Mechanistic investigation of visible light driven novel La^sub 2^CuO^sub 4^/CeO^sub 2^/rGO ternary hybrid nanocomposites for enhanced photocatalytic performance and antibacterial activity

A facile approach for the synthesis of La2CuO4, CeO2, La2CuO4/CeO2 and novel La2CuO4/CeO2/rGO hybrid nanocomposites were demonstrated via solvothermal assisted homogeneous precipitation method. The surface morphology, phase and crystal structure of the synthesized materials were characterized by field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), High resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). The photocatalytic performance to oxidize a target pollutant RB160 dye and inactivation of bacteria in aqueous solution was investigated under the illumination of visible light. Absorption range and band gap energy were investigated by UV-vis diffuse reflectance spectroscopy (UV-vis DRS). The combination of rGO with La2CuO4/CeO2 nanocomposites leads to a better photocatalytic activity than other bare synthesized materials. Typically, 10 mg/l of RB160 could be almost completely oxidized in 150 min and 0.01 g/l of La2CuO4/CeO2/rGO, exhibiting a promising application of the photocatalyst in the degradation of aqueous organic pollutants. The efficiency of RB160 decomposition increased with increasing pH (5-11) and catalyst dosage (0.01-0.03 g/l), but it gets decreased with increasing initial RB160 concentration (10-30 mg/l) and from that the optimum condition for the better photocatalytic performance was identified. Furthermore, the antibacterial activity of La2CuO4/CeO2/rGO hybrid nanocomposite was also investigated by using two different bacteria in typical aqueous medium and the results were showed highly efficient visible light driven photocatalytic antibacterial activity. The enhanced photocatalytic and antibacterial activity of La2CuO4/CeO2/rGO is promising for the further application of visible light driven photocatalyst in polluted water treatment.