“…30 Similarly, in Fe 3 O 4 a broad absorbance in the region between 200 and 700 nm is ascribed to a ligand to metal charge transition. 46 As anticipated, higher absorbance in the visible region is observed in all the heterostructured composites (FBV-1, FBV-2, and FBV-3), indicating the synergistic effect of both the components on photocatalytic activity. Importantly, the intensity of the visible light absorption increases with the Fe content in the composites due to the charge transfer transitions.…”