Synthesis and Electrochemical Properties of CuO Nanobelts
4
Materials Chemistry and Physics 112 (2008) 726–729 Contents lists available at ScienceDirect Materials Chemistry and Physics journal homepage: www.elsevier.com/locate/matchemphys Materials science communication Synthesis and electrochemical properties of CuO nanobelts Xiaojun Zhang a,b,∗ , Guangfeng Wang a,c , Xiaowang Liu a,b , Huaqiang Wu a,b,∗ a College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, PR China b Anhui Key Laboratory of Functional Molecular Solids, Anhui Normal University, Wuhu 241000, PR China c Anhui Key Laboratory of Chem-Biosensing, Anhui Normal University, Wuhu 241000, PR China article info Article history: Received 14 November 2007 Received in revised form 26 January 2008 Accepted 29 June 2008 Keywords: Inorganic compounds Chemical synthesis Crystal growths Electrochemical properties Nanostructures abstract CuO nanobelts have been successfully prepared with high yield via a simple hydrothermal reduction process at a low temperature. The as-prepared CuO nanowires were characterized by XRD, SEM, TEM and HRTEM techniques. The growth mechanism of these nanostructures is discussed. The electrochemical tests show that the ultrafine CuO nanobelts, as a promising electrode material, can deliver a large discharge capacity of about 500 mA h g −1 . © 2008 Elsevier B.V. All rights reserved. 1. Introduction The study of one-dimensional nanostructures is one of the most active areas due to their peculiar, fascinating physical, chemical and mechanical properties different from the bulk material. In particular, their important role as both interconnect and active component for fabricating nanoscale electronic and phonic devices has attracted attention [1–3]. Cupric oxide (CuO) is a p-type semi- conductor with a narrow band gap (1.2eV) and exhibits a number of interesting properties [4]. Copper-oxide-based materials have widespread applications [5–8], such as high-temperature super- conductors, optical switch and anode electrodes for batteries. And then, CuO has been exploited powerfully heterogeneous catal- yse capability to convert hydrocarbons completely into carbon dioxide and water [9]. Several methods have been developed to prepare one-dimensional nanostructures. Among these, chemical vapor deposition (CVD) [10], laser vaporization, electrochemi- cal techniques [11,12], hydrothermal treatment [13,14] and the exfoliating method [15] have been documented. Although these templates were effective in preparing nanobelts with uniform and controllable dimensions, they usually lead to complicated process. ∗ Corresponding authors. Tel.: +86 553 3869303; fax: +86 553 3869303. E-mail address: [email protected] (X. Zhang). Here we report a new method of the synthesis and characteriza- tion of CuO nanobelts. The synthesis was performed using a simple hydrothermal reduction process at a low temperature. 2. Experimental All of the chemical reagents used were of analytical grade. In a typical synthesis process, 0.5 g CuSO4 is first dissolved in 50 ml distilled water. Then, 30 ml ammonia (0.15 M) solution is added to the CuSO4 solution under constant stirring. A blue pre- cipitate of Cu(OH)2 is produced when 5 ml NaOH (1.2 M) solution is added dropwise to the above solution. After stirring for 15min, the blue Cu(OH)2 precipitate was dried in an oven at 50 ◦ C for 12h. The product was washed with distilled water and ethanol for several times to remove the impurities before characterizations. The samples, which were recorded at a scanning rate of 0.05 ◦ s −1 with the 2 range from 10 ◦ to 80 ◦ , were characterized by XRD using an X-ray diffractometer with high-intensity Cu K radiation ( =0.154178nm). FE-SEM was used JEOL JSM-6700 FESEM (operated at 10kV). Teflon cells were made to study the electrochemical properties of the product. The positive electrode consisted of the prepared CuO (80 wt% nanobelts and nanoparticles), carbon black (10 wt%) and polyvinylidene (PVDF, 10 wt%). The cells were assembled in an argon filled glove box in which both the moisture and the oxygen levels were less than 1 ppm. The electrochemical tests were made in the voltage range of 0.5–3.5 V at a current density of 0.1 mA cm −2 . 3. Results and discussion Fig. 1 shows the XRD profiles taken from the as-prepared Cu(OH) 2 nanobelts and CuO nanobelts. The peaks in Fig. 1a can all be well indexed in the orthorhombic Cu(OH) 2 structure with lattice constants a = 2:951 Å, b = 10:59 Å and c = 5:273 Å (JCPDS 35- 0505). And as shown in Fig. 1b, all of the reflections of the 0254-0584/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.matchemphys.2008.06.064
Transcript of Synthesis and Electrochemical Properties of CuO Nanobelts
-
Materials Chemistry and Physics 112 (2008) 726729
Contents lists available at ScienceDirect
Materials Chemistry and Physics
journa l homepage: www.e lsev ier .com/ lo
Materials
SyntheCuO na
Xiaojun Z uaqa College of Cheb Anhui Key Lab inac Anhui Key Lab
a r t i c l
Article history:Received 14 NReceived in reAccepted 29 Ju
Keywords:Inorganic comChemical syntCrystal growthElectrochemicNanostructure
y prereparnisms, as a
1. Introduction
The studactive areasand mechaparticular,componenthas attracteconductor wof interestiwidespreadconductorsthen, CuOyse capabildioxide andprepare onevapor depocal techniqexfoliatingtemplatesand controprocess.
