U.S. patent application number 16/134424 was filed with the patent office on 2020-02-27 for process for preparing porous iron oxide-zirconia composite catalyst, porous iron oxide-zirconia composite catalyst prepared ther.
The applicant listed for this patent is SOGANG UNIVERSITY RESEARCH FOUNDATION. Invention is credited to Jae Hyun Lee, Jun Hyuk Moon.
Application Number | 20200061586 16/134424 |
Document ID | / |
Family ID | 69583346 |
Filed Date | 2020-02-27 |
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United States Patent
Application |
20200061586 |
Kind Code |
A1 |
Moon; Jun Hyuk ; et
al. |
February 27, 2020 |
PROCESS FOR PREPARING POROUS IRON OXIDE-ZIRCONIA COMPOSITE
CATALYST, POROUS IRON OXIDE-ZIRCONIA COMPOSITE CATALYST PREPARED
THEREBY, AND METHOD FOR PRODUCING ALCOHOL USING THE CATALYST
Abstract
The present invention relates to a porous iron oxide-zirconia
composite catalyst, a preparation method thereof, and a method for
producing alcohol using the same, and the iron oxide-zirconia
composite catalyst having a porous structure may produce alcohol at
low cost by carrying out an excellent methane reforming reaction
even under room temperature and room pressure conditions through an
electrochemical reaction.
Inventors: |
Moon; Jun Hyuk; (Seoul,
KR) ; Lee; Jae Hyun; (Seoul, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SOGANG UNIVERSITY RESEARCH FOUNDATION |
Seoul |
|
KR |
|
|
Family ID: |
69583346 |
Appl. No.: |
16/134424 |
Filed: |
September 18, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01J 37/0236 20130101;
B01J 37/086 20130101; B01J 35/1023 20130101; B01J 35/1071 20130101;
C07C 29/48 20130101; B01J 35/1076 20130101; B01J 35/1009 20130101;
B01J 35/1019 20130101; B01J 35/1066 20130101; B01J 37/0201
20130101; B01J 35/1014 20130101; B01J 23/002 20130101; B01J 21/066
20130101; B01J 37/0234 20130101; B01J 37/0018 20130101; B01J 23/745
20130101; C25B 3/02 20130101; B01J 35/002 20130101; B01J 37/088
20130101; C25B 11/04 20130101; B01J 37/084 20130101 |
International
Class: |
B01J 23/745 20060101
B01J023/745; B01J 21/06 20060101 B01J021/06; B01J 35/10 20060101
B01J035/10; B01J 37/00 20060101 B01J037/00; B01J 37/02 20060101
B01J037/02; B01J 37/08 20060101 B01J037/08; C07C 29/48 20060101
C07C029/48 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 22, 2018 |
KR |
10-2018-0098264 |
Claims
1. A method for preparing a porous iron oxide-zirconia composite
catalyst, the method including: impregnating a polymer template
mold with a precursor mixture of iron oxide precursor and a
zirconia precursor; drying the polymer template mold impregnated
with the precursor mixture; and sintering the dried polymer
template mold.
2. The method of claim 1, wherein the iron oxide precursor is one
or more selected from the group consisting of iron (III) nitrate,
iron (III) chlorate, and iron (III) sulfate.
3. The method of claim 1, wherein the zirconia precursor is one or
more selected from the group consisting of zirconium oxynitrate,
zirconium nitrate, and zirconium sulfate.
4. The method of claim 1, wherein the iron oxide precursor and the
zirconia precursor are mixed at a molar ratio of 8:1 to 2:1.
5. The method of claim 1, wherein the polymer template mold
includes a spherical polymer arranged in a face centered cubic
(fcc) structure.
6. The method of claim 1, wherein the polymer template mold is
manufactured by a method including emulsion polymerization of
monomers, followed by drying step.
7. The method of claim 1, wherein the polymer template mold
includes one or more polymers selected from the group consisting of
poly(methyl methacrylate) [PMMA], poly(butyl methacrylate) [PBMA],
poly(methyl methacrylate)(butyl methacrylate), poly(hydroxyethyl
methacrylate) [PHEMA], and polystyrene.
8. A porous iron oxide-zirconia composite catalyst manufactured by
a method comprising: impregnating a polymer template mold with a
precursor mixture of iron oxide precursor and a zirconia precursor;
drying the polymer template mold impregnated with the precursor
mixture; and sintering the dried polymer template mold, wherein the
average pore size is 50 to 900 nm.
9. The porous iron oxide-zirconia composite catalyst of claim 8,
wherein the porous iron oxide-zirconia composite catalyst has a
specific surface area of 1 to 1,000 m.sup.2/g.
