- Nano Express
- Open Access
Synthesis of copper micro-rods with layered nano-structure by thermal decomposition of the coordination complex Cu(BTA)2
© Qu et al.; licensee Springer. 2015
- Received: 10 December 2014
- Accepted: 19 January 2015
- Published: 5 February 2015
Porous metallic copper was successfully prepared by a simple thermal decomposition strategy. A coordination compound of Cu(BTA)2 with the morphology of micro-rod crystal was synthesized as the precursor. The precursor to copper transformation was performed and annealed at 600°C with the shape preserved. The copper micro-rods are assembled from unique thin lamellar layers, each with the thickness of approximately 200 nm and nano-pores of approximately 20 to 100 nm. This morphology is highly related to the crystal structure of the precursor. The mechanism of the morphology formation is proposed, which would be able to offer a guideline toward porous metals with controllable macro/micro/nano-structures by the precursor crystal growth and design.
- Porous metallic copper
- Thermal decomposition
- Lamellar layers
Porous metallic materials have become a burgeoning field in both applied technology and basic scientific research, especially for their significant thermal or electron conductivity, catalysis properties, importance in interface engineering, energy industry, and biomedical applications [1-4]. During the past two decades, the synthesis methods of porous metals evolved with the development of nano-science and nano-technology. Sol-gel, dealloying, and soft-template methods are typical synthetic strategies [5-8]. Among the periodic table of elements, metals of silver, nickel, copper, palladium, ruthenium, titanium, and platinum have been intensively investigated for their porous foam. For example, Walsh et al. used dextran as a sacrificial template to fabricate silver sponges, Yamauchi and co-workers prepared mesoporous nickel by an electroless deposition method in the presence of lyotropic liquid crystals, and Kuroda et al. reported 2D hexagonally ordered mesoporous metals (Ru, Pt, or Pd) by dissolving silica replica [9-11]. In addition to these methods, the combustion technology is a general method to synthesize various porous metals and oxides [12-14]. Compared with porous noble metals [15-17], porous copper was less focused, possibly for its high reactivity of oxidization in ambient atmosphere [18-26].
Materials and equipment
All chemicals were purchased from commercial sources (Sigma-Aldrich, St. Louis, MO, USA) and were used without further purification. Single-crystal X-ray diffraction measurements were carried out on a Bruker SMART APEX CCD (Bruker AXS, Inc., Madison, WI, USA). Thermogravimetric analyses (TGA) were measured on a simultaneous SDT 2960 thermal analyzer with a heating rate of 20°C∙min−1 under N2 atmosphere. Powder X-ray diffraction (XRD) patterns were collected using a Bruker D8 ADVANCE X-ray diffractometer equipped with Cu-Kα radiation (λ = 1.5418 Å) at 40 kV and 40 mA. Scanning electron microscopy (SEM) characterizations were performed on a Hitachi S-4800 SEM (Hitachi, Ltd, Chiyoda-ku, Japan), equipped with energy-dispersive X-ray spectroscopy (EDS). The transmission electron microscopy (TEM) images were obtained from JEOL JEM-2100 (JEOL Ltd., Akishima-shi, Japan) operating at 200 kV. The electronic semiconducting property f the samples was recorded by the semiconductor device analyzer B1500A from Agilent Technologies (Santa Clara, CA, USA). Elemental analysis is measured by Elementar vario MICRO (Hanau, Germany). The Fourier transform infrared (FTIR) spectrum was measured by a VECTOR 22 spectrometer with KBr pellets (Bruker AXS, Inc., Madison, WI, USA).
A mixture of CuCl2 · 2H2O (AR, 0.1 mmol), BTA (99%, 0.1 mmol), and NH3 · H2O (AR, 25 to 28 wt%, 1.0 ml) in CH3CN (AR, 5 ml) was sealed in a Teflon-lined stainless steel autoclave and heated to 100°C under autogenous pressure for 48 h. When cooled to room temperature, blue rodlike Cu(BTA)2 crystals were isolated. They were rinsed with CH3CN and dried in vacuum at 60°C overnight. The Cu(BTA)2 was decomposed and annealed in an Ar flow atmosphere at 600°C to yield the porous metallic copper.
Single-crystal X-ray diffraction reveals that the crystal structure of the precursor belongs to the monoclinic space group C2/c (Figure 1). The mononuclear complex contains one four-coordinated Cu(II) cation and two BTA anions with the formula Cu(BTA)2. Each of the BTA ligands provides two donor N atoms to coordinate to the Cu(II) ions, exhibiting a distorted tetrahedron coordination geometry (Additional file 1: Figure S1). The Cu-N bond lengths for each ligand are 1.954 and 1.969 Å, and the dihedral angle of two BTA planes is 36.35°. The CCDC no. 1035211 contains the supplementary crystallographic data for the Cu(BTA)2 complex (Additional file 2).
