Construction of binary BiVO₄/g-C₃N₄ photocatalyst and their photocatalytic performance for reactive blue 19 reduction from aqueous solution coupling with H₂O₂

A highly efficient binary composite consisting of ripple-like sheet g-C₃N₄ doped with paramecium-shape BiVO₄ has been successfully fabricated in a mild method and was further characterized by X-ray diffraction, Transmission electron microscopy, Fourier-transform infrared spectroscopy, UV–Vis diffuse reflectance spectrum, and photoluminescence. Their photocatalytic performances were estimated by monitoring the degradation process of reactive blue 19 (RB19) in the aqueous phase under visible light irradiation. The results showed that when the mass ratio of BiVO₄ and g-C₃N₄ was 1:5, the binary composite presented the best catalytic activities during the photocatalytic degradation of RB19, and the synthesized composite with H₂O₂ addition could further promote the photocatalytic activities. It is worth mentioning that H₂O₂ acted only as a electron acceptor for accelerating the separation of electron–hole pairs. The trapping experiments showed that ·O₂⁻ was main active species in photocatalytic degradation of RB19. The improving of photocatalytic performance can be put down to the synergistic effect of g-C₃N₄, BiVO₄, and H₂O₂ in Z-scheme mechanism, which give rise to enlarge optical absorption range and suppress the recombination of photo-generated charge carrier.