Synthesis of Vanadium Oxide Nanofibers with Variable Crystallinity and V/V Ratios.

Tailoring the morphological, chemical, and physical properties of vanadium oxides (VOx) is crucial to optimize their performance in current and future applications. The present contribution proposes a new route to obtain VOx nanofibers with different V/V ratios and crystallinity. The method involves the exclusive electrospinning of water-free NHVO-saturated solutions including a reductant. Subsequent air-annealing under suitable conditions yields vanadium oxide fibers of 20-90 nm diameter and 10-50 m/g surface area. The presence of the reductant gives rise to VOx nanofibers with a considerable proportion of V. Then, the right choice of the calcination heating rate and temperature permits to modify the V/V ratio as well as the crystalline phase and crystallite size of the fibers. With the proposed methodology, long-range continuous single-phase orthorhombic VO and monoclinic VO nanofibers are obtained.