International Journal of Scientific & Engineering Research, Volume 5, Issue 3, March-2014 ISSN

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1 156 Copper Nanoparticles: Green Synthesis Characterization Y.Suresh*1, S.Annapurna*2, G.Bhikshamaiah*3, A.K.Singh#4 Abstract Present work describes the synthesis nanoparticles using papaya extract as a capping agent. preparation nanoparticles by using papaya extract has desired quality with low cost convenient methods. papaya extract was mixed with salt solution by heating to a temperature C the reduction reaction was studied by observing the color change. resulting nanoparticles were characterized by UV Visible Absorption Spectrometer, X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM) Transmission Electron Microscopy (TEM) experiments. X-ray diffraction analysis shows that the particles are FCC crystalline in nature. FTIR spectrum analysis has confirmed the presence functional groups stabilizer papaya in capping the nanoparticles. SEM TEM results display the formation nanoparticles with an average size 20 nm. Copper nanoparticles exhibit an absorption peak at around 560 nm. Index Terms - Papaya, Copper Nanoparticles, Reduction Reaction, Green Synthesis, Capping Agent, XRD, FTIR 1 INTRODUCTION Noble metal nanoparticles have been the For the last few years, many efforts have subject focused research due to their unique been made on the synthesis metallic optical, chemical nanoparticles in condensed phases with shape, size properties that are significantly different from growth control. Several methodologies have those bulk materials. For these reasons, metallic been proposed with interesting approaches to nanoparticles many control the nanomaterial properties such as size applications in different fields, such as catalysis, shape; these include metal vapor deposition, photonics, electronics. Preparation electrochemical reduction, thermal decomposition, nanoparticles has attracted considerable attention radiolytic reduction chemical reduction etc. due to their diverse properties uses, like [3], [4]. electronic, have mechanical found uses in catalysis, antimicrobial antibacterial activities, Most these methods are extremely surface-enhanced Raman scattering (SERS) [1], expensive also involve the use toxic, [2]. hazardous chemicals. This may pose potential * Department Physics, Osmania University, Hyderabad , India 1 su_msc@yahoo.com, 2sathirajua@yahoo.com, 3 gbhyd08@gmail.com # Defence metallurgical Research Laboratory, Kanchanbag, Hyderabad , India 4 singh_ashok3@rediffmail.com environmental biological risks. Since noble metal nanoparticles are widely applied to areas human contact, there is a growing need to develop environmentally friendly processes for nanoparticle synthesis that do not use toxic chemicals. Sometimes the synthesis nanoparticles using plants or parts plants can 2014

2 prove advantageous over other biological Characterization XRD patterns nanoparticles processes by eliminating the elaborate processes maintaining microbial cultures [5], [6]. were recorded using Philips X-ray diffractometer 2 EXPERIMENTAL coupled 2.1 Materials scanning was done using Cu Kα radiation in the with graphite monochrometer. All chemicals used were analytical range 2θ from 0 to 80. Crystallite size was reagent grade. chloride, calculated using Scherrer s formula given by sulphate, nitrate, L-Ascorbic acid, NaOH, equation (1). Hydrazine Hydrate (HH) was used as received. All D solutions were made with millipore water. 2.2 Synthesis Copper Nanoparticles In the present method, salts were where 0.89λ βcosθ is wavelength X-rays, (1) is the full used as basic precursors, papaya extract as width at half maximum X-ray prile θ is stabilizer, HH as reducing agent, L-Ascorbic acid the Bragg angle. as an anti-oxidant agent. NaOH was used as a FTIR spectra were recorded using catalyst also to adjust the ph to 12. Copper FTIR spectrometer. A known amount sample chloride solution was prepared separately. L- was ground with KBr the pellet form the Ascorbic acid was dissolved in Millipore water. samples was analyzed with FTIR instrument. Papaya extract the solution L-Ascorbic acid green synthesis nanoparticles was were added to chloride solution by heating monitored by UV-Vis spectroscopy. All spectra to a temperature C under rapid stirring. were corrected against the background spectrum n the solutions HH NaOH were added water as reference. Morphology size to the mixed salt solution under stirring. nanoparticles were investigated using initial blue color the reaction mixture scanning transmission electron microscopes eventually turned to brown-black color. Stirring (SEM TEM). was continued for another 1 hr to complete the 3 RESULTS AND DISCUSSION reaction. precipitate was washed twice with 3.1 XRD XRD patterns nanoparticles methanol after filtration then dried then the powder procedure, was obtained. Following nanoparticles were same (CuNPs) synthesized using different salts also papaya extract as stabilizer are shown in prepared using the other salts, Fig. 1. sulphate nitrate. 2014

