Alternative structure of TiO2 with higher energy valence band edge
  We propose an alternative structure of TiO2 anatase that has a higher energy oxygen p-like valence band maximum than the pristine TiO2 anatase and thus has a much better alignment with the water splitting levels. This alternative structure is unique when considering a large subspace of possible structural distortions of TiO2 anatase. We propose two routes towards this state and argue that one of them might have been realized in the recently discovered so-called black TiO2. 
Sinisa Coh and Peter Y. Yu and Yuta Aoki and Susumu Saito and Steven   G. Louie and Marvin L. Cohen
cond-mat.mtrl-sci