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A facile hydrothermal route to synthesize novel Co3O4 nanoplates
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Materials Letters 62 (2008) 1507 – 1510 www.elsevier.com/locate/matlet
A facile hydrothermal route to synthesize novel Co3O4 nanoplates Lili Li, Ying Chu ⁎ , Yang Liu, Jinling Song, Dan Wang, Xingwei Du Department of Chemistry, Northeast Normal University, Changchun, Jilin 130024, PR China Received 27 June 2007; accepted 11 September 2007 Available online 18 September 2007
Abstract Novel Co3O4 nanoplates and nanobelts were formed on a large scale by a facile and efficient hydrothermal process. The samples were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD). In the same experiment situation, 1D Ni(OH)2 nanowires and ZnO irregular nanoplates were synthesized. The concentration of OH− is important to control the shape of final product. TBAB is the key reactant to form 1D nanostructure. In this report, we demonstrate the fabrication of Co3O4 with various morphologies (plate-, belt-, cube-, urchin-like). The method is a good way to synthesize other 1D metal oxide nanostructures. © 2007 Elsevier B.V. All rights reserved. Keywords: Co3O4; Nanoplate; Hydrothermal; Nanomaterial; Microstructure
1. Introduction Since the discovery of carbon nanotubes in 1991, [1] onedimensional nanomaterials, such as nanotubes,[2] nanowires,[3] and nanobelts or nanoribbons[4] have attracted much attention in the past decade because of their novel physical properties and potential applications in constructing nanoscale electric and optoelectronic devices.[5] In particular, one-dimensional nanostructures of metal oxides such as ZnO, SnO2, α-Fe2O3, WO3, and Ta2O5,[6] so-called functional materials, have been widely studied. Metal (oxide) nanoparticles have received widespread interest recently because of their envisioned applications in electronics, optics, and magnetic storage devices.[7] Furthermore, Co3O4 nanoparticles show some interesting magnetic, optical, and transport properties[8]. So various methods were used to synthesize spinel oxide Co3O4, such as thermal decomposition of a solid cobalt nitrate, chemical spray pyrolysis, chemical vapor deposition, and the traditional sol–gel method [9]. But it is a challenge to synthesize many metal oxides in the same experiment.
⁎ Corresponding author. E-mail address: [email protected] (Y. Chu). 0167-577X/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.matlet.2007.09.012
In this report, we demonstrate the fabrication of Co3O4 with various morphologies (plate-, belt-, cube-, urchin-like). To our best knowledge, such plate-, belt-like Co3O4 was first reported. In such experiment situation, one-dimensional Ni(OH)2 nanowires and ZnO nanoplates was synthesized. The methods are easy and mild, and could synthesize other metal oxide. 2. Experiment Co3O4 was prepared as follows: 0.036 M CoCl2, 0.002 M tetrabutylammonium bromide (TBAB) and 0.125 M NaOH were dissolved in deionized water until a transparent solution was obtained. The solution was then sealed into a Teflon-lined autoclave, followed by hydrothermal treatment at 160 °C for 24 h. After the treatment, Co3O4 were collected by filtration, washed several times with deionized water and ethanol, and dried at room temperature for 6 h. 3. Results and discussion Fig. 1. (a)XRD pattern of Co3O4 nanoplates; (b) Overview and (c) high-magnification SEM images of Co3O4 nanoplates (CCo2+ = 0.036 M, CTBAB = 0.002 M and COH− = 0.125 M). A typical X-ray diffraction (XRD) pattern of the as-prepared samples is shown in Fig. 1a. In Fig. 1a, the as-prepared Co3O4 is identified as the
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L. Li et al. / Materials Letters 62 (2008) 1507–1510
single phase Co3O4 with a suitably crystalline cubic structure (JCPDS file No. 78-1970). Compared with the standard diffraction patterns, no peaks from other phases are found, suggesting high purity of the as-synthesized product. To investigate the morphology of the as-prepared samples on a large scale, the obtained sample was further characterized by scanning electron microscopy (SEM). Parts b and c of Fig. 1 display the typical low-and high-magnification SEM images of the samples, respectively. As observed in Fig. 1b, the sample mainly consists of large nanoplates, including triangular and hexagonal shapes with an average width and thickness of about 200–500 nm and 2–5 nm, respectively. The thickness of the nanoplates was measured of the plates standing against the substrate (indicated by arrows in Fig. 1c.). To shed light on the formation mechanism of Co3O4 nanoplates, their growth process has been followed by