Calcination-Induced Oxygen Vacancies Enhancing the Photocatalytic Performance of a Recycled Bi2O3/BiOCl Heterojunction Nanosheet

With the rapid development of industry, bismuth-based semiconductors have been widely used for the photocatalytic degradation of organic contaminants discharged into wastewater. Herein, a Bi2O3/BiOCl (BBOC) heterojunction was constructed with high photocatalytic activity toward Rhodamine B (RhB) in the first cycle of the photocatalysis test, while the photocatalytic performance was drastically reduced after repeated testing. The adsorbed RhB molecules occupying the facial active sites of BBOC contributed to the decline of photocatalytic activity. The spent BBOC can be reactivated by the decomposition of the adsorbed RhB and the introduction of oxygen vacancies during calcination under an air atmosphere. The BBOC thus recovered exhibited a superior apparent rate constant of 0.08087 min-1 compared with 0.05228 min-1 of pristine BBOC. This study provided an effective strategy to investigate the deactivation/activation mechanism of bismuth-based heterojunction photocatalysts.

Automated summary

In this study, a Bi2O3/BiOCl heterojunction with high photocatalytic activity was constructed. However, the photocatalytic performance decreased after repeated testing. The adsorption of RhB molecules on the active sites of BBOC was identified as the cause of the decline. The spent BBOC can be reactivated through calcination, leading to the recovery of its high photocatalytic activity.