Synthesis of anatase TiO 2 with exposed {001} and {101} facets and photocatalytic activity

Anatase titanium(IV) oxide (TiO 2 ) particles with exposed {001} and {101} facets were prepared by hydrothermal treatment of amorphous TiO 2 with H 2 O 2 –NH 3 solution. Crystal phase, shape, and size of TiO 2 particles are found to be greatly dependent on the ratio of H 2 O 2 –NH 3 solution. The prepared TiO 2 particles with specific exposed crystal faces show higher photocatalytic activity for acetaldehyde decomposition than commercial spherical TiO 2 particles. This result implies that recombination is prevented by spatial separation of redox sites in the particles because of selective migration of electrons and positive holes to specific exposed crystal faces and/or different reactivity of electrons and positive holes on the specific exposed crystal face.