Stepwise Growth of Hollow Hexagonal α-Fe₂O₃ Nanocrystals

Figure 2

Morphological evolution of hollow hexagonal α-Fe₂O₃ nanocrystals with different reaction times, as revealed by the SEM images of the products prepared at 220°C for (a) 1, (b) 4, (c) 12, and (d) 24 h. Insets give the selected magnification of product at each reaction time.

(a)

(b)

(c)

(d)