Self-Assembly 2D Ti3C2/g-C3N4 MXene Heterojunction for Highly Efficient Photocatalytic Degradation of Tetracycline in Visible Wavelength Range

• Published in: Nanomaterials (Basel, Switzerland) Vol. 12; no. 22; p. 4015
• Main Authors: Li, Chunmin, Kan, Changjie, Meng, Xiangtai, Liu, Mengxue, Shang, Qianqian, Yang, Yikai, Wang, Yu, Cui, Xiaoxue
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 15-11-2022; MDPI
• Subjects: 2D catalysis; Antibiotics; Biodegradation; Carbon nitride; Catalytic activity; Composite materials; Conduction bands; Efficiency; Electrochemical impedance spectroscopy; Electrochemistry; Electromagnetic absorption; Electron microscopy; Etching; g-C3N4; Heterojunctions; Morphology; MXenes; Oxidation; Performance degradation; Photocatalysis; Photodegradation; Photoelectrons; Photoluminescence; Photons; Pollutants; Quantum efficiency; Radicals; Scanning electron microscopy; Self-assembly; Spectra; Spectroscopy; Superoxide; tetracycline degradation; Ti3C2 MXene; Ultrasonic imaging; Valence band; X ray photoelectron spectroscopy; China
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano12224015

An ultrathin 2D Ti3C2/g-C3N4 MXene (2D-TC/CN) heterojunction was synthesized, using a facile self-assembly method; the perfect microscopic-morphology and the lattice structure presented in the sample with a 2 wt% content of Ti3C2 were observed by the field-emission scanning electron microscopy (SEM) and transmission electron microscope (TEM). The optimized sample (2-TC/CN) exhibited excellent performance in degrading the tetracycline (TC), and the degradation rate reached 93.93% in the conditions of 20 mg/L, 50 mL of tetracycline within 60 min. Except for the increased specific-surface area, investigated by UV-vis diffuse reflectance spectra (UV-vis DRS) and X-ray photoelectron microscopy (XPS) valence spectra, the significantly enhanced photocatalytic activity of the 2-TC/CN could also be ascribed to the formation of Ti-N bonds between Ti3C2 and g-C3N4 nanosheets, which reduced the width of the band gap through adjusting the position of the valence band, thus resulting in the broadened light-absorption. Furthermore, the facilitated electron transmission was also proved by time-resolved photoluminescence (TRPL) and electrochemical impedance spectroscopy (EIS), which is effective in improving the quantum efficiency of photo-generated electrons. In addition, the resulting radical-capture experiment suggested that superoxide radicals have the greatest influence on photodegradation performance, with the photodegradation rate of TC reducing from 93.16% to 32.08% after the capture of superoxide radicals, which can be attributed to the production of superoxide radicals only, by the 2-TC/CN composites with a high conduction-band value (−0.62 eV). These facilely designed 2D Ti3C2/g-C3N4 composites possess great application potential for the photodegradation of tetracycline and other antibiotics.