Influences of different carbon substrates on the morphologies of carbon/g-C3N4 photocatalytic composites and the purification capacities of different composites in the weak UV underwater environment

In order to explore the influence of various carbon introduction on the morphology and photodegradation performance of C/g-C 3 N 4 composites, three kinds of different carbon materials: carbon nanotubes (CNT), graphene (GN) and carbon fibers (CF) were introduced to modify g-C 3 N 4 , and the morphologies, light absorption capacities and the underwater purifications of the composite photocatalysts were investigated. Results showed that the composites synthesized with different carbon substrates shows great differences in growth morphology. In addition, the introduction of various carbon sources also has a great impact on the physical and chemical properties of the composites. Compared with GN/g-C 3 N 4 and CF/g-C 3 N 4 , CNT/g-C 3 N 4 shows strong light absorption ability, especially in long-wavelength region (570–660 nm). To further study the difference of degradation ability of the composites in the underwater environment , the purification performance of modified g-C 3 N 4 at different water depths were carried out. The results show that under 40 cm of water, where the light intensity and ultra violet spectral are seriously attenuated, the purification efficiency of CNT/g-C 3 N 4 at 40 cm is 3.35 times than that of g-C 3 N 4 . This work provides insight in the design of highly efficient metal-free photocatalysts for the environmental remediation.