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The preparation of nanoparticle zirconium phosphate
Materials Letters 61 (2007) 3258 – 3261 www.elsevier.com/locate/matlet
The preparation of nanoparticle zirconium phosphate Yingjun Feng, Wen He ⁎, Xudong Zhang, Xingtao Jia, Hongshi Zhao Department of Material Science and Engineering, Shandong Institute of Light Industry, Jinan 250353, P.R. China Received 29 May 2006; accepted 9 November 2006 Available online 10 January 2007
Abstract Nano-sized zirconium phosphate was synthesized by the solvothermal method using stoichiometric amounts of inorganic zirconium and phosphate salts by surfactant anilin (An) and polyoxyethylene sorbitan monooleate (Tween). The formation of zirconium phosphate was investigated by means of XRD. The pure zirconium phosphate crystalline phase was obtained under mild synthesis conditions; this indicated that ethanol replaced part of water as solvent favoring the formation of zirconium phosphate. TEM showed that zirconium phosphate particles were basically regular in shapes, which included cube, hexagon and sphere. These particles were well dispersed and the mean grain size was about 100 nm, meanwhile, the successive processes occurring during the growth of hexagonal structure were investigated through TEM. SEM proved again that the morphology of zirconium phosphate was regular and most particles had similar grain size. © 2007 Published by Elsevier B.V. Keywords: Nanoparticles; Zirconium phosphate; Surfactant
1. Introduction The choice of solvent is very important for the synthesis of targeted compound and also changes the reactivity of the reactants as well. A different choice of solvent always leads to different results. Mixed solvents are more complex systems than simple solvent. Some studies have shown that products with special morphology or special properties could be obtained in the mixed solvent [1]. Zirconium phosphate is an important class of inorganic material that is widely studied in different chemical fields including ion exchange [2,3], high temperature stability [4–6], ion conduct [7–10] and catalysis [11–13], and has received considerable attention. Although some scientists are devoted to the layer zirconium phosphate, a few reports involved the regular crystalline zirconium phosphate. Recently, extensive attention has been drawn in the field of energy and environmental protection, and nanoparticles science to the preparation and characterization of zirconium phosphate,
⁎ Corresponding author. 0167-577X/$ - see front matter © 2007 Published by Elsevier B.V. doi:10.1016/j.matlet.2006.11.132
which has attracted more and more attention. However, most people target the layered formation because it can host other ions with good catalyst, in fact, crystalline particles were also important materials that can be used in some motor industry for good thermal stability and chemical stability such as motor exhaust system and motor resisted part; meanwhile, it can be used in some special environment which can improve the using duration of some industrial products such as ceramics, resisted acid and base materials. In this paper, we describe the development of different synthesis methods with interesting morphologies via the solvothermal route using the An–ethanol solvent and spantween–ethanol solvent synthesis. 2. Experiment 2.1. Preparation of solid Zirconyl chloride octahydrate (ZrOCl2·8H2O) was used as a zirconium precursor salt in all experiments. H3PO4 was used as precipitating agent. Span-tween and An were chosen as typical surfactant, respectively. All the agents were of high purity grade.
Y. Feng et al. / Materials Letters 61 (2007) 3258–3261
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2 h. On addition of phosphoric acid, the preparation of zirconium phosphate began almost immediately. After 2 h, the stirring was stopped and the mixture was allowed to age at ambient temperature for 12 h. After the aging step, the precipitate was filtered and washed with ethanol. The white powder obtained was finally dried in an air oven at 120 overnight. The samples contain the surfactant molecules calcined at 1083 K for 12 h. 2.2. Characterization
Fig. 1. XRD patterns of powder synthesis in ethanol.
