Inorganic fullerene-type WS2 nanoparticles: processing, characterization and its photocatalytic performance on malachite green

In this work, we have employed a hydrothermal route for the synthesis of fullerene-type tungsten disulfide (WS2) nanoparticles. X-ray diffraction analysis signifies a hexagonal crystal structure of WS2 with the crystallites experiencing preferred orientations along (002) and (103) planes. The agglomerated nanoparticles and inorganic fullerene (IF)-type structures are apparently observable from the high-resolution electron micrographs. Raman spectrum shows prominent E-2g(1) and A(1g) modes emanating from the IF nano-WS2 system. The Tauc's plot obtained from the optical absorption data predicts a direct band gap of similar to 1.91 eV for the nano-WS2 system; whereas, photoluminescence analysis reveals a broad emission peak located at similar to 638 nm and is ascribed to the associated transition from the indirect to direct nature of the band gap. The photocatalytic decomposition of malachite green (MG) solution (30 mg/l) by WS2 (100 mg/l) under UV and visible light irradiation has been evaluated. The latter condition exhibited a better photocatalytic response with the MG degradation as high as 71.2%, revealed for 120 min. Photocatalytic and optoelectronic features of IF-type nanoWS(2) would bring new insights not only to resolve issues related to environmental hazards, but also in functional devices of technological relevance.