Fabrication of Nanosized Ag Colloids by Hydrazine Hydrate

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ORIENTAL JOURNAL OF CHEMISTRY

An International Open Free Access, Peer Reviewed Research Journal

www.orientjchem.org

ISSN: 0970-020 X
CODEN: OJCHEG
2016, Vol. 32, No. (1):
Pg. 463-465

# Fabrication of Nanosized Ag Colloids by Hydrazine Hydrate

Behrad Mosavar Rahmani and Hamid Reza Ghorbani*

¹Department of Chemical Engineering, Central Tehran Branch,

Islamic Azad University, Central Tehran, Iran
*Corresponding author: Email: hamidghorbani6@gmail.com

http://dx.doi.org/10.13005/ojc/320152

(Received: November 28, 2015; Accepted: January 26, 2016)

Abstract

In this work, we develop a simple method to synthesize nanosized Ag colloids with the addition
of hydrazine hydrate. UV–vis absorption spectra, dynamic light scattering (DLS) and transmission
electron microscopy (TEM) have been used to trace the growth process and elucidate the structure
of the silver nanoparticles. A solution in its UV–Vis absorption spectrum showed surface plasmon
resonance absorption bands about 421 nm. We obtain silver colloids of average size 92 nm with a
standard deviation of 30 nm after separation and washing procedures.

Key words: chemical synthesis, Ag colloids, hydrazine hydrate

Introduction

Due to its excellent electrical, thermal,
optical and/or catalytic properties, nanosized silver
colloids have received a great deal of attention in
recent years for various potential applications, such
as conductors, catalysts, chemical sensors, etc.it is
important to synthesize colloidal silver dispersions
with small sizes and narrow distribution.Silvert et al.
(1997) obtained finesized Ag particles whose size
distribution was between 15 and 36 nm by polyol
reduction. Despite these efforts, it remains difficult to
prepare silver particles of less than 20 nm and with
a narrow distribution from an aqueous solution. For
the polyol process, the reaction temperature must
consistently remain at 120 8C or higher, which adds

to the cost of production. Much finer particles (less
than 10 nm) can be fabricated using micelles and the
microemulsion method, but this also requires the use
of organic solvents 1 . Further, the initial concentration
of silver precursor in this method is still limited to less
than 0.05 M for size control purposes 2,3,4 . Citrate route
developed by Turkevich et al. is an excellentmethod
for the preparation of aqueous colloidal solution of
silver and gold. Direct large-scale synthesis can be
done by various chemical methods but we opine that
the use of additional mild reducing agent may offer
better particle morphology via an intermediate ionic
state 5 . Thus silver powder of modified surfaces with
controlled morphology can be prepared by several
methods including the reduction of silver nitrate by
reducing agents 6,7 .

464 Rahmani & Ghorbani, _Orient. J. Chem.,_ Vol. 32 (1), 463-465 (2016)

We herein describe an easy synthetic route for silver
nanoparticles byhydrazine hydrate as reducing
agent. The nanoparticles were characterized by
various techniques.

Materials and methods

All the chemicals and reagents used were
of analytical grade.An aqueous solution of hydrazine
hydrate was added to an aqueous solution of
silver nitrate (0.1 M). The drop-wise addition under
continuous stirring at room temperature afforded a
precipitate. After the complete addition of hydrazine
hydrate, stirring was continued for an additional 5

min.The reduction of the Ag+ ions by hydrazine
hydrate in the solutions was monitored by sampling
the aqueous component (2 ml) and measuring
the UV–Vis spectrum of solutions.Particle-size
distributions of the samples were also obtained
usingdynamic light scattering (DLS). Furthermore,
the silver nanoparticles were characterized by
transmission electron microscopy (TEM).

Results and discussions

It is well known that silver can be reduced
from Ag+ to Ag0 by various reducing agents same
hydrazine.The absorption band at about 421 nm is
known to be due to surface plasmon resonance in
nano-silver solutions. In fact, the energy ofabsorption
would depend on the degree of plasmon resonance
i.e. it may shift either side of this value depending
on the ratio of silver ions and zero-valent silver. The
UV–Visible spectrum (Fig. 1) of the solution showed
a well-defined surface plasmon resonance at <“421
nm.The technique outlined above has proven to be
very useful for analyzing nanoparticles 8 .

Dynamic light scatteringis a used method
for the determination of nanoparticle size.The silver
particles’ size histograms show that the nanoparticles
size is 92± 30 nm (Fig. 2).TEM micrograph of silver
colloidal particles is shown in Fig. 3. It can be noticed
that the graphs show that the particles are spherical
Fig. 1: UV–Visible spectrum of Ag
in shape.

nanoparticles

Fig. 2: A particle size distribution histogram of Ag nanoparticles

465 Rahmani & Ghorbani, _Orient. J. Chem.,_ Vol. 32 (1), 463-465 (2016)

Conclusions

Colloidal silver nanoparticles were
synthesized by hydrazine hydrate. The size of
the silver nanoparticles was 92± 30 nm. UV–Vis
spectroscopy confirmed silver nanoparticles. Also,
nanoparticles were characterized by DLS and TEM.
From a technological point of view, these obtained
silver nanoparticles have potential applications in the
various fields and this simple procedure has several
advantages such as cost effectiveness and scale
commercial production.

Fig. 3: TEM micrograph of Ag nanoparticles

References

1. Silvert, P. Y.;Urbina, R. H.;Elhsissen,K. T. _J._
_Mater. Chem_ ., 1997 _, 7_, 293.
2. Egorova, E. M.;Revina,A. A. _Colloids Surf. A:_
_Physicochem. Eng. Asp_ ., 2006, _168_, 87.
3. Xie, Y.; R. Ye; Liu, H. _Colloids Surf. A:_
_Physicochem. Eng. Asp.,_ 2006 _, 279_, 175.
4. Xue, F.; Liu, Z.; Su, Yi.;Varahramyan, K.
_Microelectron. Eng_ ., 2006, _83_, 298.

5. Ghorbani, H.R. Orient J chem., 2015, 31(1),
303.
6. Maleknia, L.,;Rashidi, A. S.Orient J chem.,
2015, 31(1), 257.
_7._ _Joerger, R.; Klaus, T.; Granqvist, C.G. Adv_
_Mater_ , 2000, _12,_ 407 _._
8. Ghorbani, H.R.; Soltani, S. Orient J chem.,
2015, 31(1), 303.

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