Construction of amorphous Ta₂O₅/g-C₃N₄ nanosheet hybrids with superior visible-light photoactivities for organic dye degradation and mechanism insight

In this paper, amorphous Ta₂O₅/g-C₃N₄ nanosheet (ATCN) hybrid was firstly constructed by a facile ultrasonic dispersion process. In this way, amorphous Ta₂O₅ nanoparticles anchored evenly onto the surface of g-C₃N₄ nanosheets, forming the intimate interfacial contacts. The as-prepared ATCN composites exhibited significantly enhanced photocatalytic activities for the degradation of RhB compared to pure g-C₃N₄ and amorphous Ta₂O₅ nanoparticles under visible light illumination (λ > 420 nm). The optimal ATCN-3 photocatalyst possessed the highest visible-light photocatalytic activity (99.14%) and the degradation rate constant was 2.0055 h^-1, which was almost 6.2 and 14.9 times as high as those of individual g-C₃N₄ and amorphous Ta₂O₅, respectively. Particularly, ATCN sample had good reusability and stability even after four cycles. Interestingly, amorphous Ta₂O₅/g-C₃N₄ nanosheet hybrid showed higher photocatalytic activity than crystalline Ta₂O₅/g-C₃N₄. The enhanced photocatalytic performance was assigned to the synergistic effects including high surface area, enhanced visible light harvesting, efficiently interfacial charge transfer and reduced charge recombination. The plausible mechanism for improved photocatalytic properties was elucidated.