Visible-light-activated Zn-MOF-5/g-C3N4/Fe3O4 nanocomposites: synthesis, structure and application in photodegradation of three dyes†

In this work, a facile solvothermal approach was used to synthesize a ternary nanocomposite for photocatalytic performance, based on a novel MOF-5/g-C₃N₄/Fe₃O₄ (MGF). The development of an effective heterostructured nanocatalyst composed of MOF-5/g-C₃N₄ (MG) anchored with Fe₃O₄ nanoparticles is presented. The proposed research revealed that the novel composite had a higher sunlight-active photocatalytic performance (95% in 90 min) against rhodamine B dye degradation. The structure and optical properties of the generated photocatalysts were studied using XRD, FTIR, N₂ adsorption–desorption, diffuse reflectance spectroscopy, and photoluminescence. The photocatalytic degradation was investigated using the nanocomposites in aqueous solution under solar irradiation. The three tested dyes have the following order of degradation efficiency: rhodamine B > methylene violet > coriacide black MR. The optimized heterojunction improves charge separation and photocatalytic activity. The ternary nanohybrid (MGF) exhibited a greater photocatalytic efficacy for the degradation of rhodamine B compared to both single and binary nanocomposites and the excitation wavelength was shifted from the ultraviolet to the visible spectrum. The MGF heterostructures exhibited potential performance in visible light because of their low bandgap and decreased electron–hole recombination rate. The scavenger experiment verified that the superoxide radicals, holes and hydroxyl radicals successfully triggered the rhodamine B photodegradation process. Therefore, MGF is a dependable visible-light sensitive heterostructure photocatalyst capable of efficiently separating and transporting photoinduced electrons and holes.