U.S. patent application number 14/593439 was filed with the patent office on 2015-04-30 for method for fabricating hollow metal nano particles and hollow metal nano particles fabricated by the method.
The applicant listed for this patent is LG CHEM, LTD.. Invention is credited to Jun Yeon CHO, Gyo Hyun HWANG, Kwanghyun KIM, Sang Hoon KIM.
Application Number | 20150118496 14/593439 |
Document ID | / |
Family ID | 49551019 |
Filed Date | 2015-04-30 |
United States Patent
Application |
20150118496 |
Kind Code |
A1 |
CHO; Jun Yeon ; et
al. |
April 30, 2015 |
METHOD FOR FABRICATING HOLLOW METAL NANO PARTICLES AND HOLLOW METAL
NANO PARTICLES FABRICATED BY THE METHOD
Abstract
The present application provides a method for fabricating hollow
metal nano particles and hollow metal nano particles fabricated by
the same.
Inventors: |
CHO; Jun Yeon; (Daejeon,
KR) ; KIM; Sang Hoon; (Daejeon, KR) ; HWANG;
Gyo Hyun; (Daejeon, KR) ; KIM; Kwanghyun;
(Daejeon, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LG CHEM, LTD. |
Seoul |
|
KR |
|
|
Family ID: |
49551019 |
Appl. No.: |
14/593439 |
Filed: |
January 9, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14344258 |
Mar 14, 2014 |
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PCT/KR2013/004177 |
May 10, 2013 |
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14593439 |
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Current U.S.
Class: |
428/402 ; 75/344;
75/371; 75/373; 75/374 |
Current CPC
Class: |
C22C 5/04 20130101; B22F
2001/0029 20130101; B22F 1/0018 20130101; B82Y 30/00 20130101; B22F
1/0044 20130101; B22F 2304/05 20130101; B22F 2304/052 20130101;
Y10T 428/2982 20150115; B22F 1/0051 20130101; Y10T 428/12181
20150115; B22F 2304/054 20130101; B22F 9/24 20130101; C01P 2004/34
20130101; B22F 1/0062 20130101 |
Class at
Publication: |
428/402 ; 75/344;
75/371; 75/373; 75/374 |
International
Class: |
B22F 9/24 20060101
B22F009/24 |
Foreign Application Data
Date |
Code |
Application Number |
May 11, 2012 |
KR |
1020120050483 |
Jan 30, 2013 |
KR |
1020130010526 |
Claims
1. A method for fabricating hollow metal nano particles, the method
comprising: forming a solution by adding a first metal salt, a
second metal salt, and a surfactant to a solvent; and forming
hollow metal nano particles by adding a reducing agent to the
solution, wherein the forming of the solution comprises forming a
micelle by the surfactant, and surrounding an outer portion of the
micelle with the first metal salt and the second metal salt, and
the forming of the hollow metal nano particles comprises forming
the micelle region to a hollow form.
2. The method of claim 1, wherein a carbon number of the chains of
the surfactant is 15 or less.
3. The method of claim 1, wherein the surfactant is an anionic
surfactant.
4. The method of claim 3, wherein the anionic surfactant comprises
NH.sub.4.sup.+, K.sup.+, Na.sup.+, or Li.sup.+ as a counter
ion.
5. The method of claim 3, wherein the anionic surfactant is
selected from the group consisting of potassium laurate,
triethanolamine stearate, ammonium lauryl sulfate, lithium dodecyl
sulfate, sodium lauryl sulfate, sodium dodecyl sulfate, alkyl
polyoxyethylene sulfate, sodium alginate, dioctyl sodium
sulfosuccinate, phosphatidyl glycerol, phosphatidyl inositol,
phosphatidylserine, phosphatidic acid and salts thereof, glyceryl
ester, sodium carboxymethylcellulose, bile acid and salts thereof,
cholic acid, deoxycholic acid, glycocholic acid, taurocholic acid,
glycodeoxycholic acid, alkyl sulfonate, aryl sulfonate, alkyl
phosphate, alkyl sulfonate, stearic acid and salts thereof, calcium
stearate, phosphate, sodium carboxymethyl cellulose, dioctyl
sulfosuccinate, dialkyl ester of sodium sulfosuccinic acid,
phospholipid and calcium carboxymethyl cellulose.
6. The method of claim 1, wherein the surfactant is a cationic
surfactant.
7. The method of claim 6, wherein the cationic surfactant comprises
I.sup.-, Br.sup.-, or Cl.sup.- as a counter ion.
8. The method of claim 6, wherein the cationic surfactant is
selected from the group consisting of quaternary ammonium
compounds, benzalkonium chloride, cetyl trimethyl ammonium bromide,
chitonic acid, lauryl dimethyl benzyl ammonium chloride, acyl
carnitine hydrochloride, alkyl pyridinium halide, cetylpyridinium
chloride, cationic lipids, polymethylmethacrylate trimethyl
ammonium bromide, sulfonium compounds,
polyvinylpyrrolidone-2-dimethylaminoethyl methacrylate dimethyl
sulfate, hexadecyl trimethyl ammonium bromide, phosphonium
compounds, quaternary ammonium compounds,
benzyl-di(2-chloroethyl)ethyl ammonium bromide, coconut trimethyl
ammonium chloride, coconut trimethyl ammonium bromide, coconut
methyl dihydroxyethyl ammonium chloride, coconut methyl
dihydroxyethyl ammonium bromide, decyl triethyl ammonium chloride,
decyl dimethyl hydroxyethyl ammonium chloride, decyl dimethyl
hydroxyethyl ammonium chloride bromide, C.sub.12-15-dimethyl
hydroxyethyl ammonium chloride, C.sub.12-15-dimethyl hydroxyethyl
ammonium chloride bromide, coconut dimethyl hydroxyethyl ammonium
chloride, coconut dimethyl hydroxyethyl ammonium bromide, myristyl
trimethyl ammonium methyl sulphate, lauryl dimethyl benzyl ammonium
chloride, lauryl dimethyl benzyl ammonium bromide, lauryl dimethyl
(ethenoxy).sub.4 ammonium chloride, lauryl dimethyl
(ethenoxy).sub.4 ammonium bromide, N-alkyl
(C.sub.12-18)dimethylbenzyl ammonium chloride, N-alkyl
(C.sub.14-18)dimethyl-benzyl ammonium chloride,
N-tetradecyldimethylbenzyl ammonium chloride monohydrate, dimethyl
didecyl ammonium chloride, N-alkyl (C.sub.12-14)dimethyl
1-naphthylmethyl ammonium chloride, trimethylammonium halide
alkyl-trimethylammonium salts, dialkyl-dimethylammonium salts,
lauryl trimethyl ammonium chloride, ethoxylated
alkyamidoalkyldialkylammonium salts, ethoxylated trialkyl ammonium
salts, dialkylbenzene dialkylammonium chloride, N-didecyldimethyl
ammonium chloride, N-tetradecyldimethylbenzyl ammonium chloride
monohydrate, N-alkyl(C.sub.12-14) dimethyl 1-naphthylmethyl
ammonium chloride, dodecyldimethylbenzyl ammonium chloride, dialkyl
benzenealkyl ammonium chloride, lauryl trimethyl ammonium chloride,
alkylbenzyl methyl ammonium chloride, alkyl benzyl dimethyl
ammonium bromide, C.sub.12 trimethyl ammonium bromide, C.sub.15
trimethyl ammonium bromide, C.sub.17 trimethyl ammonium bromide,
dodecylbenzyl triethyl ammonium chloride,
polydiallyldimethylammonium chloride, dimethyl ammonium chloride,
alkyldimethylammonium halogenide, tricetyl methyl ammonium
chloride, decyltrimethylammonium bromide, dodecyltriethylammonium
bromide, tetradecyltrimethylammonium bromide, methyl
trioctylammonium chloride, POLYQUAT 10, tetrabutylammonium bromide,
benzyl trimethylammonium bromide, choline ester, benzalkonium
chloride, stearalkonium chloride, cetyl pyridinium bromide, cetyl
pyridinium chloride, halide salts of quaternized
polyoxyethylalkylamines, MIRAPOL Alkaquat, alkyl pyridinium salts,
amine, amine salts, imide azolinium salts, protonated quaternary
acrylamides, methylated quaternary polymers, cationic gua gum,
benzalkonium chloride, dodecyl trimethyl ammonium bromide,
triethanolamine, and poloxamine.