10. The porous iron oxide-zirconia composite catalyst of claim 8,
wherein the composite catalyst has a molar ratio of iron oxide to
zirconia of 9.9:0.1 to 4.0:6.0.
11. The porous iron oxide-zirconia composite catalyst of claim 8,
wherein zirconia in the porous iron oxide-zirconia composite
catalyst is in the form of tetragonal phase.
12. A method for manufacturing alcohols, the method comprising:
contacting the porous iron oxide-zirconia composite catalyst of
claim 8 with methane.
13. The method of claim 12, wherein the contacting is carried out
at a temperature of 5 to 40.degree. C.
14. The method of claim 12, wherein the contacting is carried out
at a pressure of 1 to 20 bar.
15. The method of claim 12, wherein the alcohol is methanol,
1-propanol, 2-propanol, or ethanol.
Description
FIELD
[0001] The present invention relates to a process for preparing
porous iron oxide-zirconia composite catalyst, a porous iron
oxide-zirconia composite catalyst prepared thereby, and a method
for producing alcohol using the catalyst.
BACKGROUND
[0002] Methane, which is a main component of gas, has problems with
transportation and storage unlike liquid petroleum resources due to
physical properties, so that when the production site is far away
from the market, the use thereof is limited. It is possible to
increase the added value of the gas, of which the use is so limited
and of which the value is low, by physical liquefaction (LNG) or
chemical conversion.
[0003] In the chemical methane conversion method, an indirect
conversion route via a syngas (CO/H.sub.2) is used. In order to
produce the syngas in the indirect conversion route, there are a
reforming process, a Fischer-Tropsch (FT) synthesis process for
producing olefin or a liquid hydrocarbon from the syngas, a process
for synthesizing methanol from the syngas, a process for producing
gasoline or olefin via methanol, and the like, and through these
processes, almost all fuel and chemical products, which may be
obtained from existing petroleum-based raw materials, may be
obtained from methane.
[0004] In brief, the conversion process of methane goes through a
two-step process including a dry reforming reaction that produces a
syngas by a partial oxidation reaction of methane and a process for
producing products from the syngas. The standard reaction enthalpy
of the dry reforming reaction is 247 kJ/mol, and such a process
requires a catalyst under high temperature conditions. Accordingly,
most of the methane conversion catalyst studies have been conducted
from the viewpoint of cost reduction of commercialized processes
targeting the conversion of methane into a syngas at lower
temperature.
[0005] However, the conversion into the syngas is inefficient
because the conversion goes through CO as an intermediate.
Accordingly, studies on directly converting methane into products
have become gradually important. The direct conversion of methane
directly produces products by a reaction of a partial oxidation of
methane (hereinafter, referred to as POM) or by a reaction of an
oxidative coupling of methane (hereinafter, referred to as OCM).
Since the direct conversion of methane directly obtains products,
the selectivity is an important point.
[0006] Between the reactions, the partial oxidation reaction is
generally advantageous in obtaining a specific product because the
partial oxidation reaction exhibits high selectivity toward the
specific product as compared to the OCM reaction. For the direct
conversion of methane, numerous studies on a reaction of obtaining
methanol and formaldehyde have been conducted.
[0007] A study conducted by Ceri Hammond et al., accomplished a
conversion of methane into methanol by using a Cu-ZSM-5 catalyst
under NO conditions, but still requires high temperature conditions
at 150.degree. C. and exhibits low selectivity and a low yield.
[0008] A study conducted by Jun Xu et al., achieved methanol
selectivity of 92% at low temperature by using a Cu- and
Fe-improved ZSM-5 catalyst, but exhibited a very low methane
conversion of 0.5%.
SUMMARY
[0009] Accordingly, a technical object of the present invention is
to provide a process for preparing a porous iron oxide-zirconia
composite catalyst, which can produce alcohols with low cost by
oxidating methane in room temperature and pressure, a porous iron
oxide-zirconia composite catalyst prepared thereof, and a method
for producing alcohols using the catalyst.
[0010] To solve the above-mentioned technical issues, an aspect of
the present invention provides a process for preparing a porous
iron oxide-zirconia composite catalyst including the following
steps:
[0011] impregnating a polymer template mold with a precursor
mixture of iron oxide precursor and a zirconia precursor;
[0012] drying the polymer template mold impregnated with the
precursor mixture; and
[0013] sintering the dried polymer template mold.
[0014] Another aspect of the present invention provides a porous
iron oxide-zirconia composite catalyst prepared by the
above-mentioned process and the average pore size thereof is 50 to
100 nm.