CorresponE-mail add
Herewe report a newmethod of the synthesis and characteriza-tion of CuO nanobelts. The synthesis was performed using a simple
0254-0584/$ doi:10.1016/j.my of one-dimensional nanostructures is one of themostdue to their peculiar, fascinating physical, chemical
nical properties different from the bulk material. Intheir important role as both interconnect and activefor fabricating nanoscale electronic and phonic devicesd attention [13]. Cupric oxide (CuO) is a p-type semi-ith a narrow band gap (1.2 eV) and exhibits a number
ng properties [4]. Copper-oxide-based materials haveapplications [58], such as high-temperature super-
, optical switch and anode electrodes for batteries. Andhas been exploited powerfully heterogeneous catal-ity to convert hydrocarbons completely into carbonwater [9]. Several methods have been developed to-dimensional nanostructures. Among these, chemicalsition (CVD) [10], laser vaporization, electrochemi-ues [11,12], hydrothermal treatment [13,14] and themethod [15] have been documented. Although thesewere effective in preparing nanobelts with uniformllable dimensions, they usually lead to complicated
ding authors. Tel.: +86 553 3869303; fax: +86 553 3869303.ress: [email protected] (X. Zhang).
hydrothermal reduction process at a low temperature.
2. Experimental
All of the chemical reagents used were of analytical grade. In a typical synthesisprocess, 0.5 g CuSO4 is rst dissolved in 50ml distilled water. Then, 30ml ammonia(0.15M) solution is added to the CuSO4 solution under constant stirring. A blue pre-cipitate of Cu(OH)2 is producedwhen 5ml NaOH (1.2M) solution is added dropwiseto the above solution. After stirring for 15min, the blue Cu(OH)2 precipitate wasdried in an oven at 50 C for 12h. The product was washed with distilled water andethanol for several times to remove the impurities before characterizations.
The samples, which were recorded at a scanning rate of 0.05 s1 with the 2range from10 to 80 , were characterized byXRDusing anX-ray diffractometerwithhigh-intensity Cu K radiation (=0.154178nm). FE-SEM was used JEOL JSM-6700FESEM (operated at 10kV). Teon cells were made to study the electrochemicalproperties of the product. The positive electrode consisted of the prepared CuO(80wt% nanobelts and nanoparticles), carbon black (10wt%) and polyvinylidene(PVDF, 10wt%). The cells were assembled in an argon lled glove box in which boththe moisture and the oxygen levels were less than 1ppm. The electrochemical testswere made in the voltage range of 0.53.5V at a current density of 0.1mAcm2.
3. Results and discussion
Fig. 1 shows the XRD proles taken from the as-preparedCu(OH)2 nanobelts and CuO nanobelts. The peaks in Fig. 1a canall be well indexed in the orthorhombic Cu(OH)2 structure withlattice constants a=2:951, b=10:59 and c=5:273 (JCPDS 35-0505). And as shown in Fig. 1b, all of the reections of the
see front matter 2008 Elsevier B.V. All rights reserved.atchemphys.2008.06.064science communication
sis and electrochemical properties ofnobelts
hanga,b,, Guangfeng Wanga,c, Xiaowang Liua,b, Hmistry and Materials Science, Anhui Normal University, Wuhu 241000, PR Chinaoratory of Functional Molecular Solids, Anhui Normal University, Wuhu 241000, PR Choratory of Chem-Biosensing, Anhui Normal University, Wuhu 241000, PR China
e i n f o
ovember 2007vised form 26 January 2008ne 2008
poundshesissal propertiess
a b s t r a c t
CuO nanobelts have been successfullprocess at a low temperature. The as-pHRTEMtechniques. Thegrowthmechashow that the ultrane CuO nanobeltcapacity of about 500mAhg1.cate /matchemphys
iang Wua,b,
pared with high yield via a simple hydrothermal reductioned CuO nanowires were characterized by XRD, SEM, TEM andof thesenanostructures is discussed. Theelectrochemical testspromising electrode material, can deliver a large discharge
2008 Elsevier B.V. All rights reserved.
-
X. Zhang et al. / Materials Chemistry and Physics 112 (2008) 726729 727
Fig. 1. XRD pattern of the CuO nanobelts.
