K2TiO(C2O4)(2)-mediated synthesis of rutile TiO2 mesocrystals and their ability to assist photodegradation of sulfosalicylic acid in water

Flower-like rutile TiO2 mesocrystals were fabricated by a K2TiO(C2O4)(2)-mediated Ti-H2O2 interaction at 80 degrees C and under atmospheric pressure. Both thin films precipitated on the metallic Ti substrates and powders collected from the solutions were subjected to detailed characterizations of the nanostructures and photocatalytic performances. The Ti-H2O2 interaction at 80 degrees C resulted in arrays of hydrogen titanate nanowires on Ti substrates and the corresponding nanowires in the solution as well. With the additive of K2TiO(C2O4)(2), flower-like rutile TiO2 mesocrystals appeared via an oriented attachment self-assembly approach. The hydrogen titanate nanowires decomposed to anatase TiO2 nanowires when heated in air at 450 degrees C; whilst the rutile TiO2 mesocrystals remained unchanged upon the subsequent calcination. The photocatalytic activity of both thin films and powders after the calcination was evaluated by photodegradation of sulfosalicylic acid (SSA) in water under the UV light illumination. It was found that anatase favored the degradation of SSA rather than rutile; however, the larger specific surface area of mesocrystals, as well as the high charge separation rate inherent from their single crystal nature, compensated effectively the photocatalytic performance for the flower-like rutile TiO2 mesocrystals.