[0015] Still another aspect of the present invention relates to a
method for producing alcohol, the method including: bringing a
porous iron oxide-zirconia composite catalyst into contact with
methane.
[0016] According to an aspect of the present invention, by
preparing a porous iron oxide-zirconia composite catalyst with
improved reactivity by structure control and with excellent
selectivity, alcohols may be produced at low cost by oxidating
methane at room temperature and pressure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1A is a high-magnification electron microscope image
(magnification: .times.5,000) of a porous iron oxide-zirconia
composite catalyst produced according to the exemplary embodiment 1
of the present invention.
[0018] FIG. 1B is a high-magnification electron microscope image
(magnification: .times.3,500) of a porous iron oxide-zirconia
composite catalyst produced according to the exemplary embodiment 2
of the present invention.
[0019] FIG. 1C is a high-magnification electron microscope image
(magnification: .times.3,000) of a porous iron oxide-zirconia
composite catalyst produced according to the exemplary embodiment 3
of the present invention.
[0020] FIG. 1D is a high-magnification electron microscope image
(magnification: .times.10,000) of a porous iron oxide-zirconia
composite catalyst produced according to the exemplary embodiment 1
of the present invention.
[0021] FIG. 1E is a high-magnification electron microscope image
(magnification: .times.3,000) of a porous iron oxide-zirconia
composite catalyst produced according to the exemplary embodiment 4
of the present invention.
[0022] FIG. 2A is a transmission electron microscopy (TEM) image of
inverse opal (IO) particles of a porous iron oxide-zirconia
composite catalyst produced according to the exemplary embodiment 1
of the present invention.
[0023] FIG. 2B is an image of an TEM-EDS (energy dispersive
spectroscopy) analysis result exhibiting the distribution of oxygen
elements for the IO particles of the porous iron oxide-zirconia
composite catalyst produced according to an exemplary embodiment 1
of the present invention.
[0024] FIG. 2C is an image of an TEM-EDS(energy dispersive
spectroscopy) analysis result exhibiting the distribution of iron
elements for the IO particles of the porous iron oxide-zirconia
composite catalyst produced according to an exemplary embodiment 1
of the present invention.
[0025] FIG. 2D is an image of an TEM-EDS (energy dispersive
spectroscopy) analysis result exhibiting the distribution of
zirconium elements for the IO particles of the porous iron
oxide-zirconia composite catalyst produced according to an
exemplary embodiment 1 of the present invention.
[0026] FIG. 3 is a graph showing an XRD (X-ray diffraction)
analysis result of the porous iron oxide-zirconia composite
catalyst produced according to an exemplary embodiment 1 to 3 of
the present invention.
[0027] FIG. 4A is a graph showing an XPS (X-ray photoelectron
spectroscopy) (Fe 2p) analysis result of the porous iron
oxide-zirconia composite catalyst produced according to the
exemplary embodiment 1 to 3 of the present invention.
[0028] FIG. 4B is a graph showing an XPS (Zr 3d) analysis result of
the porous iron oxide-zirconia composite catalyst produced
according to the exemplary embodiment 1 to 3 of the present
invention.
[0029] FIG. 5A is a graph showing a cyclic voltammetry analysis
result of the porous iron oxide-zirconia composite catalysts
produced according to the exemplary embodiment 1 of the present
invention with respect to methane saturated solutions.
[0030] FIG. 5B is a graph showing a cyclic voltammetry analysis
result of the porous iron oxide-zirconia composite catalysts
produced according to the exemplary embodiment 2 of the present
invention with respect to methane saturated solutions.
[0031] FIG. 5C is a graph showing a cyclic voltammetry analysis
result of the porous iron oxide-zirconia composite catalysts
produced according to the exemplary embodiment 3 of the present
invention with respect to methane saturated solutions.
[0032] FIG. 6 is an NMR (Nuclear Magnetic Resonance Spectroscopy)
spectrum of the product of the methane oxidation reaction using the
porous iron oxide-zirconia composite catalyst produced according to
the exemplary embodiment 1 of the present invention.
[0033] FIG. 7 is a graph showing results of analyzing a
concentration of methanol produced according to the time for a
methane oxidation reaction using the porous iron oxide-zirconia
composite catalyst produced according to the exemplary embodiment 1
to 3 of the present invention.
DETAILED DESCRIPTION
[0034] Hereinafter, the process for preparing the porous iron
oxide-zirconia composite catalyst, the porous iron oxide-zirconia
composite catalyst prepared thereby, and method for producing
alcohol using the catalyst, according to an aspect of the present
invention, will be described in more detail.
