Highly Stable Hierarchical Flower-like β-In 2 S 3 Assembled from 2D Nanosheets with high Adsorption-Photodecolorization Activities for the Treatment of Wastewater

Abstract

The hierarchical flower-like β-In₂S₃ catalyst assembled from 2D nanosheets was prepared using an organic-component depletion method utilizing inorganic-organic hybrids indium diethyldithiocarbamate (In-DDTC) as a single-source precursor. The crystallization, morphology and composition of the as-synthesized β-In₂S₃ were characterized by XRD, SEM, TEM, EDS and XPS, respectively. The β-In₂S₃ possessed high specific surface area of 134.1 m² g^-1, adsorption capacity of 195.5 mg g^-1 for methylene blue, and extreme photodecolorization speed under visible light irradiation for the complete removal of methyl orange (MO) dye within 15 min and tetracycline within 60 min. Although methyl orange concentration decreased quickly, the total organic carbon (TOC) decreased slowly. UV-vis and mass spectrometry (MS) were applied to analyze the intermediates coming from the photodecolorization of MO. In order to estimate the roles of active species during the decolorization of MO, trapping experiments were conducted to determine the main active species during the decolorization process. The results indicated that ^. O₂⁻ radicals and e^-1 were the key intermediates. This enhanced activity was attributed to its unique structures assembled from 2D nanosheets with thickness of ca. 5-7 nm, leading to high specific surface area, wide range of pore size distribution and great efficiency in absorbing light and electron/hole separation. The hierarchical flower-like β-In₂S₃ demonstrated great advantages in the treatment of various wastewater pollutants including textile dyes and antibiotics.

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