Ternary Bi₂S₃/MoS₂/TiO₂ with double Z-scheme configuration as high performance photocatalyst

Due to unique electron transport properties, nanostructured catalysts with certain morphology, such as nanotube, nanosheet and nanorods, have shown outstanding photocatalytic performance. Herein, preparation of ternary photocatalytic architecture is demonstrated using a facile microwave-assisted hydrothermal method. The as-prepared ternary photocatalyst (denoted as Bi₂S₃/MoS₂/TiO₂) comprises bismuth sulfide (Bi₂S₃) nanorods, molybdenum sulfide (MoS₂) nanosheets, and titanium dioxide (TiO₂) nanotubes. The photocatalytic performance of the as-prepared nanocomposite is evaluated by monitoring water splitting and dye degradation. The results show that the Bi₂S₃/MoS₂/TiO₂ exhibits stable and highly efficient photocatalytic hydrogen production under visible light, and photocatalytic degradation of methylene blue (MB) under sunlight. The photocatalytic performance of Bi₂S₃/MoS₂/TiO₂ is much better than that of TiO₂, MoS₂, or Bi₂S₃. The improved performance is correlated to the high surface area and the formation of the double Z-scheme heterostructure, which together render abundant catalytic sites and efficient charge separation with strong redox capability. Additionally, X-ray photoelectron spectroscopy and electron spin resonance spectroscopies, combined with reactive species trapping experiments, confirm that the surface charge transport in Bi₂S₃/MoS₂/TiO₂ occurs through the double Z-scheme approach. This work paves the way for designing more photocatalytic systems with double Z-scheme for high efficiency and wide practical applications.