[0035] The process for preparing a porous iron oxide-zirconia
composite catalyst according to an aspect of the present invention
includes impregnating polymer template mold with a precursor
mixture of iron oxide precursor and a zirconia precursor; drying
the polymer template mold impregnated with the precursor mixture;
and sintering the dried polymer template mold.
[0036] The process for producing the porous iron oxide-zirconia
composite catalyst according to an aspect of the present invention
may produce a catalyst having uniform pores with a simple
method.
[0037] The above-mentioned iron oxide precursor may be one or more
selected from the group consisting of iron (III) nitrate, iron
(III) chlorate, and iron (III) sulfate.
[0038] The zirconia precursor may be one or more selected from the
group consisting of zirconium oxynitrate, zirconium nitrate, and
zirconium sulfate.
[0039] The iron oxide precursor and the zirconia precursor may be
injected at a molar ratio of 8:1 to 2:1, for example, 8:1. When
using the iron oxide precursor and the zirconia precursor within
the above range of the ratio, the composite catalyst may be
advantageous in methane oxidation reaction as an electrochemical
catalyst, since the composite catalyst has high
electroconductivity.
[0040] The iron oxide precursor and the zirconia precursor may be
used in solution state using water, methanol or ethanol as a
solvent
[0041] The polymer template mold may include a spherical polymer
arranged in a face centered cubic (fcc) structure.
[0042] The polymer template mold may be prepared by a method
including emulsion polymerization of monomers and subsequent
drying. Specifically, a spherical polymer template mold arranged in
a face centered cubic (fcc) structure may be obtained by
emulsion-polymerizing a reaction mixture including monomers, an
initiator and an organic solvent, and centrifuging the emulsion
including the polymer manufactured, followed by drying the
product.
[0043] Being arranged in a fcc structure means that colloidal
particles confined to fine liquid drops approach to each other due
to the action of the capillary force generated by contraction
phenomenon according to evaporation of the solvent, and finally
form a self-assembly. Especially, being arranged in a fcc structure
means that when a colloidal solution, the particle sizes thereof
are uniform, self-assembled in a fcc structure, the colloidal
solution may be used as a template mold for manufacturing an
arranged three dimensional structure since the colloidal particles
are assembled in a periodically arranged shape.
[0044] When centrifuging the emulsion, the centrifuging may be
carried out at 6000 to 10000 rpm for 5 minutes to 30 minutes, but
may be carried out at different condition according to the
manufactured polymer. The emulsion may not include emulsifier when
polymerized.
[0045] The polymer template mold may be a polymer template mold
including one or more polymers selected from the group consisting
of poly(methyl methacrylate) [PMMA], poly(butyl methacrylate)
[PBMA], poly(methyl methacrylate)(butyl methacrylate),
poly(hydroxyethyl methacrylate) [PHEMA], and polystyrene. A polymer
template mold may include, for example, polystyrene.
[0046] impregnating a polymer template mold with the precursor
mixture of the iron oxide precursor and the zirconia precursor may
be carried out by adding distilled water to the iron oxide
precursor and the zirconia precursor, and immersing the polymer
template mold therein.
[0047] The polymer template mold may be impregnated with the
mixture of the precursors at room temperature for 10 to 60 minutes,
for example, for 30 minutes.
[0048] Next, the polymer template mold impregnated with the
precursor mixture is taken out of the mixture and dried. The
polymer template mold may be dried at 50.degree. C. to 80.degree.
C., for example, at 65.degree. C. for 10 hours to 15 hours, for
example, for 12 hours, but are not limited thereto.
[0049] Next, the porous iron oxide-zirconia composite may be
obtained by sintering the dried polymer template mold to carbonize
the polymer template mold.
[0050] The dried polymer template mold may be sintered at
500.degree. C. to 1300.degree. C., for example at 700.degree. C. to
1100.degree. C., for example at 900.degree. C., for 2 to 6 hours, 3
to 5 hours, for example for 4 hours.
[0051] The porous iron oxide-zirconia composite catalyst having
uniform pores may be obtained by the above-mentioned method.
