The facile soft-template-morphology-controlled (STMC) synthesis of ZnIn2S4 nanostructures and their excellent morphology-dependent adsorption properties

Abstract

Fabricating nanostructures (NS) with well-developed morphologies and high surface areas is vital to the success of any designed material for its application in adsorption and catalysis. In this study, we prepared ZnIn₂S₄ NS with different morphologies using a soft-template-based precipitation method. X-ray diffraction data show that the NS are crystalline with a hexagonal structure. Field emission scanning electron microscopy suggests that the NS are formed with different morphologies, such as lamellar structures, nanobeads, and nanopetal/nanoflake hybrids. Moreover, transmission electron microscopy confirmed the lamellar structure, which was composed of vertically grown 2D nanosheets. Brunauer–Emmett–Teller analysis indicates the specific surface area (135.36 to 197.63 m² g⁻¹) and pore width (1.41 to 4.54 nm) values of the NS vary with varying soft templates. The obtained NS have efficient adsorption performance towards malachite green dye and dichromate (Cr₂O₇²⁻), with maximum adsorption capacities of 1525 and 313 mg g⁻¹, respectively, which are considerably higher than those of many other previously reported nanoadsorbents. The adsorption process follows the Freundlich isotherm model for the lamellar structure and the Langmuir isotherm model for the other morphologies. All adsorbents conformed to a pseudo-second-order rate kinetics model, and the best adsorbent could be recycled up to five times without significant loss of efficiency.