Rational designed novel TiO_2-x/Bi₆Cr₂O₁₅/Bi quantum dots: Bi-based plasmonic photocatalysts for boosted detoxifying organic and inorganic wastewaters under visible light

We combined brown TiO_2-x with Bi₆Cr₂O₁₅ and Bi using a facile procedure to fabricate Bi-based plasmonic TiO_2-x/Bi₆Cr₂O₁₅/Bi photocatalysts for detoxifying organic and inorganic wastewaters upon visible light. The TEM and HRTEM analyses provided strong evidence for the construction of quantum dots of the photocatalyst with diameter of almost 8.2 nm and intimate contact among TiO_2-x, Bi₆Cr₂O₁₅, and Bi components. The TiO_2-x/Bi₆Cr₂O₁₅/Bi nanocomposites exhibited boosted activity in the degradation of tetracycline (TC), azithromycin (Azi), rhodamine B (RhB), methylene blue (MB), and photoreduction of Cr (VI) pollutants, and the performance was 12.9, 1.67, 10.4, 3.50, and 6.91-folds greater than TiO_2-x, and 19.1, 1.60, 3.44, 2.88, and 1.90-times higher than Bi₆Cr₂O₁₅ photocatalysts, respectively. In particular, h⁺ and ^•OH species were identified as the key species involved in the TC degradation reaction. The electrochemical analyses, including EIS, Bode plots and photocurrent density, and PL spectroscopy exhibited efficacious segregation and transportation of charge carriers within the ternary photocatalyst. Finally, the biocompatibility of TC-treated solution over the TiO_2-x/Bi₆Cr₂O₁₅/Bi photocatalyst was verified by the growth of lentil seeds.