The electrospinning setup (Nanospider) suitable for the multigram synthesis of W and WS2 fibers was described elsewhere. In the past, silicotungstic acid (HSiW) was used as a useful tungsten oxide precursor for electrospinning. The fabricated green nanofibers were calcined at 600 °C. Careful analysis showed that they consist of WO3 grains attached to an amorphous silica phase (for brevity, named -WO3/a-SiO2). The mean diameter of the -WO3/a-SiO2 fibers was 225 ± 88 nm. The preparation process of the precursor and material characterization are presented in Supplementary Experimental Part 1. The nanowhiskers have the tendency to form bundles during growth, which adversely affects their further processing into functional electronic devices or converting them into WS2 nanotubes of high crystalline order.