U.S. patent application number 15/699151 was filed with the patent office on 2018-01-11 for methanol generation device, method for generating methanol, and electrode for generating methanol.
The applicant listed for this patent is Panasonic Intellectual Property Management Co., Ltd.. Invention is credited to Masahiro DEGUCHI, Hiroshi HASHIBA, Yuka YAMADA, Satoshi YOTSUHASHI.
Application Number | 20180010255 15/699151 |
Document ID | / |
Family ID | 52141394 |
Filed Date | 2018-01-11 |
United States Patent
Application |
20180010255 |
Kind Code |
A1 |
HASHIBA; Hiroshi ; et
al. |
January 11, 2018 |
METHANOL GENERATION DEVICE, METHOD FOR GENERATING METHANOL, AND
ELECTRODE FOR GENERATING METHANOL
Abstract
The present invention provides a methanol generation device for
generating methanol by reducing carbon dioxide, comprising: a
container for storing an electrolyte solution containing carbon
dioxide; a cathode electrode disposed in the container so as to be
in contact with the electrolyte solution; an anode electrode
disposed in the container so as to be in contact with the
electrolyte solution; and an external power supply for applying a
voltage so that a potential of the cathode electrode is negative
with respect to a potential of the anode electrode. The cathode
electrode has a region of Cu.sub.1-x-yNi.sub.xAu.sub.y (0<x,
0<y, and x+y<1). The anode electrode has a region of a metal
or a metal compound.
Inventors: |
HASHIBA; Hiroshi; (Osaka,
JP) ; DEGUCHI; Masahiro; (Osaka, JP) ;
YOTSUHASHI; Satoshi; (Osaka, JP) ; YAMADA; Yuka;
(Osaka, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Panasonic Intellectual Property Management Co., Ltd. |
Osaka |
|
JP |
|
|
Family ID: |
52141394 |
Appl. No.: |
15/699151 |
Filed: |
September 8, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14565462 |
Dec 10, 2014 |
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15699151 |
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PCT/JP2014/003030 |
Jun 6, 2014 |
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14565462 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C25B 11/0405 20130101;
C25B 9/08 20130101; C25B 15/02 20130101; C25B 11/0473 20130101;
C25B 11/0431 20130101; C25B 3/04 20130101; C25B 11/0494
20130101 |
International
Class: |
C25B 3/04 20060101
C25B003/04; C25B 11/04 20060101 C25B011/04; C25B 9/08 20060101
C25B009/08; C25B 15/02 20060101 C25B015/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 28, 2013 |
JP |
2013-135824 |
Claims
1. A method for generating methanol using a methanol generation
device, the method comprising: (a) preparing the methanol
generation device comprising: a container; a cathode electrode; and
an anode electrode, wherein the cathode electrode includes a region
of Cu.sub.1-x-yNi.sub.xAu.sub.y (0<x, 0<y, and x+y<1); the
anode electrode includes a region of a metal or a metal compound;
an electrolyte solution is stored in the container; the cathode
electrode is in contact with the electrolyte solution; the anode
electrode is in contact with the electrolyte solution; and the
electrolyte solution contains carbon dioxide; and (b) reducing the
carbon dioxide contained in the electrolyte solution by applying a
voltage so that a potential of the cathode electrode is negative
with respect to a potential of the anode electrode to generate
methanol on the cathode electrode.
2. The method according to claim 1, wherein the methanol generation
device is placed under room temperature and atmospheric pressure in
step (b).
3. The method according to claim 1, wherein the
Cu.sub.1-x-yNi.sub.xAu.sub.y is a solid solution or intermetallic
compound of Cu, Ni, and Au.
4. The method according to claim 1, wherein the value of x is more
than 0 and not more than 0.20; and the value of y is not less than
0.005 and not more than 0.05.
5. The method according to claim 1, wherein the anode electrode is
formed of carbon, platinum, gold, silver, copper, titanium, iridium
oxide, or an alloy thereof.
6. The method according to claim 1, wherein the electrolyte
solution is a potassium chloride aqueous solution or a sodium
chloride aqueous solution.
