Synergetic effects of Cu2O photocatalyst with titania and enhanced photoactivity under visible irradiation

Heterogeneous TiO₂/Cu₂O nanocomposite was synthesized for photocatalysis through surface impregnation in conjunction with the environmentally friendly soft chemical reduction strategy. The detailed structural, compositional, optical and photoelectrochemical properties of the obtained products are analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), photoluminescence spectra (PL) and electron spin resonance (ESR) spectroscopy techniques. Moreover, methyl orange (MO) dye was chosen as the probe molecule for evaluation of the photocatalytic activities of the samples under visible light (λ > 420 nm) irradiation. The experiments demonstrated that MO in aqueous solution was more efficiently photodegraded using TiO₂/Cu₂O composite photocatalysts than pure Cu₂O alone. This was attributed to the good crystallinity, wide visible-light absorption range, and the efficient electron-hole pair separation properties of the TiO₂/Cu₂O nanoheterostructures. In this photocatalyst, visiblelight- active Cu₂O component was used as a medium to absorb photons and convert them into photogenerated charges, and TiO₂ nanoparticles were used as charge collectors to transport the photoinduced charges. The TiO₂/Cu₂O hybrid material showed improved separation of photoinduced electron-hole pairs owing to the potential-energy differences between Cu₂O and TiO₂, and therefore exhibited enhanced photocatalytic activity.