Preparation and activity evaluation of n-p CuO/CeO2ZrO2 heterojunction photocatalyst for degradation of organic azo dye in wastewater under visible light irradiation

In this work, the auto solution combustion method was used to prepare p-CuO/n-CeO2ZrO2 with different concentrations of p-CuO, which was found to be an effective photocatalyst for degrading azo dye under visible light irradiation. To investigate the photocatalytic activity of p-CuO/n-CeO2ZrO2, nonbiodegradable azo dyes such as acid orange 7 (AO7) were chosen as the modal target. The catalyst was characterised using X-ray diffraction (XRD), EDS, SEM, XPS, BET, and UV-vis DRS. Under visible light irradiation, AO7 solution easily mineralized with existing p-CuO/n-CeO2ZrO2. Experiments were carried out to determine the adsorption potential of acid orange 7 on p-CuO/n-CeO2ZrO2 at different pH values. Using some radical scavengers to evaluate intermediates, a potential degradation pathway for photocatalytic degradations has been proposed. Under similar visible light conditions, the photodegradation rate of this azo dye catalysed by p-CuO/n-CeO2ZrO2 is much faster than that of n-type CeO2ZrO2. The photocatalytic activity of the sample with a p-n CuO/ CeO2-ZrO2 molar ratio of 0.021 was 35% higher than that of n-type CeO2ZrO2. The impact of pH on photocatalytic activity of the photocatalyst was also studied. At a pH of 3, acid orange 7 showed the most degradation.