7. The method according to claim 1, wherein an absolute value of
the voltage is not less than 2.5 volts.
8. The method according to claim 1, wherein the methanol generation
device further comprises: a reference electrode disposed in the
container so as to be in contact with the electrolyte solution; and
an external supply, the reference electrode has a region of
Ag/AgCl; and the voltage to be applied by the external power supply
to the cathode electrode with respect to a potential of the
reference electrode is not more than -1.7 volts.
9. A method for generating methanol using a methanol generation
device, the method comprising: (a) preparing the methanol
generation device comprising: a cathode container; an anode
container; a cathode electrode; an anode electrode; and a solid
electrolyte membrane, wherein the cathode container and the anode
container are separated by the solid electrolyte membrane; the
cathode electrode includes a region of Cu.sub.1-x-yNi.sub.xAu.sub.y
(0<x, 0<y, and x+y<1); the anode electrode includes a
region of a metal or a metal compound; a first electrolyte solution
containing carbon dioxide is stored in the cathode container; a
second electrolyte solution is stored in the anode container; the
cathode electrode is in contact with the first electrolyte
solution; and the anode electrode is in contact with the second
electrolyte solution; and (b) reducing the carbon dioxide contained
in the first electrolyte solution by applying a voltage so that a
potential of the cathode electrode is negative with respect to a
potential of the anode electrode to generate methanol on the
cathode electrode.
10. The method according to claim 9, wherein the first electrolyte
solution is a potassium chloride aqueous solution or a sodium
chloride aqueous solution; and the second electrolyte solution is a
potassium hydrogen carbonate aqueous solution, a sodium hydrogen
carbonate aqueous solution, or a potassium sulfate aqueous
solution.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 14/565,462, filed on Dec. 10, 2014 is a
continuation of International Application No. PCT/JP2014/003030,
with an international filing date of Jun. 6, 2014, which claims
priority of Japanese Patent Application No. 2013-135824, filed on
Jun. 28, 2013, the contents of which are hereby incorporated by
reference.
BACKGROUND
1. Technical Field
[0002] The present disclosure relates to a methanol generation
device, a method for generating methanol, and an electrode for
generating methanol.
2. Description of the Related Art
[0003] Japanese Patent Application laid-open Publication No.
2000-254508A, Japanese Patent Application laid-open Publication No.
Hei 1-313313A, U.S. Pat. No. 5,234,768, Japanese Patent Application
laid-open Publication No. 2004-176129A, and Y. Hori, "Modern
Aspects of Electrochemistry", 2008, vol. 42, p.p. 89-189 disclose a
method for reducing carbon dioxide.
[0004] Japanese Patent Application laid-open Publication No.
2000-254508A and Japanese Patent Application laid-open Publication
No. Hei 1-313313A disclose a method for reducing carbon dioxide
using a gas phase reaction performed under high temperature.
[0005] U.S. Pat. No. 5,234,768 discloses a method for reducing
carbon dioxide electrochemically using a phthalocyanine metal
complex.
[0006] Japanese Patent Application laid-open Publication No.
2004-176129A, Y. Hori, "Electrochemical CO2 Reduction on Metal
Electrodes", Modern Aspects of Electrochemistry, 2008, vol. 42,
p.p. 89-189, and Y. Hori et. al. "Nickel and Iron Modified Copper
Electrode for Electroreduction of CO.sub.2 by In-situ
Electrodeposition", Chemistry Letters, pp. 1567-1570, 1989 disclose
a method for reducing carbon dioxide electrochemically using metal
copper, copper halide or nickel-plated copper.
SUMMARY
[0007] The present invention provides a methanol generation device
for generating methanol by reducing carbon dioxide, comprising:
[0008] a container for storing an electrolyte solution containing
carbon dioxide;
[0009] a cathode electrode disposed in the container so as to be in
contact with the electrolyte solution;
[0010] an anode electrode disposed in the container so as to be in
contact with the electrolyte solution; and
[0011] an external power supply for applying a voltage so that a
potential of the cathode electrode is negative with respect to a
potential of the anode electrode;
[0012] wherein
[0013] the cathode electrode has a region of
Cu.sub.1-x-yNi.sub.xAu.sub.y (0<x, 0<y, and x+y<1);
and
[0014] the anode electrode has a region of a metal or a metal
compound.
