Sol-gel synthesized hexagonal boron nitride/titania nanocomposites with enhanced photocatalytic activity

摘要

Hexagonal boron nitride (H-BN)/titania (TiO2) nanocomposites photocatalysts were synthesized by a facile sol-gel method. The structure was verified by comprehensive analysis from X-ray diffraction, Raman, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscope and transmission electron microscope. The degradation of organic dyes such as rhodamine B (RhB) and methylene blue (MB) under UV light irradiation was used to measure the photocatalytic activity of the h-BN/TiO2 nanocomposites. The photocatalytic performance and the stability of H-BN/TiO2 nanocomposites in the degradation of dyes (MB and RhB) significantly outperformed pure TiO2 nanoparticles. The formed B-O-Ti bond in H-BN/TiO2 gave rise to a strong link between h-BN sheets and TiO2 nanoparticles, and thus the charge transportation rate was improved and the recombination of electrons and holes was suppressed in the photocatalytic processes. The degradation percentage for RhB and MB reached 98% and 92% within 50 min irradiation. The degradation rate (k) of first-order linear value of h-BN/TiO2 nanocomposites (0.05952 and 0.0498) for RhB and MB degradation was 3.64 and 4.22 times higher than that of pure TiO2 (0.01637 and 0.0118). The enhanced photocatalytic property of the nanocomposites was attributed to the reduction in charge recombination and the adsorption interaction between organic dyes and h-BN. Consequently, h-BN sheets hold a great promise to enhance the photocatalytic activity of semiconductive materials.