A novel ternary TiO 2 /CQDs/BiOX (X = Cl, Br, I) heterostructure as photocatalyst for water purification under solar irradiation

Abstract A series of novel binary TiO 2 /BiOX (X = Cl, Br, I) and ternary TiO 2 /CQDs/BiOBr hybrid photocatalysts were prepared through a facile hydrothermal method. TiO 2 /BiOX heterostructures were fabricated by varying the halogen ions. The photocatalysts were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV–Vis diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. Among the binary TiO 2 /BiOX, TiO 2 /BiOBr showed the most preferable photocatalytic activities due to suitable band gap alignment and photo stability, reaching almost 80% MO degradation during 180 min irradiation under simulated sunlight. Moreover, the effects of synthesis temperature, Ti/Bi ratio on the composition and structure were investigated, the results indicated TiO 2 /BiOBr with Bi/Ti = 10% prepared at 120 °C possessed the best photocatalytic performance. Carbon quantum dots were introduced to accelerate electrons transfer at interface or prevent charges recombination on the surface, resulting a much better photocatalytic performance for TiO 2 /CQDs/BiOBr hybrid photocatalysts.