[0052] In another aspect of the present invention, the porous iron
oxide-zirconia composite catalyst may be manufactured by the
above-mentioned method, and have the average pore size of 50 nm to
900 nm. For example, the average pore size may be 55 nm to 900 nm,
60 nm to 900 nm, 65 nm to 900 nm, 70 nm to 900 nm, 50 nm to 800 nm,
55 nm to 800 nm, 60 nm to 800 nm, 65 nm to 800 nm, 70 nm to 800 nm,
50 nm to 700 nm, 55 nm to 700 nm, 60 nm to 700 nm, 65 nm to 700 nm,
70 nm to 700 nm, 50 nm to 600 nm, 55 nm to 600 nm, 60 nm to 600 nm,
65 nm to 600 nm, 70 nm to 600 nm, 50 nm to 500 nm, 55 nm to 500 nm,
60 nm to.500 nm, 65 nm to 500 nm, 70 nm to 500 nm, for example, 400
nm, but not limited thereto.
[0053] The porous iron oxide-zirconia composite catalyst may have a
specific surface area of 1 to 1,000 m.sup.2/g, 10 to 1,000
m.sup.2/g, 20 to 1,000 m.sup.2/g, 30 to 1,000 m.sup.2/g, 40 to
1,000 m.sup.2/g, 50 to 1,000 m.sup.2/g, 60 to 1,000 m.sup.2/g, 70
to 1,000 m.sup.2/g, 1 to 800 m.sup.2/g, 10 to 800 m.sup.2/g, 20 to
800 m.sup.2/g, 30 to 800 m.sup.2/g, 40 to 800 m.sup.2/g, 50 to 800
m.sup.2/g, 60 to 800 m.sup.2/g, 70 to 800 m.sup.2/g, 1 to 600
m.sup.2/g, 10 to 600 m.sup.2/g, 20 to 600 m.sup.2/g, 30 to 600
m.sup.2/g, 40 to 600 m.sup.2/g, 50 to 600 m.sup.2/g, 60 to 600
m.sup.2/g, 70 to 600 m.sup.2/g, 1 to 400 m.sup.2/g, 10 to 400
m.sup.2/g, 20 to 400 m.sup.2/g, 30 to 400 m.sup.2/g, 40 to 400
m.sup.2/g, 50 to 400 m.sup.2/g, 60 to 400 m.sup.2/g, 70 to 400
m.sup.2/g, 1 to 200 m.sup.2/g, 10 to 200 m.sup.2/g, 20 to 200
m.sup.2/g, 30 to 200 m.sup.2/g, 40 to 200 m.sup.2/g, 50 to 200
m.sup.2/g, 60 to 200 m.sup.2/g, 70 to 200 m.sup.2/g, 1 to 100
m.sup.2/g, 10 to 100 m.sup.2/g, 20 to 100 m.sup.2/g, 30 to 100
m.sup.2/g, 40 to 100 m.sup.2/g, 50 to 100 m.sup.2/g, 60 to 100
m.sup.2/g or 70 to 100 m.sup.2/g, for example, 70 m.sup.2/g.
[0054] The porous iron oxide-zirconia composite catalyst may have a
porosity of 1 to 99%, 1 to 90%, 1 to 80%, 10 to 99%, 10 to 90%, 10
to 80%, 20 to 99%, 20 to 90%, 20 to 80%, 30 to 99%, 30 to 90%, 30
to 80%, 40 to 99%, 40 to 90%, 40 to 80%, 50 to 99%, 50 to 90%, 50
to 80%, 60 to 99%, 60 to 90%, 60 to 80%, for example, 70%.
[0055] In the porous iron oxide-zirconia composite catalyst, the
average pore size and the porosity may be controlled according to
the particle size of a polymer template mold.
[0056] The composite catalyst may have a molar ratio of iron oxide
to zirconia of 9.9:0.1 to 4.0:6.0, 9.0:1.0 to 4.0:6.0, for example,
9.0:1.0, 8.0:2.0, 7.0:3.0 or 6.0:4.0, but the molar ratio is not
limited thereto.
[0057] In the porous iron oxide-zirconia composite catalyst,
zirconia may be present in the form of tetragonal phase.
[0058] The methane oxidation reaction by the electrochemical
reaction goes through a process in which CO.sub.3.sup.2- is
absorbed onto zirconia, and methane activated by iron oxide is
oxidized by O.sup.2- transferred from the surface of zirconia.
Accordingly, it is ideal that iron oxide and zirconia elements are
present in a uniformly dispersed state.
[0059] Since the tetragonal phase zirconia has Lewis acid positions
which are 3.5 times more than those of the monoclinic phase
zirconia, the tetragonal phase zirconia has a structure which is
advantageous in an electrochemical methane oxidation reaction in
carbonate ion absorption characteristics.