XRD pattern of the as-synthesized CuO nanobelts could be easilyindexed to the monoclinic-phase CuO (space group C2/c), which isvery close to the reported data (JCPDS 41-0254). At the same timeno characteristic peaks of impurities can be detected. This indi-cated that CuO products were obtained under current syntheticconditions.
Morphology and size of the product were studied by SEM.SEM images of the as-synthesized CuO nanobelts are shown inFig. 2. Bulk quantities of the nested CuO nanobelts were fabricatedwith relatively uniform diameters. The nanowires are relativelystraight and long, resulting in a large aspect ratio. The diametersof nanowires range from 5 to 20nm. It can be seen that mostnanowireshundreds o10nm estim
TEM images of the sample are shown in Fig. 3. A large amountof nanobelts with a diameter of 820nm are observed in Fig. 3a.The HRTEM image reveals that the CuO nanobelts are also poly-crystalline with a nanocrystal size around 38nm (Fig. 3b).
For CuO nanobelts we suggest the following mechanism. First,Cu2+ cations in the CuSO4 solution form a square-planar com-plex [Cu(NH3)4]2+ with the addition of ammonia. When NaOH isadded, the pH value of the solution increases and the stability ofthe [Cu(NH3)4]2+ decreases. The effects of pH and ammonia onthe Cu(OH)2 morphology have been studied by Wang et al. [16],Cu(OH)2 precipitates because it is more stable than [Cu(NH3)4]2+.It is conceivable that the nucleation of Cu(OH)2 starts from local-ized regions with relatively high concentrations of OH wherethe [Cu(NH3)4]2+ complex is unstable. Because a large number ofnuclei are formed simultaneously,many Cu(OH)2 nanocrystals pre-cipitate. However, is a layered structure and the growth rate isanisotropic. Therefore, the shape of the Cu(OH)2 nanocrystals isnot spherical and they prefer a morphology with one dimensionlonger than the others. At a certain point the nanocrystals aggre-gate and assemble to formnanowires. The formationmechanismofthe CuO nanobelts is easy to understand. During the heating pro-cess, the Cu(OH)2 nanobelts loose H2O molecules and transforminto CuO while the nanobelt morphology still remains. A detailedtransformation process from Cu(OH)2 to CuO was suggested byCudennec and Lecert [17]. The loss of water is performed by anoxolation mechanism, which involves a dehydration process andthe formation of OCuO bridges. Bridges are formed after the lossof watermolecules followed by a contraction of the structure alongthe [010] direction. Simultaneously shifts of CuO4 groups or Cuatoms along (001) direction are performed to promote the evolu-tion towards crystallized CuO.
The electrochemical property of the as-synthesized CuOlts is studied by galvanostatic method using CuO/Li Teonhe vof 0.5
Fig. 2. (a) HigLow-magnicahave diameters of ca. 10nm, and the lengths of up tof micrometers. The average diameter of nanowires is ca.ated from the SEM images.
nanobecells. Trange oh-magnication view about Cu(OH)2 nanobelts. (b) Low-magnication view about Cu(OHtion view about CuO nanobelts.ltage versus capacity for the CuO/Li cell in the voltage3.5V at a current density of 0.1mAcm2 is shown in
)2 nanobelts. (c) High-magnication view about CuO nanobelts. (d)
-
728 X. Zhang et al. / Materials Chemistry and Physics 112 (2008) 726729
EM im
Fig. 4a. Theity of 940mrst discharthe reductiocannot be eabsorbed onappears beccompletely.CuO is 940suggested tions into thFig. 4b shoThe dischaaround 500which mighlithium intocycles, the dremains relstill remaincal CuO nancapacity is othe dischargtrochemicamight be a gcurrently u
4. Conclus
In summpared withFig. 3. (a) TEM image of CuO nanobelts and (b) HRTFig. 4. Charge curve (a) and cycling behavior (b) of the as-sy
as-synthesized CuO shows an initial discharge capac-Ahg1. We can nd an additional plateau at 2V in thege curve after close observation. It may be attributed ton of O2 and H2O [18]. The participation of O2 and H2Oxcluded, since these species are known to be stronglythe CuO surface. At the second charge, the plateau dis-ause O2 andH2O absorbed on the CuO surface decreaseThe reason is why the initial discharge capacity ofmAhg1. According to previous research [19,20], wehat the discharge reaction involves intercalation of Li+
e CuO lattice according to CuO+ xLi+ + xe LixCuO.ws the cycling behavior of the CuO/Li Teon cells.rge capacity decreases greatly from 940mAhg1 tomAhg1 during the second charge/discharge cycle,t be due to the irreversible insertion/deinsertion ofthe host structure during the cycle. In the prolongedischarge capacity of the as-synthesized CuO nanobeltsatively stable. After 30 cycles, the discharge capacitys 480mAhg1. The electrochemical property of spheri-oparticles products is also studied. The initial dischargenly 760mAhg1, and after 30 charge/discharge cycles,e capacity rapidly decreased to 300mAhg1. The elec-l study indicates that the as-synthesized CuO nanobeltsood replacement for the carbon-based anodematerialssed in the Li ion batteries.
