Phosphorus-Doping Engineering of One-Dimensional Porous Carbon Nitride Nanotubes for Enhanced Photocatalytic Performance

The practical application of g-C3N4 for wastewater treatment is hindered by limited reactive sites, poor visible light absorption, and high exciton binding energy. Herein, we report a facile one-step phosphorus doping strategy that concurrently constructs a porous nanotubular architecture and tunes the electronic band structure, overcoming both kinetic and thermodynamic limitations within a single thermal treatment. The optimized P-doped nanotubes exhibit a tetracycline hydrochloride degradation efficiency of 82.38%, which is 1.49 times that of pristine g-C3N4, and a 2.06-fold increase in the reaction rate constant. They retain over 90% of initial activity after five consecutive cycles, demonstrating robust reusability. When applied to real wastewater, the catalyst still achieves 82.58% degradation efficiency, demonstrating promising potential for application in complex wastewater matrices. Mechanistic investigations via radical trapping identify superoxide radicals (\(\text{O}_2^-\)) and holes (h+) as the oxidative species. Our results underscore that the combination of morphological reconstruction and heteroatom incorporation not only compensates for the scarcity of active sites but also optimizes the redox potential, providing a scalable and viable pathway to enhance the photocatalytic performance of carbon nitride materials for the removal of persistent organic pollutants.