Magnetic Separable Bi2Fe4O9/Bi2MoO6 Heterojunctions in Z-Scheme with Enhanced Visible-Light Photocatalytic Activity for Organic Pollutant Degradation

Abstract

A magnetic Bi2Fe4O9/Bi2MoO6 heterojunction was synthesized by a facile one-pot solvothermal method, and the photodegradation performance was evaluated by degrading methylene blue (MB) and tetracycline hydrochloride (TC). Compared with pure Bi2MoO6 composite, the Bi2Fe4O9/Bi2MoO6 heterojunction with 10% Bi2Fe4O9 had much higher catalytic performance, which can degrade MB and TC completely within 150 and 180 min. The characterization results show that a p–n heterojunction formed between Bi2Fe4O9 and Bi2MoO6. Combining with trapping experiments, a direct Z-scheme mechanism was proposed to effectively separate photodegradable electron–hole pairs at the Bi2Fe4O9/Bi2MoO6 heterojunction interface. Moreover, the obtained catalysts can be recovered easily from liquid system via the external magnet field due to the sufficient magnetism. After five recycles, no significant decrease on the degradation efficiency of MB and TC can be found show that BiFeMo-2 has excellent chemical stability in the application of organic pollutants degradation under visible-light irradiation. Thus, the prepared Bi2Fe4O9/Bi2MoO6 catalyst has the advantages of high visible light catalytic activity, excellent chemical stability and magnetic separation, and has broad application prospects in environmental purification. A novel magnetic recoverable Bi2Fe4O9/Bi2MoO6 catalyst was facilely prepared. BiFeMo-2 sample showed a higher activities for MB and TC photodegradation under visible-light irradiation due to formation of a p–n heterojunction with high quality interface between Bi2Fe4O9 (220) and Bi2MoO6 (131), which can improve charge transfer effectively follow the Z-scheme mechanism.