Synthesis of Ba doped ZnO‐Al2O3 nanocomposite from layered double hydroxide structure and their photocatalytic activity for the degradation of caffeine

Abstract

In this research, BaCO3/ZnO‐Al2O3 nanocomposite photocatalyst at different amount of Ba (1, 3 and 5 wt%) was prepared from Zn‐Al‐CO3 layered double hydroxides precursors using ceramic process. A range of physicochemical techniques including X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) with energy dispersive X‐ray analysis (EDX), were employed to characterize the as‐prepared catalysts. The photocatalytic activity of the catalysts was evaluated for the photocatalytic degradation of caffeine as a model of pharmaceutical pollutant in aqueous solutions under UV irradiation. Detailed photocatalytic experiments based on the effects of dopant amount, irradiation time, catalyst dose, initial pH and reuse were performed and presented in this study. The enhancement of photocatalytic activity was strongly dependent on the Ba amount and adsorption process. The 1%Ba/ZnO‐Al2O3 sample with high adsorption capacity showed the highest photocatalytic activity with a degradation efficiency of 98.2% after 70 min of irradiation. It showed a significantly higher rate of degradation compared to undoped, pure ZnO and standard Degussa P‐25 titanium dioxide. The photocatalyst showed high stability after three regeneration cycles.

Keywords

• Ba/ZnO‐Al2O3
• Mixed metal oxides photocatalyst
• Photocatalytic property
• Caffeine degradation
• UV irradiation