Large-scale growth of hollow Sb microspheres

Article abstract of DOI:10.1246/cl.2004.1476

Uniform hollow antimony micron spheres were synthesized on a large scale using SbCl₃ and dithizone as starting reagents in ethylenediamine at 140°C for 72 h. XRD and Raman results reveal that the as-obtained final product is pure Sb. FE-SEM and TEM observation reveals that the prepared hollow microspheres are composed of nanoparticles. The possible formation mechanism was briefly discussed.

Full text of DOI:10.1246/cl.2004.1476

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Chemistry Letters Vol.33, No.11 (2004)
Large-scale Growth of Hollow Sb Microspheres
ꢀ
Wanqun Zhang, Liqiang Xu, Guangchen Xi, Weichao Yu, and Yitai Qian
Department of Chemistry, University Science and Technology of China, Hefei, Anhui, 230026, P. R. China
(Received August 9, 2004; CL-040938)
Uniform hollow antimony micron spheres were synthesized
on a large scale using SbCl3 and dithizone as starting reagents in
ethylenediamine at 140 C for 72 h. XRD and Raman results re-
SEM images were obtained by a JSM-6700F field emission
scanning electron microscope. XRD patterns of the products
were recorded by employing a Philips X’pert X-ray diffractom-
ꢁ
ꢀ
veal that the as-obtained final product is pure Sb. FE-SEM and
TEM observation reveals that the prepared hollow microspheres
are composed of nanoparticles. The possible formation mecha-
nism was briefly discussed.
eter with Cu Kꢀ radiation (ꢁ ¼ 1:54187 A). The Raman spectra
were produced at room temperature with a LABRAM-HR Con-
focal Laser MicroRaman spectrometer. TEM images were col-
lected on a Hitachi Model H-800 instrument using an accelerat-
ing voltage of 200 kV.
The XRD pattern of sample was shown in Figure 1. All
of the peaks can be indexed as the rhombohedral structure of
Recently, fabrication of uniform hollow spheres with di-
mensions from nanometer to micrometer has become a focus
in nanoscience and nanotechnology because of their broad range
of applications. For example, they can serve as photonic crystals,
catalysts, coatings, composites, fillers, and the protection of the
light-sensitive components, especially as delivery vehicle sys-
tems for the controlled release of drugs, cosmetics, inks, and
dyes.1 Several methods have been developed for the fabrica-
tion of micrometer hollow sphere of inorganic materials, such
ꢀ
antimony with calculated lattice parameter a ¼ 4:290 A and
ꢀ
c ¼ 11:267 A, which is consistent with the reported data
ꢀ
ꢀ
(a ¼ 4:307 A, c ¼ 11:273 A, JCPDS NO. 71-1173). The crystal
size calculated by the Scherrer formula from antimony (012)
peak is about 53.9 nm. No characteristic peak for impurities
was detected.
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The Raman spectrum of the as-prepared antimony hollow
spheres is shown in Figure 2. The bulk trigonal Sb has two
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as liquid droplets, latex templates, polymer beads, or inorgan-
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first-order Raman modes, Eg mode at 117 cm
ꢂ1 14
and A1g at
Comparing the Raman spectrum of hollow spheres
ic nanoparticles. Generally, the above methods require addi-
152 cm
.
tional template materials to build sphere architectures and the
template needs to be removed later. It is obvious that the proce-
dure to obtain hollow-sphere structures of inorganic materials
will be greatly simplified if only the essential reactants are used
in the reaction process, with no need for supporting templates.
Antimony is an important element in both fundamental re-
search and practical application. For example, Sb is an important
component in forming III–V antimony-based semiconductor
materials that are valuable in electronics and optoelectronics
with that of Sb, it is clear that Raman lines of the hollow spheres
(especially Eg mode) are blue-shifted. The blue-shift in Raman
line shape probably results from the nanosize effect according
to analysis of Anushree et al. Obviously, the Raman spectrum
reveals that the as-obtained antimony hollow spheres are com-
posed of Sb nanoparticles with a rhombohedral structure.
From FE-SEM image (Figure 3a), one can see that the pan-
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as well as in forming thermoelectric materials. Amorphous
or polycrystalline antimony nanowires have been prepared in po-
rous anodic alumina templates using the vapor-phase deposition
technique and their particular transport properties have been also
studied.11 Single-crystalline antimony nanowires arrays have
been prepared by pulsed electropodeposition in anodic alumina
membranes.12 Recently, our group have reported the synthesis
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of Sb nanotubes by solvothermal route. However, no hollow
antimony spheres are reported in the literature. Herein, we re-
ported a novel template-free route to fabricate hollow antimony
micron spheres via a simple low-temperature solvothermal com-
plexing–reduction approach. In the system, dithizone (H2Dz)
acted as both ligand and reducing agent.
Figure 1. XRD pattern of the as-prepared antimony.
All the reagents are of analytical grade and purchased from
Shanghai Chemical. In a typical synthesis, SbCl3 (0.7 mmol) and
H2Dz (2.1 mmol) were put into 50 mL of ethylenediamine and
the mixture was stirred vigorously for about 1 h to form a homo-
geneous solution. The resulting solution was transferred into a
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0-mL Teflon-lined autoclave, then, the autoclave was sealed
ꢁ
and maintained at 140 C for 72 h, and then was cooled to room
temperature on standing. The precipitate was filtered off and
washed with distilled water and absolute ethanol several times
ꢁ
and dried in vacuum at 60 C for 7 h.
Figure 2. Raman spectrum of the sample.
Copyright ꢀ 2004 The Chemical Society of Japan

Chemistry Letters Vol.33, No.11 (2004)
1477
In the route, solvent has great influence on the final product.
When ammonia or sodium hydroxide solution was used, with
other conditions kept constant, only Sb2O3 was obtained. Be-
sides the influence of solvent, it was found that the reaction time
also has an important effect on the morphology of Sb crystals.
When the reaction time was shorter than 24 h, only Sb aggregat-
ed nanoparticles were obtained, prolonging the reaction time to
4
8 h, hollow antimony micron spheres will be obtained. The op-
Figure 3. Morphology of the as-prepared product. (a) FE-SEM
ꢁ
timum reaction time for hollow sphere structure of Sb is no
shorter than 72 h.
image of the sample obtained at 140 C for 72 h. (inset is the mag-
nified FE-SEM image of the ‘‘open’’ structure of the hollow
ꢁ
In conclusion, hollow antimony micron spheres have been
successfully prepared in a simple system containing SbCl3,
H2Dz and ethylenediamine without assistant of any template.
The hollow Sb antimony spheres were formed via self-assembly
of small nanoparticles. Compared with those methods assisted
by templates, the template-free route is very simple and facile.
This work was supported by the National Natural Science
Foundation of China and the 973 Project of China.
spheres) (b) TEM image of the sample obtained at 140 C for 28 h.
Figure 4. Schematic illustration of the possible mechanism for
Sb hollow spheres.
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Published on the web (Advance View) October 16, 2004; DOI 10.1246/cl.2004.1476