Ternary novel TiO₂/MgBi₂O₆/Bi₂O₃ nanocomposites with n-n-p heterojunctions: Impressive visible-light-triggered photocatalytic degradation of tetracycline

A series of novel ternary TiO₂/MgBi₂O₆/Bi₂O₃ nanocomposites were synthesized by a facile hydrothermal method. The ternary nanocomposites were characterized by XRD, FESEM, HRTEM, EDX, PL, EIS, Photocurrent, UV–vis DRS, BET, XPS, Raman, and FT-IR analyses. The photocatalytic performance of TiO₂ for the degradation of tetracycline antibiotic after combining with MgBi₂O₆/Bi₂O₃ was significantly improved, which is 46.1 and 18.5 times higher than pristine TiO₂ and MgBi₂O₆/Bi₂O₃ photocatalysts, respectively. Furthermore, the ternary photocatalyst efficiently degraded MO, RhB, and MB dye pollutants, which is 22.5, 30.4, and 30.0 as high as TiO₂ and 11.2, 14.4, and 17.8 folds larger than MgBi₂O₆/Bi₂O₃ photocatalysts, respectively. The photoluminescence and electrochemical analyses confirmed promoted separation and facile transfer of the charges thanks to construction of n-n-p heterojunctions among n-TiO₂, n-MgBi₂O₆, and p-Bi₂O₃ components and more production of charge carriers due to integration of small band gap MgBi₂O₆ and Bi₂O₃ components with wide band gap TiO₂.