[0015] The present invention provides a methanol generation device
having high methanol generation efficiency.
[0016] Other features, elements, processes, steps, characteristics
and advantages of the present invention will become more apparent
from the following detailed description of preferred embodiments of
the present invention with reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1A shows a schematic view of a methanol generation
device according to the present disclosure.
[0018] FIG. 1B shows a schematic view of a methanol generation
device according to the present disclosure.
[0019] FIG. 10 shows a schematic view of a methanol generation
device according to the present disclosure.
[0020] FIG. 2 is a graph showing results of the inventive example 1
and the comparative examples 1-2.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0021] The embodiments of the methanol generation device and method
for generating methanol according to the present disclosure will be
described with reference to the drawings.
[0022] (Methanol Generation Device)
[0023] FIG. 1A-FIG. 1C each show a schematic view of a methanol
generation device for generating methanol by reducing carbon
dioxide.
[0024] A methanol generation device 10 comprises a container 11, a
cathode electrode 12, an anode electrode 13, and an external power
supply 14. As shown in FIG. 1A, the methanol generation device 10
may have a voltage measurement device 15 and a current measurement
device 16, each of which is used to monitor how carbon dioxide is
reduced.
[0025] An electrolyte solution 17 is stored in the container 11. As
one example, the electrolyte solution 17 is a potassium chloride
aqueous solution, a sodium chloride aqueous solution, a sodium
hydrogen carbonate aqueous solution, or a sodium sulfate aqueous
solution. In particular, a potassium chloride aqueous solution or a
sodium chloride aqueous solution is desirable. It is desirable that
the electrolyte solution 17 has a concentration of not less than
0.05 mol/L and not more than 5.0 mol/L.
[0026] The cathode electrode 12 has CuNiAu which is a
copper-nickel-gold alloy. Hereinafter, copper is referred to as
"Cu", nickel is referred to as "Ni", and gold is referred to as
"Au". CuNiAu has a composition formula of
Cu.sub.1-x-yNi.sub.xAu.sub.y (where 0<x, 0<y, and
x+y<1).
[0027] It is desirable that CuNiAu is in a state of a solid
solution or an intermetallic compound. The solid solution means an
alloy in which the elements constituting the alloy are randomly
mixed at the atomic level. The intermetallic compound means a
compound in which the elements constituting the compound are
arranged regularly at the atomic level.
[0028] An example of a method for fabricating CuNiAu in the state
of the solid solution is a vacuum melting method or an arc melting
method. The value of x in the composition formula
Cu.sub.1-x-yNi.sub.xAu.sub.y represents the composition ratio of Ni
to CuNiAu. The value of y in the composition formula
Cu.sub.1-x-yNi.sub.xAu.sub.y represents the composition ratio of Au
to CuNiAu. It is desirable that the value of x is more than 0 and
not more than 0.50 and the value of y is not less than 0.001 and
not more than 0.10. In particular, it is more desirable that the
value of x is more than 0 and not more than 0.20 and the value of y
is not less than 0.005 and not more than 0.05.
[0029] CuNiAu which constitutes the cathode electrode 12 may
contain elements other than Cu, Ni and Au, as long as the
crystalline structure of CuNiAu is free from disturbance. CuNiAu
fabricated by a vacuum melting method or an arc melting method may
contain impurities at a normally acceptable level. The crystalline
structure of CuNiAu can be observed, for example, by conducting an
X-ray diffraction measurement. An example of a method for measuring
the composition ratio of each element contained in the alloy is an
energy dispersive X-ray analysis method. In this method, the
measurement limit value of Ni is approximately 0.1% at an atomic
ratio.