ion
ary, uniformCuOnanobelts have been successfully pre-high yield via a simple hydrothermal reduction process
at a low temtures is discrelatively lobe extendedchemical tegood replacused in the
Acknowled
We deepscience resProgram oftic Resear(2005JQ104China (No. 2
References
[1] A. Bachto[2] Y. Huang,
1313.[3] R. Martel
2447.[4] A.O. Musa[5] P. Poizot,
496.[6] J.M. Taras[7] S. Grugeo
Electroch[8] E. Shemb
Solid Statage of CuO nanobelts.nthesized CuO nanobelts.
perature. The growth mechanism of these nanostruc-ussed. The preparation method has the advantages ofw cost, high purity and large-scale production, andmayto the synthesis of other nanostructures. The electro-
st of the CuO nanobelts indicated that they might beement for the carbon-based anode materials currentlyLi ion batteries.
gements
ly appreciate the support of the foundation for doctorearch of Anhui Normal University, the Young TeacherAnhui Normal University (160-720672), the Scien-
ch Program of Anhui Province College Young Teacher8ZD) and the National Natural Science Foundation of0675001).
ld, P. Hadley, T. Nakanishi, C. Dekker, Science 294 (2001) 1317.X.F. Duan, Y. Cui, L.J. Lauhon, K.H. Kim, C.M. Lieber, Science 294 (2001)
, T. Schmidt, H.R. Shea, T. Hertel, P. Avouris, Appl. Phys. Lett. 73 (1998)
, T. Akomolafe, M.J. Carter, Sol. Energy Mater. Sol. Cells 51 (1998) 305.S. Laruelle, S. Grugeon, L. Dupont, J.M. Tarascon, Nature 407 (2000)
con, M. Armand, Nature 414 (2001) 359.n, S. Laruelle, R. Herrera-Urbina, L. Dupont, P. Poizot, J.M. Tarascon, J.em. Soc. 148 (2001) 285.el, R. Apostolova, V. Nagirny, I. Kirsanova, Ph. Grebenkin, P. Lytvyn, J.e Electrochem. 9 (2005) 96.
-
X. Zhang et al. / Materials Chemistry and Physics 112 (2008) 726729 729
[9] J.B. Reitz, E.I. Solomon, J. Am. Chem. Soc. 120 (1998) 11467.[10] Z.W. Pan, Z.R. Dai, Z.L. Wang, Science 291 (2001) 1947.[11] E.W. Bohannan, H.M. Kothari, I.M. Nicic, J.A. Switzer, J. Am. Chem. Soc. 126
(2004) 488.[12] J.J. Zhu, S.W. Liu, O. Palchik, Y. Koltypin, A. Gedanken, Langmuir 16 (2000) 6396.[13] H.T. Zhu, C.Y. Zhang, Y.M. Tang, J.X. Wang, J. Phys. Chem. C 111 (2007) 1646.[14] Y. Liu, Y. Chu, Y. Zhuo, M. Li, L. Li, L. Dong, Cryst. Growth Des. 7 (2007) 467.[15] G.H. Du, L.-M. Peng, Q. Chen, S. Zhang, W.Z. Zhou, Appl. Phys. Lett. 83 (2003)
1638.
[16] W.Z. Wang, C. Lan, Y.Z. Li, K.Q. Hong, G.H. Wang, Chem. Phys. Lett. 366 (2002)220.
[17] Y. Cudennec, A. Lecert, Solid State Sci. 5 (2003) 1471.[18] P. Podhajecky, J. Power Sources 14 (1985) 269.[19] P. Novak, Electrochim. Acta 30 (1985) 1687.[20] X.P. Gao, J.L. Bao, G.L. Pan, H.Y. Zhu, P.X. Huang, F. Wu, D.Y. Song, J. Phys. Chem.
B 108 (2004) 5547.
Synthesis and electrochemical properties of CuO nanobeltsIntroductionExperimentalResults and discussionConclusionAcknowledgementsReferences
![Epitaxial Strain-Induced Growth of CuO at Cu O/ZnO …folk.uio.no/olem/papers/gunnaes2016.pdf · Epitaxial Strain-Induced Growth of CuO at Cu ... CuO interfacial plane we have (111)[11̅0]](https://static.fdocuments.in/doc/165x107/5a9a85b57f8b9aba4a8d8aa8/epitaxial-strain-induced-growth-of-cuo-at-cu-ozno-folkuionoolempapers-strain-induced.jpg)
