3D flower-shaped g-C3N4/MoS2 composite with structure defect for synergistic degradation of dyes

Three dimensions (3D) flower-shaped g-C3N4/MoS2 composite was prepared by immobilizing molybdenum disulfide (MoS2) on carbon nitride (C3N4) with structural defects by in-situ hydrothermal assay. The morphological structure and photochemical properties of the obtained catalysts were characterized by SEM, TEM, EDS, FTIR, XRD and XPS. Using methylene blue (MB) as the target pollutant, the photocatalytic performance cyclic stability of g-C3N4/MoS2 composite were studied under simulated sunlight. The results showed that the prepared catalyst could remove 98 % of MB within 60 min and still reached 96.4 % after 5 cycles with good stability and regeneration. Its apparent rate constant was 0.0523 min−1, which was 11.5, 8.2 and 13.9 times higher than those of g-C3N4 (0.00453 min−1), C3N4 with structural defects (0.00635 min−1) and MoS2 (0.00377 min−1), indicating that the synergistic effect of structural defects, heterojunctions and 3D structure has achieved efficient degradation of MB. Furthermore, the photocatalytic mechanism of g-C3N4/MoS2 composite was proposed by combining free radical capture experiment and electron paramagnetic resonance (EPR) spectroscopy and the results showed that that ·OH and ·O2- played a primary role in the catalytic degradation.