252593.fig.001a
(a)
252593.fig.001b
(b)
252593.fig.001c
(c)
252593.fig.001d
(d)
Figure 1: (a) SEM images of the undoped NiO/PVP nanofibers before calcination. (b) SEM images of the undoped NiO/PVP nanofibers after calcination. (c) SEM images of the Fe-doped NiO/PVP composite nanofibers before calcination. (d) SEM images of the Fe-doped NiO/PVP composite nanofibers after calcination.