Hierarchical TiO2 photocatalysts with a one-dimensional heterojunction for improved photocatalytic activities

Hierarchical TiO2 photocatalysts with a one-dimensional heterojunction were synthesized via a facile template-free hydrothermal method. The TiO2 photo- catalysts were flower-like microspheres with a 3 μm diameter. The base structure of the flower-like microspheres was a uniform nanowire with a 10 nm diameter. Anatase films were evenly coated onto the surface of the rutile TiO2 nanowires to form a one-dimensional core--shell base structure. This kind of one-dimensional heterojunction is conducive to the separation of charge carriers. In addition, the hierarchical TiO2 microspheres possessed a good mesoporous structure with a high specific surface area of 260 m2/g. Thus, the light scattering and utilization efficiency were improved in this structure. The photocatalysts exhibited better performance in both photocatalytic oxidation and reduction reactions. Moreover, the novel TiO2 photocatalysts displayed excellent stability in these reactions. This kind of hierarchical TiO2 structure has never been reported in the literature. The hierarchical structure and one-dimensional heterojunction were vital to the increase in quantum efficiency. Therefore, these hierarchical TiO2 photocatalysts have potential applications in the environmental and energy fields, such as in photocatalytic degradation, hydrogen production, Li-ion batteries, and dye-sensitized solar cells.