Figure 2

X-ray diffraction pattern and FESEM images. (A) The X-ray diffraction pattern and (B) FESEM image of the white precipitate after the precipitation reaction between ZnSO₄·7H₂O and (NH₄)₂CO₃ with a molar ratio at 1.0:3.6. (C) The X-ray diffraction pattern and (D) FESEM image of ZnO micro-tubes after the heat treatment of the precipitate in (A).