Figure 4.

SEM images of various nanostructures obtained from sample III. (A) SEM image of the shuttle-like nanostructures. (B) High-resolution SEM image of a shuttle-like nanostructure. (C) SEM image of a solid nanosphere and several shuttle-like nanostructures. (D) SEM image of several nanoshuttles, nanofibers, and irregular species. The aging time is 15 min.