9. The method of claim 1, wherein the forming of the hollow metal
nano particles comprises further adding a non-ionic surfactant.
10. The method of claim 9, wherein the non-ionic surfactant is
selected from the group consisting of polyoxyethylene fatty alcohol
ether, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene
fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene
castor oil derivatives, sorbitan ester, glyceryl ester, glycerol
monostearate, polyethylene glycol, polypropylene glycol,
polypropylene glycol ester, cetyl alcohol, cetostearyl alcohol,
stearyl alcohol, aryl alkyl polyether alcohol, polyoxyethylene
polyoxypropylene copolymers, poloxamer, poloxamine,
methylcellulose, hydroxycellulose, hydroxymethylcellulose,
hydroxyethylcellulose, hydroxypropylcellulose,
hydroxypropylmethylcellulose, hydroxypropylmethylcellulose
phthalate, noncrystalline cellulose, polysaccharides, starch,
starch derivatives, hydroxyethyl starch, polyvinyl alcohol,
triethanolamine stearate, amine oxide, dextran, glycerol, gum
acacia, cholesterol, tragacanth, and polyvinylpyrrolidone.
11. The method of claim 1, wherein the forming of the hollow metal
nano particles comprises further adding a stabilizer.
12. The method of claim 11, wherein the stabilizer comprises one or
two or more selected from the group consisting of disodium
phosphate, dipotassium phosphate, disodium citrate, and trisodium
citrate.
13. The method of claim 1, wherein the first metal of the first
metal salt and the second metal of the second metal salt are each
independently selected from the group consisting of metals
belonging to Group 3 to Group 15 of the periodic table, metalloids,
lanthanide metals, and actinide metals.
14. The method of claim 1, wherein the first metal of the first
metal salt and the second metal of the second metal salt are each
independently selected from the group consisting of platinum (Pt),
ruthenium (Ru), rhodium (Rh), molybdenum (Mo), osmium (Os), iridium
(Ir), rhenium (Re), palladium (Pd), vanadium (V), tungsten (W),
cobalt (Co), iron (Fe), selenium (Se), nickel (Ni), bismuth (Bi),
tin (Sn), chromium (Cr), titanium (Ti), gold (Au), cerium (Ce),
silver (Ag), and copper (Cu).
15. The method of claim 1, wherein the first meal salt and the
second metal salt are nitrate, halide, hydroxide, or sulfate of the
first metal and the second metal, respectively.
16. The method of claim 1, wherein the solvent comprises water.
17. The method of claim 1, wherein a molar ratio of the first metal
salt to the second metal salt in the solution is 1:5 to 10:1.
18. The method of claim 1, wherein the solvent is water, and a
concentration of the surfactant in the solution is one time to five
times of a critical micelle concentration (CMC) to water.
19. The method of claim 1, wherein the fabrication method is
carried out at normal temperature.
20. The method of claim 1, wherein the reducing agent has a
standard reduction potential of -0.23 V or less.
21. The method of claim 1, wherein the reducing agent is one or two
or more selected from the group consisting of NaBH.sub.4,
NH.sub.2NH.sub.2, LiA1H.sub.4, and LiBEt.sub.3H.
22. The method of claim 1, wherein an average particle diameter of
the hollow metal nano particles is within a range from 80% to 120%
of an average particle diameter of hollow metal nano particles.
23. The method of claim 1, further comprising: removing a
surfactant inside the hollow metal nano particles after the forming
of the hollow metal nano particles.
24. The method of claim 1, wherein the hollow metal nano particles
have an average particle diameter of 30 nm or less.
25. The method of claim 1, wherein the hollow metal nano particles
have an average particle diameter of 20 nm or less.
26. The method of claim 1, wherein the hollow metal nano particles
have an average particle diameter of 10 nm or less.
27. The method of claim 1, wherein the hollow metal nano particles
have an average particle diameter of 6 nm or less.
28. The method of claim 1, wherein the hollow metal nano particles
have a spherical shape.
29. The method of claim 1, wherein a volume of the hollows is 50%
by volume or more of a total volume of the hollow metal nano
particles.
30. The method of claim 1, wherein the hollow metal nano particles
comprise: a hollow core; at least one first shell comprising a
first metal; and at least one second shell comprising a second
metal.
31. The method of claim 1, wherein the hollow metal nano particles
comprise: a hollow core; and at least one shell comprising a first
metal and a second metal.
32. The method of claim 30, wherein each of the shells has a
thickness of 5 nm or less.
33. The method of claim 30, wherein each of the shells has a
thickness of 3 nm or less.
34. Hollow metal nano particles fabricated by the method of claim
1.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority to and the benefit
of Korean Patent Application No. 10-2012-0050483 filed in the
Korean Intellectual Property Office on May 11, 2012, and claims
priority to and the benefit of Korean Patent Application No.
10-2013-0010526 filed in the Korean Intellectual Property Office on
Jan. 30, 2013, the entire contents of which are incorporated herein
by reference.
TECHNICAL FIELD
[0002] The present application relates to a method for fabricating
hollow metal nano particles and hollow metal nano particles
fabricated by the method.
BACKGROUND ART
[0003] Nano particles are particles having a nano-scaled particle
size, and exhibit optical, electric, and magnetic characteristics
completely different from those of a bulk-state material due to a
quantum confinement effect in which the energy required for
electron transfer is changed depending on the size of material, and
a large specific surface area. Thus, due to these properties, much
interests have been focused on the applicability in the fields of
catalysts, electro-magnetics, optics, medicine, and the like. Nano
particles may be an intermediate between bulk and molecule, and in
terms of an approach in two ways, that is, a "Top-down" approach
and a "Bottom-up" approach, it is possible to synthesize nano
particles.
[0004] Examples of a method for synthesizing metal nano particles
include a method for reducing metal ions with a reducing agent in a
solution, a method using gamma rays, an electrochemical method, and
the like. However, methods in the related art are problematic in
that it is difficult to synthesize nano particles having a uniform
size and shape, or the use of an organic solvent leads to
environmental pollution, high costs, and the like. For these
various reasons, it was difficult to economically mass-produce
high-quality nano particles.
[0005] Meanwhile, in order to fabricate hollow metal nano particles
in the related art, hollow metal nano particles have been
fabricated by synthesizing particles with a low reduction
potential, such as Ag, Cu, Co, and Ni, substituting the surface of
particles, such as Ag, Cu, Co, Ni, or the like with a metal having
a higher reduction potential than the particles with a low
reduction potential, for example, Pt, Pd, or Au by a potential
difference substitution method, and after the surface substitution,
melting Ag, Cu, Co, Ni, and the like remaining inside the particles
through an acid treatment. In this case, there is a problem in the
process in that a post-treatment needs to be performed with an
acid. Since the potential difference substitution method is a
natural reaction, there are few factors that may be controlled, and
thus it is difficult to fabricate uniform particles. Therefore,
there is a need for a method for fabricating uniform hollow metal
nano particles, which is easier than the methods in the related
art.
