Mechanical ball milling: A sustainable route to induce structural transformations in tungsten disulfide for its photocatalytic applications

Abstract

An improved method for mass production of good-quality tungsten disulfide (WS2) nanosheets via ball milling of commercial powder of WS2 with different ball sizes is reported in this paper. Bulk/Commercial WS2 (Wc) powder was milled in a high energy planetary ball milling machine using two different ball sizes with diameter 0.5 mm and 7 mm in two separate milling jars. The as-prepared WS2 nanosheets (W0.5 and W7) corresponding to 0.5 mm and 7 mm ball size respectively, were investigated in detail using several characterization techniques, such as Scanning electron microscopy (SEM) for morphological analysis, X-ray diffractometry (XRD) for crystal structure analysis, Fourier transform infrared spectroscopy (FTIR) for functional group analysis and Brunauer-Emmett-Teller (BET) characterization for surface area and pore size/distribution analysis. Ultraviolet–Visible diffuse reflectance spectroscopy (UV–Vis DRS) was performed for bandgap analysis, Time resolved photoluminescence (TRPL) was done for exciton decay studies and Mott-Schottky (MSK) characterization for flat band positions. W7, as a photocatalyst showed enhanced performance of ∼95% in degrading both Methylene blue (MB) and Methyl orange (MO) dyes while as W0.5 showed enhanced surface area. Highly efficient adsorbents were obtained in this whole process of wet ball milling optimized for the degradation of MB and MO dyes. So, the prepared material is potential candidate for wastewater treatment.