A Hybrid Z-Scheme Heterojunction Using GQD, g-C3N5, and NiCo LDH for Rhodamine B Degradation under Visible Light Irradiation

Degradation of organic pollutants in aquatic environments is crucial because of the importance of environmental preservation and maintenance of cleanliness. Despite the existence of numerous methods for degrading organic pollutants, photocatalysts have garnered significant attention from researchers in the fields of chemistry and environmental science owing to their numerous advantages. In this study, a highly attractive ternary nanocomposite composed of GQD (graphene quantum dot)/g-C ₃ N ₅ /NiCo LDH (layered double hydroxide), synthesized by combining hydrothermal and ultrasonic techniques, was employed as a light-active catalyst for the degradation of Rhodamine B (RhB), a highly harmful pollutant to water and the environment. Several techniques, including FESEM, TEM, FTIR, XRD, EDS, XPS, and UV-Vis DRS, were used to characterize the produced materials. Under optimal conditions of pH 7 and a catalyst dosage of 0.15 g/L, the system is capable of degrading 98.9% of RhB within 90 minutes. The key parameters influencing the degradation of this pollutant, such as the effects of pH, catalyst dosage, and initial pollutant concentration, were investigated and optimized. Additionally, pollutant degradation percentages and rates were examined. Finally, the overall degradation mechanism and scavengers influencing the photocatalytic degradation process were analyzed. The findings showed that a key factor in the photocatalytic degradation of RhB is superoxide radicals. Our findings demonstrate that a dual Z-scheme system of GQD/g-C ₃ N ₅ /NiCo LDH effectively degrades RhB.