Flower-like n-Bi2O3/n-BiOCl heterojunction with excellent photocatalytic performance for visible light degradation of Bisphenol A and Methylene blue

Abstract

In this work, the flower-like BB-3 (n-Bi2O3/n-BiOCl) heterojunction photocatalyst was reported for the first time to improve the photocatalytic performance under visible light irradiation. Firstly, a facile one-step stirring method was proposed to synthesize the BB-3 heterojunction at room temperature. The as-prepared BB-3 nanoflowers with the average diameter of 3 µm were assembled by nanoplates and nanoparticles. Secondly, the BB-3 heterojunction (97.03%) shows a superior photocatalytic performance than the pure Bi2O3 (9.9%) and BiOCl (14.18%) in the photocatalysis of Bisphenol A (BPA). And the enhanced factor could up to 25 and 30, respectively. Additionally, the BB-3 photocatalyzed degradation Methylene Blue (MB) (99.65%) with the degradation concentration of 20 mg/L in 60 min. The enhanced photocatalytic activity could be ascribed to the n-Bi2O3/n-BiOCl heterojunction, which enlarged the absorption region and facilitated the generation of built-in electric field. Therefore, the separation, generation, and migration of the photogenerated charge carriers could be significantly enhanced. The BB-3 heterojunction also possess high photocatalytic durability, which could maintain 86.54% and 97.99% photocatalytic ability in the degradation of BPA and MB after four photodegradation cycles, respectively. The active species trapping experiments indicated that the holes and superoxide radicals show dominant roles in photocatalysis. Last, the photocatalytic mechanism for the operation of n-n heterojunction was proposed, which would open up a new avenue for designing the other photocatalysts.