TiO2 colloids were prepared via hydrolysis of 10 mM TiCl4 at 120 °C, followed by centrifugation to remove residues and particle aggregates. The supernatant was retained for use in photocatalytic experiments. GO was prepared via modified Hummers method.64 A diluted GO suspension of 0.1 mg/mL was prepared and irradiated with water-filtered white light from Xe lamp to promote photoreduction of GO to RGO. Photocatalytic experiments with TiO2 and RGO were carried out using white light from Xe lamp at 250 mW/cm2 after passing through a 10 cm water filter. A Cary 50 UV−visible absorption spectrophotometer was used to measure the changes in absorption. TiO2-RGO samples were irradiated in a 1 cm quartz cuvette with continuous bubbling of O2. Transmission electron micrographs were obtained using a FEI 300−80 Titan transmission electron microscope after dispensing one drop of solution over carbon grids.