ZIF-8 derived ZnO/Zn6Al2O9/Al2O3 nanocomposite with excellent photocatalytic performance under simulated sunlight irradiation

In this contribution, the ternary ZnO/Zn6Al2O9/Al2O3 nanocomposite was obtained by in situ incorporation of Al3+ during the synthesis of ZIF-8, aiming to improve the adsorption and photocatalytic performance of ZIF-8-derived ZnO under simulated sunlight irradiation. XRD, SEM, TEM, HRTEM, XPS, UV-vis DRS, BET and PL techniques were employed for the analysis of the crystalline structure, composition, morphology, light absorption and charge separation of the samples. The photocatalytic activity of the samples was evaluated by the degradation of methyl orange (MO) under simulated sunlight irradiation. Compared to ZIF-8-derived ZnO, the formation of the ZnO/Zn6Al2O9/Al2O3 nanocomposite can provide a high BET specific surface area, reduce the band gap, inhibit the recombination of the electron-hole pairs, and hence greatly improve the photocatalytic activity. The maximum photocatalytic degradation rate of 97.5% for a high initial MO concentration of 150 mg L-1 was obtained over the ZnO/Zn6Al2O9/Al2O3 nanocomposite with a 1:1 molar ratio of Al/Zn under simulated sunlight irradiation for 60 min, which is 3.18 times higher than that of ZIF-8-derived ZnO.