In a typical experiment, the An and span-tween were separately dissolved in 30 ml of ethanol under stirring at room temperature until the amphiphilic molecules dissolved completely. In a certain instance, the An and span-tween were employed as the surfactant, the surfactant was according to different structures. Next, adjusted the pH value by adding HCl until below pH = 2, the zirconium ion was added slowly, dropby-drop to the mixture and stirred under ambient condition for
Thermogravimetric determination was carried out in air by a machine at a heating rate of 10 °C /min; some determinations were also carried out by heating the sample at fixed temperature up to constant weight. X-ray diffraction (XRD) patterns were recorded with computer controlled D/MAX-III diffractometer using Ni-filtered Cu–Kα radiation. The transmission electron micrographs were recorded using Hitachi H-800 at an accelerating voltage of 120 kV, the sample was dissolved in acetic. The analysis of the microscopic structure of the sample was conducted on Scanning Electron Micrographs of ESEM Quanta-200. 3. Results and discussion The TG/DTG profiles of a representative sample are in agreement with a former report. The total weight loss of the sample is in the range of 33%–40%. There are two distinct weight loss stages on the TG
Fig. 2. TEM images of zirconium phosphate synthesized in ethanol with different surfactants. (A) An; (B) span-tween; (C) An; (D) span-tween.
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Fig. 3. SEM images of regular morphology of prepared zirconium phosphate via different surfactants. (A) Cube with ethanol span-tween and (B) sphere with ethanol.
profile of zirconium phosphate, corresponding to removal of hydration water and combustion of organic components. The XRD spectrum in Fig. 1 shows the synthesis in span-tween and An as surfactant, separately. All the reflection peaks in B and C were indexed to the reported data in the JCPDS cards that can be readily indexed to zirconium phosphate crystal, which is also consistent with the data reported. Spectrum (B) and spectrum (C) show complete crystal derived from the span-tween and An according to the B and C in TEM. There are not distinctive differences between them, which indicate that the crystalline system is the same, although the concrete morphologies are obviously different. Meanwhile, although the cubic structure could be also attributed to some other phosphates (e.g. pyrophosphates), complete chemical quantitative analysis that corroborated with XRD confirmed the former index and indicates that the crystal mainly is the zirconium phosphate. In the synthesis process, the molar ratio of surfactant/ethanol has been well controlled, which is very important to obtain different particle morphologies. Fig. 2 shows typical TEM images of zirconium phosphate products obtained by different surfactants. All photos show that the morphology of the crystal is similar and the grain size is approximately about 100 nm, which include cube, hexagon and sphere. The process of hexagonal samples is different from other samples which are derived from An. Fig. 2(A) shows that the complete crystal is a regular sphere and the grain size is approximately 100 nm. The regular particles indicate that surfactant having less chain length assembles compared to small spherical micelles, so the amphibian condensing forms the spherical structure and the inorganic ion condensing forms the corresponding spheres. Fig. 2(B) and (C) respectively shows the regular hexagonal and cubic structure and the SAED validated single crystal. As we know zirconium phosphate and zirconia form layer easily, but there is not any layer structure in the solvent, it verifies again that the solvent is critical to controlling the crystalline growth. The hexagonal structure has a definite process of grain growth. It is a typical surfactant having strong impact on the layer formation process because of the long chain length, which easily causes the layer to expand slowly and the H-bonds become weak. The zirconium phosphate precipitate may firstly form layer structure because Zr ion coordinates with PO4, the span-tween intercalating and generally connecting with other layers by H-bonds, so that the layer-by-layer easily twist when sample is calcined. The layers will gradually bend as the temperature increases and as the surfactant effect. The nanobar firstly formed, continuing to conglomerate until the regular hexagonal morphology. There were many samples in our experiments that were hexagonal with nanobar, but it was puzzling why it had hexagonal
with nanobar but not pentagon and others. It needs more work to be done. The SEM images in Fig. 3 show that the regular cubic particles conglomerate, which cannot disperse entirely in ethanol even under microwave treatment. Although there are agglomeration and the accurate grain size is calculated differently. The cubes are clear and the size is similar within the experimental error. Fig. 3(B) clearly shows the spherical particle which is similar in diameter, although there is some incomplete particle which is ellipse. XRD and SAED showed that the hexagon and cubic nanoparticles were all well crystallized. The irregular pellet reveals that the experiments have some defects such as uneven dispersion, uneven grain growth and some incomplete crystals.
