JP2004058029A - Energy-saving electrochemical reaction system and activation method thereof - Google Patents

Abstract

An object of the present invention is to provide a chemical reaction system and the like that can efficiently purify nitrogen oxides with low power consumption when excess oxygen is present in combustion exhaust gas.
An oxygen ion conductor (ion conduction phase) for performing a chemical reaction of a substance to be treated, and a cathode (reduction phase) and an anode (oxidation phase) opposed to each other with the oxygen ion conductor interposed therebetween, or oxidation and / or oxidation In a chemical reaction system in which a chemical reaction unit is configured with a reduction catalyst as a basic unit, current is applied to or applied to the above-mentioned chemical reaction unit, or reduction or heat treatment is performed under reduced pressure, thereby adsorbing the chemical reaction unit and inhibiting the reaction. A chemical reaction system, a method for using the same, and a method for activating the same, characterized in that the ability to ionize and remove oxygen is activated.
[Selection diagram] None

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an energy-saving electrochemical reaction system and a method for activating the same, and more specifically, for example, a chemical reaction system for efficiently purifying nitrogen oxides from combustion exhaust gas containing oxygen, a method for using the same, and a method for using the same. It relates to an activation method. The present invention provides, for example, a method for refining the above chemical reaction system with a small amount of power consumption, when purifying nitrogen oxides in exhaust gas by an electrochemical reaction system, while reducing reactivity due to adsorption of oxygen molecules on the surface. The present invention is useful for providing a new chemical reaction system, a method for using the same, and a method for activating the same, which can be activated to perform a chemical reaction of a substance to be treated with high efficiency.
[0002]
[Prior art]
At present, a method using a three-way catalyst is mainly used for purifying nitrogen oxides generated from a gasoline engine. However, in lean-burn engines and diesel engines that can improve fuel efficiency, the excess amount of oxygen in the combustion exhaust gas causes a problem of a sharp decrease in catalytic activity due to adsorption of oxygen to the surface of the three-way catalyst. I can't purify things.
[0003]
On the other hand, using a solid electrolyte membrane having oxygen ion conductivity and passing a current therethrough, oxygen in exhaust gas is removed without being adsorbed on the catalyst surface. As a proposed catalytic reactor, a system is known that removes surface oxygen and simultaneously decomposes nitrogen oxides into oxygen and nitrogen by applying a voltage to a solid electrolyte sandwiched on both sides of an electrode. .
[0004]
However, in the above method, when excess oxygen is present in the combustion exhaust gas, the adsorption and decomposition reaction sites of the coexisting oxygen and the nitrogen oxide are composed of the same oxygen defect, so that the adsorption probability of the nitrogen oxide to oxygen molecules is Is remarkably low from the viewpoint of molecular selectivity and the number ratio of coexisting molecules, so that a large amount of current needs to be passed to decompose nitrogen oxides, and there is a problem that power consumption increases.
[0005]
Under such circumstances, the present inventors have already found that in a chemical reactor, the inner structure of the cathode is surrounded by a through-hole of nanometer size in the upper part of the same layer, and the electron conductor and the ionic conductor become nano-sized. By adopting a structure that is distributed in the form of a network closely adhered to each other with a size of less than a meter to a micron, it becomes possible to reduce excess oxygen that becomes an interfering gas when performing a chemical reaction of the substance to be treated, It has been found that a substance to be treated can be efficiently processed with low power consumption (Japanese Patent Application No. 2001-225034). However, in this method, it is necessary to continuously supply a current to remove coexisting oxygen molecules, and there is a problem in that power consumption is not sufficiently reduced.
[0006]
[Problems to be solved by the invention]
In view of the above prior art, the present inventors have conducted intensive studies with the aim of solving these problems, and as a result, the working electrode layer located above the cathode in the chemical reaction section has an Simultaneous adsorption and nitrogen oxide adsorption-reduction reactions create a local reaction field to enable efficient chemical reactions.Furthermore, after adsorbing a certain amount of oxygen molecules, energize the chemical reaction system. Thus, the inventors have found that oxygen molecules can be ionized to be removed and reactivated, and the present invention has been accomplished.
That is, an object of the present invention is to solve the above problems, and when excess oxygen is present in flue gas, a substance having a selective adsorption property to oxygen molecules and nitrogen oxide molecules is provided. By reducing the amount of current required to decompose nitrogen oxides by making it easier to adsorb nitrogen oxides, at the same time, reactivating the chemical reaction system by conducting electricity after adsorbing a certain amount of oxygen, An object of the present invention is to provide a chemical reaction system capable of purifying nitrogen oxides with high efficiency with low power consumption.