SUMMARY OF THE INVENTION
[0006] The present application has been made in an effort to
provide a method for fabricating hollow metal nano particles, which
generates no environmental pollution and is capable of easily
implementing mass production with relatively low costs.
[0007] Further, the present application has been made in an effort
to provide hollow metal nano particles fabricated by the
fabrication method.
[0008] The problems of the present application to be solved are not
limited to the aforementioned technical problems, and other
technical problems, which have not been mentioned, may be obviously
understood by a person with ordinary skill in the art from the
following description.
[0009] An exemplary embodiment of the present application include a
method for fabricating hollow metal nano particles, the method
including: forming a solution by adding a first metal salt, a
second metal salt, and a surfactant to a solvent; and forming
hollow metal nano particles by adding a reducing agent to the
solution,
[0010] in which the forming of the solution includes forming a
micelle by the surfactant, and surrounding an outer portion of the
micelle with the first metal salt and the second metal salt,
and
[0011] the forming of the hollow metal nano particles includes
forming the micelle region to a hollow form.
[0012] An exemplary embodiment of the present application provides
hollow metal nano particles fabricated by the fabrication
method.
[0013] The present application is advantageous in that it is
possible to mass-produce hollow metal nano particles having a
uniform size of several nanometers, there is a cost reduction
effect, and no environmental pollution is generated in the
fabrication process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 illustrates a model of hollow metal nano particles
fabricated according to Example 1.
[0015] FIG. 2 illustrates a transmission electron microscope (TEM)
image of the hollow metal nano particles fabricated according to
Example 1.
[0016] FIG. 3 illustrate a transmission electron microscope (TEM)
image of the hollow metal nano particles fabricated according to
Example 1, which is magnified two times more than the image of FIG.
2.
[0017] FIG. 4 illustrates a transmission electron microscope (TEM)
image of hollow metal nano particles fabricated according to
Comparative Example 1.
[0018] FIG. 5 illustrates a model of hollow metal nano particles in
which a surfactant is included, among hollow metal nano particles
fabricated according to Example 5.
[0019] FIG. 6 illustrates a model of hollow metal nano particles
from which a surfactant is removed, among the hollow metal nano
particles fabricated according to Example 5.
[0020] FIG. 7 illustrates a transmission electron microscope (TEM)
image of hollow metal nano particles fabricated according to
Example 2.
[0021] FIG. 8 illustrates a transmission electron microscope (TEM)
image of hollow metal nano particles fabricated according to
Example 3.
[0022] FIG. 9 illustrates a transmission electron microscope (TEM)
image of hollow metal nano particles fabricated according to
Example 4.
[0023] FIG. 10 illustrates a transmission electron microscope (TEM)
image of hollow metal nano particles fabricated according to
Example 5.
DETAILED DESCRIPTION
[0024] The advantages and features of the present application, and
methods of accomplishing these will become obvious with reference
to the exemplary embodiments to be described below in detail along
with the accompanying drawings. However, the present application is
not limited to exemplary embodiments to be disclosed below, but
will be implemented in various forms different from each other. The
exemplary embodiments are merely intended to make the disclosure of
the present application complete and provided to completely notify
the scope of the invention to the person with ordinary skill in the
art to which the present application belongs, and the present
application is only defined by the scope of the claims. The size
and relative size of the constituent elements marked in the
drawings may be exaggerated for clarity of description.
[0025] Unless otherwise defined, all terms (including technical and
scientific terms) used in the present specification may be used as
the meaning which may be commonly understood by the person with
ordinary skill in the art to which the present application belongs.
It will be further understood that terms defined in commonly used
dictionaries should not be interpreted ideally or excessively
unless expressly and specifically defined.
[0026] Hereinafter, the present application will be described in
detail.
[0027] In the present specification, hollow means that the core
parts of hollow metal nano particles are empty. In addition, the
hollow may also be used as the same meaning as a hollow core. The
hollow includes the terms of hollow, hole, void, and porous. The
hollow may include a space in which an internal material is not
present by 50% by volume or more, specifically 70% by volume or
more, and more specifically 80% by volume or more. Furthermore, the
hollow may also include a space of which the inside is empty by 50%
by volume or more, specifically 70% by volume or more, and more
specifically 80% by volume or more. Further, the hollow includes a
space having an internal porosity of 50% by volume or more,
specifically 70% by volume or more, and more specifically 80% by
volume.
[0028] The fabrication method according to an exemplary embodiment
of the present application provides a method for fabricating hollow
metal nano particles, the method including: forming a solution by
adding a first metal salt, a second metal salt, and a surfactant to
a solvent; and forming hollow metal nano particles by adding a
reducing agent to the solution,
[0029] in which the forming of the solution includes forming a
micelle by the surfactant, and surrounding an outer portion of the
micelle with the first metal salt and the second metal salt,
and
[0030] the forming of the hollow metal nano particles includes
forming the micelle region to a hollow form.
[0031] The fabrication method according to an exemplary embodiment
of the present application does not use a reduction potential
difference, and thus is advantageous in that a reduction potential
between a first metal and a second metal is not considered. Since
charges between metal ions are used, the fabrication method is
advantageous in that the method is simpler than the fabrication
method in the related art, and thus facilitates mass
production.
[0032] In an exemplary embodiment of the present application, the
first metal salt is not particularly limited as long as the first
metal salt may be ionized in a solution to provide metal ions of a
first metal. The first metal salt may include the first metal.
Here, the first metal may be different from a second metal.
[0033] Here, the first metal of the first metal salt may be
selected from the group consisting of metals belonging to Group 3
to Group 15 of the periodic table, metalloids, lanthanide metals,
and actinide metals, and specifically, may be one selected from the
group consisting of platinum (Pt), ruthenium (Ru), rhodium (Rh),
molybdenum (Mo), osmium (Os), iridium (Ir), rhenium (Re), palladium
(Pd), vanadium (V), tungsten (W), cobalt (Co), iron (Fe), selenium
(Se), nickel (Ni), bismuth (Bi), tin (Sn), chromium (Cr), titanium
(Ti), gold (Au), cerium (Ce), silver (Ag), and copper (Cu). More
specifically, the first metal may be selected from the group
consisting of ruthenium (Ru), rhodium (Rh), molybdenum (Mo), osmium
(Os), iridium (Ir), rhenium (Re), palladium (Pd), vanadium (V),
tungsten (W), cobalt (Co), iron (Fe), selenium (Se), nickel (Ni),
bismuth (Bi), tin (Sn), chromium (Cr), titanium (Ti), cerium (Ce),
silver (Ag), and copper (Cu), and even more specifically, may be
nickel (Ni).
[0034] In an exemplary embodiment of the present application, the
second metal salt is not particularly limited as long as the second
metal salt may be ionized in a solution to provide metal ions of
the second metal. The second metal salt may include the second
metal. Here, the second metal may be different from the first
metal.
[0035] Here, the second metal of the second metal salt may be
selected from the group consisting of metals belonging to Group 3
to Group 15 of the periodic table, metalloids, lanthanide metals,
and actinide metals, and specifically, may be one selected from the
group consisting of platinum (Pt), ruthenium (Ru), rhodium (Rh),
molybdenum (Mo), osmium (Os), iridium (Ir), rhenium (Re), palladium
(Pd), vanadium (V), tungsten (W), cobalt (Co), iron (Fe), selenium
(Se), nickel (Ni), bismuth (Bi), tin (Sn), chromium (Cr), titanium
(Ti), gold (Au), cerium (Ce), silver (Ag), and copper (Cu). More
specifically, the second metal may be selected from the group
consisting of platinum (Pt), palladium (Pt), and gold (Au), and
even more specifically, may be platinum (Pt).
