Fabrication of ZiF-8 metal organic framework (MOFs)-based CuO-ZnO photocatalyst with enhanced solar-light-driven property for degradation of organic dyes

Abstract

In this study, CuO-ZnO/ZiF-8 was successfully synthesized with different percentages of ZiF-8 Metal-organic Framework (MOF) via ultrasound assisted precipitation method. The physic-chemical properties of the samples were studied by XRD, FESEM, EDX, BET-BJH, FTIR, DRS, and pH pzc techniques. The results showed that the CuO-ZnO/ZiF-8 (20) sample possesses high photocatalytic activity with 98.1% removal of 80 ppm AO7 in 100 min. It could be attributed to the increases the surface area, the pore volume, and pore diameter, as well as efficient homogenous distribution of active sites due to the use of ultrasound irradiation. Furthermore, the presence of ZiF-8 increases light absorption and reduces the recombination rate of electron-hole pairs. • Successfully synthesis of CuO-ZnO/ZiF-8 by ultrasonic assisted precipitation method. • Promising physicochemical and optical properties of the synthesized nanocomposites. • High photocatalytic activity of CuO-ZnO/ZiF-8 (20) (98.1% degradation of AO7) • Investigation of the effective operating parameters on AO7 photodegradation performance. In this research, novel CuO-ZnO/ZiF-8 metal–organic frameworks (MOFs) photocatalyst with different mass percentages of ZiF-8 were prepared for water purification applications under visible light. The precipitation method was used to synthesize CuO-ZnO/ZiF-8 photocatalysts. Some techniques, including XRD, FESEM, EDX, BET-BJH, FTIR, DRS, and pH pzc, were performed to determine the structural, chemical, and optical properties of the prepared samples. DRS analysis represented that CuO-ZnO/ZiF-8(20) had narrower band gap energy compared to CuO-ZnO and ZiF-8. Also, BET-BJH analysis results showed that CuO-ZnO had a low surface area that impeded the absorption of pollutant molecules. In contrast, the CuO-ZnO/ZiF-8(20) sample, due to the presence of ZiF-8, had a high specific surface area which enabled higher pollutant adsorption on the photocatalyst surface. Moreover, the synthesized samples were evaluated for the solar-light-driven removal of different organic dyes, such as Acid Orange 7, Methylene blue, and Malachite green. The tremendously enhanced photocatalytic activity under the simulated solar light with 98.1% removal of AO7 was observed over CuO-ZnO/ZiF-8(20) sample. Then, the effect of initial solution pH as an essential factor on photocatalytic activity was investigated. Finally, the reaction mechanism of AO7 degradation over CuO-ZnO/ZiF-8(20) was proposed.