The effect of surfactant on sol-gel synthesis of CuO/TiO2 nanocomposites for the photocatalytic activities under UV-Visible and Visible Light illuminations

Effective and low-cost photocatalysts CuO/TiO2 nanocomposites have been prepared at room temperature by surfactant assisted sol-gel method using titanium (IV) isopropoxide and copper (II) nitrate as precursors. In the current work, surfactant like Hexadecyltrimethylammonium bromide had used in the sol-gel method to reduce agglomeration of CuO/TiO2 nanocomposites. The framework substitution of CuO in TiO2 nanostructure was established by various characterization techniques like XRD, TEM and HRTEM and the results confirmed that CuO and TiO2 bound one over the other and formed a heterojunction CuO/TiO2 nanocomposite nature. The optical properties revealed an extended tailing of the absorption edge toward the visible region upon CuO doping and CuO serves as electron reservoir by receiving electrons from TiO2, which suppresses the recombination of e−/h+ and transfers the received electron to split water, which results in enhanced photocatalytic activities. Concentration of CuO in the TiO2 nanostructure has been fine-tuned to improve the photocatalytic activities. The synergy between the CuO and TiO2 has an optimum for concentration of 0.5 wt% CuO/TiO2 nanocomposites. The optimized product has produced promising hydrogen evolution of 1634 µmol g-1 under illumination with a UV and visible light sources. The optimized product has shown promising photocatalytic degradation of Rhodamine B dye. The CuO/TiO2 nanocomposites also showed better photochemical reduction of Cr+6 in sunlight and UV lights sources.