A high-performance photocatalyst of ZnTCPP sensitized porous graphitic carbon nitride for antibiotic degradation under visible light irradiation

In this paper, a highly efficient photocatalyst of ZnTCPP sensitized g-C₃N₄ was successfully constructed via a facile thermal polycondensation method. The FT-IR and XRD data indicated that ZnTCPP molecules were successfully condensed on the surface of g-C₃N₄ through amide groups as the bridging units. The optimum 10%ZnTCPP/g-C₃N₄ composites exhibits excellent enhanced photocatalytic activity for decomposing both methylene blue (MB) and tetracycline (TC) under visible light with long-term reusability and elimination rates of 96% and 80.3%, respectively. The superior visible light photocatalytic performance was mainly attributed to the highly efficient separation of electron-hole pairs and the enhanced solar light utilization, as demonstrated by photoluminescence (PL), electrochemical impedance spectra (EIS), photocurrent responses, and UV–vis diffuse reflectance spectroscopy (DRS). The active species trapping and terephthalic acid (TA) fluorescence experiments indicated that OH was the dominating reactive oxidizing species for TC degradation. Furthermore, the possible photocatalytic degradation pathways for MB and TC have been proposed based on the UPLC-MS spectrometry. The excellent degradation efficiency of ZnTCPP/g-C₃N₄ reveals that it has great potential as photocatalysts for practical application to eliminate recalcitrant organic contaminants.