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Chemistry Letters Vol.37, No.7 (2008)
Fabrication of Urchin-like Bismuth Nanostructures via a Facile Solvothermal Route
ꢀ
Chunjuan Tang, Y. X. Zhang, Guozhong Wang, H. Q. Wang, and Guanghai Li
Anhui Key Laboratory of Nanomaterials and Nanotechnology, Institute of Solid State Physics, Chinese Academy of Sciences,
P. O. Box 1129. Hefei 230031, P. R. China
(Received April 15, 2008; CL-080391; E-mail: ghli@issp.ac.cn)
A facile solution-phase process has been demonstrated for
the preparation of urchin-like bismuth nanostructures by
reducing bismuth nitrate with ethylene glycol. X-ray diffraction
(
XRD), field emission scanning electron microscopy (FESEM),
transmission electron microscopy (TEM), and selected area
electron diffraction (SAED) have been used to characterize
the as-prepared products. The formation mechanism has been
proposed.
Fabrication of nanoscale inorganic crystals with controlled
size, shape, and hierarchy has attracted intensive research
interest, since they are potential building blocks for advanced
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electronic and optoelectronic devices. Size- and shape-control-
led synthesis of nanocrystal materials is a crucial issue for the
exploitation of their novel properties. Extensive work has been
devoted to the investigation of effective and efficient methods
to fabricate one-dimensional (1D) nanostructures such as
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Figure 1. XRD pattern of bismuth prepared at 180 C for 10 h.
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nanowires, nanobelts, and nanotubes in the past few years.
Compared to 1D nanostructures, complex three-dimensional
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(
structures from the self-assembly of polyhedral mesosphere
3D) architectures, such as branched Cu2O crystals, hierarchical
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crystals, tetragonal PbWO4 microcrystals, and hyperbranched
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–11
CdTe and CdSe with rich 3D structures,
may offer opportu-
nities to explore novel properties of nanocrystals and be em-
ployed as novel building blocks to produce more complicated
and advanced nanomaterials.
Figure 2. (a) Low- and (b) high-magnification FESEM images
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of bismuth prepared at 180 C for 10 h.
As a semimetal with a small band overlap (38 meV at 5 K)
with a very anisotropic electron effective-mass tensor, bismuth
has unusual electronic properties and holds promise for optical
No. 05-0519). No other diffraction peaks belonging to oxides
or impurities can be observed in this pattern, indicating that
the resulting product is highly crystallized elemental bismuth
with high purity under current synthetic conditions.
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and thermoelectric applications.
been developed to fabricate bismuth nanomaterials in the form
Different methods have
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of nanotubes,
wire arrays.1
nanowires, triangular nanoplate, and nano-
However, there is no report on the preparation
The morphology of the as-prepared product was determined
by FESEM. Figure 2a shows a low-magnification FESEM image
of the product. Large-scale urchin-like bismuth nanostructures
composed of many nanorods can be clearly seen. The urchin-like
bismuth structures have the diameter of about 3 mm with acicular
nanorods radiating from the center and have nearly uniform size
distribution. The yield of the urchin-like bismuth is about 85%.
The high-magnification FESEM image shown in Figure 2b
clearly demonstrates that the nanorods with diameter of about
20 nm grown from the center of the urchin and that some of
the nanorods aligned together.
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of bismuth nanocrystals with 3D structures. It is necessary to
explore a simple method to prepare bismuth with 3D nanostruc-
tures, which might have novel properties. In this letter, we
reported the large-scale preparation of 3D structured bismuth
nanocrystals with urchin-like morphology by a facile solvother-
mal method.
.
In a typical preparation process, 0.61 g of Bi(NO3)3 5H2O
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was dissolved into 50 mL of ethylene glycol (EG) at 80 C.
The solution was stirred vigorously for 1 h and transferred into
a stainless steel autoclave with a Teflon liner. The autoclave
Figure 3a shows the TEM image of the bismuth nanorods.
The urchin-like bismuth nanostructure is very sensitive to
electron beam radiation because of very lower melting point of
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was sealed and maintained at 180 C for 10 h, then cooled to
room temperature naturally. The obtained black solids were
washed with deionized water and absolute ethanol for several
times and dried in vacuum for 4 h.
XRD was used to determine the phase of the as-prepared
product. All the diffraction peaks (Figure 1) can be indexed
to hexagonal rhomb-centered phase bismuth (JCPDS card
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bismuth (271 C). Once the electron beam was focused on them,
the nanorods quickly became small bismuth liquid droplets.
From Figure 3a, one can see that many small bismuth nanopar-
ticles align into a nanorod shape. The analysis of the intrinsic
structure for the nanorods is very difficult owing to their sensitiv-
Copyright ꢀ 2008 The Chemical Society of Japan
Tang, Chunjuan
