Black TiO₂ samples with different concentrations of Ti³⁺ on the surface were fabricated by heat treatment in air. After heat treatment, the concentrations of Ti³⁺ on the surface of black TiO₂ samples decreased and a layered structure was not observed. Oxygen vacancies were demonstrated to be the origin of visible light absorption. Ti³⁺ oxidation on the surface of black TiO₂ samples caused the decrease of oxygen vacancies. In addition, black TiO₂ samples with different Ti³⁺ concentrations showed differences in visible light absorbance, band gap, fate of photogenerated electrons, and photocatalytic activity. The optimum concentration of Ti³⁺ for achieving is shown to be the highest photocatalytic activity under the irradiation of visible light.

通过在空气中热处理制备了表面上具有不同浓度的Ti ^3+的黑色TiO ₂样品。热处理后，黑色TiO ₂样品表面上的Ti ³⁺浓度降低，未观察到层状结构。氧空位被证明是可见光吸收的起源。黑色TiO ₂样品表面的Ti ³⁺氧化导致氧空位的降低。此外，具有不同Ti ^3+的黑色TiO ₂样品浓度显示出可见光吸收率，带隙，光生电子的命运以及光催化活性的差异。在可见光的照射下，实现Ti ³⁺的最佳浓度是最高的光催化活性。