Synthesis of O-doped porous g-C3N4 nanosheets to enhance the photocatalytic degradation of rhodamine B

O- doped porous g-C 3 N 4 (OPCN) photocatalyst was synthesized by simply calcinating the mixture of dicyandiamide, urea and ammonium oxalate in muffle furnace. The microstructure and photocatalytic degradation of rhodamine B (RhB) by OPCN and bulk g-C 3 N 4 (BCN) and porous g-C 3 N 4 (PCN) photocatalysts were comparatively investigated. The results showed that O atoms were successfully incorporated into the skeleton of OPCN by replacing N atoms. The photodegradation performance of OPCN was greatly enhanced compared with that of BCN and PCN. The photodegradation mechanism was related to the O-dopants, which decreased the bandgap of OPCN to expand the absorption range, enlarged the specific surface area to provide more active sites, and improved the transfer and separation efficiencies of photogenerated electron-hole pairs. This study provided a simple and efficient method to enhance the photodegradation performance of g-C 3 N 4 for the removal organic pollutants in wastewater. • O-doped porous g-C 3 N 4 (OPCN) nanosheets were synthesized by a facile method. • The separation efficiency of photogenerated carriers in OPCN was improved. • OPCN displayed enlarged specific surface area. • OPCN exhibited excellent photodegradation performance for rhodamine B.