In-situ preparation of double Z-scheme Bi2S3/BiVO4/TiO2 ternary photocatalysts for enhanced photoelectrochemical and photocatalytic performance

Highlights: • In situ synthesis of Bi₂S₃/BiVO₄/TiO₂ ternary heterostructured arrays. • The Bi₂S₃/BiVO₄/TiO₂ photocatalyst with superior visible light absorption. • Excellent photoelectrochemical and photocatalytic properties of Bi₂S₃/BiVO₄/TiO₂ photocatalysts. • The Bi₂S₃/BiVO₄/TiO₂ ternary heterostructure with a unique double Z-scheme charge transfer mechanism. In this study, novel double-Z-scheme Bi₂S₃/BiVO₄/TiO₂ (BVT) heterostructured photocatalysts were prepared using continuous hydrothermal methods. The in situ conversion of BiVO₄/TiO₂ (VT) binary photocatalysts into BVT ternary photocatalysts with large optical absorption coefficients was achieved. Compared to TiO₂ nanorod (TNR) arrays, BVT photocatalysts extend the light absorption range to the near-infrared with consistently high absorption intensities. Photoelectrochemical tests demonstrate that BVT(4) achieves the highest transient photocurrent (110 µA/cm²) of approximately 11 times that of TiO₂ (10 µA/cm²). The photocatalytic performances of all samples were investigated by degrading methyl orange (MO) under visible light irradiation. The results show that BVT(4) possesses the best degradation efficiency (76.3%) which is about 4 times higher than that of bare TNR (19.7%). The outstanding photocatalytic performance can be attributed to the double Z-scheme charge transfer path, which effectively promotes the separation and transfer of electron-hole pairs, resulting in a strong redox activity of the accumulated charge to decompose organic dyes during a degradation reaction.