Designing and Fabricating a Vulcanized ZnAl LDH-Modified g-C₃N₄ Heterojunction for Enhanced Visible-Light-Driven Photocatalytic Degradation Activity

Abstract

Modulation of the structure and composition of a binary heterojunction can skillfully transfer photoinduced charge carriers and perfectly boost the photodegradation performance of pollutants in wastewater under a 300 W Xe lamp illumination. Herein, a novel binary heterojunction ZnAlSx@g-C3N4 with different load proportions of ZnAlSx was perfectly constructed by readily hydrothermal treatment and characterized experimentally by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, UV–vis spectroscopy, diffuse reflectance spectroscopy, photoluminescence, and so forth. The photodegradation performance of tetracycline (TC) by prepared ZnAlSx@g-C3N4 was measured under various photocatalytic conditions, including TC pollutant concentration, catalyst dosage, pH values, and competing ions in the photocatalytic system. The results suggested that the ZASCN-3 (30 wt % of ZAS compared to CN) composites exhibited the best photodegradation activity (94.05%), with h+ as the primary active substance and O2•– as the second-most important substance, which was over 2.2 and 5.0 orders of degradation rate higher than pure ZAS and CN, respectively. The improved photocatalytic ability of ZASCN composites was put down to intimate contact interfaces between ZAS and CN and Z-scheme electron–hole pairs induced, which were sped up by the efficient separation of photogenerated carriers. In addition, the ZASCN-3 composites exhibited an outstanding stable photodegradation activity based on the cycling test and the superior widespread applicability toward other pollutants, including dyes, antibiotics, and environmental water. The plausible Z-scheme photocatalytic mechanism for TC degradation over the ZASCN hybrid was surmised according to the trapping experiments.

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