[0060] Iron is known to have an excellent performance in activating
the C--H bond of methane. Under high temperature conditions, it is
possible to oxidize methane while providing oxygen ions along with
the activation of methane. However, it is difficult to break the
C--H bond of methane and provide oxygen ions under room temperature
conditions. CO.sub.3.sup.2- in an alkaline solution provides oxygen
to iron oxide to form Ferryl 0, and CH.sub.4 is oxidized by Ferryl
0 to form methanol.
[0061] Zirconia is known to adsorb carbonate well. However,
zirconia has a bonding interval of 5 eV, so that electrons cannot
be transferred, and an electrochemical reaction cannot occur when
zirconia is used alone. Accordingly, when zirconia is used alone,
it is difficult for a reaction of oxidizing methane to occur
because it is difficult for a reaction of electrochemically
reducing CO.sub.3.sup.2- to CO.sub.2 to occur. Therefore, in a
methane oxidation reaction at room temperature, two elements of
iron oxide which serves to activate the C--H bond of methane and
zirconia which helps oxidation are essential.
[0062] Still another aspect of the present invention relates to a
method for producing alcohol, the method including: bringing a
porous iron oxide-zirconia composite catalyst into contact with
methane.
[0063] The method for producing alcohol may include allowing the
porous iron oxide-zirconia composite catalyst according to the
present invention to react with a solution including methane.
[0064] The production method may be carried out at 5 to 40.degree.
C., 5 to 35.degree. C., 5 to 30.degree. C., 5 to 25.degree. C., 5
to 20.degree. C., 10 to 40.degree. C., 10 to 35.degree. C., 10 to
30.degree. C., 10 to 25.degree. C., 10 to 20.degree. C., 15 to
40.degree. C., 15 to 35.degree. C., 15 to 30.degree. C., 15 to
25.degree. C., 15 to 20.degree. C., 20 to 40.degree. C., 20 to
35.degree. C., 20 to 30.degree. C. or 20 to 25.degree. C., and may
be carried out, for example, at 20.degree. C., and the production
method may be carried out within a temperature range which does not
impair a reactor and electrodes, and the higher the temperature is,
the more advantageous the reaction is, but there may occur a
problem in that the methane saturation degree deteriorates.
[0065] The production method may be carried out at a pressure of 1
to 20 bar, 1 to 15 bar, 1 to 10 bar, 1 to 5 bar, 1 to 3 bar, 1 to 2
bar or 1 to 1.5 bar, and may be carried out at a pressure of, for
example, 1 bar. As the pressure is increased within a range which
does not impair a reactor, the methane saturation degree in the
solution is increased, which is advantageous in the reaction, but
the production method may be carried out at room pressure in
consideration of economic feasibility with respect to the
reaction.
[0066] The catalyst may be used for producing alcohol,
formaldehyde, acetaldehyde, or acetone, for example, for producing
alcohol, but not limited thereto.
[0067] The alcohol may be methanol, 1-propanol, 2-propanol, or
ethanol, but is not limited thereto.
[0068] Hereinafter, the present invention will be described in more
detail through Examples. These Examples are provided only for more
specifically describing the present invention, and it will be
obvious to a person with ordinary skill in the art to which the
present invention pertains that the scope of the present invention
is not limited by these Examples according to the gist of the
present invention.
EXAMPLES
Example 1
Preparation of Porous Iron Oxide-Zirconia Catalyst
[0069] A polystyrene was manufactured using 10 g of Styrene (Sigma
Aldrich, Acs reagent, 99% US) and not using emulsifier.
Specifically, 4.685 mL of Styrene was added to 200 mL of distilled
water strong agitation and the temperature raised to 80.degree. C.,
followed by 30 minutes of nitrogen purging. When the state of the
solution was sufficiently stabilized to 80.degree. C., 0.47 g of
potassium persulfate (KPS, Sigma Aldrich, Acs reagent, 99%, US) was
taken into the reactor as initiator, and then the solution was
polymerized by stirring it at 200 rpm, 80.degree. C. for 12 hours.
By centrifuging the emulsion including the polystyrene of the same
size at 8000 rpm for 15 minutes, followed by drying the resultant
at room temperature for a day, a spherical polymer template mold
arranged in an fcc structure and having the average pore size of
1.1 .mu.m was obtained.
[0070] After iron(III) nitrate anhydride and zirconium (IV)
oxynitrate hydrate was mixed in molar ratio of 8:1, followed by
adding 20 mL of distilled water, the mixture was stirred at room
temperature enough, and then injected into the spherical polymer
template mold above manufacture. And then, the polymer template
mold was dried under the condition of 65.degree. C. for 12 hours.
