In situ anion exchange synthesis of In2S3/In(OH)3 heterostructures for efficient photocatalytic degradation of MO under solar light

Abstract

Fabrication of heterostructure photocatalysts to improve photocatalytic performance is always a hot topic in the photocatalytic field. In this paper, In₂S₃/In(OH)₃ heterostructure photocatalysts were synthesized via a simple combination of an in situ anion exchange reaction and the hydrothermal process. The obtained heterostructures were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectra (UV-vis DRS) and photocurrent experiment. The photocatalytic activity of the as-formed samples was evaluated by the degradation of methyl orange (MO), salicylic acid and 4-chlorophenol aqueous solution under simulated solar light irradiation (200 nm < λ < 800 nm). The results showed that the photocatalytic activities of In₂S₃/In(OH)₃ heterostructures were greatly improved as compared to single phase In(OH)₃ and In₂S₃. The enhancement in their photocatalytic activity could be attributed to the efficient charge transfer in In₂S₃/In(OH)₃ heterostructures, the improved light absorbance capacity and the increased surface area. As compared, In₂S₃/In(OH)₃ displayed higher photocatalytic activity than In₂S₃/In₂O₃ at the same In₂S₃ content. The excellent activity of In₂S₃/In(OH)₃ with respect to In₂S₃/In₂O₃ was mainly due to the high concentrations of ˙O₂⁻ radicals and the strong oxidation capacity (h⁺). The current research provides a new insight into the construction of a narrow-band-gap with a wide-band-gap to form heterostructures as promising and efficient photocatalysts for the removal of harmful organic compounds in aqueous solution.