Facile Synthesis of r-GO@Pd/TiO2 Nanocomposites and Its Photocatalytic Activity Under Visible Light.

Reduced Graphene Oxide Wrapped Pd/TiO2 (r-GO@Pd/TiO2) which exhibited high photocatalytic activity under visible light was synthesized from commercial chemicals. The classic sol-gel method and the Ar gas bubbling composition was used in the preparation of the catalyst. Furthermore, the best Pd-doping concentration in crystals, the wrapping concentration of r-GO over nanoparticles, and the optimal calcination temperature were investigated to enhance the photocatalytic activity of the hybrid catalyst. The experimental results showed that the catalytic efficiency of r-GO@Pd/TiO2 reached maximum value at the optimum synthesis conditions: 0.7 wt% Pd-doped TiO2 by sol-gel process, calcination temperature of 550 °C, 1 mg of GO for 100 .gram wrapped Pd/TiO2. X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM) techniques were conducted to determine the nanostructure of the catalysts. The average crystallite size of nanoparticles was 14 nm with perfect dispersion of Pd dots and wraps of r-GO membrane. Methyl Blue was used as an organic dye model to test the ability in wastewater treatment of the catalysts. A comparison between different catalysts' characteristics was also studied. The r-GO@Pd/TiO2 showed a higher photocatalytic activity compared to Pd/TiO2 and commercial P25. Additionally, the complete dye reduction under visible light excitation indicated that wrapping r-GO round Pd/TiO2 improved the photocatalytic activity of catalysts. The determination of the stability of r-GO@Pd/TiO2 showed that its photocatalysis was persistent over several times of recycling examination. Therefore, r-GO@ Pd/TiO2 in wastewater treatment.