Fabrication of iodine vacancy-modulated dual S-scheme BiOI/BiSI/BiOBr heterojunction for enhanced tetracycline hydrochloride degradation

In this work, an iodine vacancy-modulated dual S-scheme BiOI/BiSI/BiOBr heterojunction was prepared via a hydrothermal method, and its photocatalytic efficiency was assessed through the degradation of tetracycline hydrochloride (TCH). The results reveal that the combined effects of improved visible light absorption, iodine vacancies, S-scheme charge transfer, and electron sacrificial agent significantly enhance photocatalytic activity. Under visible light irradiation for 240 min, the BiOI/BiSI/BiOBr heterojunction achieves an impressive TCH degradation rate of 89.51 %, which is approximately 2.06 times higher than that of BiOBr. Additionally, the heterojunction remains stable throughout the photocatalytic process as long as surface-adsorbed TCH is removed with deionized water and anhydrous ethanol after each cycle. The anion vacancy-modulated dual S-scheme charge transfer offers valuable insights into the photocatalytic oxidation of contaminants.