Phosphorus-Doped Carbon Nitride Materials for Enhanced Photocatalytic Degradation of Organic Pollutants under Visible-Light Irradiation.

In this study, phosphorus-doped graphitic carbon nitride (P-doped g-CN, denoted PCN) was synthesized via thermal polymerization. Phosphorus doping significantly enhanced the photocatalytic efficiency by improving light absorption capabilities and promoting charge carrier separation. This photocatalyst was used for removing persistent antibiotics, such as trimethoprim (TMP), from aquatic environments. TMP's high photostability necessitates effective treatment strategies. The optimized catalyst, 0.1 PCN, achieved over 99% degradation of TMP within 90 min under 405 nm LED irradiation. Mechanistic investigations identified singlet oxygen (O) and superoxide radicals (·O ). Moreover, 0.1 PCN demonstrated excellent stability and recyclability across multiple operational cycles, maintaining high degradation efficiency even in a complex matrix such as tap water and lake water. This research highlights the significant potential of P-doped g-CN as an effective, sustainable, and metal-free photocatalyst for the removal of antibiotic contaminants from water.