The XRD analysis in Figs. 4 and 5 show the sample Al-3 and
sample Al-7 calcined at different temperatures, respectively. As
show in Fig. 4, The obtained precursor from Al-3 was amorphous,
Diffraction peaks corresponding to g-Al2O3 appeared at 800 C. The
amount of a-Al2O3 increased drastically when the calcination
temperature reached to 1000 C with small amount of g-Al2O3
remained. When the calcination temperature increased up to
1100 C, the phase transformation of g-Al2O3 to a-Al2O3 completed.
Throughout the calcination, there was no other alumina phase
except for g-Al2O3 and a-Al2O3. Showing the addition of glucose
promoted the g-Al2O3 transformed to a-Al2O3 directing, which is
due to the relaxation of amorphous aluminum hydroxide powders
reduced the defects and lattice distortion in g-Al2O3 powders