Controlled hydrothermal synthesis and photoelectrochemical properties of Bi2S3/TiO2 nanotube arrays heterostructure

Bi2S3, an efficient sensitizer for TiO2 nanotube arrays (TiO2 NTAs), was synthesized by a hydrothermal method. The morphology and size of Bi2S3 nanostructures can be tuned by controlling the crystalline state of TiO2 NTAs and the concentration of precursor solution. X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) were used to characterize the crystalline structure and morphologies, respectively, of all the samples. The growth mechanism of nanostructured Bi2S3 in TiO2 NTAs was established in great detail in this work. In addition, the photoelectrochemical (PEC) properties of Bi2S3/TiO2 NTAs composite electrodes were evaluated. The results demonstrated that the best PEC properties were obtained when amorphous TiO2 NTAs were used as the starting material and the concentration of Bi3+ ions (N) was 0.5 mM in precursor solution. With AM 1.5G illumination at 100 mW cm−2, the short-circuit current density (Jsc), open-circuit voltage (Voc) and photoconversion efficiency (η) were 5.75 mA cm−2, 0.89 V and 2.32%, respectively. •The TiO2 NTAs can be crystallized in a low temperature hydrothermal process.•Characteristics of the Bi2S3 nanostructure can be simultaneously controlled in above process.•Bi2S3/TiO2 NTAs heterostructure electrode displayed excellent PEC properties.•The highest photoconversion efficiency of 2.32% was obtained.