Insight into the Novel Zif-8@ N-Cqds/Zif-67 Nanocomposite for Photocatalytic Degradation of Methylene Blue Under Visible Light Irradiation

摘要: In this work, a novel and stable composite of ZIF-8@ N-CQDs/ZIF-67 was synthesized using simple hydrothermal methods. The structural and morphological properties of the composite were investigated using FTIR, XRD, SEM, TEM, EDX, Zeta potential, and BET surface area characterization techniques. The ability of N-CQDs to improve the photocatalytic activity of ZIF-8@ ZIF-67 for the photodegradation of methylene blue (MB) using visible and solar light was tested. The photocatalytic degradation efficiency of the ZIF-8@ N-CQDs/ZIF-67 photocatalyst was higher than that of its individual complements. The composite exhibits higher light adsorption and charge separation capabilities than N-CQDs and ZIF-8@ ZIF-67. The degradation% of MB under visible light irradiation reached 94%(32 ppm) after 180 min, and the composite maintained its photoactivity after four cycles with a minimal decrease in the degradation efficiency. Also, the photocatalytic retained its high photocatalytic efficiency over a wide range of pH. This photocatalytic degradation efficiency enhancement can be attributed to the synergistic effects of the individual components and the narrow band gap energy of ZIF-8@ N-CQDs/ZIF-67 photocatalyst. Scavenging tests indicated that the free electrons (superoxide radicals) played a major role in the photodegradation of MB, which is followed by hydroxyl radicals and holes. Therefore, this work provides a new, stable, environmentally friendly, and highly effective photocatalyst for the treatment of various organic pollutants under visible light irradiation.