Enhanced photocatalytic activity for degradation of ofloxacin and dye by hierarchical flower-like ZnS/MoS2/Bi2WO6 heterojunction: Synergetic effect of 2D/2D coupling interface and solid sulfide solutions

Abstract

To strengthen the photocatalytic degradation of antibiotics and organic dyes, the band structure engineering serves as an efficient approach, which can be realized by constructing heterostucture photocatalysts. Herein, 0D/2D/2D ZnS/MoS2/Bi2WO6 (ZMB) hierarchical flower-like microspheres were smoothly prepared via in-situ growth of Bi2WO6 nanoparticles on ZnS/MoS2 surfaces. The results illustrated that the content of Bi2WO6 played a crucial role in regulating the photocatalytic activity of ZMB heterostructures. ZMB-7 showed a better degradation capacity compared to ZnS/MoS2 and other ZMB composites, and the degradation rates of ofloxacin (OFL) and rhodamine B (RhB) respectively reached 98.5% and 91.1% under light illumination. The enhanced photocatalytic activity could be attributed to the large specific surface, improved separation of photogenerated carriers, as well as rapid charge transfer by combining the advantage of 2D coupling interfaces generated from MoS2/Bi2WO6 and composition-controlled band gap in solid sulfide solutions. On the basis of active species trapping experiments and HPLC-MS tests, a possible photocatalytic mechanism and gradation pathway for OFL were further proposed. The ternary ZnS/MoS2/Bi2WO6 heterojunction with enhanced photocatalytic activities in the work may have vital applications for environmental purification owing to its synergistic effects between composition and microstructure.