Construction of CuS/g-C3N4 heterojunction composite by in-situ synthesis for enhanced photocatalytic degradation of malachite green

Abstract

ABSTRACT The poor efficiency caused by the quick charge recombination limited the most prominent photocatalyst g-C3N4’s photocatalytic activity. This work effectively synthesized highly efficient g-C3N4, and (CuS & CuS/g-C3N4 heterojunction composites) by utilizing simple thermal treatment and microwave-assisted methods, respectively. The synthesized materials were analyzed by XRD, UV-Vis DRS, FTIR, FESEM, PL, XPS, and HRTEM analysis. The CuS/g-C3N4 composites was validated by XRD analysis, which showed changes in peak intensity as the g-C3N4 content increased. When compared to the individual components, the CuS/g-C3N4 composites had a smaller band gap, which improved their absorption of visible light, according to UV-Vis DRS. The produced materials’ distinctive stretching vibrations were detected by FTIR spectra, and their emission characteristics were revealed by PL spectra. CuS nanospheres implanted on g-C3N4 nanosheets were visible in FESEM pictures. The components C, N, O, S, and Cu, as well as their chemical states, were verified by XPS analysis of the 1:3 composite. The intricate microstructure and interface morphology of the composites were further clarified by HRTEM. Using a 250W halogen lamp in a handmade photocatalytic reactor, the composites’ photocatalytic effectiveness was assessed for the degradation of malachite green (MG) dye in aqueous solution when exposed to visible light. By creating CuS/g-C3N4 heterojunction composites, this work seeks to improve the photocatalytic efficiency of g-C3N4, which is generally hampered by rapid charge carrier recombination. The outcomes showed that the CuS/g-C3N4 heterojunction performed better photocatalytically than either CuS or g-C3N4 alone. After 120 minutes, the 1:3 composite showed the best degrading efficiency of all the CuS/g-C3N4 ratios, higher than both CuS/g-C3N4 (1:2) at 73.5% and CuS/g-C3N4 (1:1) at 58.9%. On the other hand, the efficiency of pure MG, g-C3N4, and CuS were just 0.8%, 22.7%, and 60.1%, respectively. Rapid charge carrier recombination considerably reduces the photocatalytic efficacy of g-C3N4. CuS/g-C3N4 heterojunction composites were created as a solution, which improved photocatalytic efficiency. In comparison to individual components and various composite ratios, the optimized 1:3 CuS/g-C3N4 composite demonstrated improved degradation of malachite green (MG) dye under visible light. This improvement is ascribed to the development of a heterojunction interface between CuS and g-C3N4, which leads to enhanced charge separation and prolonged visible-light absorption. The research study indicates that heterojunction engineering can effectively modify photocatalytic characteristics, with encouraging prospects for wastewater treatment and environmental remediation applications.