MOF derived hierarchical α-Bi2O3-BiVO4-CuFe2O4 multijunction heterostructure with conjugated S-scheme charge mobilization: Photocatalytic decontamination study, toxicity assessment and mechanistic elucidation

A series of hierarchical α-BiO-BiVO-CuFeO multijunction heterostructure was designed by integrating one-pot MOF derived BiO-BiVO microrods with CuFeO nanosheets. The MOF-derived route afforded BiO-BiVO with interconnecting porous architecture. Comprehensive investigations revealed preservation of crystalline phases, optimal light harvesting ability, higher lifetime, large electrochemically active surface area and improved charge dynamics. The heterostructure efficiently performed the photo-degradation of potentially toxic and mutagenic mesotrione (MTE) herbicide with rates 6–12 times greater than the parent semiconductors. The photo-degraded end products displayed profoundly less acute toxicity, bioaccumulation factor and mutagenic nature than parent MTE as analyzed by QSAR protocol. The heterostructure was equally effective for complete photo-inactivation of bacteria within 60 min of irradiation. SEM, AFM height profile and confocal microscopic investigation provided crucial information about the photo-inactivation process. A conjugated S-scheme electron transfer mechanism was proposed based on detailed band structure analysis to elucidate the improved activity of the multijunction photocatalyst.