examining the products synthesized on different reaction conditions. By simply adjusting the concentration of NaOH in the reaction solution, Co3O4 nanoparticles with different shapes can be obtained. The transmission electron microscopy (TEM; JEOL 2010) image of the sample obtained at COH− = 0.05 M indicates that, under this condition, regular Co3O4 nanocube came into being with 75 nm in edge width (Fig. 2). Moreover, the higher the concentration of 0.156 M, the morphology is nanobelt (Fig. 2c). The nanosphere which are assembled by many small nanoparticle at COH− = 0.313 M (Fig. 2d). It is obviously that with increasing the concentration value of OH−, the shapes changed from nanocubes to nanosphere. At higher concentration, more nanoparticles are synthesized at short time, and such particles easily
assemble together. It is the reason that at higher concentration the morphology is sphere with 300–500 nm in diameter. It indicates that in an appropriate NaOH concentration range perfect Co3O4 nanoplates can only be obtained. According to the mechanism supposed by Xie et al[10] and our previous work,[11] the unit concentration of the nucleophile OH− may have an influence on the scrolling of Co(OH)2 and then have a direct influence on the morphology of the final products. Fig. 2e shows the scheme for the growth mechanism of Co3O4 synthesized at different concentration of OH−. When the Co2+ is substituted by the Ni2+ and Zn2+, low dimension nanostructure was formed. At Ni2+ as reactant, the nanowire with 5 nm in diameter and 2–5 μm in length was formed. With Zn2+ as reactant, the irregular nanoplate was formed. When the Co2+, Ni2+, Zn2+ were reactant, the final products were all low dimension nanostructure. The surfactant is important to form low dimension nanostructure. It is well known that the surfactant in the solution will aggregate into micelles. Moreover, depending on the surrounding medium of the surfactant, the micelles display different shapes, such as spherical, lay-like, and rodlike shapes. Besides the strong repulsion force between the inorganic cation and the cation surfactant (TBAB), it makes the micelles have the similar structure. When the metal oxide was formed, the cation surfactant (TBAB) adsorbed on the surface of metal oxide. The surfactant will lead to metal oxide along one direction. To illustrate the importance of surfactant (TBAB), we used ployvinylpyrrolidone(PVP) and trisodium citrate dehydrate as surfactant. Fig. 3 shows the TEM images of Co3O4 with trisodium citrate dehydrate and PVP as surfactant. While trisodium citrate as surfactant, we get urchin-like structure which was
Fig. 1. (a)XRD pattern of Co3O4 nanoplates; (b) Overview and (c) high-magnification SEM images of Co3O4 nanoplates (CCo2+ = 0.036 M, CTBAB = 0.002 M and COH− = 0.125 M).
L. Li et al. / Materials Letters 62 (2008) 1507–1510
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Fig. 2. TEM images of Co3O4 samples synthesized at different concentration of OH− (a) 0.05 M, (b) 0.125 M, (c) 0.156 M, (d) 0.313 M, (e) Scheme for illustrating the growth mechanism of Co3O4 synthesized at different concentration of OH−.
assembled by many nanorods (Fig. 3a). At PVP as surfactant, irregular structures was formed(Fig. 3b). From the results of above experiment, the surfactant TBAB has predominance in forming 1D nanostructure.
More 1D metal oxide structure was synthesized with TBAB as surfactant. In future work, we will try our best to study the mechanism of the forming 1D structure.
Fig. 3. TEM images of Co3O4 samples with different surfactant (a) trisodium citrate, (b) polyvinylpyrrolidone(PVP).
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L. Li et al. / Materials Letters 62 (2008) 1507–1510
4. Conclusion In summary, we find an economical and efficient process to synthesis large scale 1D mental oxide (Co3O4, Ni(OH)2, ZnO). The concentration of OH-is important to the shape of final product. TBAB is a key reactant to form 1D nanostructure. Although the reason of TBAB forming 1D nanostructure is unclear, the method is a good way to synthesize other 1D metal oxide nanostructure. Acknowledgment This work was financially supported by the National Natural Science Foundation of China (20573017), the Science and Technology Development Project of Jilin province (20040566), and Analysis and Testing Foundation of Northeast Normal University. References [1] Iijima, Nature 358 (1992) 23. [2] P.M. Ajayan, Chem. Rev 99 (1999) 1787. [3] (a) A.M. Morales, C.M. Lieber, Science 279 (1998) 208; (b) Y.F. Zhang, Y.H. Tang, N. Wang, D.P. Yu, C.S. Lee, I. Bello, S.T. Lee, Appl. Phys. Lett. 72 (1998) 1835. [4] Z.W. Pan, Z.R. Dai, Z.L Wang, Science 291 (2001) 1947.
