Figure 2

(a–c) The FE-SEM images of the NH₄V₄O₁₀ nanowire arrays and (d–f) the as-prepared Ni₃V₂O₈ nanowire arrays; (a,b,d,e) the top-view FE-SEM images; and (c,f) the cross-sectional FE-SEM images. The inset in (a) shows a digital image of the NH₄V₄O₁₀ nanowire arrays on Ti foil.