4. Conclusion Zirconium phosphate powders have been prepared by the coprecipitation method while keeping a constant pH and changing the type of surfactant. During heat-treatment, no other phase occurs except zirconium phosphate. The different surfactants show different effects on the morphology of zirconium phosphate. TEM shows successive process of hexagonal particle growth. SEM images indicated the uniform and perfect morphology of the crystal nanoparticles. Acknowledgement Supported by Shandong Province Nature Fund. References [1] Hongzhi Wang, Lian Gao, Koichi Niihara, Materials Science & Engineering. A, Structural Materials: Properties, Microstructure and Processing 288 (2000) 1–4. [2] P. Armento, M. Casciola, M. Pica, F. Marmottini, R. Palombari, F. Ziarelli, Solid State Ionics 166 (2004) 19–25. [3] S.I. Borovkov, L.M. Sharygin, Russian Journal of Applied Chemistry 78 (2) (2005) 229–233. [4] C.V. Kumar, A. Chaudharis, Microporous and Mesoporous Materials 57 (2003) 181–190. [5] C.V. Kumar, A. Chaudharis, Microporous and Mesoporous Materials 91 (2005) 477–483. [6] G.L. Zhao, Z.Y. Yuan, T.H. Chen, Materials Research Bulletin 40 (2005) 1922–1928.
Y. Feng et al. / Materials Letters 61 (2007) 3258–3261 [7] P. Armento, M. Casciola, M. Pica, F. Marmottini, R. Paombari, F. Ziarellio, Solid State Ionics 166 (2004) 19–25. [8] Sukanta Pe, Amitabha De, Ajay Das, S.K. De, Materials Chemistry and Physics 91 (2005) 177–483. [9] Nathalie Fripiat, Paul Grange, Catalysis Letters 62 (1999) 53–57. [10] Jingbing Xiao, Jinsuo Xu, Yumin Wu, Zi Gao, Applied Catalysis. A, General 181 (1999) 313–322.
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[11] Hakan Altan, Feng Huanf, John F. Federici, Aidong, Haim Grebel, Journal of Applied Physics 96 (11 (1)) (2004). [12] A. Clearfield, P.S. Thakur, Applied Catalysis 26 (1986) 1–5. [13] B. Tian, X. Liu, B. Tu, C. Yu, J. Fan, L. Wang, S. Xie, G.D. Stuky, D. Zhao, Nature Materials 2 (2003) 159–163.
The preparation of nanoparticle zirconium phosphate Yingjun Feng, Wen He ⁎, Xudong Zhang, Xingtao Jia, Hongshi Zhao Department of Material Science and Engineering, Shandong Institute of Light Industry, Jinan 250353, P.R. China Received 29 May 2006; accepted 9 November 2006 Available online 10 January 2007
Abstract Nano-sized zirconium phosphate was synthesized by the solvothermal method using stoichiometric amounts of inorganic zirconium and phosphate salts by surfactant anilin (An) and polyoxyethylene sorbitan monooleate (Tween). The formation of zirconium phosphate was investigated by means of XRD. The pure zirconium phosphate crystalline phase was obtained under mild synthesis conditions; this indicated that ethanol replaced part of water as solvent favoring the formation of zirconium phosphate. TEM showed that zirconium phosphate particles were basically regular in shapes, which included cube, hexagon and sphere. These particles were well dispersed and the mean grain size was about 100 nm, meanwhile, the successive processes occurring during the growth of hexagonal structure were investigated through TEM. SEM proved again that the morphology of zirconium phosphate was regular and most particles had similar grain size. © 2007 Published by Elsevier B.V. Keywords: Nanoparticles; Zirconium phosphate; Surfactant
1. Introduction The choice of solvent is very important for the synthesis of targeted compound and also changes the reactivity of the reactants as well. A different choice of solvent always leads to different results. Mixed solvents are more complex systems than simple solvent. Some studies have shown that products with special morphology or special properties could be obtained in the mixed solvent [1]. Zirconium phosphate is an important class of inorganic material that is widely studied in different chemical fields including ion exchange [2,3], high temperature stability [4–6], ion conduct [7–10] and catalysis [11–13], and has received considerable attention. Although some scientists are devoted to the layer zirconium phosphate, a few reports involved the regular crystalline zirconium phosphate. Recently, extensive attention has been drawn in the field of energy and environmental protection, and nanoparticles science to the preparation and characterization of zirconium phosphate,
⁎ Corresponding author. 0167-577X/$ - see front matter © 2007 Published by Elsevier B.V. doi:10.1016/j.matlet.2006.11.132
which has attracted more and more attention. However, most people target the layered formation because it can host other ions with good catalyst, in fact, crystalline particles were also important materials that can be used in some motor industry for good thermal stability and chemical stability such as motor exhaust system and motor resisted part; meanwhile, it can be used in some special environment which can improve the using duration of some industrial products such as ceramics, resisted acid and base materials. In this paper, we describe the development of different synthesis methods with interesting morphologies via the solvothermal route using the An–ethanol solvent and spantween–ethanol solvent synthesis. 2. Experiment 2.1. Preparation of solid Zirconyl chloride octahydrate (ZrOCl2·8H2O) was used as a zirconium precursor salt in all experiments. H3PO4 was used as precipitating agent. Span-tween and An were chosen as typical surfactant, respectively. All the agents were of high purity grade.
