High interfacial charge separation in visible-light active Z- scheme g-C₃N₄/MoS₂ heterojunction: Mechanism and degradation of sulfasalazine

Examination of highly proficient photoactive materials for the degradation of antibiotics from the aqueous solution is the need of the hour. In the present study, a 2D/2D binary junction GCM, formed between graphitic-carbon nitride (g-C₃N₄) and molybdenum disulphide (MoS₂), was synthesized using facile hydrothermal method and its photo-efficacy was tested for the degradation of sulfasalazine (SUL) from aqueous solution under visible-light irradiation. Morphological analysis indicated the nanosheets arrangement of MoS₂ and g-C₃N₄. The visible-light driven experiments indicated that 97% antibiotic was degraded by GCM-30% within 90 min which was found to be quite high than pristine g-C₃N₄ and MoS₂ at solution pH of 6, GCM-30% dose of 20 mg, and SUL concentration of 20 mgL^-1. The degradation performance of GCM-30% was selectively improved due to enhanced visible-light absorption, high charge carrier separation, and high redox ability of the photogenerated charges which was induced by the effective Z-scheme 2D/2D heterojunction formed between g-C₃N₄ and MoS₂. The reactive radicals as determined by the scavenging study were •O₂^-, and h⁺. A detailed degradation mechanism of SUL by GCM-30% was also predicted based on the detailed examination of the band gaps of g-C₃N₄ and MoS₂.