See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/250349345
Synthesis of Magnesium Oxide Nanoparticles by Sol-Gel Process Article in Materials Science Forum · October 2007 DOI: 10.4028/www.scientific.net/MSF.558-559.983
CITATIONS
READS
13
3,801
5 authors, including: S G Ansari
Mushtaq A. Dar
Jamia Millia Islamia
University of Nebraska at Lincoln
180 PUBLICATIONS 2,728 CITATIONS
48 PUBLICATIONS 659 CITATIONS
SEE PROFILE
SEE PROFILE
Young Soon Kim Rensselaer Polytechnic Institute 92 PUBLICATIONS 2,106 CITATIONS SEE PROFILE
All content following this page was uploaded by S G Ansari on 06 September 2014. The user has requested enhancement of the downloaded file.
Materials Science Forum Vols. 558-559 (2007) pp. 983-986 online at http://www.scientific.net © (2007) Trans Tech Publications, Switzerland
Synthesis of magnesium oxide nanoparticles by sol-gel process Rizwan Wahab1,a, S.G. Ansari1,b, M.A. Dar1,c, Y.S. Kim1,d and H.S. Shin 1,e 1
Thin film Technology laboratory, School of Chemical Engineering, Chonbuk National University, Chonju, S.Korea, 561-756 a
[email protected],
[email protected],
[email protected] d
[email protected],
[email protected]
Keywords: MgO, Sol-gel, Cubic nanoparticles
Abstract. Cubic shaped Magnesium oxide nanoparticles were successfully synthesized by sol-gel method using magnesium nitrate and sodium hydroxide at room temperature. Hydrated Magnesium oxide nanoparticles were annealed in air at 300 and 500ºC. X-ray diffraction patterns indicate that the obtain nanoparticles are in good crystallinity, pure magnesium oxide periclase phase with (200) orientation. Morphological investigation by FESEM reveals that the typical sizes of the grown nanoparticles are in the range of 50-70nm. Powder composition was analyzed by the FTIR spectroscopy and the results confirms that the conversion of brucite phase magnesium hydroxide in to magnesium oxide periclase phase was achieved at 300ºC.The Thermo-gravimetric analysis showed the phase transition of the synthesized magnesium oxide nanoparticles occurs at 280-300ºC. Introduction Nanoparticles have attracted a great attention in recent years because of their unique physical and chemical properties such as high strength with good thermal conductivity, higher damping property and mechanical stability [1]. The high surface reactivity, high chemical and thermal stability of MgO makes it a promising material for the application in sensors, catalysis, paint and additives etc [2-8]. Magnesium oxide nanoparticles and micro particles are largely used as a reinforcing reagent, as well as a component in super conductors [9]. Due to the high surface reactivity, highly chemical and high thermal stability with the catalytic properties, the magnesium oxide nanoparticles have particular interest [10]. The vast applications of magnesium oxide nanomaterials inclined to work on this material. Various kinds of fabrication techniques are employed to grow magnesium oxide nanoparticles such as vapor-liquid-solid (VLS), chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), Pulsed laser deposition (PLD), laser ablation, molecular beam epitaxy (MBE) and sputtering method have been frequently employed [4]. All these methods require high temperature or sophisticated and/or expensive instruments. The chemical route, Sol-gel processes, has become a promising option for the synthesis and large-scale production of nanostructured materials as well as magnesium oxide. In this paper, we present synthesis and characterization of crystalline cubic shaped MgO nanoparticles by sol-gel method at room temperature. Experimental Magnesium oxide nanoparticles were synthesized using magnesium nitrate (MgNO3.6H2O) as a source material with sodium hydroxide. All the chemicals used for this synthesis were purchased from Aldrich Chemical Corporation and used without further purification. For the typical experimental procedure; 0.2M magnesium nitrate (MgNO3.6H2O) was dissolved in 100 ml of deionized water. 0.5M sodium hydroxide solution was added drop wise to the prepared magnesium nitrate (MgNO3.6H2O) solution while stirring it continuously. White precipitate of magnesium hydroxide appeared in beaker after few minutes. The stirring was continued for 30 minutes. The pH of the solutions was 12.5, as measured by the expandable ion analyzer (EA 940, Orian, Korea). The precipitate was filtered and washed with methanol three to four times to remove ionic impurities All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of the publisher: Trans Tech Publications Ltd, Switzerland, www.ttp.net. (ID: 210.117.167.213-25/05/07,01:04:34)
984
Recrystallization and Grain Growth III
