Tungsten disulfide polycrystalline microfibers were successfully synthesized by a process involving electrospinning, calcination, and sulfidation steps. We used an aqueous solution of silicotungstic acid (H4SiW12O40) and polyvinyl alcohol as precursors for the synthesis of composite fibers by the needle-less electrospinning technique. The obtained green composite fibers (av. diam. 460 nm) were converted by calcination in air to tungsten oxide WO3 fibers with traces of SiO2 and a smaller diameter (av. diam. 335 nm). The heat treatment of the WO3 fibers under flowing H2/H2S/N2 stream led to conversion to tungsten disulfide WS2 with retention of the fibrous morphology (av. diam. 196 nm). Characterization of the intermediate and final fibers was performed by the XRD, SEM, TEM, HAADF STEM EDS, elemental analyses ICP-OES, and IR spectroscopy methods.

We thank Dr. Y. Feldman for the XRD analysis. This research has been financially supported by the MEYS CR under the project CEITEC 2020 (LQ1601) and the Horizon 2020 Research and Innovation Programme under the Grant Agreement No. 810626 (SINNCE). CIISB research infrastructure project LM2018127 funded by the MEYS CR is gratefully acknowledged for the financial support of the measurements at the CEITEC MU CF X-ray Diffraction and Bio-SAXS and the CF Cryo-electron Microscopy and Tomography. The support of the Irving and Cherna Moskowitz Center for Nano and Bio-Nano Imaging, the Perlman Family Foundation, the Kimmel Center for Nanoscale Science Grant No. 43535000350000, is greatly acknowledged.