One-Pot Template-Free Hydrothermal Synthesis of Monoclinic BiVO₄ Hollow Microspheres and Their Enhanced Visible-Light Photocatalytic Activity

Figure 5

SEM images of BiVO₄ samples prepared with 9 g urea at different reaction time from 1 (a), 6 (b), to 12 h (c).

(a)

(b)

(c)