[5] J.T. Hu, T.W. Odom, C.M Lieber, Acc. Chem. Res 32 (1999) 435. [6] (a) Z.W. Pan, Z.R. Dai, Z.L Wang, Science 291 (2001) 1947; (b) J.H. He, T.H. Wu, C.L. Hsin, K.M. Li, L.J. Chen, Y.L. Chueh, et al., Small 2 (2006) 116; (c) M.H. Cao, T. Liu, S. Gao, G. Sun, X. Wu, Z.L. Wang, et al., Angew. Chem. Int. Ed. 44 (2005) 4197; (d) J. Zhou, Y. Ding, S.Z. Deng, L. Gong, N.S. Xu, Z.L. Wang, Adv. Mater 17 (2005) 2107. [7] P. Poizot, S. Laruelle, S. Grugeon, L. Dupont, J.M. Tarascon, Nature 407 (2000) 496. [8] (a) S. Takada, M. Fujii, S. Kohiki, T. Bahasaki, H. Deguchi, M. Mitome, et al., Nano. Lett. 1 (2001) 379; (b) H. Yamamoto, S. Tanaka, T. Naito, K. Hirao, Appl. Phys. Lett. 81 (2002) 999; (c) J. Tejada, X.X. Zhang, E. Barco del, E.J.M. Hernandez, E.M. Chudnovsky, Phys. Rev. Lett. 79 (1997) 1754. [9] (a) M.R. Tarasevich, B.N. Efremov, Electrodes of ConductiveMetallic Oxides, Part A, Elsevier, Amsterdam, 1980, Chapter 5; (b) R.N. Singh, J.F. Koenig, G. Poillerat, P.J. Chartier, Electrochem. Soc. 137 (1990) 1480; (c) M. Hamdani, J.F. Koenig, P.J. Chartier, Appl. Electrochem. 18 (1988) 568; (d) C.S. Cheng, M. Serizawa, H. Sakata, T. Hirayama, Mater. Chem. Phys. 53 (1998) 255; (e) M.E. Baydi, G. Poillerat, J.L. Rehspringer, J.L. Gautier, J.F. Koenig, P.J. Chartier, Solid State Chem 109 (1994) 281. [10] H. Hou, Y. Xie, Q. Li, Cryst. Growth Des. 5 (2005) 201. [11] Y. Liu, Y. Chu, M.Y. Li, L.L. Li, L.H. Dong, J. Mater. Chem. 16 (2006) 192.
Materials Letters 62 (2008) 1507 – 1510 www.elsevier.com/locate/matlet
A facile hydrothermal route to synthesize novel Co3O4 nanoplates Lili Li, Ying Chu ⁎ , Yang Liu, Jinling Song, Dan Wang, Xingwei Du Department of Chemistry, Northeast Normal University, Changchun, Jilin 130024, PR China Received 27 June 2007; accepted 11 September 2007 Available online 18 September 2007
Abstract Novel Co3O4 nanoplates and nanobelts were formed on a large scale by a facile and efficient hydrothermal process. The samples were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD). In the same experiment situation, 1D Ni(OH)2 nanowires and ZnO irregular nanoplates were synthesized. The concentration of OH− is important to control the shape of final product. TBAB is the key reactant to form 1D nanostructure. In this report, we demonstrate the fabrication of Co3O4 with various morphologies (plate-, belt-, cube-, urchin-like). The method is a good way to synthesize other 1D metal oxide nanostructures. © 2007 Elsevier B.V. All rights reserved. Keywords: Co3O4; Nanoplate; Hydrothermal; Nanomaterial; Microstructure
1. Introduction Since the discovery of carbon nanotubes in 1991, [1] onedimensional nanomaterials, such as nanotubes,[2] nanowires,[3] and nanobelts or nanoribbons[4] have attracted much attention in the past decade because of their novel physical properties and potential applications in constructing nanoscale electric and optoelectronic devices.[5] In particular, one-dimensional nanostructures of metal oxides such as ZnO, SnO2, α-Fe2O3, WO3, and Ta2O5,[6] so-called functional materials, have been widely studied. Metal (oxide) nanoparticles have received widespread interest recently because of their envisioned applications in electronics, optics, and magnetic storage devices.[7] Furthermore, Co3O4 nanoparticles show some interesting magnetic, optical, and transport properties[8]. So various methods were used to synthesize spinel oxide Co3O4, such as thermal decomposition of a solid cobalt nitrate, chemical spray pyrolysis, chemical vapor deposition, and the traditional sol–gel method [9]. But it is a challenge to synthesize many metal oxides in the same experiment.
