Photonic crystals in biology

Poster Session, Tuesday, June 15
Synthesis and Characterization of Palladium Nanoparticles Stabilized by Tannic Acid
Emrah Bulut 1 ,Mustafa Can 2 *, Hilal Köse 1 and Mahmut Özacar 1
1 Sakarya University, Department of Chemistry, 54187 Sakarya, Turkey
2
Sakarya University, Institute of Sciences and Technology, 54187 Sakarya, Turkey
Theme A1 - B702
Abstract-Palladium nanop articles were prepared with the sol-gel method using tannic acid as reducing and stabilizing agent. The OH
groups of tannic acid oxidized by the reduction of palladium ions and then formed metallic palladium nanop articles stabilized by the
tannic acid derivatives. Formed palladium nanop articles were characterized by XRD, SEM and EDS.
Nanoscale materials have received considerable attention
because the particles in the nanometric size range are
thought of as a bridge between molecules and bulk
materials. These nanomaterials often exhibit very
interesting chemical, optical, electronic, and magnetic
properties that are unachievable in bulk materials.
Moreover, ultrafine particles of noble metals have
attracted particular interest because their increased number
of edges, corners, and faces gives them a high
surface/volume ratio and therefore they are useful in
various fields of chemistry. Because of these unique
characteristics, metal nanoparticles are being intensively
studied for applications in catalysis, optoelectronics,
preservatives, and biosensing, biological labeling,
controlled drug delivery, etc. [1-3].
Catalysis provides a natural application for nanoparticles
because their large surface area-to-volume ratio allows
effective utilization of expensive metals. Without a
suitable support, however, metal particles aggregate,
reducing surface area and restricting control over particle
size. To overcome this problem, catalytic nanoparticles
have been stabilized by capping ligands that range from
small organic molecules to large polymers. Encapsulation
by polymers is advantageous because in addition to
stabilizing and protecting the particles, polymers offer
unique possibilities for modifying both the environment
around catalytic sites and access to these sites [2-5].
More recently, with the development of nanotechnology,
this purpose may be achieved via stabilizing them by
synthetic polymers. Ideally, the stabilizers should have
moderate affinity towards metal nanoparticles, so that the
aggregation of metal nanoparticles can be prevented. In
this study, we describe “tannic acid-stabilized method” for
the preparation of palladium nanoparticles. The general
characteristic of tannic acid are able to chelate with many
kinds of metal ions through their dense ortho-phenolic
hydroxyls, and capable of scavenging free radicals so as to
prevent metal species from oxidation. The property of
tannic acid implies that it could be used as an ideal
stabilizer for preparing stabilized-metal nanoparticles. It is
reported that silver nanoparticles have been successfully
prepared by using polyphenols as the stabilizers [6-7].
Using a tannic acid as the stabilizer, our research group
also developed a facile route for the synthesis of Pd(0)
nanoparticles.
In the present study, palladium nanoparticles are
prepared using tannic acid acting as both the reducing and
stabilizing agent. A novel and facile method was applied
to synthesize palladium nanoparticles that have catalysts
feature by using tannic acid which have reduction effect
with involving -OH groups and keeps the prepared
particles stable because of its mo lecular structure.
The tannic acid stabilizes the newly born Pd 0 clusters and
can influence the growth of the nucleation and hence
particle size. No other reducing agents were used during
palladium nanoparticle synthesis. Pd 2+ 0 reaction
occurs in aqueous tannic acid above 50 o C.
Characterization of the resulting nanoparticles by X-Ray
Diffraction (XRD) and Scanning Electron Micrographs
(SEM) are presented in Figure. 1 and 2.
Figure 1. SEM image of Pd nanoparticles
Figure 2. XRD pattern of Pd nanoparticles
* Corresponding author: mstfacan@gmail.com
[1] A. Nemamcha, J.-L. Rehspringer and D. Khatmi, J. Phys.
Chem. B 110, 383 (2006).
[2] P.S. Roy, J. Bagchi and S.K. Bhattacharya, Transition Met.
Chem. 34, 447 (2009).
[3] S. Kidambi and M. L. Bruening, Chem. Mater. 17, 301
(2005).
[4] N. Karousis et al., J. Phys. Chem. C 112, 13463 (2008).
[5] X. Huang et al., Catal Lett. 133, 192 (2009).
[6] E Bulut and M. Özacar, A Facile Aqueous-Phase Route to
Synthesis of Silver Nanoparticles and Nanosheets, 4. Ulusal
-13 Haziran, 2008,
[7] E. Bulut, M. Özacar, Ind. Eng. Chem. Res. 48, 5686 (2009).
6th Nanoscience and Nanotechnology Conference, zmir, 2010 273