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.