The XRD measurement reveals that after the decomposition at 600°C, Cu(BTA)2 completely transformed into metallic copper. The diffraction peaks (Figure 2b) can be indexed to (111), (200), and (220) crystal planes of fcc copper (pdf #88-1326). The original morphology of the Cu(BTA)2 crystals was largely inherited by the metallic copper, showing a short rodlike shape, while at the same time, remarkable size shrinkage (up to approximately 90% volume shrinkage) is observed for the metallic copper compared with the Cu(BTA)2 crystal precursor.
In summary, we report a thermal decomposition method to prepare copper micro-rods with layered porous structure for the first time, by using a well-designed coordination compound of Cu(BTA)2 crystal as the precursor. The shape of the crystals was preserved for the copper product. This allows us to obtain copper with various morphologies by the growth of the precursor crystals of different sizes and shapes, without changing the molecule itself. Moreover, the layered nano-structure is highly related to the crystal parameters of the precursor. It could be expected that the same precursor crystallizes in different crystalline spaces; accordingly, the micro/nano-structure would be tuned.
This work was supported by the Major State Basic Research Development Program of China (Grant Nos. 2013CB922102 and 2011CB808704), the National Natural Science Foundation of China (Grant Nos. 91022031 and 21301089), Jiangsu Province Science Foundation for Youths (BK20130562), and the Natural Science Foundation of Jiangsu Province (BK20130054).
- Li Y, Fu ZY, Su BL. Hierarchically structured porous materials for energy conversion and storage. Adv Funct Mater. 2012;22:4634–67.View ArticleGoogle Scholar
- Valtchev V, Tosheva L. Porous nanosized particles: preparation, properties, and applications. Chem Rev. 2013;113:6734–60.View ArticleGoogle Scholar
- Zhang J, Li CM. Nanoporous metals: fabrication strategies and advanced electrochemical applications in catalysis, sensing and energy systems. Chem Soc Rev. 2012;41:7016–31.View ArticleGoogle Scholar
- Brockway L, Vasiraju V, Asayesh-Ardakani H, Shahbazian-Yassar R, Vaddiraju S. Thermoelectric properties of large-scale Zn3P2 nanowire assemblies. Nanotechnol. 2014;25:145401–8.View ArticleGoogle Scholar
- Warren SC, Perkins MR, Adams AM, Kamperman M, Burns AA, Arora H, et al. A silica sol–gel design strategy for nanostructured metallic materials. Nat Mater. 2012;11:460–7.View ArticleGoogle Scholar
- Chen LY, Yu JS, Fujita T, Chen MW. Nanoporous copper with tunable nanoporosity for SERS applications. Adv Funct Mater. 2009;19:1221–6.View ArticleGoogle Scholar
- Yamauchi Y, Kuroda K. Rational design of mesoporous metals and related nanomaterials by a soft-template approach. Chem Asia J. 2008;3:664–76.View ArticleGoogle Scholar
- Warren SC, Messina LC, Slaughter LS, Kamperman M, Zhou Q, Gruner SM, et al. Ordered mesoporous materials from metal nanoparticle-block copolymer self-assembly. Science. 2008;320:1748–52.View ArticleGoogle Scholar
- Walsh D, Arcelli L, Ikoma T, Tanaka J, Mann S. Dextran templating for the synthesis of metallic and metal oxide sponges. Nat Mater. 2003;2:386–90.View ArticleGoogle Scholar
- Yamauchi Y, Yokoshima T, Mukaibo H, Tezuka M, Shigeno T, Momma T, et al. Highly ordered mesoporous Ni particles prepared by electroless deposition from lyotropic liquid crystals. Chem Lett. 2004;33:542–3.View ArticleGoogle Scholar
- Takai A, Doi Y, Yamauchi Y, Kuroda K. A rational repeating template method for synthesis of 2D hexagonally ordered mesoporous precious metals. Chem Asia J. 2011;6:881–7.View ArticleGoogle Scholar
- Guo L, Arafune H, Teramae N. Synthesis of mesoporous metal oxide by the thermal decomposition of oxalate precursor. Langmuir. 2013;29:4404–12.View ArticleGoogle Scholar
- Zhang L, Wu HB, Xu R, Lou XW. Porous Fe2O3 nanocubes derived from MOFs for highly reversible lithium storage. CrystEngComm. 2013;15:9332–5.View ArticleGoogle Scholar
