Rational Design of MIL‐88@BiFeO ₃ Nanocomposite for Enhanced Photocatalytic Degradation of Organic Dyes

ABSTRACT In this study, BiFeO 3 was modified with MIL‐88 to synthesize a novel heterojunction nanocomposite MIL‐88@BiFeO 3 using solvothermal method as a photocatalyst to accelerate the methylene blue (MB) dye degradation. The catalyst was investigated by X‐ray diffraction patterns (XRD), Fourier transform infrared (FT‐IR), energy dispersive X‐ray (EDX) analysis, and scanning electron microscopy (SEM). Detailed structural and microstructural characteristics indicate the fabrication of a heterojunction nanocomposite made up of BiFeO 3 nanoparticles and MIL‐88 nanorods. Using UV–visible spectroscopy, the sample's photocatalytic efficiency for the MB dye degradation was examined under solar light. The MIL‐88@BiFeO 3 heterojunction nanocomposite exhibits superior photocatalytic activity compared to pure MIL‐88 and BiFeO 3 , with a degradation rate of 82% after 60 min of exposure to solar light. The improved photocatalytic efficiency is further supported by MIL‐88@BiFeO 3 's greatest rate constant ( k = 0.01964 min −1 ). In the as‐synthesized MIL‐88@BiFeO 3 nanocomposite, the MIL‐88 framework and BiFeO 3 might function as effective oxidation and reduction sites, releasing non‐toxic byproducts for the mineralization of MB dye, such as superoxide (O 2 •− ) and hydroxyl (•OH) species. The dye system adopted a pseudo‐first‐order model based on degradation kinetics, and the Langmuir–Hinshelwood mechanism strongly supports this model. The synergistic interaction between MIL‐88 and BiFeO 3 explains the increased efficiency of MIL‐88@BiFeO 3 .