[0030] The cathode electrode 12 may be composed only of CuNiAu;
however, the cathode electrode 12 may have a stacked structure
having a CuNiAu layer and a substrate for supporting the CuNiAu
layer. For example, the cathode electrode 12 is a stacked structure
obtained by forming a CuNiAu thin film on the substrate formed of
glass or glassy carbon. Instead, the cathode electrode 12 may be
formed by arranging a lot of CuNiAu fine particles on a conductive
substrate. The cathode electrode 12 is not limited, as long as the
cathode electrode 12 is capable of reducing carbon dioxide and
generating methanol.
[0031] The cathode electrode 12 is in contact with the electrolyte
solution 17. More accurately, CuNiAu contained in the cathode
electrode 12 is in contact with the electrolyte solution 17. As
long as CuNiAu is in contact with the electrolyte solution 17, only
a part of the cathode electrode 12 has to be immersed in the
electrolyte solution 17.
[0032] The anode electrode 13 has a conductive material. An example
of the conductive material is carbon, platinum, gold, silver,
copper, titanium, iridium oxide, or an alloy thereof. The
conductive material is not limited, as long as the conductive
material is not decomposed through the oxidation reaction of the
conductive material itself.
[0033] The oxidation reaction of water performed in the anode
electrode 13 is independent of the reduction reaction of carbon
dioxide performed in the cathode electrode 12. The material of the
anode electrode 13 does not have an influence on the reaction
performed on the cathode electrode 12.
[0034] The anode electrode 13 is also in contact with the
electrolyte solution 17. More accurately, the conductive material
included in the anode electrode 13 is in contact with the
electrolyte solution 17. As long as the conductive material is in
contact with the electrolyte solution 17, only a part of the anode
electrode 13 has to be immersed in the electrolyte solution 17.
[0035] As shown in FIG. 1A, the methanol generation device 10 may
have a tube 18 in the container 11. Carbon dioxide may be supplied
through the tube 18 to the electrolyte solution 17. One end of the
tube 18 is immersed in the electrolyte solution 17.
[0036] As shown in FIG. 1B, a methanol generation device 100 may
comprise a solid electrolyte membrane 19 in the container 11. The
solid electrolyte membrane 19 divides the electrolyte solution 17
into an anode-side electrolyte solution 17L and a cathode-side
electrolyte solution 17R. In other words, the solid electrolyte
membrane 19 divides the inside of the container 11 into an anode
container for storing the anode-side electrolyte solution 17L and a
cathode container for storing the cathode-side electrolyte solution
17R.
[0037] The solid electrolyte membrane 19 prevents the anode-side
electrolyte solution 17L and the cathode-side electrolyte solution
17R from being mixed with each other. Since the solid electrolyte
membrane 19 allows passage of protons therethrough, the solid
electrolyte membrane 19 connects the cathode-side electrolyte
solution 17R with the anode-side electrolyte solution 17L
electrically. An example of the solid electrolyte membrane 19 is a
Nafion membrane available from Du Pont. The reason why the
electrolyte solution 17 is divided using the solid electrolyte
membrane 19 will be described later.
[0038] As shown in FIG. 10, a methanol generation device 200 may
comprise a reference electrode 20 near the cathode electrode 12.
The reference electrode 20 is in contact with the cathode-side
electrolyte solution 17R. The reference electrode 20 is used for
measuring the electric potential of the cathode electrode 12 and is
connected to the cathode electrode 12 through the voltage
measurement device 15. An example of the reference electrode 20 is
a silver/silver chloride electrode (hereinafter, referred to as
"Ag/AgCl electrode").
[0039] (Method for Generating Methanol)
[0040] A method for generating methanol using the above-mentioned
methanol generation device will be described below.
[0041] The methanol generation device may be placed under room
temperature and atmospheric pressure.
[0042] A voltage is applied to the cathode electrode 12 using the
external power supply 14 so that the voltage is negative with
respect to the potential of the anode electrode 13. A voltage
exceeding a threshold for establishing the methanol generation
reaction has to be applied using the external power supply 14. The
threshold varies depending on the interval between the cathode
electrode 12 and the anode electrode 13, the materials constituting
the cathode electrode 12 and the anode electrode 13, and the
concentration of the electrolyte solution 17. It is desirable that
the threshold is not less than 2.5 volts.
