Bi ₂ O ₃ ‐Modified Rice‐Like Brookite TiO ₂ for Enhancing the Photocatalytic Activity under Visible‐Light Irradiation

Abstract

Abstract Brookite TiO 2 is a metastable crystalline phase, which is difficult to prepare manually. In this study, brookite TiO 2 with controllable morphology was synthesized by a simple hydrothermal method. The prepared brookite TiO 2 was a complete rice‐like granular particle with a smooth surface and sharp edges at the tip of both ends. And the diameter of an individual brookite TiO 2 was approximately 200 nm. Then, to improve the photocatalytic degradation performance of brookite TiO 2 , we prepared Bi 2 O 3 /brookite TiO 2 nanocomposites. After Bi 2 O 3 composite, the crystalline phase of brookite TiO 2 did not change, and still maintained high purity and crystallinity. The Bi 2 O 3 nanoparticles were dispersed on the surface of brookite TiO 2 , forming heterogeneous structures in close contact. The Bi 2 O 3 /brookite TiO 2 nanocomposite exhibited a significantly higher degradation rate of ofloxacin (20 mg L −1 ) under visible light (300 W Xenon lamp, λ ≥ 400 nm) compared to pure brookite TiO 2 . The photocatalytic activity of 5 mol% Bi 2 O 3 /brookite TiO 2 was the best, the degradation rate of OFX reached 90.7%. The enhancement of photocatalytic activity of Bi 2 O 3 /brookite TiO 2 nanocomposites was attributed to the formation of Bi 2 O 3 /brookite TiO 2 heterojunction, which accelerated the photogenerated charge‐hole separation. This study provided theoretical support for efficient photocatalytic degradation of pollutants.