Then, the dried polymer template mold was sintered under the
condition of 900.degree. C. for 4 hours to carbonize it and
removed, thereby obtaining the porous iron oxide-zirconia composite
catalyst having the average pore size of 900 nm.
Example 2
Preparation of Porous Iron Oxide-Zirconia Catalyst
[0071] Except that the molar ratio in which iron (III) nitrate
anhydride and zirconium (IV) oxynitrate hydrate was 4:1, the porous
iron oxide-zirconia composite catalyst was obtained by the same
method as the method of the example 1.
Example 3
Preparation of Porous Iron Oxide-Zirconia Catalyst
[0072] Except that the molar ratio in which iron (III) nitrate
anhydride and.zirconium (IV) oxynitrate hydrate was 2:1, the porous
iron oxide-zirconia composite catalyst was obtained by the same
method as the method of the example 1.
Example 4
Preparation of Porous Iron Oxide-Zirconia Catalyst
[0073] Except using 18 mL rather than 4.685 mL of Styrene and 0.21
g rather than 0.47 g of KPS to form spherical polymer template mold
having the average size of 200 nm, the porous iron oxide-zirconia
composite catalyst having the average pore size of 170 nm was
obtained by the same method as that in Example 1.
Experimental Example 1
Electron Microscope Image Analysis
[0074] Catalyst particles from the catalysts in the examples were
attached onto a carbon tape by using an electron microscope (JEOL,
Japan), the carbon tape was coated with gold, and then the catalyst
were measured with an SEM at a magnification of .times.10,000, and
the results thereof are illustrated in FIGS. 1A to 1E.
[0075] As can be confirmed from FIG. 1A to 1E, the iron
oxide-zirconia composite catalyst prepared in the examples
exhibited a porous structure.
Experimental Example 2
Transmission Electron Microscopy (TEM) Analysis
[0076] 5 mg of the catalyst in the Example 1 was dispersed in 1 ml
of a water solvent with ultrasonic waves for about 5 minutes, and
then a TEM (manufactured by JEOL, model name JEM-2100F) analysis
was performed by loading the catalyst onto a TEM grid, and the
result thereof is illustrated in FIG. 2A.
[0077] As can be confirmed from FIG. 2A, a porous structure was
uniformly manufactured.
Experimental Example 3
Energy Dispersive Spectroscopy (EDS) Mapping Analysis
[0078] During the TEM analysis, the TEM images were captured, the
EDS mapping analyses for iron, zirconium, and oxygen elements were
performed at the corresponding positions through the EDS analysis
functions, and the results thereof are illustrated in FIGS. 2B to
2D.
[0079] As can be confirmed from FIGS. 2B to 2D, iron oxide and
zirconia were present in mixture in the catalyst in the Example 1
to 3 and iron and zirconia elements were uniformly distributed
along the IO (Inverse Opal) framework.
Experimental Example 4
XRD (X-Ray Diffraction) Analysis
[0080] The porous iron oxide-zirconia composite catalyst was
applied onto a grid, and then while the grid was irradiated with an
X-ray beam, the crystallinity of the corresponding particles was
analyzed by measuring the diffraction of the beam while changing
the angle of the beam into 2 theta/min, and the results thereof are
illustrated in FIG. 3. (Used device manufactured by Rigaku, model
name: MINIFLEX)
[0081] As can be confirmed from FIG. 3, alpha phase iron oxide
peaks at 33.12.degree. (104), 35.63.degree. (110), 40.64.degree.
(113) and 49.47.degree. (024), and tetragonal phase zirconia at
30.2.degree. (111) were identified.
Experimental Example 5
XPS (X-Ray. Photoelectron Spectroscopy) Analysis
[0082] An XPS analysis was performed on a catalyst prepared by
mixing iron (III) nitrate anhydride and zirconium (IV) oxynitrate
hydrate at a molar ratio of examples 1 to 3 by using an X-ray beam
with MXR1 Gun--400 .mu.m 15 kV. Specifically, by using an XPS
device manufactured by Thermo Fisher Scientific Inc. (Britain), an
X-ray source was monochromated Al Ka (hv=1,486.6 eV), the catalyst
were measured at an energy of 15 kV and 100 W by scanning the
energy at 0.1 eV, and the results thereof are illustrated in FIGS.
4A and 4B.
[0083] As can be confirmed from FIGS. 4A and 4B, it was confirmed
that the chemical interaction between iron oxide and zirconia was
present, and specifically, XPS peak of the BE (binding energy) of
Fe 2p 1/2 of the iron oxide appeared markedly around 724.5-725.2
eV, XPS peak of the BE of Fe 2p 3/2 appeared markedly around
711-711.4 eV. The BE XPS peak of the Zr 3d 3/2 of zirconia appeared
markedly around 184-184.3 eV, the BE XPS peak of Zr 3d 5/2 of
zirconia appeared markedly around 181.6-182 eV. It is determined
that the bonding energy results from a chemical interaction instead
of a physical interaction.
