Mesocrystal nanosheet of rutile TiO ₂ and its reaction selectivity as a photocatalyst

Mesocrystal nanosheet of rutile TiO ₂ has been synthesized in an aqueous solution in the absence of any organic molecules at room temperature. In general, it is not easy to tune the morphologies of rutile crystals in two-dimensional structures. The rutile nanosheets 10 nm in thickness and 200-600 nm in width consisted of the oriented nanocrystals 2-3 nm in size. The unit rutile nanocrystals were surrounded by the combination of the (101) and (110) faces or the (111) and (110) faces. Compared to the single crystalline nanosheet, different crystal faces can be exposed on the surface. In addition, a higher specific surface area was achieved on the nanosheet with a mesocrystal interior. The introduction of substrates and a titanium source TiCl ₃ facilitates the formation of the mesocrystal nanosheets in aqueous solution. The oxidation-preferred face of (111) or (101) and the reduction-preferred face of (110) can be exposed on the surface of the nanosheets. The oxidation reaction preferentially proceeded on the photocatalytic decomposition of an organic dye.