[0043] A part of the electric energy applied to the cathode
electrode 12 with respect to the anode electrode 13 is consumed for
the oxidization reaction of water which occurs on the anode
electrode 13. For this reason, in the case of using the methanol
generation device shown in FIG. 1A or FIG. 1B, it is difficult to
know the actual voltage applied to the cathode electrode 12. On the
other hand, in the case of using the methanol generation device
shown in FIG. 10, the actual voltage applied to the cathode
electrode 12 can be determined accurately. The potential of the
cathode electrode 12 with respect to the potential of the reference
electrode 20 may vary depending on the materials of the reference
electrode 20. It is desirable that the potential of the cathode
electrode 12 with respect to the potential of the reference
electrode 20 is not more than -1.7 volts.
[0044] As just described, by applying an appropriate voltage to the
cathode electrode 12, the carbon dioxide contained in the
electrolyte solution 17 is reduced on the cathode electrode 12. As
a result, methanol is generated on the surface of the cathode
electrode 12.
[0045] On the other hand, oxygen is generated on the anode
electrode 13 through the oxidization reaction of water. In a case
where the electrolyte solution 17 contains methanol, not only water
but also methanol is oxidized. In other words, a part of the
methanol generated on the cathode electrode 12 may reach the anode
electrode 13, and oxidized on the anode electrode 13. As a result,
the generated methanol is returned to carbon dioxide. In order to
prevent such a reverse reaction, as shown in FIG. 1B and FIG. 10,
the cathode-side electrolyte solution 17R and the anode-side
electrolyte solution 17L are preferably separated from each other
using the solid electrolyte membrane 19.
[0046] A reaction current flows through the cathode electrode 12,
since carbon dioxide is reduced on the cathode electrode 12 and
water is oxidized on the anode electrode 13 by using the methanol
generation device. As shown in FIG. 1A-FIG. 1C, the amount of the
reaction current can be monitored using the current measurement
device 16.
EXAMPLES
[0047] Hereinafter, the present disclosure will be described with
reference to the following examples.
Inventive Example 1
[0048] (Fabrication of the Cathode Electrode)
[0049] A cathode electrode formed of CuNiAu according to the
inventive example 1 was fabricated below.
[0050] First, Ni and Au were dissolved in Cu by a vacuum melting
method so that x and y were respectively equal to 0.0558 and
0.0167. Subsequently, the dissolved material was solidified. In
this way, CuNiAu was obtained. The obtained CuNiAu was shaped into
a plate having a length of 20 millimeters, a width of 20
millimeters, and a thickness of 2 millimeters. The surface of the
plate was washed using an organic solvent.
[0051] The composition of the CuNiAu plate was confirmed using an
X-ray diffractometer. As a result, no peak of Au in the state of
the elementary substance was observed. The formation of CuNiAu in
which Au and Ni were dissolved in Cu was observed.
[0052] And then, the obtained CuNiAu plate was adhered to a glass
substrate. In this way, the cathode electrode according to the
inventive example 1 was fabricated.
[0053] (Assembling of the Device)
[0054] The methanol generation device shown in FIG. 1C was
fabricated using the above-mentioned cathode electrode. The
elements of the methanol generation device are described below.
[0055] Cathode electrode: CuNiAu (Composition formula:
Cu.sub.0.9275Ni.sub.0.0558Au.sub.0.0167)
[0056] Anode electrode: Platinum
[0057] Electrode interval: approximately 8 centimeters
[0058] Reference electrode: Ag/AgCl
[0059] Anode-side electrolyte solution: potassium hydrogen
carbonate aqueous solution having a concentration of 0.5 mol/L
[0060] Cathode-side electrolyte solution: potassium chloride
aqueous solution having a concentration of 0.5 mol/L
[0061] Solid electrolyte membrane: Nafion membrane (available from
Du Pont, Trade name: Nafion 117)
[0062] Carbon dioxide was supplied through a tube to the
cathode-side electrolyte solution by bubbling the cathode-side
electrolyte solution using a carbon dioxide gas for thirty minutes
(carbon dioxide flow rate: 200 milliliters/minute).