[0007]
[Means for Solving the Problems]
The present invention for solving the above-mentioned problems includes the following technical means.
(1) Oxygen ion conductor (ion conduction phase) and cathode (reduction phase) and anode (oxidation phase) opposed to each other across the oxygen ion conductor (2) oxidation And / or a reduction catalyst, in a chemical reaction system comprising a chemical reaction unit as a basic unit, by applying an electric current or applying an electric field to the chemical reaction unit, or reducing or heat-treating the chemical reaction unit under reduced pressure, thereby adsorbing the chemical reaction unit. A chemical reaction system characterized in that the ability to ionize and remove oxygen that inhibits the reaction is activated.
(2) As the chemical reaction section, a reduced phase having selectivity for each of oxygen and the substance to be treated, and a micrometer or less required for efficiently supplying and treating the substance to be treated to the reduced phase. The chemical reaction system according to the above (1), wherein a chemical reaction section having pores is used.
(3) As the above-mentioned chemical reaction part, an electric current, an electric field is applied, or a reduction or A chemical reaction system characterized by using a chemical reaction part in which a small reaction region in which a redox reaction is performed on a substance to be treated is introduced into a part of the chemical reaction part by heat treatment under reduced pressure.
(4) As the above-mentioned minute reaction region, from the metal phase part of the electron conduction phase, the oxygen deficient part of the ion conduction phase, and the minute space part (void) around the contact point between the electron conduction phase and the ion conduction phase. The chemical reaction system according to the above (3), wherein a chemical reaction section having an interface formed is used.
(5) The chemical reaction system according to (3), wherein a chemical reaction unit having a cathode into which a minute reaction region in which the redox reaction is performed is used as the chemical reaction unit.
(6) As the chemical reaction part, a working electrode layer for performing a redox reaction is provided above the cathode, and in the same layer, a minute reaction region having a size of nanometer to micrometer in which the redox is performed is provided. The chemical reaction system according to (1), wherein the introduced chemical reaction section is used.
(7) The chemical reaction system according to (1), wherein the substance to be treated is nitrogen oxide.
(8) The chemical reaction system according to (6), wherein the chemical reaction is a reductive decomposition of nitrogen oxide.
(9) A method using a chemical reaction system for performing a chemical reaction of a substance to be treated according to any one of the above (1) to (8), wherein the temperature of the chemical reaction system is 400 to 700 ° C. Or increasing or decreasing the temperature in the same temperature range, energizing or applying an electric field at intervals of time, and activating the chemical reaction section.
(10) A method for activating a chemical reaction system for performing a chemical reaction of a substance to be treated according to any one of (1) to (8), wherein the temperature of the chemical reaction system is 400 to 700. A method for activating a chemical reaction system, comprising maintaining the temperature at 0 ° C. or raising or lowering the temperature in the same temperature range, and applying a current or applying an electric field between the cathode and the anode for 1 minute to 3 hours.
(11) The method for activating a chemical reaction system according to the above (10), wherein an applied current of 5 mA to 1 A or an applied voltage of 0.5 V to 2.5 V is applied to cause an electrochemical reaction.
(12) The method for activating a chemical reaction system according to (10), wherein the energization or the electric field treatment is performed at an oxygen partial pressure of 0% to 21% (in the atmosphere).
(13) A method for activating a chemical reaction system for performing a chemical reaction of a substance to be treated according to any one of (1) to (8), wherein the temperature of the chemical reaction system is 500 ° C. or higher. Or a heat treatment under reduced or reduced pressure by raising or lowering the temperature in the same temperature range.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the present invention will be described in more detail.
The present invention relates to a chemical reaction system for performing a chemical reaction of a substance to be treated, and the chemical reaction system includes a chemical reaction unit that advances the chemical reaction of the substance to be treated, and And a barrier layer for inhibiting ionization.
[0009]
Preferably, the chemical reaction section for performing a chemical reaction of the substance to be treated includes a reducing phase that supplies electrons to elements contained in the substance to be treated to generate ions, and an ion conductive phase that conducts ions from the reducing phase. And an oxidizing phase that emits electrons from the ions conducted through the ion conducting phase. However, the present invention is not limited to these, and oxidation and / or reduction catalysts having functions equivalent to these, that is, oxidation catalysts and reduction catalysts Alternatively, it is also possible to appropriately configure a redox catalyst as a basic unit. In this case, those constituent components are not particularly limited.
