Structuring Tight Heterojunction between PCN-224 and g-C3N4 for Enhanced Photocatalytic Water Purification

Abstract

Interfacing two semiconductors for heterojuctions construction has been considered as an effective way to facilitate electron-hole separation, thus improving the photocatalytic activity. In this paper, PCN-224/g-C₃N₄ heterojunction was constructed by PCN-224 and g-C₃N₄ using a solvothermal method. Transmission electron microscopy (TEM) images reveal a well-matched, smooth interface between PCN-224 and g-C₃N₄, demonstrating the successful formation of a tight junction. Photoelectric performance tests confirm that the heterojunction significantly enhances the light absorption capability within the visible range and improves the efficiency of electron-hole separation. Herein, the PCN-224/g-C₃N₄ heterojunction exhibited excellent photocatalytic activity in both disinfection and organic pollutant degradation. Under visible light irradiation (λ > 420 nm) for 3 h, it completely degraded phenol and effectively inactivated E. coli. In the photocatalytic process, electrons migrate from the conduction band of g-C₃N₄ to PCN-224, while holes transfer from the valence band of PCN-224 to the valence band of g-C₃N₄, thereby generating \({\text{O}}_{2}^{{\bullet - }}\) and h⁺ radicals. These generated radicals effectively oxidize and degrade phenol.