Synthesis and Structural Characterization of Copper Oxide

‫ الفيزياء‬2102 ‫ نيسان‬22-22 ‫ الجامعة المستنصرية‬/ ‫المؤتمر العلمي التخصصي الحادي والعشرين لكلية التربية‬

Synthesis and Structural Characterization of Copper Oxide Nanoparticles Preparation by Two Different Sol-Gel Methods Tagreed. M. Al-Saadi1 and Noor A. Hameed2 1Department of Physics, College of Education for Pure Science Ibn-Al-Haithm , University of Baghdad, Baghdad, Iraq 2Department of Physics, College of Science, University of Diyala, Diyala, Iraq

Abstract In this study, Copper oxide nanoparticles (CuO-NPs) was prepared by sol-gel technique using Cu(NO3)2. H2O as precursor in two methods. Two samples were under study, first one is prepared by using , Cu(NO3)2. H2O and ethanol and the second one is by using Cu(NO3)2. H2O and NaOH. From the XRD data and Dicvol 91 software analysis, the crystal system was found to be monoclinic structure for both samples with ( a=4.652 Å, b=3.410 Å and c=5.108 Å) (α=γ= 90°and β= 99.478°) for method (1) and (a=4.647Å, b=3.417Å and c=5.160Å)(α=γ=90°and β=98.817°) for method (2). According to Debye-Scherrer’s formula the average . size for method (1) is 20.3 nm and for method (2) is 19.5 nm. The effect of particle size on the specific surface area, dislocation density and morphology index was discussed. The morphology of particle is characterized using scanning electron microscopy (SEM). There is a good agreement between data produced by spectroscopy and the microscopic measurements. The qualitative phase analysis performed by Rietveld analysis using “Fullprof” program of CuO-NPs for both methods. Keywords: CuO Nanoparticles ,Sol-gel , Structural properties , Rietveld refinement.

‫ جل ودراسة خصائصه التركيبية‬-‫تحضير أوكسيد النحاس النانوي بطريقتين مختلفتين للصول‬ 2

‫ ونور عامرالصفار‬0‫تغريد مسلم الساعدي‬

‫ العراق‬/ ‫ بغداد‬/ ‫ جامعة بغداد‬/ ‫ كلية التربية للعلوم الصرفة – إبن الهيثم‬/ ‫قسم الفيزياء‬1 ‫ العراق‬/ ‫ ديالى‬/ ‫ جامعة ديالى‬/ ‫ كلية العلوم‬/ ‫قسم الفيزياء‬2 ‫ حضرت العينة االولى‬.‫ جل وبطريقتين مختلفتين‬-‫تم في هذه الدراسة تحضيرأوكسيد النحاس النانوي من خالل تقنية الصول‬ ‫ وهيدروكسيد‬Cu(NO3)2. H2O ‫ واإليثانول والثانية بإستعمال نترات النحاس‬Cu(NO3)2. H2O ‫بإستعمال نترات النحاس‬ ‫ تم الحصول على معلمات‬، ‫) للفهرسة‬Dicvol 91) ‫) وبرنامج‬XRD) ‫ بإستعمال بيانات حيود الشعاع السيني‬. NaOH ‫الصوديوم‬ ( a=4.652 Å, b=3.410 Å and c=5.108 Å) (α=γ= 90°and β= ‫الشبيكة للعينتين والتي تعود للنظام أحادي الميل حيث كانت‬ ً ‫ وفقا‬.‫( للعينة الثانية‬a=4.647Å, b=3.417Å and c=5.160Å)(α=γ=90°and β=98.817°) ‫ للعينة األولى و‬99.478°) ‫ درس تأثير حجم‬.20.3 nm ‫) هو‬2( ‫ و للطريقة‬19.5 nm ‫) هو‬1( ‫ شيرر وجد أن متوسط حجم الحبيبات للطريقة‬-‫لمعادلة ديباي‬ ً‫ وجد ان هناك توافقا ً جيدا‬. ‫ معامل المورفولوجيا وغيرها من العوامل‬, ‫ كثافة اإلنخالعات‬, ‫الحبيبات على المساحة السطحية النوعية‬ ‫ كما تم التعرف على أشكال الحبيبات المحضرة بإستخدام المجهر‬, ‫بين البيانات الناتجة من التحليل الطيفي وحيود االشعة السينية‬ ‫ إجريت تحليالت الطور النوعية وعملية تصفية لبيانات حيود الشعاع السيني بإستعمال تحليالت ريتفيلد البرمجية‬. ‫األلكتروني الماسح‬ . ‫" لكال العينتين‬Fullprof "‫من خالل توظيف برنامج‬ . ‫ تصفية ريتفيلد‬, ‫ الخصائص التركيبية‬, ‫ الصول – جل‬, ‫ حبيبات أوكسيد النحاس النانوية‬: ‫الكلمات المفتاحية‬

1- Introduction Nano size materials exhibit unique electronic, magnetic, optical, catalytic and medicinal properties as compared with the traditional and commercial bulk materials. It is due to its quantum size effect, large surface to volume ratio is occurred [1]. CuONPs belong to monoclinic structure system and are of great interest due to their easiness of preparation and It has wide different applications according to the physical and chemical properties, such as superconductivity, photovoltaic properties, relatively stable, low cost and the antimicrobial activity [2]. CuO-NPs are important due to their applications as antimicrobials and in gas sensors, batteries, high temperature superconductors, solar cells applications, thermal conductivity and antioxidant [3-5]. Different methods are available to prepare CuO-NPs such as sol–gel technique [6], direct thermal decomposition [7], microwave irradiations [8], electrochemical methods [9], alcohothermal synthesis[10], thermal decomposition of precursor [11], etc. In the present study, we have synthesized (CuO-NPs) using different technique by a low cost sol-gel process. The aim of the present paper is to study the 544 (1)‫المجلد‬/ ‫مجلة كلية التربية عدد خاص‬


effect of different technique of Sol-Gel method on the structure, microstructure and size of CuO-NPs synthesized by this route.

