Lotus-bud like hexagonal ZnO/g-C₃N₄ composites for the photodegradation of benzene present in aqueous solution

This study used a one-pot paralysis approach to combine hexagonal ZnO lotus buds with graphitic carbon nitride (g-C₃N₄) nanosheets to create ZnO/g-C₃N₄ composites. For the purpose of investigating the charge carrier interface for photocatalytic improvement, ZnO/g-C₃N₄ composites in various molar ratios of ZnO and g-C₃N₄ were produced. X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy, ultraviolet–visible diffuse reflectance spectroscopy (UV-DRS), and electrochemical impedance spectroscopy (EIS) were used to investigate the coupling of the ZnO particles to the g-C₃N₄ nanosheets. For the degradation of benzene, pure ZnO, pure g-C₃N₄, and their composites were utilized. High purity ZnO with a clearly defined hexagonal wurtzite crystal phase was shown by elemental mapping and XRD patterns, and optical characteristics measured by UV-DRS, PL spectroscopy, and spectroscopy of electrochemical impedance (EIS). For the degradation of benzene, pure ZnO, pure g-C₃N₄, and their composites were employed. High purity and a clearly defined hexagonal wurtzite crystal phase were revealed by elemental mapping and XRD patterns for ZnO, and optical properties examined by UV-DRS, PL spectroscopy, and EIS revealed improved visible light absorbance with a substantially reduced electron-hole recombination rate. The prepared samples were applied to test the photodegradation of benzene in the presence of visible light. The 40 %ZnO/g-C₃N₄ sample shown the largest photocatalytic activity for the degradation among all the produced samples, with high stability up to five cycles. The combined photocatalyst and degradation mechanism were proposed as a Z-scheme.