Y. Feng et al. / Materials Letters 61 (2007) 3258–3261
3259
2 h. On addition of phosphoric acid, the preparation of zirconium phosphate began almost immediately. After 2 h, the stirring was stopped and the mixture was allowed to age at ambient temperature for 12 h. After the aging step, the precipitate was filtered and washed with ethanol. The white powder obtained was finally dried in an air oven at 120 overnight. The samples contain the surfactant molecules calcined at 1083 K for 12 h. 2.2. Characterization
Fig. 1. XRD patterns of powder synthesis in ethanol.
In a typical experiment, the An and span-tween were separately dissolved in 30 ml of ethanol under stirring at room temperature until the amphiphilic molecules dissolved completely. In a certain instance, the An and span-tween were employed as the surfactant, the surfactant was according to different structures. Next, adjusted the pH value by adding HCl until below pH = 2, the zirconium ion was added slowly, dropby-drop to the mixture and stirred under ambient condition for
Thermogravimetric determination was carried out in air by a machine at a heating rate of 10 °C /min; some determinations were also carried out by heating the sample at fixed temperature up to constant weight. X-ray diffraction (XRD) patterns were recorded with computer controlled D/MAX-III diffractometer using Ni-filtered Cu–Kα radiation. The transmission electron micrographs were recorded using Hitachi H-800 at an accelerating voltage of 120 kV, the sample was dissolved in acetic. The analysis of the microscopic structure of the sample was conducted on Scanning Electron Micrographs of ESEM Quanta-200. 3. Results and discussion The TG/DTG profiles of a representative sample are in agreement with a former report. The total weight loss of the sample is in the range of 33%–40%. There are two distinct weight loss stages on the TG
Fig. 2. TEM images of zirconium phosphate synthesized in ethanol with different surfactants. (A) An; (B) span-tween; (C) An; (D) span-tween.
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Fig. 3. SEM images of regular morphology of prepared zirconium phosphate via different surfactants. (A) Cube with ethanol span-tween and (B) sphere with ethanol.
