Dimensionality-dependent performance of nanostructured bismuth sulfide in photodegradation of organic dyes

Nano-scaled semiconductors serving as photocatalysts in wastewater treatment are an important research area and the synergistic effect of adsorption and photocatalytic reaction should be considered in degradation. Bi2S3 nanostructures with different dimensionalities including dots, rods, and sheets have been synthesized for the study on their photocatalytic activities in degradation of organic dyes. X-ray diffraction and transmission electron microscopy results show that the orthorhombic structured samples have the dominant surface facets of (001), (010), and (100) for dots, rods, and sheets, respectively. The nanocrystals could selectively enhance the photodegradation of three typical dyes including rhodamine B, methylene blue, methyl orange, and the efficiencies are dependent on dimensionalities. Langmuir–Hinshelwood mode simulation studies reveal that the photodegradation satisfies the first-order dynamics for rods and sheets, while first-order exponential decay for dots. Investigations on the adsorption efficiency, visible-light irradiation, and activities on several cycles exhibit that the improvement in photodegradation efficiency of dots on rhodamine B is resulted from the synergistic effect of strong adsorption and photocatalytic reaction.