[0036] In an exemplary embodiment of the present application, the
first metal salt and the second metal salt may be nitrate
(NO.sub.3.sup.-), halide such as chloride (Cl.sup.-), bromide
(Br.sup.-), and iodide (I.sup.-), hydroxide (OH.sup.-), or sulfate
(SO.sub.4.sup.-) of the first metal and the second metal,
respectively, but is not limited thereto.
[0037] According to an exemplary embodiment of the present
application, the first metal and the second metal may form the
hollow metal nano particles. Specifically, the first metal and the
second metal may form a shell portion of the hollow metal nano
particles, and the shell portion may include a first shell and a
second shell.
[0038] Specifically, according to an exemplary embodiment of the
present application, the shell portion may be formed of the first
shell including the first metal and the second shell including the
second metal.
[0039] Further, according to an exemplary embodiment of the present
application, the first shell and the second shell may include
different metals.
[0040] Alternatively, the shell portion of the present
specification may include one shell including the first metal and
the second metal.
[0041] The shell portion of the present application may be present
on the entire surface outside of hollow portion, and may also be
present in the form of surrounding the hollow portion.
Specifically, according to an exemplary embodiment of the present
application, the shell portion may be formed throughout on the
outer side surface of hollow portion That is, the shell portion of
the present application may constitute the forms of the hollow
metal nano particles.
[0042] According to an exemplary embodiment of the present
application, the shell portion of the hollow metal nano particles
may be formed of a metal including the first metal and the second
metal. That is, the shell portion of the hollow metal nano
particles of the present application may be formed of a metal
instead of a metal oxide.
[0043] According to an exemplary embodiment of the present
application, the hollow metal nano particles may have a spherical
shape. In this case, the form of the shell portion of the present
application may have a spherical shape including a hollow core.
[0044] The spherical shape of the present application does not mean
only a completely spherical shape, and may include an approximately
spherical shape. For example, in the hollow metal nano particles,
the spherically shaped outer surface may not be flat, and the
radius of curvature in one hollow metal nano particle may not be
uniform.
[0045] According to an exemplary embodiment of the present
application, the first metal salt may be in the form of surrounding
the outer surface of a surfactant forming a micelle. In addition,
the second metal salt may be in the form of surrounding the first
metal salt. The first metal salt and the second metal salt may form
shell portions including the first metal and the second metal,
respectively by a reducing agent.
[0046] In an exemplary embodiment of the present application, the
molar ratio of the first metal salt to the second metal salt may be
1:5 to 10:1, specifically, 2:1 to 5:1. When the mole number of the
first metal salt is smaller than the mole number of the second
metal salt, it is difficult for the first metal to form a first
shell including hollow portions. Furthermore, when the mole number
of the first metal salt exceeds the mole number of the second metal
salt by 10 times, it is difficult for the second metal salt to form
a second shell surrounding the first shell.
[0047] According to an exemplary embodiment of the present
application, the atomic percentage ratio of the first metal to the
second metal of the shell portion may be 1:5 to 10:1. When the
shell portion is formed of the first shell and the second shell,
the atomic percentage ratio may be an atomic percentage ratio of
the first metal of the first shell to the second metal of the
second shell. Alternatively, the atomic percentage ratio may be an
atomic percentage ratio of the first metal to the second metal when
the shell portion is formed of one shell including the first metal
and the second metal.
[0048] According to an exemplary embodiment of the present
application, when the shell portion is formed of one shell
including the first metal and the second metal, the first metal and
the second metal may also be mixed uniformly or non-uniformly.
[0049] Alternatively, according to an exemplary embodiment of the
present application, the shell portion may be present in a state
where the first metal and the second metal are gradated, the first
metal may be present in an amount of 50% by volume or more or 70%
by volume or more at a portion adjacent to the hollow core in the
shell portion, and the second metal may be present in an amount of
50% by volume or more or 70% by volume or more at a surface portion
adjacent to the outer portion of nano particles in the shell
portion.
[0050] According to an exemplary embodiment of the present
application, the solvent may be a solvent including water.
Specifically, in an exemplary embodiment of the present
application, the solvent serves to dissolve the first metal salt
and the second metal salt, and may be water or a mixture of water
and a C.sub.1 to C.sub.6 alcohol, specifically, water. When water
is used as a solvent in the present application, an organic solvent
is not used, and thus a post-treatment process of treating an
organic solvent in the fabrication process is not needed.
Therefore, there are effects of reducing costs and preventing
environmental pollution.
[0051] According to an exemplary embodiment of the present
application, the surfactant may form a micelle in the solution. It
is possible to classify electric charges of the surfactant
depending on the type of electric charge on the outer side surface
of the micelle. That is, when the electric charge on the outer side
surface of the micelle is anionic, the surfactant forming the
micelle may be an anionic surfactant. Further, when the electric
charge on the outer side surface of the micelle is cationic, the
surfactant forming the micelle may be a cationic surfactant.
[0052] In an exemplary embodiment of the present application, the
surfactant may be an anionic surfactant. Specifically, the anionic
surfactant may be selected from the group consisting of potassium
laurate, triethanolamine stearate, ammonium lauryl sulfate, lithium
dodecyl sulfate, sodium lauryl sulfate, sodium dodecyl sulfate,
alkyl polyoxyethylene sulfate, sodium alginate, dioctyl sodium
sulfosuccinate, phosphatidyl glycerol, phosphatidyl inositol,
phosphatidylserine, phosphatidic acid and salts thereof, glyceryl
ester, sodium carboxymethylcellulose, bile acid and salts thereof,
cholic acid, deoxycholic acid, glycocholic acid, taurocholic acid,
glycodeoxycholic acid, alkyl sulfonate, aryl sulfonate, alkyl
phosphate, alkyl sulfonate, stearic acid and salts thereof, calcium
stearate, phosphate, sodium carboxymethyl cellulose, dioctyl
sulfosuccinate, dialkyl ester of sodium sulfosuccinic acid,
phospholipid and calcium carboxymethyl cellulose.
[0053] When the surfactant is an anionic surfactant, the outer side
surface of the surfactant forming the micelle is anionically
charged, and thus may be surrounded by the first metal salt that is
cationally charged. Furthermore, the first metal salt may be
surrounded by the second metal salt that is anionically
charged.
[0054] According to an exemplary embodiment of the present
application, the first metal salt that is cationically charged and
the second metal salt that is anionically charged are not present
in a region where the anionic surfactant forms a micelle, thereby
forming hollow portions. That is, when the first metal salt and the
second metal salt are formed of a shell portion including the first
metal and the second metal by a reducing agent, the region
constituting the micelle may become a hollow core that does not
include a metal.
