CHEM01200604004 Shri Sanyasinaidu Boddu - Homi Bhabha ...

Figure 19 (a-d) shows SEM images of GaOOH samples prepared with different
concentration of urea. All the samples are having rod shaped morphology. With increase in
the concentration of urea up to 80 mmol, the length and width of the nanorods increases from
0.6-0.8 and 0.1-0.15 mm to 2.4-3.0 and 1.5-2.5 mm, respectively. For further addition of urea,
irregular shaped particle aggregates start forming along with nanorods. This can be explained
based on nucleation and growth process which are controlled by number of hydroxyl ions
generated in the reaction medium. Initially, upto 80 mmol of urea, nanorods growth take
place in a particular direction due to the presence of hydroxyl ions whereas above that
number of hydroxyl ions increases and growth takes place in all directions. As a result,
irregular shaped particles start forming.
(a)
(b)
(c)
(d)
Fig.19. SEM images of GaOOH nanorods prepared with (a) 15 mmol, (b) 80 mmol, (c) 115
mmol and (d) 180 mmol of urea
3.3. Effect of lanthanide ion concentration on morphology and crystal structure of
GaOOH: The lanthanide doped GaOOH nanomaterials were prepared by co-precipitation
method using hydrolysis of Ga(NO 3 ) 3 and Ln(NO 3 ) 3 .xH 2 O by urea. In all preparations
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