Advanced gC3N4/ZnCuFe2O4 composite photocatalysts for effective methylene blue degradation

Abstract In this study, a gC₃N₄/Zn₀.₅Cu₀.₅Fe₂O₄ composite photocatalyst was synthesized to evaluate its efficacy in degrading methylene blue (MB) dye under visible light. The photocatalyst, prepared using mechanical milling techniques, demonstrated enhanced photocatalytic performance due to the synergistic effects of its components. The degradation efficiency for MB was measured at 95.41% with the 1g1ZCF composite (1:1 weight ratio of gC₃N₄ and Zn₀.₅Cu₀.₅Fe₂O₄) under Xenon lamp irradiation for 90 min. The corresponding reaction rate constant was calculated as 0.03174 min⁻ 1 , outperforming the pristine Zn₀.₅Cu₀.₅Fe₂O₄ and 2g1ZCF composites, which achieved degradation rates of 89.2% and 92.16%, respectively. The structural, morphological and optical properties of the synthesized samples were investigated by characterization techniques such as XRD, FESEM, FTIR and UV–Vis spectroscopy. XRD analyses revealed that the ZnCuFe₂O₄ nanoparticles exhibit a cubic spinel structure. FESEM investigations demonstrated that the gC₃N₄ nanosheets are uniformly coated with clustered ZnCuFe₂O₄ nanoparticles. The EDS spectra of the nanocomposites confirmed the presence of Zn, Cu, Fe, and O elements. Furthermore, an examination of colour tone changes indicated a noticeable reduction in the yellowness index of the samples upon the incorporation of gC₃N₄.The composites exhibited reduced bandgaps, with values of 1.92 eV for 1g1ZCF compared to 2.32 eV for pure Zn₀.₅Cu₀.₅Fe₂O₄. The material's recyclability was evaluated over five cycles, maintaining significant activity with a slight decrease attributed to catalyst loss. This work highlights the potential of gC₃N₄/Zn₀.₅Cu₀.₅Fe₂O₄ composites as efficient and recyclable photocatalysts for wastewater treatment applications, providing a promising solution to mitigate environmental pollution from dye contaminants.