3 158 Three main characteristic diffraction peaks capping reducing agent for the for Cu were observed at around 2θ = 43, 50, 74 nanoparticles synthesized using papaya extract which correspond to the (111), (200), (220) stabilizer. FTIR spectra nanoparticles crystallographic planes face-centered cubic (fcc) synthesized using different salts stabilized Cu phase (JCPDS No ). A small peak is also by papaya extract are shown in Fig. 2. broad observed at around 29 indicates that a small bs observed at around 3480 cm cm-1 amount is oxidized converted into illustrates the stretching frequency hydroxyl oxide. group (OH group) present in the surface the Transmittance(%) Relative intensity (a.u) nanoparticle Position ( 2ta) Wavelength(cm ) Fig.1. XRD patterns CuNPs Papaya lattice parameter a has been calculated by using these priles the average Fig.2. FTIR spectra CuNPs 3.3 UV-Vis Spectra Analysis value lattice parameter is found to be in the 1.0 agree with each other but also in agreement with reported value A in literature ([7]). In general, the width XRD peaks is related to crystallite size. Crystallite size nanoparticles was calculated using the Scherer s equation (1), found to be around 10 nm. Absorbance(a.u) range 3.61 A A. se values not only 3.2 FTIR FTIR measurement was carried out to Wavelength(nm) identify the possible molecules responsible for Fig.3. UV Visible spectra CuNPs

4 159 UV-Vis absorption spectra the SEM images nanoparticles nanoparticles are shown in Fig. 3. stabilized by papaya extract prepared using nanoparticles prepared using different salts chloride, sulphate nitrate are papaya extract stabilizer display an absorption shown in Fig.4 (a-c). Copper nanoparticles by this peak at around 560 nm. This peak can be assigned method show nearly monodispersed distribution to the absorption nanoparticles. particle sizes. average particle size the Cu broadness the absorption peak probably stems nanoparticles is around 20 nm. composition from the wide size distribution nanoparticles. nanoparticles was further probed by 3.4 SEM energy-dispersive X-ray (EDX) analysis. Fig. 5 shows the EDX pattern CuNPs prepared using sulphate, which indicates the presence Cu small amount oxygen. Fig.5. EDX pattern CuNPs prepared using sulphate 3.5 TEM Transmission electron microscopy (TEM) has been employed to characterize the size, shape morphology synthesized nanoparticles. is found to be the best precursor that gives better result among other salts used for the synthesis CuNPs, i.e., good Fig.4. SEM images CuNPs prepared using different particles size control along with papaya extract as salts, (a) (b) (c) capping nanoparticles synthesized using sulphate 2014 agent. TEM image

5 stabilized by papaya extract is shown in Fig REFERRENCES average size nanoparticles is around 20 [1] nm. sample studied reveal monodispersity [2] the metal particles. [3] [4] [5] [6] [7] S.C. Singh, R.K. Swarnkar R. Gopal, J. Nanosci. Nanotech. 1 (2009) 9. B. Balamurugan, B.R. Mehta S.M. Shivprasad, Appl. Phys. Lett (2001) 79. H. Lin, C. Wang, H.C. Shih, J. Chen C. Hsieh, J. Appl. Phys., 5889 (2004)95. J.J. Zhang, J.F. Liu Y.D. Li, Chem. Mater. 867 (2006) 18. Dhas NA, Raj CP, Gedanken A (1998). Synthesis, characterization, properties metallic nanoparticles. Chem. Mater., 10(5): Samim M, Kaushik N K Maitra A 2007 Bull. Mater. Sci Otte, H.M., J. Appl. Phys., 32, 1536 (1961). Fig.6. TEM image CuNPs prepared using sulphate 4 CONCLUSIONS A novel green approach for the synthesis Cu nanoparticles using papaya extract has been presented. This is a simple, green efficient method to synthesize nanoparticles at room temperature without using any harmful chemicals. It has been concluded that the green synthesized nanoparticles are nearly spherical crystalline. average particles size nanoparticles is around 20 nm. ACKNOWLEDGMENT authors thank DMRL, Hyderabad CFRD (Central facilities for Research Development), Osmania University, Hyderabad for providing experimental characterization facilities. authors are also grateful to the Head, Department Physics, Osmania University, Hyderabad for the needful assistance. 2014