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

Abstract

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.