[0055] In an exemplary embodiment of the present application, the
surfactant may be a cationic surfactant. Specifically, the cationic
surfactant may be selected from the group consisting of quaternary
ammonium compounds, benzalkonium chloride, cetyl trimethyl ammonium
bromide, chitonic acid, lauryl dimethyl benzyl ammonium chloride,
acyl carnitine hydrochloride, alkyl pyridinium halide,
cetylpyridinium chloride, cationic lipids, polymethylmethacrylate
trimethyl ammonium bromide, sulfonium compounds,
polyvinylpyrrolidone-2-dimethylaminoethyl methacrylate dimethyl
sulfate, hexadecyl trimethyl ammonium bromide, phosphonium
compounds, benzyl-di(2-chloroethyl)ethyl ammonium bromide, coconut
trimethyl ammonium chloride, coconut trimethyl ammonium bromide,
coconut methyl dihydroxyethyl ammonium chloride, coconut methyl
dihydroxyethyl ammonium bromide, decyl triethyl ammonium chloride,
decyl dimethyl hydroxyethyl ammonium chloride bromide,
C.sub.12-15-dimethyl hydroxyethyl ammonium chloride,
C.sub.12-15-dimethyl hydroxyethyl ammonium chloride bromide,
coconut dimethyl hydroxyethyl ammonium chloride, coconut dimethyl
hydroxyethyl ammonium bromide, myristyl trimethyl ammonium methyl
sulphate, lauryl dimethyl benzyl ammonium chloride, lauryl dimethyl
benzyl ammonium bromide, lauryl dimethyl (ethenoxy).sub.4 ammonium
chloride, lauryl dimethyl (ethenoxy).sub.4 ammonium bromide,
N-alkyl (C.sub.12-18)dimethylbenzyl ammonium chloride, N-alkyl
(C.sub.14-18)dimethyl-benzyl ammonium chloride,
N-tetradecyldimethylbenzyl ammonium chloride monohydrate, dimethyl
didecyl ammonium chloride, N-alkyl (C.sub.12-14) dimethyl
1-naphthylmethyl ammonium chloride, trimethylammonium halide
alkyl-trimethylammonium salts, dialkyl-dimethylammonium salts,
lauryl trimethyl ammonium chloride, ethoxylated
alkyamidoalkyldialkylammonium salts, ethoxylated trialkyl ammonium
salts, dialkylbenzene dialkylammonium chloride, N-didecyldimethyl
ammonium chloride, N-tetradecyldimethylbenzyl ammonium chloride
monohydrate, N-alkyl(C.sub.12-14) dimethyl 1-naphthylmethyl
ammonium chloride, dodecyldimethylbenzyl ammonium chloride, dialkyl
benzenealkyl ammonium chloride, lauryl trimethyl ammonium chloride,
alkylbenzyl methyl ammonium chloride, alkyl benzyl dimethyl
ammonium bromide, C.sub.12 trimethyl ammonium bromide, C.sub.15
trimethyl ammonium bromide, C.sub.17 trimethyl ammonium bromide,
dodecylbenzyl triethyl ammonium chloride,
polydiallyldimethylammonium chloride, dimethyl ammonium chloride,
alkyldimethylammonium halogenide, tricetyl methyl ammonium
chloride, decyltrimethylammonium bromide, dodecyltriethylammonium
bromide, tetradecyltrimethylammonium bromide, methyl
trioctylammonium chloride, POLYQUAT 10, tetrabutylammonium bromide,
benzyl trimethylammonium bromide, choline esters, benzalkonium
chloride, stearalkonium chloride, cetyl pyridinium bromide, cetyl
pyridinium chloride, halide salts of quaternized
polyoxyethylalkylamines, "MIRAPOL" (polyquaternium-2), "Alkaquat"
(alkyl dimethyl benzylammonium chloride, manufactured by Rhodia),
alkyl pyridinium salts, amine, amine salts, imide azolinium salts,
protonated quaternary acrylamides, methylated quaternary polymers,
cationic gua gum, benzalkonium chloride, dodecyl trimethyl ammonium
bromide, triethanolamine, and poloxamine.
[0056] When the surfactant is a cationic surfactant, the outer side
surface of the surfactant forming the micelle is cationically
charged, and thus may be surrounded by the first metal salt that is
anionically charged. Furthermore, the first metal salt may be
surrounded by the second metal salt that is cationically
charged.
[0057] According to an exemplary embodiment of the present
application, the first metal salt that is anionically charged and
the second metal salt that is cationically charged are not present
in a region where the cationic surfactant forms a micelle, thereby
forming hollow portions. That is, when the first metal salt and the
second metal salt are formed of a shell portion including the first
metal and the second metal by a reducing agent, the region
constituting the micelle may become a hollow core that does not
include a metal.
[0058] In an exemplary embodiment of the present application, when
water is selected as the solvent, the concentration of surfactant
in the solution may be one time or more and 5 times or less of the
critical micelle concentration (CMC) to water.
[0059] When the concentration of the surfactant is one time less
than the critical micelle concentration, the concentration of the
surfactant adsorbed to the first metal salt may be relatively
decreased. Accordingly, the amount of a surfactant forming a core
to be formed may also be entirely decreased. Meanwhile, when the
concentration of the surfactant is 5 times higher than the critical
micelle concentration, the concentration of the surfactant is
relatively increased, and thus the surfactant which forms the
hollow core and metal particles which do not form the hollow core
may be mixed and aggregated.
[0060] According to an exemplary embodiment of the present
application, it is possible to control the size of the hollow metal
nano particles by controlling the surfactant which forms the
micelle and/or the first and second metal salts which surround the
micelle.
[0061] According to an exemplary embodiment of the present
application, it is possible to control the size of hollow metal
nano particles by the chain length of the surfactant which forms
the micelle. Specifically, when the chain length of the surfactant
is short, the size of the micelle may be decreased and the hollow
size may also be decreased, thereby decreasing the size of the
hollow metal nano particles.
[0062] According to an exemplary embodiment of the present
application, the carbon number of the chains of the surfactant may
be 15 or less. Specifically, the carbon number of the chain may be
8 or more and 15 or less. Alternatively, the carbon number of the
chain may be 10 or more and 12 or less.
[0063] According to an exemplary embodiment of the present
application, it is possible to control the size of hollow metal
nano particles by controlling the type of the counter ion of the
surfactant which forms the micelle. Specifically, as the size of
the counter ion of the surfactant is increased, the bonding
strength of the outer end of the surfactant with the head portion
thereof becomes weak, and thus the size of hollow portions may be
increased. Accordingly, the size of hollow metal nano particles may
be increased.
[0064] According to an exemplary embodiment of the present
specification, when the surfactant is an anionic surfactant, the
surfactant may include NH.sub.4.sup.+, K.sup.+, Na.sup.+, or
Li.sup.+ as a counter ion.
[0065] Specifically, the size of hollow nano particles may be
decreased when the counter ion of the surfactant is NH.sub.4.sup.+,
K.sup.+, Na.sup.+, or Li.sup.+ in this order. This may be confirmed
by the Examples to be described below.
[0066] According to an exemplary embodiment of the present
specification, when the surfactant is a cationic surfactant, the
surfactant may include I.sup.-, Br.sup.-, or Cl.sup.- as a counter
ion.
[0067] Specifically, the size of hollow nano particles may be
decreased when the counter ion of the surfactant is I.sup.-,
Br.sup.-, or Cl.sup.- in this order.
[0068] According to an exemplary embodiment of the present
application, it is possible to control the size of hollow metal
nano particles by controlling the size of the head portion of the
outer end of the surfactant which forms the micelle. Furthermore,
when the size of the head portion of the surfactant formed on the
outer surface of the micelle is increased, the repulsive force
between head portions of the surfactant is increased, and thus the
size of hollows may be increased. Accordingly, the size of hollow
metal nano particles may be increased.
[0069] According to an exemplary embodiment of the present
application, the size of hollow metal nano particles may be
determined by complex action of the factors as described above.
[0070] According to an exemplary embodiment of the present
application, the fabrication method may be carried out at normal
temperature. Specifically, the fabrication method may be carried
out at a temperature in a range from 4.degree. C. to 35.degree. C.,
more specifically, at 15.degree. C. to 28.degree. C.