[0010]
In the present invention, preferably, the substance to be treated is nitrogen oxide in the combustion exhaust gas, the nitrogen oxide is reduced in the reduction phase to generate oxygen ions, and the oxygen ions are transmitted in the ion conduction phase. However, the substance to be treated in the present invention is not limited to nitrogen oxide. The chemical reactor of the present invention is applied to generating carbon monoxide by reducing carbon dioxide, generating a mixed gas of hydrogen and carbon monoxide from methane, or generating hydrogen from water. be able to.
[0011]
Examples of the form of the chemical reaction system include, for example, a tubular shape, a flat plate shape, and a honeycomb shape.In particular, a tubular shape, such as a honeycomb shape, has one or more through holes having a pair of openings. Preferably, a chemical reaction portion is located in each through hole.
[0012]
In the chemical reaction section, it is preferable that the reducing phase is porous and made of a substance that selectively adsorbs a substance to be reacted. In the reduction, it is preferable to use a conductive material in order to supply electrons to the elements contained in the substance to be treated, generate ions, and transmit the generated ions to the ion conductive phase. In addition, the reduced phase may be made of a mixed conductive material having both electron conductivity and ion conductivity, or a mixture of an electron conductive material and an ion conductive material, in order to promote the transfer of electrons and ions. More preferably. The reduced phase may have a structure in which at least two or more phases of these substances are stacked.
[0013]
The conductive substance and the ionic conductive substance used as the reducing phase are not particularly limited. As the conductive substance, for example, noble metals such as platinum and palladium, and metal oxides such as nickel oxide, cobalt oxide, copper oxide, lanthanum manganite, lanthanum cobaltite, and lanthanum chromite are used. Barium-containing oxides and zeolites that selectively adsorb the substance to be treated are also used as the reduced phase. It is also preferable to use at least one kind of the above substances as a mixture with at least one kind of ion conductive substance. As the ion conductive substance, for example, zirconia stabilized with yttria or scandium oxide, ceria stabilized with gadolinium oxide or samarium oxide, lanthanum gallate, or the like is used. It is also preferable that the reduced phase has a structure in which the substance is laminated at least in two or more phases. More preferably, the reduced phase has a structure in which two phases of a conductive substance phase made of a noble metal such as platinum and a mixed phase of nickel oxide and zirconia stabilized with yttria or scandium oxide are stacked.
[0014]
The ion conductive phase is made of a solid electrolyte having ion conductivity, and preferably is a solid electrolyte having oxygen ion conductivity. Examples of the solid electrolyte having oxygen ion conductivity include, but are not limited to, zirconia stabilized with yttria or scandium oxide, ceria and lanthanum gallate stabilized with gadolinium oxide or samarium oxide. Preferably, zirconia stabilized with yttria or scandium oxide having high conductivity and strength and having excellent long-term stability is used.
[0015]
The oxidized phase contains a conductive substance to release electrons from ions from the ion conductive phase. In order to promote the transfer of electrons and ions, it is preferable to use a mixed conductive material having both electron conductivity and ion conductivity, or to use a mixture of an electron conductive material and an ion conductive material. The conductive substance and the ion conductive substance used as the oxidized phase are not particularly limited. As the conductive substance, for example, noble metals such as platinum and palladium, and metal oxides such as nickel oxide, cobalt oxide, copper oxide, lanthanum manganite, lanthanum cobaltite, and lanthanum chromite are used. As the ion conductive substance, for example, zirconia stabilized with yttria or scandium oxide, ceria stabilized with gadolinium oxide or samarium oxide, or lanthanum gallate is used.
[0016]
The barrier layer aims at preventing supply of electrons necessary for generating oxygen ions when oxygen molecules are adsorbed on the surface. Alternatively, oxygen ions are provided in the chemical reaction section for the purpose of preventing a metal (for example, metal nickel) generated by a reduction reaction of a conductive oxide (for example, nickel oxide) from being re-oxidized. In particular, it has a material and a structure for suppressing the electrons supplied by the reduction layer from reaching the surface. This barrier layer is desirably an ion conductor, a mixed conductor, or an insulator. In the case of a mixed conductor, when the electron conductivity is large, the effect of suppressing the electron conduction is reduced, so that the ratio of the electron conductivity is minimized. Desirably small.
