Fig. 1. The formation of a surface complex of TiO₂ and its implications: a and b, the possible adsorption sites of TMA onto the rutile (110) and anatase (101) surfaces of TiO₂; c, schematic (not to scale) of the band alignment of TMA onto the surface of Degussa P25 TiO₂; d, UV-visible absorbance spectroscopy of Degussa P25 TiO₂ and the complex between TMA and TiO₂.