Synthesis of Vanadium Oxide Nanofibers with Variable Crystallinity and V(5+)/V(4+) Ratios

[Image: see text] 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(4+)/V(5+) ratios and crystallinity. The method involves the exclusive electrospinning of water-free NH(4)VO(3)-saturated solutions including a reductant. Subsequent air-annealing under suitable conditions yields vanadium oxide fibers of 20–90 nm diameter and 10–50 m(2)/g surface area. The presence of the reductant gives rise to VOx nanofibers with a considerable proportion of V(4+). Then, the right choice of the calcination heating rate and temperature permits to modify the V(4+)/V(5+) ratio as well as the crystalline phase and crystallite size of the fibers. With the proposed methodology, long-range continuous single-phase orthorhombic V(2)O(5) and monoclinic V(3)O(7) nanofibers are obtained.