[0017]
The present invention provides an oxygen ion conductor (ion conduction phase) and a cathode (reduction phase) and an anode (oxidation phase) opposed to each other with the oxygen ion conductor (ion conduction phase), or oxidized and / or In a chemical reaction system in which a chemical reaction unit is configured with a reduction catalyst as a basic unit, for example, a current is applied or an electric field is applied between a cathode and an anode of the chemical reaction unit, or a reduction or a heat treatment is performed under reduced pressure. It is characterized in that the ability to ionize and remove oxygen that is adsorbed on the reaction part and inhibits the reaction is activated. In the present invention, as the chemical reaction section, an ion conductor, an electron conductor, and a contact between an electron conduction phase and an ion conduction phase formed by combining any one of a mixed conductor are energized, applied with an electric field, or reduced. Alternatively, by performing a heat treatment under reduced pressure, a chemical reaction unit in which a small reaction region in which a redox reaction is performed on a substance to be treated is introduced into a part of the chemical reaction unit, and oxygen and oxygen are used as the chemical reaction unit. The use of a reduced phase having selectivity for each of the substances to be treated and a chemical reaction section having pores smaller than micrometers required for efficiently supplying and treating the substances to be treated to the reduced phase. In addition, as the above-mentioned minute reaction region, a metal phase portion of the electron conduction phase, an oxygen deficient portion of the ion conduction phase, and a minute space portion (void) around the contact point between the electron conduction phase and the ion conduction phase. A chemical reaction section having an interface formed therein, and a chemical reaction section having a cathode into which a minute reaction region in which the oxidation-reduction reaction is performed is used as the chemical reaction section. As a part, a chemical reaction part which has a working electrode layer that controls the oxidation-reduction reaction on the upper part of the cathode and in which a small area of nanometer to micrometer in which the above-mentioned oxidation and reduction are performed is introduced is used. Is a preferred example.
[0018]
The working electrode layer located above the cathode in the chemical reaction section has been developed by the present inventors in addition to the highly efficient adsorption and decomposition of the substance to be treated (Japanese Patent Application No. 2001-225034) and the addition of oxygen molecules. It has a structure in which the adsorption and the adsorption of the substance to be treated can be performed simultaneously by different substances suitable for each reaction. That is, a metal phase generated by reduction of an oxide or initially contained (preferably in the form of ultrafine particles (10 to 100 nm in diameter for high reactivity)) and an oxygen deficiency of an ion conductive phase existing in the vicinity thereof (A region estimated to be about 5 nm from the calculation based on the Debye length) is in contact with and a small space of about several to several hundreds nm coexists around the contact part. Power consumption is significantly reduced by selectively adsorbing and decomposing oxygen molecules in an oxygen-deficient portion and an object to be processed in a metal phase.
[0019]
Such a structure may be subjected to a heat treatment process (a zirconia-nickel oxide-based heat treatment at 1400 to 1450 ° C. in the air) necessary for forming the structure previously found, as well as an energizing treatment to the chemical reaction system or a reducing atmosphere. It is formed by performing a heat treatment such as described above. That is, a reduced phase is formed by using an oxide that is relatively easily reduced and energizing at a high temperature of several hundred degrees Celsius or more. In the process, the volume change of the crystal phase due to the oxidation-reduction reaction causes the generation of pores of nanometer to micrometer size suitable for introducing the gas to be treated, the formation of ultrafine particles by recrystallization of the reduction phase, and the oxidation-reduction A microstructure favorable for a highly efficient reaction, such as formation of an oxygen deficient portion of the ion conductive phase through the reaction, is formed. FIG. 2 shows an example of a local structure which is formed as described above and is desirable as an internal structure of the working electrode layer.
[0020]
As a substance constituting such a fine structure, a combination of an ion conductive phase and an electronic conductive phase, a mixed conductive phase or a combination thereof with an ion conductive phase and an electronic conductive phase are possible. When the object to be treated is nitrogen oxide, a metal phase such as nickel is more preferable as the reducing phase because it exhibits high selective adsorption.
[0021]
In order to reactivate the chemical reaction system, in addition to the method by introducing a reducing agent, which has already been described as a conventional technique, a structure in which carbon or the like is integrated in the chemical reaction system in advance, and carbon is oxidized during the chemical reaction. In addition, a method of reducing the oxidized metal phase by doing so has also been proposed (K. Miura et al., Chemical Engineering Science 56, 1623 (2001)). However, these methods require a reducing agent, and reactivation cannot be performed without the reducing agent. Therefore, in order to use the system for a long time or to use the system continuously, an electric reactivation method is required. Is preferred.
