Preparation and Photocatalytic Performance of p-n Heterojunction Photocatalyst Bi 2 O 3 /TiO 2

The p-n heterojunction Bi 2 O 3 /TiO 2 catalysts with different mass ratios of Bi 2 O 3 were prepared by the sol–gel method. Under simulated solar irradiation, the photocatalytic degradation effects of Bi 2 O 3 , TiO 2 , and p-n heterojunction Bi 2 O 3 /TiO 2 on acid red 18 (AR18) were evaluated. The characterizations show that the diffraction peaks were all anatase phase and Bi 2 O 3 was evenly distributed on the surface of TiO 2 . With the increase of Bi 2 O 3 content, the band gap of the composites gradually decreased. When the dosage of catalyst (Bi 2 O 3 mass ratio was 10%) was 0.5 g/L and the initial concentration of dye was 50 mg/L, the photocatalytic experiment was carried out under a xenon lamp (500 W), the p-n heterojunction formed by Bi 2 O 3 and TiO 2 improved the performance of the photocatalyst and showed good catalytic performance under acidic conditions. Compared with TiO 2 and Bi 2 O 3 , when the mass ratio of Bi 2 O 3 was 10%, the photocatalytic degradation performance of the material was the best, and the degradation rate of AR18 could reach 99.76% after 210 min illumination.