High Degradation of Methylene Blue Using a New Nanocomposite Based on Zeolitic Imidazolate Framework‑8

• Published in: ACS omega 2021-10, Vol.6 (40), p.26210-26220
• Main Authors: Abd El Khalk, Amira Ahmed, Betiha, Mohamed Ahmed, Mansour, Ahmed Sadek, Abd El Wahed, Mohamed Gamal, Al-Sabagh, Ahmad Mohamad
• Format: Article
• Language: English
• ISSN: 2470-1343; 2470-1343
• DOI: 10.1021/acsomega.1c03195

The development of broad-spectrum ultraviolet- and visible-light photocatalysts constitutes one of the most significant challenges in the field of photocatalytic pollutant removal. Here, the efficiency of the directly prepared nitrogen-doped quantum zeolitic imidazolate framework (ZIF)-8-dot catalyst for the photocatalytic degradation of the methylene blue dye was reported. The prepared catalysts were characterized using Brunauer–Emmett–Teller, X-ray diffraction, ultraviolet–visible spectroscopy, photoluminescence spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy techniques. Under sunlight irradiation, the 1% nitrogen-doped quantum-ZIF-8-dot catalyst showed 75% photodegradation in half an hour and ≈93% photodegradation after 3 hours compared to ≈87% for the ZIF-8 metal–organic framework. The high performance of the 1% nitrogen-doped quantum-ZIF-8-dot catalyst was attributed to the synergism between the catalyst components, upconverted fluorescence property of nitrogen-doped quantum dots, and charge (electrons–holes) separation. The reactive radical test revealed that the hydroxyl radical was dominant. The step-scheme heterojunction mechanism for photocatalytic degradation was also deduced. The kinetic study through the photocatalytic isotherms revealed that the pseudo-first-order kinetic model can describe the reaction mechanism.