Role of surfactant in tailoring the properties of Bi2S3 nanoparticles for photocatalytic degradation of methylene blue dye.

Bismuth sulfide (Bi₂S₃) nanorods have been prepared using a simple and low-cost reflux method. This method is easy to handle and opens up a way to manufacture photocatalytic pigment at a low cost. The Bi₂S₃ catalyst was subjected to X-ray diffraction (XRD), UV–Visible spectroscopy (UV–Vis), scanning electron microscope, high-resolution transmission electron microscopy, FT-IR spectroscopy, thermogravimetric analysis (TG/DTA), and X-ray photoelectron spectroscopy. The structures of the Bi₂S₃ nanorod have been investigated and were seen to be orthorhombic. The electron microscopic observations showed that surfactants greatly affect the morphologies of the as-prepared Bi₂S₃ samples. The XRD and TEM results confirmed that the Bi₂S₃ nanorods have a high surface area and are good crystallinity. TEM measurements revealed that the average breadth and length is 75 nm and 385 nm for Bi₂S₃ nanorods prepared using NaOH. The uniform one-dimensional Bi₂S₃ nanorods are due to the presence of NaOH which controls the nucleation and growth process of Bi₂S₃ nanorods. The photocatalytic activity of the Bi₂S₃ nanocrystallites has been estimated by the degradation of methylene blue (MB) under the irradiation of halogen light. It was noted that the absorption peak corresponding to MB reduced indicating the photocatalytic nature of the sample. In these conditions, the maximum degradation of the dye was achieved within 140 min for KOH added Bi₂S₃ samples and the photodegradation efficiency is 87.98%. A possible photocatalytic reaction mechanism of the Bi₂S₃ samples has also been proposed. [ABSTRACT FROM AUTHOR]