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 photocatalysts 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.