LAUSR

Bi-doped TiO2 photocatalysts were synthesized by sol with a high-pressure hydrothermal method and developed for the photocatalytic degradation of formaldehyde under the visible light irradiation and ambient temperature. According to characterization, some Bi-doped TiO2 can be transformed into the distinctive crystals phase of Bi4Ti3O12, which was crucial for improving activity. The excess Bi2O3 doping into TiO2, such as Bi2O3–N/TiO2 and Bi2O3–C/TiO2, generated a mixed oxides with Bi2O3 and Bi4Ti3O12, was not beneficial to increase the activity of HCHO oxidation, whereas Bi3+/TiO2 composed of TiO2 and Bi4Ti3O12 displayed a higher activity with good stability. It is noteworthy that Bi3+/TiO2 didn’t show the lowest binding energy. However, it exhibited a lower PL intensity, higher adsorption, and activity due to the uniform particulates, high surface areas, and the strong interaction between TiO2 and Bi4Ti3O12, attributing to create superoxide radical anion (.O2−) and hydroxyl radical (.OH). The present results of Bi3+/TiO2 indicated that HCHO could be effectively oxidized from 1.094 to 0.058 mg/m3 (94.7%) under visible light irradiation within 36 h. The current research made effort to draw out the existing state of Bi, which can be better, Bi3+ or Bi2O3, doped in the TiO2.