Facile Synthesis of Self-Assembled Hollow g-C3N4 Microtubes for Efficient High Performance Photocatalytic Degradation of Hazardous Pollutants under LED Light Illumination

Abstract

Fabricating a tubular g-C₃N₄ with environment friendly still remains a challenge. We report the synthesis of g-C₃N₄ microtubes, using hydrothermal method in water-ethanol system at a white complex having rod-shaped morphology, g-C₃N₄, was obtained, further calcination led to synthesis of a hollow microtube of g-C₃N₄ due to the generation of NH₃ in the system. We have systematically explained the formation mechanism of these hollow microtubes with the help of FESEM and TEM images. The photocatalytic performances of the as-synthesized g-C₃N₄ microrods were studied through the degradation of rhodamine B (RhB) for all the CN_X photocatalysts and then degrading tetracycline (TC) antibiotic with CN_12 photocatalyst under LED light irradiation. More than 80% degradation were observed for both RhB dye and TC antibiotic. The efficiencies were found to be much higher than the bulk g-C₃N₄. CN_12 exhibit the maximum degradation rate constant (k) of 0.0413 min^‒1 for RhB and 0.01794 min^{‒ 1} for TC degradation relatively higher than the pristine b-CN (0.0063/0.00235 min^{‒ 1}). The trapping experiments showed the superoxide radical anions (•O^{2 ‒}) is the main reactive species whereas the holes (h⁺) play a secondary role and negligible contribution of the hydroxyl radical (•OH) in photocatalytic degradation of TC over the microrods. Further, the degradation mechanism for high performance visible light activity were also explained. This work provides a guide for designing a controllable morphology for high performance photocatalyst by self-assembly mechanism.