Preparation and enhanced photocatalytic performance of N-TiO2/g-C3N4 heterostructure for Rhodamine B degradation

Highly efficient photocatalysts have been developed for the degradation of contaminated water under visible light. In this study, N-doped TiO₂ (N-TiO₂) and metal-free graphitic carbon nitride (g-C₃N₄) composites with various Ti/C molar ratios were prepared with the simple mixing-calcining method. The samples were characterized by X-ray diffraction, scanning electron microscopy, ultraviolet–visible diffuse reflectance spectroscopy, and photoluminescence spectroscopy. The photocatalytic activity of N-TiO₂/g-C₃N₄ in the degradation of Rhodamine B (RhB) was investigated, and the electrochemical method was used to determine the origin of the enhanced photoactivity of N-TiO₂/g-C₃N₄. The results showed that N-TiO₂ nanoparticles were dispersed on the surface of g-C₃N₄ and formed a stable heterojunction structure with g-C₃N₄. The heterojunction between the two semiconductors could effectively prevent the recombination of photogenerated electrons and holes and improve the photocatalytic efficiency of the photocatalyst under visible light irradiation. The photocatalyst exhibited high stability, and the RhB degradation rate was still higher than 82.3% after five cycles.