2- Experimental Part The chemicals used in this study were , Cu(NO3)2. H2O (99.5%, Fluka, Ethanol (99.8%, Sigma-Aldrich) , NaOH (99.5%, Sigma-Aldrich) , All reagents were used as received without any further purification. Method (1): For the synthesis of CuO-NPs in this method , 5 gm of Cu(NO3)2. H2O is dissolved into 20 ml of ethanol. Cu(NO3)2.H2O is dissolved in ethanol solvent and stirred for 1 hour to obtain the homogeneous solution. This solution were kept for 1 day for gel formation. Then the gel was dried at 200℃ and calcined at 300℃ for 1 hour in each step. Then the obtained powder was annealed at 500℃ for 1 hour. Method (2): CuO-NPs were prepared by a sol-gel in this method . The copper hydroxide, Cu (OH)2 used as a precursor was prepared by reacting aqueous solution of 0.3M copper nitrate Cu(NO3)2 and 0.9 M sodium hydroxide (NaOH) solution was at room temperature. The resulting black color precipitate was washed several times with distilled water until it is free from nitrate ions, later centrifuged and dried in air at 100°C for 12h. CuO-NPs were synthesized by heat treating of the dried gel in air for 3 h at the temperature of 500℃, in order to decompose the hydrous copper oxide. The reactions involved in the preparation are shown below. 55°𝐶

Cu (NO3)2 (aqueous solutions) + 2 NaOH →

Cu(OH)2 + 2NaNO3

(1)

∆

Cu(OH)2 → CuO (powder) + H2O (vapour) (2) The powder X-ray diffraction (XRD) was performed using (Shimadzu XRD6000), goniometer with copper target (Cu Kα1, 0.15406 nm), (40 KV, 30 mA), step scan 0.02° and scanning angle range (2Ө=30°-80°) for both samples. The morphology of CuO-NPs was studied using scanning electron microscope (SEM) (VEGA\\EasyProbe). FTIR spectra were recorded using (Shimadzu IRAffinity-1 FTIR Spectrophotometer).

34- Results and Discussion The X-ray diffraction pattern of the synthesized CuO-NPs for both methods is shown in figure (1). The patterns of CuO-NPs exhibited strong diffraction peaks at (35.728 °, 38.940 °, 49.031 °) and (35.680 °, 38.791 °, 48.942 °). The experimental XRD pattern for CuO-NPs according to method (1) and (2) agree with the JCPDS card no. (05-0661).

Fig. (1): XRD pattern of CuO nanoparticles for method (1) and (2)

544 (1)‫المجلد‬/ ‫مجلة كلية التربية عدد خاص‬


3-1 Particle Size Calculation The average crystalline size was determined by Debye-Scherrer’s (D-S) equation [12-15]: D = Kλ / βD cosӨ ……(1) where D: crystallite size, K: constant, λ: wavelength of Cu kα radiation and βD: is the broadening due to small crystallite size (FWHM) . Williamson-Hall (W-H) method was used to determine size and lattice strain of crystallite from XRD data[16]. The strain induced in powders arise from defects like dislocation, twinning, imperfection and distortion was determined by the equation: ɛ = βs /4tanӨ ……(2) where βs: is the peak broadening due to lattice strain, Ө: is the Bragg’s angle. From equations (1&2), the total peak broadening βhkl may be expressed as: βhkl = βD + βs ……(3) βhkl cosӨ = (Kλ / D) + (4ɛ sinӨ) ……(4) The equation (4) is W-H equation. W-H plot is shown in figure (2). It is plotted with sinӨ on the x-axis and βhkl cosӨ on the y-axis (βhkl in radian). Table (1) shows strain and grain size according to W-H and grain size according to D-S for CuO-NPs for both method. Table 1. Strain and particle size according to W- H and particle size according to D-S for CuO-NPs Samples CuO D (W-H)nm ɛ (W-H)*10-4 D (D-S) nm method 1 36.4 21 20.3 method 2 15 16 19.5 From table (1), it is shown that the average grain size of the CuO-NPs for method (2) is smaller than method (1), and the difference between grain size according to W-H and grain size according to D-S occurs because W-H method takes into account the lattice strain of crystallite arising from the defects like dislocation, twinning, imperfection and distortion.

Fig. (2): Williamson Hall plot of CuO-NPs for method (1) and method (2).

3-2 Texture Coefficient (TC) The texture coefficient (TC) represents function to describe the orientation distribution in crystallites, it is defined as [17]: TC(hkl) = [I(hkl) / Iₒ(hkl)] / [N-1 Ʃn I(hkl) / Iₒ(hkl)] ……(5) Where: I(hkl) : is the measured relative intensity of a plane (hkl). 544 (1)‫المجلد‬/ ‫مجلة كلية التربية عدد خاص‬


Iₒ(hkl) : is the standard intensity of the plane (hkl) taken from the Joint Committee on Powder Diffraction Standards (JCPDS) data. N : is the number of reflections. n : is the diffraction peaks number. TC can be described as preferred oriantation for a particular plane within the crystal for a multi - shape what is called a factor of forming compositions , when 1≤ TC, this confirms that the direction of crystal growth levels favorites (mostly) be part of this trend either when TC