Figure 2.

a, b Low-magnification SEM images of Na₇(H₃O)Nb₆O₁₉·14H₂O nanobelts, indicating the honeycomb-like micropattern. c, d High-magnification SEM images. e, f TEM images of a single nanobelt, exhibiting contrasty stripes along the growth direction. The nanobelts are composed of many smaller size nanobelts shown with a red circle.