Abstract |
Visible light-responsive ZnO-graphene-TiO2 (ZGT) composite catalyst was successfully synthesized via a simple solvothermal process. The intrinsic characteristics of as-obtained samples were examined using a variety of techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDS). The band gap energies of the samples were evaluated by UV-vis diffuse reflectance spectroscopy (UV-vis DRS). The photocatalytic activities of as-obtained catalysts were assessed based on the degradation of rhodamine B (RhB), texbrite BAC-L (TBAC) and texbrite NFW-L (TNFW) under visible-light irradiation. ZGT exhibited higher visible-light-activated photocatalytic activity than did other samples (ZGT (7.97x10-4 min-1) > ZG (3.43x10-4 min-1) > graphene (2.43x10-4 min-1) > TiO2 (2.22x10-4 min-1) > ZnO (1.87x10-4 min-1)). In addition, ZGT showed higher enhanced photocatalytic degradation of RhB than did other dyes (RhB (7.97x10-4 min-1) > TNFW (5.20x10-4 min-1) > TBAC (2.48x10-4 min-1)). It is therefore evident that the synthesized ZGT can be used as a high performance catalyst for dye wastewaters. Moreover, the detailed photocatalytic mechanism of the photodegradation process is discussed. |