Tunable Metal-Free COFs for Photocatalytic Degradation of Water Pollutants

Photocatalytic degradation is an effective method for removing organic pollutants from water; however, metal-based photocatalysts may lead to secondary pollution. Covalent organic frameworks (COFs), owing to their inherent stability and porosity, have emerged as promising candidates for photocatalysis. In this study, we report a metal-free photocatalyst, Acetylenyl-TPB-DMTP-COF, which efficiently degrades organic dyes under both UV and visible light, without requiring metal doping or sacrificial agents. The pristine COF achieves over 95% degradation efficiency and maintains more than 90% of its activity after five cycles, demonstrating excellent stability. Furthermore, functionalization via click chemistry allows the introduction of hydroxyl groups, significantly enhancing its ability to degrade sulfonamide antibiotics, with a removal efficiency of up to 58.9%. Notably, the material functions entirely without metal components or sacrificial additives, offering an environmentally friendly solution for water treatment. These results highlight the potential of metal-free COFs as efficient and sustainable photocatalysts for water purification.