Facile synthesis of nitrogen-defective g-C3N4 for superior photocatalytic degradation of rhodamine B

Developing a new photocatalyst for fast and highly efficient organic dye degradation plays an essential role in wastewater treatment. In this study, a photocatalyst graphite phase carbon nitride (g-C3N4) containing nitrogen defects (CN) is reported for the degradation of rhodamine B (RhB). The porous g-C3N4 photocatalyst is facilely synthesized through a polycondensation method and then characterized by X-ray diffraction (XRD), infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), N-2 isotherm adsorption line, and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity of the g-C3N4 is evaluated through the degradation of RhB under visible light irradiation. The results show that photocatalytic activity of the nitrogen-defective g-C3N4 can be improved by optimizating washing conditions, including washing temperature, washing dosage, drying time, and drying temperature. With the prepared nitrogen-defective g-C3N4, decolourization of RhB is able to be completed within 20 minutes, in which the degradation rate is 1.7 times higher than that of bulk g-C3N4. Moreover, the nitrogen-defective g-C3N4 has high stability and reusability in the degradation of RhB. Photocatalytic degradation mechanism investigations by ultraviolet-visible absorption spectroscopy, radical trapping experiments and high-performance liquid chromatography (HPLC) reveal that RhB achieved complete mineralization through the photocatalytic degradation reaction mediated by superoxide radicals (O-2(-)). This work thus provides a new approach for the preparation of photocatalysts for organic pollutants treatment in wastewater samples.

Automated summary

This study presents a nitrogen-defective graphite phase carbon nitride photocatalyst for efficient degradation of rhodamine B, achieving complete decolorization within 20 minutes with improved catalytic activity through optimization of washing conditions. The catalyst demonstrates high stability and reusability, providing a new approach for treating organic pollutants in wastewater samples.