Optimal Structure and Photocatalytic Performance of C₃N₄@TiO₂ Composite by Controlling the Molar Ratio of Components

Based on the heterogeneous composite design of C₃N₄ and TiO₂, composite photocatalysts of C₃N₄@TiO₂ (with varied molar ratios of C₃N₄ to TiO₂) were synthesized by a water bath method to degrade RhB in wastewater. The composition, morphology, structure, and photocatalytic properties of the materials were assessed through a variety of characterization techniques. The results show that TiO₂ nanoparticles are uniformly coated on two-dimensional g-C₃N₄ nanosheets, forming relatively dense heterostructures within the C₃N₄@TiO₂ composite. Due to the synergistic effect derived from the heterogeneous component and appropriate proportion of C₃N₄ and TiO₂, the light absorption range is extended, and the separation/transport performance of photon-generated carrier is improved. As a result, TCNT-3 (where the molar ratio of C₃N₄ to TiO₂ is 1:1) presents remarkable photocatalytic performance, the degradation rate of which for 60 min is 99.8%, and the reaction rate constant is calculated to be 0.0872 min^-1. Moreover, the degradation efficiency remains 94.4% after 5 cycles, indicating the superior cycle stability.