[0071] In an exemplary embodiment of the present application, the
forming of the solution may be carried out at normal temperature,
specifically at a temperature in a range from 4.degree. C. to
35.degree. C., more specifically, at 15.degree. C. to 28.degree. C.
When an organic solvent is used as the solvent, there is a problem
in that the fabrication method is performed at a high temperature
exceeding 100.degree. C. Since the fabrication method may be
carried out at normal temperature, the present application is
advantageous in terms of process due to a simple fabrication
method, and has a significant effect of reducing costs.
[0072] In an exemplary embodiment of the present application, the
forming of the solution may be performed for 5 minutes to 120
minutes, more specifically for 10 minutes to 90 minutes, and even
more specifically for 20 minutes to 60 minutes.
[0073] In an exemplary embodiment of the present application, the
forming of the hollow metal nano particles by adding a reducing
agent to the solution may also be carried out at normal
temperature, specifically at a temperature in a range from
4.degree. C. to 35.degree. C., and more specifically at 15.degree.
C. to 28.degree. C. Since the fabrication method may be carried out
at normal temperature, the present application is advantageous in
terms of process due to a simple fabrication method, and has a
significant effect of reducing costs.
[0074] The forming of the hollow metal nano particles may be
performed by reacting the solution with the reducing agent for a
predetermined time, specifically for 5 minutes to 120 minutes, more
specifically for 10 minutes to 90 minutes, and even more
specifically for 20 minutes to 60 minutes.
[0075] In an exemplary embodiment of the present application, the
reducing agent is not particularly limited as long as the reducing
agent is a strong reducing agent having a standard reduction
potential of -0.23 V or less, specifically from -4 V to -0.23 V,
and has a reducing power which may reduce the dissolved metal ions
to be precipitated as metal particles.
[0076] Such a reducing agent may be at least one selected from the
group consisting of, for example, NaBH.sub.4, NH.sub.2NH.sub.2,
LiAlH.sub.4, and LiBEt.sub.3H.
[0077] When a weak reducing agent is used, a reaction speed is slow
and a subsequent heating of the solution is required such that it
is difficult to achieve a continuous process, and thus there may be
a problem in terms of mass production. In particular, when ethylene
glycol, which is one of weak reducing agents, is used, there is a
problem in that the productivity is low in a continuous process due
to a decrease in flow rate caused by high viscosity.
[0078] According to an exemplary embodiment of the present
application, the forming of the hollow metal nano particles may be
further adding a non-ionic surfactant.
[0079] In an exemplary embodiment of the present application,
specifically, the non-ionic surfactant may be selected from the
group consisting of polyoxyethylene fatty alcohol ether,
polyoxyethylene sorbitan fatty acid ester, polyoxyethylene fatty
acid ester, polyoxyethylene alkyl ether, polyoxyethylene castor oil
derivatives, sorbitan ester, glyceryl ester, glycerol monostearate,
polyethylene glycol, polypropylene glycol, polypropylene glycol
ester, cetyl alcohol, cetostearyl alcohol, stearyl alcohol, aryl
alkyl polyether alcohol, polyoxyethylene polyoxypropylene
copolymers, poloxamer, poloxamine, methylcellulose,
hydroxycellulose, hydroxymethylcellulose, hydroxyethylcellulose,
hydroxypropylcellulose, hydroxypropylmethylcellulose,
hydroxypropylmethylcellulose phthalate, noncrystalline cellulose,
polysaccharides, starch, starch derivatives, hydroxyethyl starch,
polyvinyl alcohol, triethanolamine stearate, amine oxide, dextran,
glycerol, gum acacia, cholesterol, tragacanth, and
polyvinylpyrrolidone.
[0080] The non-ionic surfactant is adsorbed on the surface of the
shell, and thus serves to uniformly disperse the hollow metal nano
particles formed in the solution. Thus, the non-ionic surfactant
may prevent hollow metal particles from being conglomerated or
aggregated so as to be precipitated and allow hollow metal nano
particles to be formed in a uniform size.
[0081] According to an exemplary embodiment of the present
application, the forming of the hollow metal nano particles may be
further adding a stabilizer.
[0082] In an exemplary embodiment of the present application,
specifically, the stabilizer may include one or two or more
selected from the group consisting of disodium phosphate,
dipotassium phosphate, disodium citrate, and trisodium citrate.
[0083] In an exemplary embodiment of the present application, the
particle diameter of a plurality of hollow metal nano particles
formed may be within a range from 80% to 120% of the average
particle diameter of the hollow metal nano particles. Specifically,
the particle diameter of the hollow metal nano particles may be
within a range from 90% to 110% of the average particle diameter of
hollow metal nano particles. When the particle diameter exceeds the
range, the size of the hollow metal nano particles is overall
irregular, and thus it may be difficult to secure an intrinsic
physical property value required by the hollow metal nano
particles. For example, when hollow metal nano particles having a
particle diameter exceeding a range from 80% to 120% of the average
particle diameter of the hollow metal nano particles are used as a
catalyst, the activity of the catalyst may be a little
insufficient.
[0084] In an exemplary embodiment of the present application, the
fabrication method may further include, after the forming of the
hollow metal nano particles, removing a surfactant inside hollows.
The removing method is not particularly limited, and for example, a
method of washing the surfactant with water may be used. The
surfactant may be an anionic surfactant or a cationic
surfactant.
[0085] The method for fabricating hollow metal nano particles
according to an exemplary embodiment of the present application may
further include, after the forming of the hollow metal nano
particles, removing a first shell including a first metal by adding
an acid to the hollow metal nano particles.
[0086] In an exemplary embodiment of the present application, the
acid is not particularly limited, and for example, it is possible
to use an acid selected from the group consisting of sulfuric acid,
nitric acid, hydrochloric acid, perchloric acid, hydroiodic acid,
and hydrobromic acid.
[0087] In an exemplary embodiment of the present application, after
the hollow metal nano particles are formed, in order to precipitate
the hollow metal nano particles included in the solution, the
solution including the hollow metal nano particles may be
centrifuged. It is possible to collect only the hollow metal nano
particles separated after the centrifugation. If necessary, a
process of sintering the hollow metal nano particles may be
additionally performed.
[0088] According to an exemplary embodiment of the present
application, it is possible to fabricate hollow metal nano
particles having a uniform size of several nanometers. By methods
in the related art, it was difficult to fabricate several
nanometer-sized hollow metal nano particles, and it was more
difficult to fabricate uniform-sized hollow metal nano
particles.
[0089] In an exemplary embodiment of the present application, the
hollow metal nano particles may have an average particle diameter
of 30 nm or less, more specifically 20 nm or less, or 12 nm or
less, or 10 nm or less. Alternatively, the hollow metal nano
particles may have an average particle diameter of 6 nm or less.
The hollow metal nano particles may have an average particle
diameter of 1 nm or more. When the hollow metal nano particles have
an average particle diameter of 30 nm or less, the nano particles
are advantageous in that the nano particles may be used in various
fields. Further, when the hollow metal nano particles have an
average particle diameter of 20 nm or less, the hollow metal nano
particles are more preferred. In addition, when the hollow metal
nano particles have an average particle diameter of 10 nm or less,
or 6 nm or less, the surface area of particles is further
increased, and thus the hollow metal nano particles are
advantageous in that the applicability which may be used in various
fields is further broadened. For example, when the hollow metal
nano particles formed to have the particle diameter range are used
as a catalyst, the efficiency thereof may be significantly
enhanced.
