Nanosheets- and nanourchins-like nanostructures of MoSe for photocatalytic water purification: kinetics and reusability study.

In this paper, we are reporting a simple hydrothermal technique for preparation of MoSe nanostructures (nanourchins and nanosheets) using selenium and sodium molybdate as precursors. Samples are characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Raman spectroscopy, UV-Vis spectroscopy, Brunauer-Emmett-Teller (BET), and X-ray photoelectron spectroscopy (XPS). The FESEM revealed that the morphology of materials was varying significantly by changing pH value during synthesis. Photocatalytic degradation of anionic dye (MO), cationic dye (MB), and reduction of Cr(VI) into Cr(III) were performed. Nanosheets and nanourchins showed higher photocatalytic activity, enhanced photocatalytic degradation efficiency is correlated with the higher OH radical concentration, crystallinity of material, and large surface area as evident through XPS, XRD, and BET, respectively. Photocatalysis mechanism along with role of reactive species (OH and holes) were explained using trapping experiments. Identification of degraded products was carried out using high-performance liquid chromatography (HPLC). Reaction kinetics and reusability of materials were also studied; wherein, it was observed that the materials have reusable properties.