Rapid photo-degradation of 2-chlorophenol under visible light irradiation using cobalt oxide-loaded TiO2/reduced graphene oxide nanocomposite from aqueous media.

The photocatalytic removal of 2-chlorophenol (2-CP) from water environment was investigated by TiO 2 –RGO–CoO. Cobalt oxide-loaded TiO 2 (TiO 2 –CoO) supported with reduced graphene oxide (RGO) was synthesized using a sol–gel method and then annealed at 500 °C for 5 min. The material characteristics were analyzed by UV–Vis analysis, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy. Incorporation of cobalt oxide and RGO into the TiO 2 system (TiO 2 –RGO–CoO) lowered the band gap energy to 2.83 eV, which greatly enhanced the visible light absorption. The TiO 2 –RGO–CoO photocatalyst showed complete removal of 20 mg/L 2-CP within 8 h with the addition of 0.01% H 2 O 2 under 100 W visible light irradiation. The photo-degradation efficiency of 2-CP (10 mg/L) was 35.2, 48.9, 58.9 and 98.2% for TiO 2 , TiO 2 –RGO, TiO 2 –CoO and TiO 2 –RGO–CoO, respectively, in the presence of visible light irradiation at solution pH of 6.0. The TiO 2 –RGO–CoO photocatalyst retained its high removal efficiency even after five photocatalytic cycles. [ABSTRACT FROM AUTHOR]