2. Experimental procedure
2.1. Materials
The following chemicals zinc nitrate (99% purity, Merck),
potassium hydroxide (85% purity, Merck), lead acetate and
phenolphthalein were procured from Merck and used without
further purification.
2.2. Microwave assisted synthesis procedure
All the chemicals and reagents used in this experiment were of
analytical grade and used without further purification. Preparation process of nano ZnO rods in our study is as follows: 29.749 g
of zinc nitrate was dissolved in 200 ml of double distilled water.
Then 1 M KOH prepared in DD water was added dropwise very
slowly into the zinc nitrate aqueous solution at a stirring rate of
500–520 rpm till the required pH of 13, 11 and 9 was attained.
Also, when the viscosity of the mixture increases, the revolution
of the Teflon was so adjusted to maintain the stirring rate of 500–
520 rpm throughout the experiment. After the addition was
completed, the stirring was continued for another 30 min at
601C. During stirring a milky white suspension of Zn(OH)2was
obtained. The above solution was kept overnight at room temperature and the precipitate was filtered, washed thoroughly with double distilled water several times. The filtrates were tested for
the absence of pink color with phenolphthalein and white precipitate with lead acetate. Then the obtained precipitates were
dried at 601C and then suspended in 100 ml of double distilled
water in a 1000 ml beaker and irradiated with microwaves using
a domestic microwave oven (Samsung MW 73 V) at 180 W for
30 min. The resultant precipitates were filtered and then calcined
at 2001C under a vacuum oven for two hours. The products
obtained from three different precursor solutions of pH 13, 11 and
9 were named as A1, A2 and A3 respectively. The crystallinity and
phase identification of the samples were analyzed using powder
X-ray diffraction in steps of 0.051in 2yrange of 10–801withKa
radiation (l¼1.5406˚
A) using X’Pert X-ray diffractometer.
The morphology of the as-synthesized product was investigated
using Quanta 200 FEG High Resolution Scanning Electron Microscopy (IIT, Chennai). The optical properties of the samples were
studied by recording the Diffused Reflectance Spectra using UV–visible spectrophotometer-Schimadzu UV2450 and Photoluminescence spectra using LS45 Perkin–Elmer luminescence spectrometer. The product formation was confirmed from FT-IR
spectra in the range of 400–4000 cm
1
using a KBr pellet method