Facile Synthesis of Rambutan-Like ZnO Hierarchical Hollow Microspheres with Highly Photocatalytic Activity

Figure 7

SEM images of the products obtained at different reaction time: 2 h (a), 5 h (b), 24 h (c), and 48 h (d). Inset shows high magnification of the images (b) and (c).

(a)

(b)

(c)

(d)