and then centrifuged for 5 minutes at 5000 rpm/min and dried at room temperature. The dried white powder samples were annealed in air for two hours at 300 and 500ºC. The morphological investigation was carried out by the field emission scanning electron microscopy (FESEM, Hitachi S4700). The crystallinity and crystal phases were determined by X-ray powder diffractometer (Rigaku, XRD) with CuKα Radiation (λ=1.54178Ǻ) with Bragg angle ranging from 30 to 80°. Samples composition of the synthesized magnesium oxide nanoparticle was analyzed by the Fourier transform infrared (FTIR) spectroscopy (Bomem, Model DA8-12, Canada) in the range of 4004000 cm-1. Thermo gravimetric (TG) and differential scanning calorimetry (DSC) were conducted by TGA 2050 thermo-gravimeter and DSC 2910 differential scanning calorimeter with the heating rate of 20º and 10º min-1 respectively. Result and discussion
Fig.1 (a) and (b): as grown magnesium oxide nanoparticles; (c), (d), (e) and (f) shows the cubic form of magnesium oxide nanoparticles annealed at 300ºC and 500ºC for two hours in air. o
(c) calcined at 500 C
o
40
60
70
Mgo(222)
MgO(311)
MgH2(200)
(a) As grown
*
MgO (220)
*
MgO(511)
* 50
*
MgH2(221)
Mg(O2) 2(413)
* *
MgO (200)
Mg(O2)2(202)
(b) calcined at 300 C
MgO(222)
Mg(O2)2(312)
MgO(111)
MgH2(111)
Intensity(a.u.)
Fig1 (a) and (b) shows the FESEM images of as grown magnesium oxide nano particles at room temperature. The particles appear spherical in shape, and agglomerated. High-resolution image of annealed powder at 300˚C (Fig 1(c) and (d)) clearly shows the cubic form of separated magnesium oxide nanoparticles, with particle size of about 50-60 nm. Annealing at 500˚C, results in further agglomeration of the particle as well as deterioration of the spherical shape. The cor responding SEM images are shown in Fig. 1(e) and (f), where elongated, spherical and cubic shaped nanoparticles of magnesium can be seen. Fig 2(a) shows the X-ray diffraction spectra of as grown magnesium oxide nanoparticles at room temperature. From the peak width and intensity we can easily see that the smaller particle size and better crystallinity.Fig.2(b)and (c)shows the X-ray diffraction pattern of the samples annealed at 300 and 500°C for two hours in air. The observed diffraction peaks are well matched with the typical single crystalline periclase phase of bulk MgO and are also in good agreement with the JCPDS file for MgO (JCPDS, Card No. 36–1451). No other peaks were detected in the spectrum within the detection limit of the X-ray diffraction instrument, indicating the purity of the synthesize powder. The (200) intense and sharp peak of periclase phase in the diffraction spectrum shows the high-crystallinity of the product. The composition of the sample was analyzed by the FTIR measurement. The 30 synthesized powder was mixed with KBr
80
2θ (Degree)
and the pellet of the mixture was used for Figure 2(a): X-ray diffraction spectra of (a) as grown magnesium infrared (IR) spectroscopic measurement at oxide nanoparticles, annealed at (b) 300 and (c) 500°C for two room temperature while the wavelength was hours in air* marked peaks are unidentified varied from 400 to 4000 cm-1. Fig 3(a) shows the spectra of as grown powder sample. The absorption band at 1630-1640 cm-1 indicates the bending mode of vibration in water (HOH) and the
Materials Science Forum Vols. 558-559
985
%Weight loss
Transmittance (a.u.)
broad and shallow band observed in the region between 3000-4000 cm-1 shows the stretching mode (c) of vibration in hydroxyl group (O-H). The peak at 3700 cm-1 is due to the O-H vibration of brucite phase of Mg(OH)2 .The broad spectrum between (b) 3300cm-1 to 3600 cm-1 shows the formation of MgO [12]. Narrow peak of magnesium hydroxide (a) at 3700 cm-1 disappeared in Fig 3 (b) and 3(c), which is due to calcinations of the sample at 300 and 500°C. It clearly indicates that the brucite phase of magnesium hydroxide is converted into the 4000 3500 3000 2500 2000 1500 1000 500 -1 periclase phase at two different annealing Wavenumbers (cm ) temperatures, analogous to X-ray diffraction results. Thermo gravimetric analysis is a technique Fig. 3: FTIR spectra of (a) as grown magnesium ° by which we can measures the mass loss with 100 respect to temperature. Fig. 4(b) shows the weight loss of the as grown powder sample. Primary 90 weight loss of ~ 11.92% was observed at 103°C due to the solvent evaporation. Phase transition solvent evaporation point 80 is found to occur at about 300°C indicating the phase transition point transition from magnesium hydroxide to 70 magnesium oxide with weight loss of ~ 1519%. 60
DSC was carried out in the range of 30°C to Formed magnesium oxide 350°C temperatures. Fig.4(b) shows a broad 500 200 400 600 800 0 exothermic signal was observed between 150°C Temperature C and 300°C.The broad exothermic signal at 150°C of primary weight loss is assigned to the Fig.4(a):Thermo-gravimetric spectrum of as grown magnesium oxide.
