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

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.