Efficient photodegradation of Axetine in distilled and tap water by ZnO and CuOx/ZnO films on glass and ITO substrates

In this work, ZnO and CuOx/ZnO sol-gel films are synthesized and employed as photocatalysts for ultraviolet irradiation. The synthesis procedure is straightforward and eco-friendly, based on the photo-fixation of CuOx ions onto ZnO films via UV illumination for the first time. Photofixation involves surface functionalization through photodeposition using ultraviolet light. Utilizing the dip-coating technique, ZnO and CuOx/ZnO films are deposited on indium tin oxide (ITO) and glass substrates. The photocatalytic efficiency of the newly developed films is assessed through the degradation of Axetine in distilled and tap water. Sol-gel films on ITO demonstrate greater photocatalytic efficiency compared to those on glass substrates. Differences in surface morphology, interfacial lattice mismatch, charge transfer, and crystallinity can account for the variations in film efficiencies. Furthermore, the formation of acceptor levels in the ZnO band gap enhances the efficiency of separating photogenerated electron-hole pairs, explaining the broadening of the spectral range of CuOx/ZnO irradiation into the visible region. CuOx enhances photoactivity by generating the hyperactive oxygen radical O₂^•–. Additionally, after three cycles of use, all four types of sol-gel films maintained their photocatalytic activity, indicating their potential usefulness in the treatment of pharmaceutical wastewater.