti sites but is completely inhibited at oxygen vacancy (Vo) defects.
This inertness at Vo is due to excess unpaired electrons there since they promptly recombine with incoming photoexcited holes. It is not due to
the less active adsorption coefficient or electron transfer from Vo (as shown by density functional theory and electron energy loss
spectroscopy). This effective “screening” is site specific and spatially confined, affecting most on Vo sites and less so at adjacent Ti sites.
(Based on: Z.-T. Wang, et al., Phys. Rev. Lett. 109 266103 (2012))
For more information, please contact: Dr. Linda Olafsen 254-710-2541