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

Abstract

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.