Rhodamine B degradation over visible light promoted Bi2WO6/Bi2W0.75Mo0.25O6 and Bi2MoO6/Bi2W0.75Mo0.25O6 heterostructures: DFT and photocatalytic studies

In the recent past, the dye degradation through semiconductor photocatalysis under visible light has drawn the widespread attention. In this view, visible active (1-x)Bi2WO6/xBi2W0.75Mo0.25O6 and (1-x)Bi2MoO6/xBi2W0.75Mo0.25O6 (commonly 0.05 ≤ x ≤ 0.20 wt%) heterostructures prepared through a one-step hydrothermal process. These compounds were analyzed by XRD, FE-SEM, HRTEM, XPS, FT-IR, DFT, UV-Vis DRS and photoluminescence. In (1-x)Bi2WO6/xBi2W0.75Mo0.25O6, the 0.90Bi2WO6/0.10Bi2W0.75Mo0.25O6 heterostructure showed the highest photocatalytic activity in comparison with Bi2WO6 and Bi2W0.75Mo0.25O6. On contrary, all (1-x)Bi2MoO6/xBi2W0.75Mo0.25O6 heterostructures exhibited the less photocatalytic activity than that of Bi2MoO6. The analysis carried out on both heterostructures clearly demonstrated that (1-x)Bi2WO6/xBi2W0.75Mo0.25O6 is more active in comparison to (1-x)Bi2MoO6/xBi2W0.75Mo0.25O6. The radical trapping test was conducted for 0.90Bi2WO6/ 0.10Bi2W0.75Mo0.25O6 heterostructure, asserted that O2∙− and h+radicals were dominant species responsible for Rhodamine B (Rh B) photo-degradation. The estimated redox potentials of Bi2WO6, Bi2W0.75Mo0.25O6 establish the fact that the charge (e-/h+) migration between Bi2WO6 and Bi2W0.75Mo0.25O6 via Z scheme is accountable for the aggressive photocatalytic activity of Bi2WO6/Bi2W0.75Mo0.25O6 heterostructure. The plausible Z scheme mechanism of the generation of electron-hole pairs, charge transfer and also visible light-induced degradation of Rh B was proposed. © 2024 Elsevier GmbH