⁎ Corresponding author. E-mail address: [email protected] (Y. Chu). 0167-577X/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.matlet.2007.09.012
In this report, we demonstrate the fabrication of Co3O4 with various morphologies (plate-, belt-, cube-, urchin-like). To our best knowledge, such plate-, belt-like Co3O4 was first reported. In such experiment situation, one-dimensional Ni(OH)2 nanowires and ZnO nanoplates was synthesized. The methods are easy and mild, and could synthesize other metal oxide. 2. Experiment Co3O4 was prepared as follows: 0.036 M CoCl2, 0.002 M tetrabutylammonium bromide (TBAB) and 0.125 M NaOH were dissolved in deionized water until a transparent solution was obtained. The solution was then sealed into a Teflon-lined autoclave, followed by hydrothermal treatment at 160 °C for 24 h. After the treatment, Co3O4 were collected by filtration, washed several times with deionized water and ethanol, and dried at room temperature for 6 h. 3. Results and discussion Fig. 1. (a)XRD pattern of Co3O4 nanoplates; (b) Overview and (c) high-magnification SEM images of Co3O4 nanoplates (CCo2+ = 0.036 M, CTBAB = 0.002 M and COH− = 0.125 M). A typical X-ray diffraction (XRD) pattern of the as-prepared samples is shown in Fig. 1a. In Fig. 1a, the as-prepared Co3O4 is identified as the
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L. Li et al. / Materials Letters 62 (2008) 1507–1510
single phase Co3O4 with a suitably crystalline cubic structure (JCPDS file No. 78-1970). Compared with the standard diffraction patterns, no peaks from other phases are found, suggesting high purity of the as-synthesized product. To investigate the morphology of the as-prepared samples on a large scale, the obtained sample was further characterized by scanning electron microscopy (SEM). Parts b and c of Fig. 1 display the typical low-and high-magnification SEM images of the samples, respectively. As observed in Fig. 1b, the sample mainly consists of large nanoplates, including triangular and hexagonal shapes with an average width and thickness of about 200–500 nm and 2–5 nm, respectively. The thickness of the nanoplates was measured of the plates standing against the substrate (indicated by arrows in Fig. 1c.). To shed light on the formation mechanism of Co3O4 nanoplates, their growth process has been followed by examining the products synthesized on different reaction conditions. By simply adjusting the concentration of NaOH in the reaction solution, Co3O4 nanoparticles with different shapes can be obtained. The transmission electron microscopy (TEM; JEOL 2010) image of the sample obtained at COH− = 0.05 M indicates that, under this condition, regular Co3O4 nanocube came into being with 75 nm in edge width (Fig. 2). Moreover, the higher the concentration of 0.156 M, the morphology is nanobelt (Fig. 2c). The nanosphere which are assembled by many small nanoparticle at COH− = 0.313 M (Fig. 2d). It is obviously that with increasing the concentration value of OH−, the shapes changed from nanocubes to nanosphere. At higher concentration, more nanoparticles are synthesized at short time, and such particles easily
assemble together. It is the reason that at higher concentration the morphology is sphere with 300–500 nm in diameter. It indicates that in an appropriate NaOH concentration range perfect Co3O4 nanoplates can only be obtained. According to the mechanism supposed by Xie et al[10] and our previous work,[11] the unit concentration of the nucleophile OH− may have an influence on the scrolling of Co(OH)2 and then have a direct influence on the morphology of the final products. Fig. 2e shows the scheme for the growth mechanism of Co3O4 synthesized at different concentration of OH−. When the Co2+ is substituted by the Ni2+ and Zn2+, low dimension nanostructure was formed. At Ni2+ as reactant, the nanowire with 5 nm in diameter and 2–5 μm in length was formed. With Zn2+ as reactant, the irregular nanoplate was formed. When the Co2+, Ni2+, Zn2+ were reactant, the final products were all low dimension nanostructure. The surfactant is important to form low dimension nanostructure. It is well known that the surfactant in the solution will aggregate into micelles. Moreover, depending on the surrounding medium of the surfactant, the micelles display different shapes, such as spherical, lay-like, and rodlike shapes. Besides the strong repulsion force between the inorganic cation and the cation surfactant (TBAB), it makes the micelles have the similar structure. When the metal oxide was formed, the cation surfactant (TBAB) adsorbed on the surface of metal oxide. The surfactant will lead to metal oxide along one direction. To illustrate the importance of surfactant (TBAB), we used ployvinylpyrrolidone(PVP) and trisodium citrate dehydrate as surfactant. Fig. 3 shows the TEM images of Co3O4 with trisodium citrate dehydrate and PVP as surfactant. While trisodium citrate as surfactant, we get urchin-like structure which was
Fig. 1. (a)XRD pattern of Co3O4 nanoplates; (b) Overview and (c) high-magnification SEM images of Co3O4 nanoplates (CCo2+ = 0.036 M, CTBAB = 0.002 M and COH− = 0.125 M).
