SYNTHESIS OF SILVER NANOPARTICLES BY CHEMICAL

REDUCTION OF TOLLENS' REAGENT

-Shantanu Lanke - Ankur Chaturvedi -V. M. Balsaraf -Sonali Kokane -Bhagyashree Chalke

A brief introduction…

Silver nanoparticles are nanoparticles of silver, i.e. silver particles of between 1 nm and 100 nm in size.

There are many different synthetic routes to silver nanoparticles. They can be divided into three broad categories: physical vapour deposition,ion implantation,or wet chemistry.

A brief introduction…

We report synthesis of silver nanoparticles by reducing Tollens’ reagent with an aldehyde such as formaldehyde in presence of sodium citrate in aqueous medium. The resulting nanoparticles were found to be stable upto a few months and were characterized using UV-VIS Spectroscopy,SEM, TEM,HRTEM and SAED

Aims and Objectives

Aims:-Synthesis of silver nanoparticles at room temperature by tollen’s reagent.

Characterization of nanoparticles. Applications in the fields of medicine and

catalysis.Objectives:-1) To show room temperature feasibility of

formation of silver nanoparticles.2) To demonstrate increased reactivity of

activated silver ions from tollen’s reagent,towards weak reducing agents.

SYNTHESIS

The nanoparticles were synthesized by the bottom-up approach.

The synthesis is carried out by the chemical reduction of Tollens' reagent. This method allows selective synthesis of silver nanoparticles.

SYNTHESIS

The reaction is carried out at the room temperature in presence of trisodium citrate as a capping agent.

The resulting yellow solution indicates the formation of the silver nanoparticles ranging from the sizes 5-50nm.

SYNTHESIS

Photograph of the silver nano solution

CHARACTERIZATION

The nanoparticles were characterized by the analytical techniques such as UV-VIS spectroscopy, SEM, TEM, HRTEM and SAED.

The results are in concurrence with the existing literature

CHARACTERIZATION

UV-VIS SPECTROSCOPY-1

CHARACTERIZATION

UV-VIS SPECTROSCOPY-2

PROPERTIES

SEM IMAGE-1

PROPERTIES

SEM IMAGE-2

PROPERTIES

SEM IMAGE-3

PROPERTIES

TEM IMAGAES OF NANOPATICLES

PROPERTIES

HRTEM IMAGE ELECTRON DIFFRACTION

APPLICATIONS

Silver nanoparticles show antimicrobial activity and they can kill any microorganism within 6 mins without harming the human tissues.

Therefore, they can be used in water purification systems.

APPLICATIONS

Silver nanoparticles also used in the Surface Enhanced Raman Spectroscopy(SERS).

Silver nanoparticles have been used as the cathode in a silver-oxide battery.

They can also be used as a heterogeneous catalysis due to the very high surface area.

They can also be used as a bone cement.

APPLICATIONS

As mentioned before silver nanoparticles can be used in the catalysis of heterogeneous silver catalysed reactions due to their high surface area to volume ratio.The surface area increment due to the use of nano-catalysts is about 2 * 10^6 times that over bulk catalysts.Hence these nanoparticles can be used as catalysts in reactions like silver catalysed coupling,benzylation and alkylation reactions.

APPLICATIONS

Silver nanoparticles can be used in the formation of nanocages of palladium i.e when reacted with the solution of Na2PdCl4 palladium nanocages are formed.Nanoporous nanoparticles of platinum can be made in the same way i.e by using silver nanoparticles.

An advantage of these nanoporous particles is that they have a surface area increment of around 2 * 10^9 times that over bulk catalysts.These particles of platinum can then be used as catalysts in chemical processes(e.g:-contact process)

APPLICATIONS

SEM IMAG PALLADIUM NANOCAGES

UV-VIS SPECTRA OF PALLADIUM NANOCAGES

300 350 400 450 500 550 600 650 700 750 8000

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9Silver Nanopar-ticlesPalladium NanocagesNa2PdCl4

Wavelength /nm

Absorb

ance

ACKNOWLEDGEMENTS

Special thanks to Prof.S.J.Kulkarni(DMCE) Prof.P.M.Ingole(DMCE) Dr.(Mrs)K.S.Deshmukh(HOD-Chem

Dept,DMCE) Prof. Sonali Dhokapande(DMCE) Dr.V.V.N. Ravi Kishore (DY-Patil

University)

REFERENCES

[1] Mazur M. Electrochemistry Communications 6, (2004) 400-403. [2] Pal A., Shah S., Devi S. Colloids and Surfaces A 302, (2007) 483-487. [3] Rosemary M.J., Pradeep T. Colloids and Surfaces A 268, (2003) 81-84. [4] Xie Y., Ye R., Liu H. Colloids and Surfaces A 279, (2006) 175-178. [5] Maillard M., Giorgo S., Pileni M.P. Adv.Mater. (2002) 14(15), 1084-1086. [6] Pillai Z.S., Kamat P.V. J.Phys.Chem.B. (2004) 108, 945-951. [7] Patel K., Kapoor S., Dave D.P., Murherjee T. J.Chem.Sci. (2005), 117(1), 53-60. [8] Salkar R.A., Jeevanandam P., Aruna S.T., Koltypin Y., Gedanken A. J.Mater.Chem. 9, (1999) 1333-1335. [9] [9] Soroushian B., Lampre I., Belloni J., Mostafavi M. Radiation Physics and Chemistry (2005)

72, 111-118. [10] Starowicz M., Stypula B., Banaoe J. Electrochemistry Communications (2006) 8, 227-230.

2006. [11] Zhu J.J., Liao X.H., Zhao X.N., Hen H.Y. Materials Letters (2001) 49, 91-95. 2001. [12] Liu S., Chen S., Avivi S., Gendanken A., Journal of Non-crystalline Solids (2001) 283, 231- 236. [13] Chen Z., Gao L. Materials Research Bulletin 42 (2007), 1657-1661. [14] Kumar A., Joshi H., Pasricha R., Mandale A.B., Sastry M., Journal of Colloid and Interface Science 264 (2003) 396. [15] Li D.G., Chen S.H., Zhao S.Y., Hou X.M., Ma H.Y., Yang X.G., Thin Solid Films 460 (2004) 78.

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