Highly crystalline anatase TiO₂ nanotubes array films enhanced with Bi₂S₃ for photoelectrochemical applications

The synthesis of bismuth (III) sulphide (Bi₂S₃)-sensitized titanium dioxide nanotubes arrays (TiO₂ NTAs) was carried out using the SILAR (successive ionic layer adsorption and reaction) method. The effect of different cycles on the performance of a photoanode made of Bi₂S₃/TiO₂ NTAs in photoelectrochemical cells was investigated. Field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy and UV–visible spectroscopy were used to investigate Bi₂S₃/TiO₂ NTs morphological, elemental composition, structural and optical absorption, respectively. TiO₂ nanotubes had a tetragonal crystal structure, whereas Bi₂S₃ had an orthorhombic crystal structure, according to XRD measurements. Absorbance spectra showed that the absorbance edges shifted towards longer wavelengths as the number of cycles increased, showing that the optical properties had significantly improved following deposition. Bi₂S₃/TiO₂ NTAs photoanode was proposed as a viable alternative photoanode in photoelectrochemical applications. The photocurrent density of the Bi₂S₃/TiO₂ NTAs composite film grew first, then declined as the number of Bi₂S₃ deposition cycles increased. After three cycles of deposition of Bi₂S₃, the Bi₂S₃/TiO₂ composite films displayed the highest photoelectrochemical characteristics. The photocurrent density of Bi₂S₃-3Cy/TiO₂ NTAs was 1.427 mA cm^–2, about four times that of plain TiO₂ NTAs. The Bi₂S₃/TiO₂ NTAs photoanode was offered as a feasible alternative photoanode in photoelectrochemical applications based on the findings of this study.