- Banerjee A, Gokhale R, Bhatnagar S, Jog J, Bhardwaj M, Lefez B, et al. MOF derived porous carbon–Fe3O4 nanocomposite as a high performance, recyclable environmental superadsorbent. J Mater Chem. 2012;22:19694–9.View ArticleGoogle Scholar
- Lee MN, Mohraz A. Hierarchically porous silver monoliths from colloidal bicontinuous interfacially jammed emulsion gels. J Am Chem Soc. 2011;133:6945–7.View ArticleGoogle Scholar
- Qi J, Motwani P, Gheewala M, Brennan C, Wolfe JC, Shih WC. Surface-enhanced Raman spectroscopy with monolithic nanoporous gold disk substrates. Nanoscale. 2013;5:4105–9.View ArticleGoogle Scholar
- Lu L, Eychmüller A. Ordered macroporous bimetallic nanostructures: design, characterization, and applications. Acc Chem Res. 2008;41:244–53.View ArticleGoogle Scholar
- Shin HC, Liu M. Copper foam structures with highly porous nanostructured walls. Chem Mater. 2004;16:5460–4.View ArticleGoogle Scholar
- Kranzlin N, Niederberger M. Wet-chemical preparation of copper foam monoliths with tunable densities and complex macroscopic shapes. Adv Mater. 2013;25:5599–604.View ArticleGoogle Scholar
- Lai M, Kulak AN, Law D, Zhang Z, Meldrum FC, Riley DJ. Profiting from nature: macroporous copper with superior mechanical properties. Chem Commun. 2007;34:3547–9.View ArticleGoogle Scholar
- Zang D, Wu C, Zhu R, Zhang W, Yu X, Zhang Y. Porous copper surfaces with improved superhydrophobicity under oil and their application in oil separation and capture from water. Chem Commun. 2013;49:8410–2.View ArticleGoogle Scholar
- Liu Y, Chu Y, Zhuo Y, Dong L, Li L, Li M. Controlled synthesis of various hollow Cu nano/microstructures via a novel reduction route. Adv Funct Mater. 2007;17:933–8.View ArticleGoogle Scholar
- Liu Z, Yang Y, Liang J, Hu Z, Li S, Peng S, et al. Synthesis of copper nanowires via a complex-surfactant-assisted hydrothermal reduction process. J Phys Chem B. 2003;107:12658–61.View ArticleGoogle Scholar
- Chang Y, Lye ML, Zeng HC. Large-scale synthesis of high-quality ultralong copper nanowires. Langmuir. 2005;21:3746–8.View ArticleGoogle Scholar
- Adner D, Korb M, Schulze S, Hietschold M, Lang H. A straightforward approach to oxide-free copper nanoparticles by thermal decomposition of a copper(I) precursor. Chem Commun. 2013;49:6855–7.View ArticleGoogle Scholar
- Tappan BC, Huynh MH, Hiskey MA, Chavez DE, Luther EP, Mang JT, et al. Ultralow-density nanostructured metal foams: combustion synthesis, morphology, and composition. J Am Chem Soc. 2006;128:6589–94.View ArticleGoogle Scholar
- Friedrich M, Gálvez-Ruiz JC, Klapötke TM, Mayer P, Weber B, Weigand JJ. BTA copper complexes. Inorg Chem. 2005;44:8044–52.View ArticleGoogle Scholar
- Tappan BC, Steiner 3rd SA, Luther EP. Nanoporous metal foams. Angew Chem. 2010;49:4544–65.View ArticleGoogle Scholar
- Beaty HW, Fink DG. Standard handbook for electrical engineers. 11th. New York: McGraw-Hill; 1978.Google Scholar
- Kerner EH. The electrical conductivity of composite media. Proc Phys Soc B. 1956;69:802–7.View ArticleGoogle Scholar
- Amiri O, Salavati-Niasari M, Sabet M, Ghanbari D. Synthesis and characterization of CuInS2 microsphere under controlled reaction conditions and its application in low-cost solar cells. Mater Sci Semicond Process. 2013;16:1485–94.View ArticleGoogle Scholar
- Amiri O, Salavati-Niasari M, Rafiei A, Farangi M. 147% improved efficiency of dye synthesized solar cells by using CdS QDs, Au nanorods and Au nanoparticles. RSC Adv. 2014;4:62356–61.View ArticleGoogle Scholar
- Liu S, Sun SH, You XZ. Inorganic nanostructured materials for high performance electrochemical supercapacitors. Nanoscale. 2014;6:2037–45.View ArticleGoogle Scholar
- Kevin M, Ong WL, Lee GH, Ho GW. Formation of hybrid structures: copper oxide nanocrystals templated on ultralong copper nanowires for open network sensing at room temperature. Nanotechnol. 2011;22:235701–10.View ArticleGoogle Scholar
- Sun QC, Ding YC, Goodman SM, Funke HH, Nagpal P. Copper plasmonics and catalysis: role of electron–phonon interactions in dephasing localized surface plasmons. Nanoscale. 2014;6:12450–7.View ArticleGoogle Scholar
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.