Synthesis of anatase TiO2 with exposed {001} and {101} facets and photocatalytic activity

Anatase titanium(IV) oxide (TiO2) particles with exposed {001} and {101} facets were prepared by hydrothermal treatment of amorphous TiO2 with H2O2-NH3 solution. Crystal phase, shape, and size of TiO2 particles are found to be greatly dependent on the ratio of H2O2-NH3 solution. The prepared TiO2 particles with specific exposed crystal faces show higher photocatalytic activity for acetaldehyde decomposition than commercial spherical TiO2 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.