Synthesis and Characterization of CNT/TiO2/ZnO Composites with High Photocatalytic Performance

Novel carbon nanotubes (CNTs)/titanium dioxide (TiO2)/zinc oxide (ZnO) composites have been successfully synthesized via a two-step solution method using titanyl sulfate as the titanium precursor. Its structural performances were researched by various characterization methods, such as X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-vis diffuse reflectance spectroscopy (UV-vis DRS). The performance of the composites was tested by degrading rhodamine B (RhB) under UV-vis illumination and found to strongly rely on the content of ZnO. The experimental results showed that the CNT/TiO2/ZnO-90 wt % expressed more outstanding photocatalytic performance compared to the corresponding binary composites and the CNT/TiO2/ZnO-85 wt %, CNT/TiO2/ZnO-95 wt % materials. The improved photocatalytic activity was attributed to synergistic effect of CNT, TiO2 and ZnO, in which ZnO can absorb photons to produce electrons and holes, whereas TiO2 and CNT can reduce the electron-hole recombination.