Experimental Example 6
Electrochemical Evaluation of Cyclic Voltammetry (CV)
[0084] After methane and an inert gas were each saturated in a 0.5
M Na.sub.2CO.sub.3 solution, a three-electrode electrochemical
evaluation was performed in a 15-ml vial.
[0085] 60 .mu.g of the prepared catalyst of the examples 1 to 3 was
loaded onto a glassy carbon electrode, and then a cyclic
voltammetry evaluation was performed from 0.2 V to 1.0 V by using
the above-mentioned glassy carbon electrode as a working electrode,
an SCE electrode as a reference electrode, and Pt as a counter
electrode, and the results thereof are illustrated in FIGS. 5A, 5B
and 5C.
[0086] As can be seen in FIG. 5A, as a result of CV of iron oxide
in a CO.sub.3.sup.2- electrolyte solution, methane activation was
confirmed at 0.8 V or more. CH.sub.4-saturated condition led to the
current about three times that obtained under Ar-saturated
condition.
[0087] As can be confirmed from FIG. 5B, as a result of CV of iron
oxide in a CO.sub.3.sup.2- electrolyte solution, slight methane
activation could be identified at 0.8 V or more. About 2 times
increased current could be identified under CH.sub.4-saturated
condition compared to Ar-saturated condition, in the
above-mentioned reactions.
[0088] As can be confirmed from FIG. 5C, little methane activation
could be identified at 0.8 V or more. About 1.4 times increased
current could be identified under CH.sub.4-saturated condition
compared to Ar-saturated condition, in the aforementioned
reactions.
Experimental Example 7
Qualitative Analysis of the Product of Methane Oxidation
Reaction
[0089] In order to allow methane in a liquid phase to react, a
solution was saturated by supplying methane with a purity of
99.999% to a Na.sub.2CO.sub.3 solution at a concentration of 0.5 M
for 1 hour, and an empty space of the reactor was fully filled with
methane. Next, to both sides of the reactor, a Pt electrode as a
cathode was connected and a carbon paper, as an anode, in which the
catalyst was uniformly loaded was connected. The catalyst was
dispersed in water, placed onto the carbon paper, and then dried,
and the catalyst was loaded onto the carbon paper electrode by
fixing the catalyst using a binder, and the reactor was made
hermetically sealed and isolated from the outside.
[0090] Using the porous iron oxide-zirconia composite catalyst
prepared from Example 1, methane oxidation reaction was carried out
for 12 hours under room temperature and normal pressure condition
to obtain a product, and then the product was analyzed by NMR, with
result thereof illustrated in FIG. 6.
[0091] Generally, the .sup.1H-NMR peaks of methanol appear around
3.3.about.3.5 ppm, while the peak was detected in this reaction,
appeared at 3.36 ppm. The ethanol peaks generally appear around
1.1.about.1.2 ppm, and 3.6.about.3.7 ppm, while the peaks was
detected in this reaction, were detected at 3.63, 3.69, 3.7 ppm and
1.14, 1.16 ppm.
[0092] Compared to the major products, all minor products were
identified by negligible amount.
Experimental Example 8
Quantitative Analysis of the Product of Methane Oxidation
Reaction
[0093] The products of 12 hours of methane oxidation reaction under
1.5 V with the porous iron oxide-zirconia composite catalyst
prepared in the examples 1 to 3 were analyzed by GC/MS, and the
results thereof were illustrated in the FIG. 7 and the Table 1.
TABLE-US-00001 TABLE 1 methanol ethanol 1-propanol formaldehyde
example 1 6.03 0.43 1.1 0.02 example 2 4.18 0.52 1.59 0.008 example
3 2.45 0.76 0.08 0.007 product amount (mg/L)
[0094] FIG. 7 is a graph showing the analyzed results of the
methanol production concentration according to the methane
oxidation reaction time, in which the porous iron oxide-zirconia
composite catalyst prepared from the examples 1 to 3 of the present
invention.
[0095] As can be confirmed in the FIG. 7 and the table 1,
[0096] methanol (MeOH), ethanol (EtOH), 1-propanol (1-PrOH),
formaldehyde, and the like were detected as methane oxidation
reaction products, and methanol was detected as a main product at
high ratio.
* * * * *