Photobleaching of pollutant dye catalyzed by p-n junction ZnO-CuO photocatalyst under UV-visible light activation

The p-n junction ZnO/CuO nanocomposite photocatalysts are prepared via the copreripitation route. The detailed structural, compositional and optical characterization and physico-chemical properties of the obtained products are analyzed by X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), photoluminscience spectra (PL) and electron spin resonance (ESR) spin-trapping techniques. The experimental results showed that the absorption wavelength range of the ZnO/CuO nanocomposite was notably extended towards the visible-light region (400-500 nm). The photocataltic activity of the ZnO/CuO nanocomposite was evaluated based on the decomposition of by methyl orange (MeO) in aqueous solution under UV-vis light irradiation. The photocatalytic activity of ZnO/CuO nanocomposite is found much better than of bare ZnO photocatalyst under the identical conditions. Factors influencing photocatalytic activity and the mechanism of photocatalysis reaction were also addressed.