Exo and Endo
desorption of physically adsorbed water. The XRD spectrum (fig. 2b) of the sample annealed at 300ºC support the DSC observation, as the peaks of MgH2 disappears after calcination at 300°C. An exothermic signal with secondary weight loss was observed in between 280°C to 300°C, which is due to the phase transition of magnesium hydroxide powder in to magnesium oxide. Conclusion
50 100 150 200 250 300 350 In summary, brucite and periclase phase of 0 Temperature C magnesium oxide nanoparticles were synthesized by the sol-gel method using magnesium nitrate Fig. 4(b): Differential scanning calorimatery of as (MgNO3.6H2O) as a source material with sodium grown magnesium oxide. hydroxide. The dried white gel was annealed in air for two hours at 300 and 500ºC. SEM observations clearly show the cubic form of separated magnesium oxide nanoparticles of about 5060 nm in size. Annealing at 500˚C, results in further agglomeration of the particle as well as deterioration of the spherical shape. XRD measurements revealed typical single crystalline periclase phase of bulk MgO. No other peaks were detected in the spectrum within the detection limit of the X-ray diffraction instrument, indicating the purity of the synthesize powder. FTIR measurement
986
Recrystallization and Grain Growth III
shows that the brucite phase of magnesium hydroxide is converted into the periclase phase at the two different annealing temperatures, TGA and DSC indicates the transition from magnesium hydroxide to magnesium oxide. This method is found to be a mild and efficient route for the largescale industrial production of fine magnesium oxide nanoparticles without any template or expensive chemicals. Acknowledgement S G. Ansari acknowledges KOSEF and KRF for Brain-Pool fellowship. This work was supported by KMOST (research Grant No. 2004-01352), KOSEF (research Grant No. R01-2004-000-107920) and by the grant of Post Doc program, Chonbuk National University (01-the second half term of 2006). Authors would like to thank the Korea Basic Science Institute (Jeonju branch) for the use of their FESEM.
References [1] J.E. Gary, B. Luan, J. Alloys Comp 88(2002) 336. [2] S. Nagaoka, K. Hamasaki, T. Yamashita, T. Komata, Jpn. J. Appl. Phys. 8 (1989) 1367. [3] A.N. Basit, H.K. Kim, J. Blachere, Appl. Phys. Lett. 73 (1998) 3941. [4] S.K. Shukla, G.K. Parashar, A.P. Mishra, P. Misra, B.C. Yadav, R.K. Shukla, L.M. Bali, G.C. Dubey, Sens. Actuators B 98 (2004) 5. [5] W.Y. Hsu, R. Raj, Appl. Phys. Lett. 60 (1992) 3105. [6] P. Yang, C. M. Lieber, Science 273 (1996) 836. [7] A. Bhargava, J.A. Alarco, I D R. Mackinnon, D. Page, A. Iiyushechkin, Mater. Lett. 34 (1998) 33. [8] Y. S.Yuan, M.S. Wong, S. S. Wang, J. Mater. Res.11 (1996) 8. [9] B.M. Choudary, M.L. Kantam, K.V.S. Ranganath, K. Mahender, B. Sreedhar, J. Am. Chem. Soc. 126 (2004) 3396. [10] W.Richard, S. Li, C. Decker, O. Davidson, V. Koper, A. Zaikovski, A. Volodin, T. Richer, K.J. Klabuynde, J. Am. Chem. Soc. 122 (2000) 4921. [11] D. K. Fork, K. Nashimoto, T.H. Geballe, J. Appl.Phys.Lett. 60 (1922) 1621. [12] L.Hao, C.Zhu, X.Mo, W.Jiang, Y.Hu, Y.Zhu and Z.Chen, Inorganic chemistry comm.6(2003) 229-232.
View publication stats
