1 Department of Physics, Technical University of Denmark2 Theoretical Atomic-scale Physics, Department of Physics, Technical University of Denmark3 Experimental Surface and Nanomaterials Physics, Department of Physics, Technical University of Denmark4 Center for Atomic-scale Materials Design, Center, Technical University of Denmark
Understanding the nature of photogenerated carriers in a photocatalyst is central to understanding its photocatalytic performance. Based on density functional theory calculation we show that for TiO2, the most popular photo-catalyst, the electron hole self-trapping leads to band gap states which position is dependent on the type of surface termination. Such variations in hole state energies can lead to differences in photocatalytic activity among rutile and anatase surface facets. We find that the calculated hole state energies correlate with photo-deposition and photo-etching rates. We anticipated that our results can aid the design of more reactive photo-catalysts based on TiO2 and our approach can be utilized for other relevant photo-catalysts as well.
Energy and Environmental Science, 2012, Vol 5, Issue 12, p. 9866-9869