[0063] (Reduction of Carbon Dioxide)
[0064] After carbon dioxide was dissolved in the cathode-side
electrolyte solution, the container was sealed. Subsequently, a
voltage was applied using a potentiostat so that the potential of
the cathode electrode was negative with respect to the potential of
the anode electrode. The value of the applied voltage was
controlled using the potentiostat so that the potential of the
cathode electrode with respect to the potential of the reference
electrode was -1.9 volts.
[0065] After the voltage was applied for a certain period, the
material and amount of the reaction products generated in the
container were determined using gas chromatography and liquid
chromatography. As a result, carbon monoxide (CO), formic acid
(HCOOH), methane (CH.sub.4), ethylene (C.sub.2H.sub.4), aldehydes,
and ethanol were detected as reduction products of carbon dioxide.
Furthermore, as shown in FIG. 2, a peak was observed at the
detecting position indicating the generation of methanol (i.e. the
position indicated by the arrow depicted in the drawing) in the
product analysis of the head-space gas chromatography. In other
words, it was confirmed that methanol was generated using the
cathode electrode formed of CuNiAu.
[0066] In the inventive example 1, the production amount of
methanol per 1000 seconds of the electrolysis period was
2.2.times.10.sup.-7 mol/cm.sup.2. Note that the electrolysis period
was equal to the period for which the voltage was applied to the
cathode electrode using the external power supply.
[0067] The faraday efficiency of the methanol generation in the
inventive example 1 was calculated. As a result, the calculated
faraday efficiency was 1.00%. Note that the faraday efficiency
means a ratio of the charge amount used for the generation of the
reaction product to the charge amount used for all the reactions.
The faraday efficiency is calculated in accordance with the
following formula:
(Faraday efficiency of the methanol generation)=(the charge amount
used for the generation of methanol)/(the charge amount used for
all the reactions).times.100[%].
Comparative Example 1
[0068] An experiment similar to that of the inventive example 1 was
performed, except that a Cu.sub.0.9442Ni.sub.0.0558 electrode
containing no Au was used as the cathode electrode.
[0069] As a result, CO, HCOOH, CH.sub.4, C.sub.2H.sub.4, aldehydes,
and ethanol were detected similarly to the inventive example 1.
However, as shown in FIG. 2, no signal was found at the detecting
position of the methanol generation. In other words, methanol was
not generated in the comparative example 1.
Comparative Example 2
[0070] An experiment similar to that of the inventive example 1 was
performed, except that an Au electrode containing neither Cu nor Ni
was used as the cathode electrode.
[0071] As a result, CO and HCOOH were detected. However, as shown
in FIG. 2, no signal was found at the detecting position of the
methanol generation. In other words, methanol was not generated in
the comparative example 2.
Comparative Example 3
[0072] An experiment similar to that of the inventive example 1 was
performed, except that a Cu electrode containing neither Ni nor Au
was used as the cathode electrode.
[0073] As a result, CO, HCOOH, CH.sub.4, C.sub.2H.sub.4, aldehydes,
and ethanol were detected similarly to the inventive example 1.
However, as shown in FIG. 2, no signal was found at the detecting
position of the methanol generation. In other words, methanol was
not generated in the comparative example 3.
[0074] As just described, only in the case where the CuNiAu
electrode was used, the generation of methanol was confirmed, as
shown in FIG. 2. In other words, the present inventors believe that
a special effect which causes methanol to be generated occurs only
in the case where the CuNiAu electrode formed of an alloy of Cu, Ni
and Au is used, and that such a special effect does not occur in
the case where the CuNi electrode, the Cu electrode, or the Au
electrode is used.
Inventive Example 2
[0075] An experiment similar to that of the inventive example 1 was
performed, except that a sodium chloride aqueous solution having a
concentration of 0.5 mol/L was used as the cathode-side electrolyte
solution.
