Preparation of In2S3@TiO2 Nanobelt Heterostructures with High UV-Visible Light Photocatalytic Activities

In2S3@TiO2 nanobelt heterostructures with high photocatalytic activities both in ultraviolet (UV) and visible-light region were synthesized via a simple hydrothermal precipitation method by using sodium sulfide as the only sulfur source. The structure, chemical state, morphology and optical properties of the as-prepared photocatalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), UV-visible diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) spectroscopy. The photocatalytic activities of the heterostructured photocatalysts were investigated by degrading methyl orange (MO) solutions under UV and visible light irradiations. The results show that In2S3 nanoparticles are assembled on the rough surface of TiO2 nanobelts, forming nano-heterostructures. Comparing with P25 and the TiO2 nanobelts, the as-prepared In2S3@TiO2 heterostructures exhibit dramatically improved photocatalytic activity under both UV and visible light irradiations due to the introduction of In2S3 nanoparticles onto the surface of TiO2 nanobelts and the formation of In2S3@TiO2 nanobelt heterostructures. In2S3 nanoparticles play the role of visible light photosensitizer. A possible photocatalytic mechanism is suggested.