[0090] According to an exemplary embodiment of the present
application, the average particle diameter of the hollow metal nano
particles means a value obtained by measuring 200 or more hollow
metal nano particles using a graphic software (MAC-View), and
measuring an average particle diameter through an obtained
statistical distribution.
[0091] According to an exemplary embodiment of the present
application, the hollow metal nano particles may have an average
particle diameter from 1 nm to 30 nm.
[0092] According to an exemplary embodiment of the present
application, the hollow metal nano particles may have an average
particle diameter from 1 nm to 20 nm.
[0093] According to an exemplary embodiment of the present
application, the hollow metal nano particles may have an average
particle diameter from 1 nm to 12 nm.
[0094] According to an exemplary embodiment of the present
application, the hollow metal nano particles may have an average
particle diameter from 1 nm to 10 nm.
[0095] According to an exemplary embodiment of the present
application, the hollow metal nano particles may have an average
particle diameter from 1 nm to 6 nm.
[0096] In an exemplary embodiment of the present application, the
shell portion in the hollow metal nano particles may have a
thickness more than 0 nm and 5 nm or less, more specifically, more
than 0 nm and 3 nm or less.
[0097] For example, the hollow metal nano particles may have an
average particle diameter of 30 nm or less, and the shell portion
may have a thickness more than 0 nm and 5 nm or less. More
specifically, the hollow metal nano particles may have an average
particle diameter of 20 nm or less, or 10 nm or less, and the shell
portion may have a thickness more than 0 nm and 3 nm or less.
According to an exemplary embodiment of the present application,
the hollow metal nano particles may have an average particle
diameter from 1 nm to 10 nm, specifically, from 1 nm to 4 nm.
Furthermore, each shell may have a thickness from 0.25 nm to 5 nm,
specifically, from 0.25 nm to 3 nm. The shell portion may also be a
shell formed by mixing the first metal and the second metal, and
may be a plurality of shells including a first shell and a second
shell which are separately formed by varying the mixing ratio of a
first metal and a second metal, respectively. Alternatively, the
shell portion may be a plurality of shells including a first shell
including only a first metal and a second shell including only a
second metal.
[0098] According to an exemplary embodiment of the present
application, the hollow volume of the hollow metal nano particles
fabricated by the fabrication method may be 50% by volume or more
of, specifically 70% by volume or more of, and more specifically
80% by volume or more of the total volume of the hollow metal nano
particles.
[0099] The hollow metal nano particles fabricated by the
fabrication method of the present application may be used while
replacing existing nano particles in the field in which nano
particles may be generally used. The hollow metal nano particles of
the present application have much smaller sizes and wider specific
surface areas than the nano particles in the related art, and thus
may exhibit better activity than the nano particles in the related
art. Specifically, the hollow metal nano particles of the present
application may be used in various fields such as a catalyst, drug
delivery, and a gas sensor. The hollow metal nano particles may be
used as a catalyst, or as an active material formulation in
cosmetics, pesticides, animal nutrients, or food supplements, and
may be used as a pigment in electronic products, optical elements,
or polymers.
[0100] An exemplary embodiment of the present application provides
hollow metal nano particles fabricated by the fabrication
method.
[0101] The hollow metal nano particles according to an exemplary
embodiment of the present application may be hollow metal nano
particles including at least one shell including: a hollow core;
and a first metal and/or a second metal.
[0102] In an exemplary embodiment of the present application, the
shell may have a single layer, and two or more layers.
[0103] In an exemplary embodiment of the present application, when
the shell has a single layer, the first metal and the second metal
may be present while being mixed. At this time, the first metal and
the second metal may be mixed uniformly or non-uniformly.
[0104] In an exemplary embodiment of the present application, when
the shell has a single layer, the atomic percentage ratio of the
first metal to the second metal of the shell portion may be 1:5 to
10:1.
[0105] In an exemplary embodiment of the present application, when
the shell has a single layer, the first metal and the second metal
in the shell may be present in a state of gradation, the first
metal may be present in an amount of 50% by volume or more, or 70%
by volume or more at a portion adjacent to the hollow core in the
shell, and the second metal may be present in an amount of 50% by
volume or more or 70% by volume or more at a surface portion
adjacent to the external portion in the shell.
[0106] In an exemplary embodiment of the present application, when
the shell has a single layer, the shell may include only the first
metal or the second metal.
[0107] The hollow metal nano particles according to an exemplary
embodiment of the present application may include: a hollow core;
one or two or more first shells including a first metal; and one or
two or more second shells including a second metal.
[0108] The second shell may be present in at least one region of
the outer surface of the first shell, and may be present in the
form of surrounding the entire surface of the outer surface of the
first shell. When the second shell is present in some regions of
the outer surface of the first shell, the second shell may also be
present in the form of a discontinuous surface.
[0109] In an exemplary embodiment of the present application, the
hollow metal nano particles may include a hollow core, a first
shell including a first metal formed throughout the outer surface
of the hollow core, and a second shell including a second metal
formed throughout the outer surface of the first shell.
Alternatively, in an exemplary embodiment of the present
application, the hollow metal nano particles may include a shell of
a single layer including a first metal and a second metal, which
are formed throughout the outer surface of the hollow core. In this
case, the hollow metal nano particles may also include a surfactant
having positive charges in the hollow core.
[0110] In an exemplary embodiment of the present application, the
hollow metal nano particles may include a hollow core, a first
shell in which a first metal salt carrying positive charges is
present in at least one region of the external portion of hollows,
and a second shell in which a second metal carrying negative
charges is present in at least one region of the outer surface of
the first shell. In this case, the hollow metal nano particles may
also include a surfactant having negative charges in the hollow
core.
[0111] Hereinafter, the present application will be described in
detail with reference to Examples for a specific description.
However, the Examples according to the present application may be
modified in various forms, and the scope of the present application
is not interpreted as being limited to the Examples described in
detail below. The Examples of the present application are provided
for more completely explaining the present application to those
skilled in the art.
Example 1
[0112] 0.03 mmol of Ni(NO.sub.3).sub.2 as a first metal salt, 0.01
mmol of K.sub.2PtCl.sub.4 as a second metal salt, 0.1 mmol of
trisodium citrate as a stabilizer, and 0.48 mmol of sodium
dodecylsulfate (SDS) as a surfactant were added to and dissolved in
26 ml of water to form a solution, and the solution was stirred for
30 minutes. At this time, the molar ratio of Ni(NO.sub.3).sub.2 to
K.sub.2PtCl.sub.4 was 3:1, and at this time, the concentration of
the SDS measured was approximately two times the critical micelle
concentration (CMC) to water.
[0113] Subsequently, 0.13 mmol of NaBH.sub.4 which is a reducing
agent and 100 mg of polyvinyl pyrrolidone (PVP) as a non-ionic
surfactant were added to the solution and the mixture was left to
react for 30 minutes. After the mixture was centrifuged at 10,000
rpm for 10 minutes, the supernatant in the upper layer was
discarded, the remaining precipitate was re-dispersed in 20 ml of
water, and then the centrifugation process was repeated once more
to fabricate hollow metal nano particles composed of a hollow core,
a first shell including Ni, and a second shell including Pt.
[0114] FIG. 1 illustrates a model of the hollow metal nano
particles fabricated according to Example 1. FIG. 2 illustrates a
transmission electron microscope (TEM) image of the hollow metal
nano particles fabricated according to Example 1. FIG. 3
illustrates a transmission electron microscope (TEM) image of the
hollow metal nano particles fabricated according to Example 1,
which is magnified two times more than the image of FIG. 2.