profile of zirconium phosphate, corresponding to removal of hydration water and combustion of organic components. The XRD spectrum in Fig. 1 shows the synthesis in span-tween and An as surfactant, separately. All the reflection peaks in B and C were indexed to the reported data in the JCPDS cards that can be readily indexed to zirconium phosphate crystal, which is also consistent with the data reported. Spectrum (B) and spectrum (C) show complete crystal derived from the span-tween and An according to the B and C in TEM. There are not distinctive differences between them, which indicate that the crystalline system is the same, although the concrete morphologies are obviously different. Meanwhile, although the cubic structure could be also attributed to some other phosphates (e.g. pyrophosphates), complete chemical quantitative analysis that corroborated with XRD confirmed the former index and indicates that the crystal mainly is the zirconium phosphate. In the synthesis process, the molar ratio of surfactant/ethanol has been well controlled, which is very important to obtain different particle morphologies. Fig. 2 shows typical TEM images of zirconium phosphate products obtained by different surfactants. All photos show that the morphology of the crystal is similar and the grain size is approximately about 100 nm, which include cube, hexagon and sphere. The process of hexagonal samples is different from other samples which are derived from An. Fig. 2(A) shows that the complete crystal is a regular sphere and the grain size is approximately 100 nm. The regular particles indicate that surfactant having less chain length assembles compared to small spherical micelles, so the amphibian condensing forms the spherical structure and the inorganic ion condensing forms the corresponding spheres. Fig. 2(B) and (C) respectively shows the regular hexagonal and cubic structure and the SAED validated single crystal. As we know zirconium phosphate and zirconia form layer easily, but there is not any layer structure in the solvent, it verifies again that the solvent is critical to controlling the crystalline growth. The hexagonal structure has a definite process of grain growth. It is a typical surfactant having strong impact on the layer formation process because of the long chain length, which easily causes the layer to expand slowly and the H-bonds become weak. The zirconium phosphate precipitate may firstly form layer structure because Zr ion coordinates with PO4, the span-tween intercalating and generally connecting with other layers by H-bonds, so that the layer-by-layer easily twist when sample is calcined. The layers will gradually bend as the temperature increases and as the surfactant effect. The nanobar firstly formed, continuing to conglomerate until the regular hexagonal morphology. There were many samples in our experiments that were hexagonal with nanobar, but it was puzzling why it had hexagonal
with nanobar but not pentagon and others. It needs more work to be done. The SEM images in Fig. 3 show that the regular cubic particles conglomerate, which cannot disperse entirely in ethanol even under microwave treatment. Although there are agglomeration and the accurate grain size is calculated differently. The cubes are clear and the size is similar within the experimental error. Fig. 3(B) clearly shows the spherical particle which is similar in diameter, although there is some incomplete particle which is ellipse. XRD and SAED showed that the hexagon and cubic nanoparticles were all well crystallized. The irregular pellet reveals that the experiments have some defects such as uneven dispersion, uneven grain growth and some incomplete crystals.
4. Conclusion Zirconium phosphate powders have been prepared by the coprecipitation method while keeping a constant pH and changing the type of surfactant. During heat-treatment, no other phase occurs except zirconium phosphate. The different surfactants show different effects on the morphology of zirconium phosphate. TEM shows successive process of hexagonal particle growth. SEM images indicated the uniform and perfect morphology of the crystal nanoparticles. Acknowledgement Supported by Shandong Province Nature Fund. References [1] Hongzhi Wang, Lian Gao, Koichi Niihara, Materials Science & Engineering. A, Structural Materials: Properties, Microstructure and Processing 288 (2000) 1–4. [2] P. Armento, M. Casciola, M. Pica, F. Marmottini, R. Palombari, F. Ziarelli, Solid State Ionics 166 (2004) 19–25. [3] S.I. Borovkov, L.M. Sharygin, Russian Journal of Applied Chemistry 78 (2) (2005) 229–233. [4] C.V. Kumar, A. Chaudharis, Microporous and Mesoporous Materials 57 (2003) 181–190. [5] C.V. Kumar, A. Chaudharis, Microporous and Mesoporous Materials 91 (2005) 477–483. [6] G.L. Zhao, Z.Y. Yuan, T.H. Chen, Materials Research Bulletin 40 (2005) 1922–1928.
Y. Feng et al. / Materials Letters 61 (2007) 3258–3261 [7] P. Armento, M. Casciola, M. Pica, F. Marmottini, R. Paombari, F. Ziarellio, Solid State Ionics 166 (2004) 19–25. [8] Sukanta Pe, Amitabha De, Ajay Das, S.K. De, Materials Chemistry and Physics 91 (2005) 177–483. [9] Nathalie Fripiat, Paul Grange, Catalysis Letters 62 (1999) 53–57. [10] Jingbing Xiao, Jinsuo Xu, Yumin Wu, Zi Gao, Applied Catalysis. A, General 181 (1999) 313–322.
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[11] Hakan Altan, Feng Huanf, John F. Federici, Aidong, Haim Grebel, Journal of Applied Physics 96 (11 (1)) (2004). [12] A. Clearfield, P.S. Thakur, Applied Catalysis 26 (1986) 1–5. [13] B. Tian, X. Liu, B. Tu, C. Yu, J. Fan, L. Wang, S. Xie, G.D. Stuky, D. Zhao, Nature Materials 2 (2003) 159–163.