One-step synthesis of oxygen doped g-C₃N₄ for enhanced visible-light photodegradation of Rhodamine B

O-doped g-C₃N₄ (denoted as x-OCN, where x is the volume of 30% H₂O₂ for a given amount of urea) materials were prepared by calcining dried the mixtures of urea impregnated with H₂O₂ at 550 °C. The characterization shows that the x-OCN materials are formed by replacing N in g-C₃N₄ by O atoms, which is further supported by density functional theory calculations. The rhodamine B photodegradation performance on the x-OCN materials is higher than the pure g-C₃N₄. Among the x-OCN samples, 40-OCN shows the strongest photocatalytic activity, which could be attributed to the largest content of doped-O in the matrix of g-C₃N₄, leading to a reduced bandgap energy and a lower recombination rate of photogenerated electrons and holes, therefore enhancing the photocatalytic performance. The mechanism for the photocatalytic degradation of RhB was proposed based on the investigation on the role of active species and the pathway of RhB degradation.