L. Li et al. / Materials Letters 62 (2008) 1507–1510
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Fig. 2. TEM images of Co3O4 samples synthesized at different concentration of OH− (a) 0.05 M, (b) 0.125 M, (c) 0.156 M, (d) 0.313 M, (e) Scheme for illustrating the growth mechanism of Co3O4 synthesized at different concentration of OH−.
assembled by many nanorods (Fig. 3a). At PVP as surfactant, irregular structures was formed(Fig. 3b). From the results of above experiment, the surfactant TBAB has predominance in forming 1D nanostructure.
More 1D metal oxide structure was synthesized with TBAB as surfactant. In future work, we will try our best to study the mechanism of the forming 1D structure.
Fig. 3. TEM images of Co3O4 samples with different surfactant (a) trisodium citrate, (b) polyvinylpyrrolidone(PVP).
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4. Conclusion In summary, we find an economical and efficient process to synthesis large scale 1D mental oxide (Co3O4, Ni(OH)2, ZnO). The concentration of OH-is important to the shape of final product. TBAB is a key reactant to form 1D nanostructure. Although the reason of TBAB forming 1D nanostructure is unclear, the method is a good way to synthesize other 1D metal oxide nanostructure. Acknowledgment This work was financially supported by the National Natural Science Foundation of China (20573017), the Science and Technology Development Project of Jilin province (20040566), and Analysis and Testing Foundation of Northeast Normal University. References [1] Iijima, Nature 358 (1992) 23. [2] P.M. Ajayan, Chem. Rev 99 (1999) 1787. [3] (a) A.M. Morales, C.M. Lieber, Science 279 (1998) 208; (b) Y.F. Zhang, Y.H. Tang, N. Wang, D.P. Yu, C.S. Lee, I. Bello, S.T. Lee, Appl. Phys. Lett. 72 (1998) 1835. [4] Z.W. Pan, Z.R. Dai, Z.L Wang, Science 291 (2001) 1947.
[5] J.T. Hu, T.W. Odom, C.M Lieber, Acc. Chem. Res 32 (1999) 435. [6] (a) Z.W. Pan, Z.R. Dai, Z.L Wang, Science 291 (2001) 1947; (b) J.H. He, T.H. Wu, C.L. Hsin, K.M. Li, L.J. Chen, Y.L. Chueh, et al., Small 2 (2006) 116; (c) M.H. Cao, T. Liu, S. Gao, G. Sun, X. Wu, Z.L. Wang, et al., Angew. Chem. Int. Ed. 44 (2005) 4197; (d) J. Zhou, Y. Ding, S.Z. Deng, L. Gong, N.S. Xu, Z.L. Wang, Adv. Mater 17 (2005) 2107. [7] P. Poizot, S. Laruelle, S. Grugeon, L. Dupont, J.M. Tarascon, Nature 407 (2000) 496. [8] (a) S. Takada, M. Fujii, S. Kohiki, T. Bahasaki, H. Deguchi, M. Mitome, et al., Nano. Lett. 1 (2001) 379; (b) H. Yamamoto, S. Tanaka, T. Naito, K. Hirao, Appl. Phys. Lett. 81 (2002) 999; (c) J. Tejada, X.X. Zhang, E. Barco del, E.J.M. Hernandez, E.M. Chudnovsky, Phys. Rev. Lett. 79 (1997) 1754. [9] (a) M.R. Tarasevich, B.N. Efremov, Electrodes of ConductiveMetallic Oxides, Part A, Elsevier, Amsterdam, 1980, Chapter 5; (b) R.N. Singh, J.F. Koenig, G. Poillerat, P.J. Chartier, Electrochem. Soc. 137 (1990) 1480; (c) M. Hamdani, J.F. Koenig, P.J. Chartier, Appl. Electrochem. 18 (1988) 568; (d) C.S. Cheng, M. Serizawa, H. Sakata, T. Hirayama, Mater. Chem. Phys. 53 (1998) 255; (e) M.E. Baydi, G. Poillerat, J.L. Rehspringer, J.L. Gautier, J.F. Koenig, P.J. Chartier, Solid State Chem 109 (1994) 281. [10] H. Hou, Y. Xie, Q. Li, Cryst. Growth Des. 5 (2005) 201. [11] Y. Liu, Y. Chu, M.Y. Li, L.L. Li, L.H. Dong, J. Mater. Chem. 16 (2006) 192.