Sol-gel synthesis of Au-doped TiO2 supported SWCNT nanohybrid with visible-light-driven photocatalytic for high degradation performance toward methylene blue dye

The present article reports a novel visible light-driven photocatalyst of TiO2/Au/SWCNT nano hybrid prepared by sol-gel approach and successfully assessed for the photocatalytic degradation of the organic methylene blue. TiO2/Au/SWCNT nanohybrid was obtained by doping titanium dioxide (TiO2) lattice with gold (Au) and supporting with modified single-walled carbon nano tubes (SWCNTs). All the synthesized samples showed anatase-structure TiO2 as evaluated by XRD. Morphological analysis based on FESEM, HRTEM and EDS revealed that the SWCNTs were successfully decorated with TiO2/Au nanoparticles. UV-vis absorption spectra exhibited increased absorption and higher photo response to the visible light range after being doped with Au and SWCNTs. Based on the results of photoluminescence (PL), the TiO2/Au/SWCNT nanohybrid exhibited lower recombination rate in comparison to the TiO2 and TiO2/Au nanohybrid, thus facilitated the charge generation. The photocatalytic activity of the synthesized samples was determined by decomposing MB dye under solar-simulated light. The pristine TiO2 and TiO2/Au binary nanohybrid suffered from low photodegradation efficiency and severe recombination problems. By supporting the TiO2/Au with SWCNTs scaffold, the photocatalytic efficiency of the TiO2/Au nanohybrid can be increased significantly. The improved photocatalytic performance of TiO2/Au/SWCNT can be associated to its high surface area, the excellent visible-light photosensitivity and the incorporation of Au and SWCNTs, which enhances the charge-carriers separation.