[0115] The particle diameter of hollow metal nano particles
obtained by a Scherrer equation calculation method on the HR-TEM of
FIG. 3 was approximately less than 10 nm. The particle diameter of
hollow metal nano particles formed was measured on 200 or more
hollow metal nano particles using a graphic software (MAC-View)
based on FIG. 3, the average particle diameter was 10 nm through a
statistical distribution obtained, and the standard deviation was
calculated as 7.8%.
Example 2
[0116] 0.03 mmol of Ni(NO.sub.3).sub.2 as a first metal salt, 0.01
mmol of K.sub.2PtCl.sub.4 as a second metal salt, 0.1 mmol of
trisodium citrate as a stabilizer, and 1 ml of 30% ammonium
laurylsulfate (ALS) as a surfactant were added to and dissolved in
26 ml of water to form a solution, and the solution was stirred for
30 minutes. At this time, the molar ratio of Ni(NO.sub.3).sub.2 to
K.sub.2PtCl.sub.4 was 3:1, and at this time, the concentration of
the ALS measured was approximately two times the critical micelle
concentration (CMC) to water.
[0117] Subsequently, 0.13 mmol of NaBH.sub.4 which is a reducing
agent was added to the solution and the mixture was left to react
for 30 minutes. After the mixture was centrifuged at 10,000 rpm for
10 minutes, the supernatant in the upper layer was discarded, the
remaining precipitate was re-dispersed in 20 ml of water, and then
the centrifugation process was repeated once more to fabricate
hollow metal nano particles composed of a hollow core and a
shell.
[0118] FIG. 7 illustrates a transmission electron microscope (TEM)
image of the hollow metal nano particles fabricated according to
Example 2.
[0119] The average particle diameter of the hollow metal nano
particles obtained by Example 2 was 15 nm.
Example 3
[0120] 0.03 mmol of Ni(NO.sub.3).sub.2 as a first metal salt, 0.01
mmol of K.sub.2PtCl.sub.4 as a second metal salt, 0.12 mmol of
trisodium citrate as a stabilizer, and 1 ml of 30% ammonium
laurylsulfate (ALS) as a surfactant were added to and dissolved in
26 ml of water to form a solution, and the solution was stirred for
30 minutes. At this time, the molar ratio of Ni(NO.sub.3).sub.2 to
K.sub.2PtCl.sub.4 was 3:1, and at this time, the concentration of
the ALS measured was approximately 1.5 times the critical micelle
concentration (CMC) to water.
[0121] Subsequently, 0.13 mmol of NaBH.sub.4 which is a reducing
agent was added to the solution and the mixture was left to react
for 30 minutes. After the mixture was centrifuged at 10,000 rpm for
10 minutes, the supernatant in the upper layer was discarded, the
remaining precipitate was re-dispersed in 20 ml of water, and then
the centrifugation process was repeated once more to fabricate
hollow metal nano particles composed of a hollow core and a
shell.
[0122] FIG. 8 illustrates a transmission electron microscope (TEM)
image of the hollow metal nano particles fabricated according to
Example 3.
[0123] The average particle diameter of the hollow metal nano
particles obtained by Example 3 was 10 nm.
Example 4
[0124] 0.03 mmol of Ni(NO.sub.3).sub.2 as a first metal salt, 0.01
mmol of K.sub.2PtCl.sub.4 as a second metal salt, 0.1 mmol of
trisodium citrate as a stabilizer, and 0.45 mmol of lithium
dodecylsulfate (LiDS) as a surfactant are added to and dissolved in
26 ml of water to form a solution, and the solution was stirred for
30 minutes. At this time, the molar ratio of Ni(NO.sub.3).sub.2 to
K.sub.2PtCl.sub.4 was 3:1, and at this time, the concentration of
the LiDS measured was approximately two times the critical micelle
concentration (CMC) to water.
[0125] Subsequently, 0.13 mmol of NaBH.sub.4 which is a reducing
agent was added to the solution and the mixture was left to react
for 30 minutes. After the mixture was centrifuged at 10,000 rpm for
10 minutes, the supernatant in the upper layer was discarded, the
remaining precipitate was re-dispersed in 20 ml of water, and then
the centrifugation process was repeated once more to fabricate
hollow metal nano particles composed of a hollow core and a
shell.
[0126] FIG. 9 illustrates a transmission electron microscope (TEM)
image of the hollow metal nano particles fabricated according to
Example 4.
[0127] The average particle diameter of the hollow metal nano
particles obtained by Example 4 was 8 nm.
Example 5
[0128] 0.07 mmol of Ni(NO.sub.3).sub.2 as a first metal salt, 0.03
mmol of K.sub.2PtCl.sub.4 as a second metal salt, 0.12 mmol of
trisodium citrate as a stabilizer, and 1.21 mmol of sodium
dodecylsulfate (SDS) as a surfactant are added to and dissolved in
26 ml of water to form a solution, and the solution was stirred for
30 minutes. At this time, the molar ratio of Ni(NO.sub.3).sub.2 to
K.sub.2PtCl.sub.4 was 2:1, and at this time, the concentration of
the SDS measured was approximately five times the critical micelle
concentration (CMC) to water.
[0129] Subsequently, 0.4 mmol of NaBH.sub.4 which is a reducing
agent and 500 mg of polyvinyl pyrrolidone (PVP) as a non-ionic
surfactant were added to the solution and the mixture was left to
react for 30 minutes. After the mixture was centrifuged at 10,000
rpm for 10 minutes, the supernatant in the upper layer was
discarded, the remaining precipitate was re-dispersed in 20 ml of
water, and then the centrifugation process was repeated once more
to fabricate hollow metal nano particles composed of a hollow core
and a shell.
[0130] FIGS. 5 and 6 illustrate a model of the hollow metal nano
particles fabricated according to Example 5. FIG. 10 illustrates a
transmission electron microscope (TEM) image of the hollow metal
nano particles fabricated according to Example 5.
[0131] The average particle diameter of the hollow metal nano
particles obtained by Example 5 was about 5 nm.
Comparative Example 1
[0132] 0.03 mmol of Ni(NO.sub.3).sub.2 as a first metal salt, 0.01
mmol of K.sub.2PtCl.sub.4 as a second metal salt, 0.1 mmol of
trisodium citrate as a stabilizer, and 0.45 mmol of sodium
dodecylsulfate (SDS) as a surfactant are added to and dissolved in
26 ml of water to form a solution, and the solution was stirred for
30 minutes. At this time, the molar ratio of Ni(NO.sub.3).sub.2 to
K.sub.2PtCl.sub.4 was 3:1, and at this time, the concentration of
the SDS measured was approximately ten times the critical micelle
concentration (CMC) to water.
[0133] Subsequently, 0.13 mmol of NaBH.sub.4 which is a reducing
agent and 100 mg of polyvinyl pyrrolidone (PVP) as a non-ionic
surfactant were added to the solution and the mixture was left to
react for 30 minutes.
[0134] FIG. 4 illustrates a transmission electron microscope (TEM)
image of the hollow metal nano particles fabricated according to
Comparative Example 1. In the case of Comparative Example 1, some
of hollow metal nano particles were also observed, but particles
formed by aggregation of small particles and having a large size
more than 30 nm were also observed.
[0135] The Examples of the present application have been described
with reference to the accompanying drawings, but the present
application is not limited to the Examples and may be fabricated in
various forms, and it will be understood by a person with ordinary
skill in the art to which the present application pertains that the
present application may be implemented in other specific forms
without modifying the technical spirit or essential feature of the
present application. Therefore, it is to be appreciated that
Examples described above are intended to be illustrative in every
sense, and not restrictive. cm What is claimed is:
* * * * *