[0076] As a result, it was confirmed that methanol was generated as
the reduction product of carbon dioxide.
Inventive Example 3
[0077] An experiment similar to that of the inventive example 1 was
performed, except that an electrode was used in which CuNiAu fine
particles having a similar composition ratio to CuNiAu of the
inventive example 1 were supported on a surface of a glassy carbon
substrate.
[0078] As a result, it was confirmed that the obtained reaction
products were almost the same as those of the inventive example 1
and that methanol was generated. Similar results were obtained in
the case of using an electrode in which a CuNiAu thin film having a
similar composition ratio to that of the inventive example 1 was
laminated on the glassy carbon.
Inventive Example 4
[0079] An experiment similar to that of the inventive example 1 was
performed, except that a CuNiAu electrode formed of
Cu.sub.0.795Ni.sub.0.200Au.sub.0.005 was used as the cathode
electrode.
[0080] As a result, it was confirmed that methanol was generated as
the reduction product of carbon dioxide.
Inventive Example 5
[0081] An experiment similar to that of the inventive example 1 was
performed, except that a CuNiAu electrode formed of
Cu.sub.0.75Ni.sub.0.20Au.sub.0.05 was used as the cathode
electrode.
[0082] As a result, it was confirmed that methanol was generated as
the reduction product of carbon dioxide.
Inventive Example 6
[0083] An experiment similar to that of the inventive example 1 was
performed, except that the potentiostat was controlled so that the
potential of the cathode electrode with respect to the potential of
the reference electrode was -1.7 volts.
[0084] As a result, it was confirmed that methanol was generated as
the reduction product of carbon dioxide.
Inventive Example 7
[0085] An experiment similar to that of the inventive example 1 was
performed, except that the potentiostat was controlled so that the
potential of the cathode electrode with respect to the potential of
the reference electrode was -2.1 volts.
[0086] As a result, it was confirmed that methanol was generated as
the reduction product of carbon dioxide.
[0087] Table 1 shows the comparison of the methanol generation
amounts obtained in the inventive examples 1-7 and the comparative
examples 1-3. In Table 1, the generation amount of methanol
generated in the inventive example 1 is set to be 100%. Each of the
generation amounts of methanol generated in the inventive examples
2-7 and the comparative examples 1-3 is indicated relatively.
TABLE-US-00001 TABLE 1 Methanol generation amount (relative amount,
per unit charge amount) Inventive example 1 100 Inventive example 2
96 Inventive example 3 89 Inventive example 4 39 Inventive example
5 67 Inventive example 6 80 Inventive example 7 95 Comparative
example 1 0.0 Comparative example 2 0.0 Comparative example 3
0.0
[0088] As shown in Table 1, it was confirmed that methanol was
generated in the inventive examples 1-7 and that methanol was not
generated in the comparative examples 1-3.
[0089] As just described, it was confirmed that methanol was
generated efficiently as the reduction product of carbon dioxide on
the cathode electrode by using the cathode electrode having a
region of CuNiAu.
[0090] While the present invention has been described with respect
to preferred embodiments thereof, it will be apparent to those
skilled in the art that the disclosed invention may be modified in
numerous ways and may assume many embodiments other than those
specifically described above. Accordingly, it is intended by the
appended claims to cover all modifications of the invention that
fall within the true spirit and scope of the invention.
INDUSTRIAL APPLICABILITY
[0091] The present disclosure provides a novel device and a novel
method for generating methanol as the reduction product of carbon
dioxide by using the cathode electrode having CuNiAu.
REFERENCE SIGNS LIST
[0092] 10, 100, 200 methanol generation device [0093] 11 container
[0094] 12 cathode electrode [0095] 13 anode electrode [0096] 14
external power supply [0097] 15 voltage measurement device [0098]
16 current measurement device [0099] 17, 17L, 17R electrolyte
solution [0100] 18 tube [0101] 19 solid electrolyte membrane [0102]
20 reference electrode
* * * * *