Nature Inspired Biomimetic-Chlorophyll-Carbon Dot Decorated WS2/MIL-53(Fe) Nanocomposite for the Photocatalytic Degradation of Pharmaceutical Drugs

Abstract

In this study, an approach is used to emulate the principles of nature-inspired engineering for the photodegradation of antibiotics. A bioinspired photocatalyst of Chlorophyll-Carbon dots (Chl-CDs) decorated WS2/MIL-53(Fe) nanocomposite was synthesized via a facile hydrothermal method. The nanocomposite showed significantly enhanced visible light absorption due to the presence of Chl-CDs dots with excitation-dependent emission behavior, attributed to distinct surface states and functional groups. The average lifetime of photogenerated electron-hole pairs increased by ∼6 times compared to pure WS2 which is responsible for more efficient charge separation. Furthermore, the surface area of the nanocomposite was found to be 16 times higher than WS2, providing abundant active sites for the photocatalytic reaction. The photocatalytic performance was evaluated through the degradation of Sulfamethoxazole (SMX) and Sulfasalazine (SZ), with the Chl-CDs/WS2/MIL-53(Fe) nanocomposite achieving 90–100% degradation of SZ and SMX in 90 minutes. Electron-Paramagnetic-Resonance spectroscopy (EPR) confirmed the involvement of reactive oxygen species (ROS), while the degradation pathway was elucidated using Liquid Chromatography-Mass Spectroscopy (LCMS). The improved performance can be attributed to the enhanced charge separation, increased surface area, and the Z-scheme mechanism. This study represents the promising potential of the novel ternary Chl-CDs/WS2/MIL-53(Fe) nanocomposite for efficient photocatalytic removal of organic pollutants from water.