Epitaxial growth of Bi₂S₃ nanowires on BiVO₄ nanostructures for enhancing photoelectrochemical performance

Abstract

In this paper, a novel Bi 2 S 3 /BiVO 4 heterojunction film was prepared by a facile drop-casting and hydrothermal method for the first time. The as-prepared films were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and ultraviolet visible spectrometry (UV-Vis). Interestingly, the heterojunction film was formed by epitaxial growth of Bi 2 S 3 nanowires on BiVO 4 nanostructures and exhibited a good visible light absorption performance. The photoelectrochemical (PEC) hydrogen generation was demonstrated using the prepared films as photoanodes.The heterojunction photoelectrode showed an excellent PEC activity and generated a photocurrent density of 7.81 mA cm -2 at 0.9761 V vs. RHE (0.1 V vs.Ag/AgCl) in the electrolyte solution containing 0.35 M Na 2 SO 3 and 0.25 M Na 2 S.The present study provides new insight into the design of highly efficient heterojunction photoelectrode for hydrogen generation.of Bi 2 S 3 can extend the spectral responsive range and the formation of heterojunction can promote the separation of photogenerated carriers.

A novel Bi 2 S 3 nanowire @ TiO 2 nanorod heterogeneous nanostructure for photoelectrochemical hydrogen generation

“…In addition, on account of its highly anisotropic layer structure, Bi 2 S 3 tends to form 1D nanowire or nanorod nanostructure [53][54][55]. In our previous works, Bi 2 S 3 NWs were synthesized from the BiVO 4 via a simple hydrothermal process and the prepared films show an excellent PEC hydrogen generation performance [53]. It is very attractive and desirable to design and develop a novel 1D/1D heterogeneous architecture of Bi 2 S 3 /TiO 2 nanostructrure because such a nano-composite structure is expected to have better charge transport rate, light absorption and larger surface areas [56,57].…”

“…1D TiO 2 NRs grown directly on a transparent conductive substrate is considered as a desirable nanostructure for the PEC cells, because of its large specific surface, high electron transport rate and easy synthesis [32,52]. In addition, on account of its highly anisotropic layer structure, Bi 2 S 3 tends to form 1D nanowire or nanorod nanostructure [53][54][55]. In our previous works, Bi 2 S 3 NWs were synthesized from the BiVO 4 via a simple hydrothermal process and the prepared films show an excellent PEC hydrogen generation performance [53].…”

Construction of novel Bi2S3 nanobelt @ WO3 nanoplate arrays on FTO glass with high photoelectrochemical activity

“…Third, Bi 2 S 3 /WO 3 films can be obtained from hydrothermal the BiVO 4 /WO 3 films. BiVO 4 can react with thiourea (CN 2 H 4 S) to form Bi 2 S 3 in the hydrothermal process, which has been reported in the in our previous work [52]. Due to the high anisotropy of Bi 2 S 3 , the Bi 2 S 3 nanobelts with layer structure will be selectively formed on the WO 3 nanoplate [52e55].…”

“…As can be seen, the MS slope of BiVO 4 /WO 3 electrode was greater than that of Bi 2 S 3 /WO 3 electrode, indicating a higher charge carrier density in the Bi 2 S 3 /WO 3 electrode. Moreover, it was found that coupling with Bi 2 S 3 shifted the flat band potential to the negative direction from 2.45 V to 0.09 V. The negative shift of flat band potential implies a larger accumulation of electrons in the coupled heterostructure and reduced recombination of the electron and hole [32,52,62]. To better understand how our cell works, the schematic diagram of the cell is shown in Fig.…”

“…But for the BiVO 4 /WO 3 photoelectrode, a photoresponse over the entire testing wavelength region was also presented. It is because of the formation of Bi 2 S 3 on the WO 3 plates by the reaction between BiVO 4 and S 2À ions during the test [52]. In order to avoid formation of Bi 2 S 3 from the reaction between BiVO 4 and S 2À ions in test and ensure the correctness of analysis, we repeated the LSV measurements in a mixed solution of water and ethanol (V water :V ethanol ¼ 1:2) containing 0.2 M NaCl, in which ethanol can be used as hole sacrificial agent instead of S 2À .…”