Sono-solvothermal fabrication of ball-flowerlike Bi2O7Sn2-Bi7O9I3 nanophotocatalyst with efficient solar-light-driven activity for degradation of antibiotic tetracycline

A novel Bi2O7Sn2-Bi7O9I3 nano-heterostructure photocatalyst with the different weighted percentages and as I-type heterojunction, which acts as pseudo-type II heterojunction, were successfully synthesized using sonosolvothermal manner for the first time. The coupled nanophotocatalysts with various weighted contents of Bi2O7Sn2 and Bi7O9I3 were characterized with XRD, FESEM, EDX, DRS, BET-BJH and pH(pzc) analyses. Meanwhile, the photocatalytic activity of various nanocomposites was evaluated in the remediation of the antibiotic tetracycline after 90 min irradiation. Results depicted that the ball-flowerlike Bi2O7Sn2(60)-Bi7O9I3(40) nanophotocatalyst, as a mesoporous structure and the type I-heterostructure which appears as an efficient solar-light driven pseudo-type II heterojunction, represented the best photocatalytic efficiency. This is addressed by the suitable absorption of light range, high separation of charge carriers and its large surface area which provide more active sites for absorption of tetracycline molecules. Furthermore, to elucidate the how the influence of various parameters on the photodegradation efficiency, the different experiments were conducted over Bi2O7Sn2(60)-Bi7O9I3(40). The high activity was obtained in the medium with pH = 6, catalyst loading = 1 g/L and tetracycline concentration = 35 mg/L. Moreover, the capable of reusability and reaction mechanism of improved photodegradation on mentioned photocatalyst were investigated.