[0022]
In the present invention, it is possible to remove the oxygen adsorbed in the oxygen-deficient portion in the chemical reaction section by ionizing and pumping by conducting electricity only when the performance of the chemical reaction system is degraded. It is also possible to simultaneously re-activate the reducing phase. Thus, in the present invention, the amount of current can be significantly reduced as compared with the amount of current for oxygen pumping required in the conventional electrochemical cell system.
[0023]
In the present invention, the reactivation by oxygen pumping is performed by applying a current or applying a voltage to the chemical reaction system or performing a heat treatment in a reducing atmosphere or the like while the system is at 400 to 700 ° C. In the present invention, in the above-described chemical reaction system, the temperature is maintained at 400 to 700 ° C., or the temperature is raised or lowered in the same temperature range, and a current or electric field application treatment is performed between the cathode and the anode for 1 minute to 3 hours. preferable. In this case, applying an energizing current of 5 mA to 1 A or an applied voltage of 0.5 V to 2.5 V to cause an electrochemical reaction, and energizing or performing an electric field treatment at an oxygen partial pressure of 0% to 21% (in air). Is preferred. The processing temperature varies depending on the material and the structure of the system. For example, it is preferably around 560 ° C. when using yttria-stabilized zirconia as the solid electrolyte, and around 450 ° C. when using ceria. Further, according to the present invention, in the above chemical reaction system, the temperature is maintained at 500 ° C. or higher, or the temperature is raised or lowered in the same temperature range, and the heat treatment is performed in a reducing atmosphere or under reduced pressure. An activation method is provided.
[0024]
In addition to the conditions of the processing temperature and the constituent materials, the amount of the supplied current, the applied voltage, the supplied time, and the partial pressure of oxygen in the atmosphere or the total pressure are variable. For example, when yttria-stabilized zirconia is used as the solid electrolyte and nickel oxide and zirconia are used as the working electrode materials, a current of 100 mA and 2 V is applied for 1 hour (10% oxygen) to obtain a nitrogen oxide equivalent to that before the treatment. Restores decomposition performance. The degree of deterioration due to oxygen adsorption is about 20% after 100 hours of continuous operation (no power supply), and the performance is repeatedly restored by the power supply processing.
[0025]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a chemical reaction system according to one embodiment of the present invention. In response to the flow of the gas to be processed, the chemical reaction section 6 constituting the chemical reaction system 7 includes, in the order of 2 to 5, a working electrode layer, a cathode (reducing phase), an ion conductive phase, and an anode (oxidizing phase). ) Is located from the upstream side, and the barrier layer 1 is located on the upstream side. That is, the gas to be processed passes from 1 to 5.
Hereinafter, the case where nitrogen oxide is used as the substance to be treated will be specifically described.
[0026]
Example 1
As the ion conductive phase 4, zirconia stabilized with yttria was used, and its shape was a disk having a diameter of 20 mm and a thickness of 0.5 mm. The reduction phase 3 was a mixed layer of platinum and zirconia, and the working electrode layer 2 was a film made of a mixture of nickel oxide and yttria-stabilized zirconia. The platinum film was formed by screen printing on one surface of the ion conductive phase 4 so as to have an area of about 1.8 cm ² and then performing a heat treatment at 1200 ° C. The mixed film of nickel oxide and yttria-stabilized zirconia was formed by screen printing on a platinum film so as to have the same area as the platinum film, followed by heat treatment at 1450 ° C. The mixing ratio of nickel oxide and yttria-stabilized zirconia was 6: 4 in molar ratio. A platinum film was screen-printed on the other surface of the ion-conductive phase 4 on which the reduced phase was formed so as to have an area of about 1.8 cm ^2, and then heat-treated at 1200 ° C. to form an oxide phase 5. The barrier layer 1 was formed on the working electrode layer 2 with a thickness of about 3 μm by screen printing and heat treatment at 1400 ° C. using yttria-stabilized zirconia. Further, the temperature was raised to 650 ° C. while applying a current of 1.2 V-25 mA between the cathode 3 and the anode 5, the current was stopped for 1 hour, and then the current was stopped and the temperature was gradually cooled.
[0027]
The method for treating nitrogen oxides by the chemical reaction system of the present invention thus formed is described below. The chemical reaction system 7 was placed in the gas to be treated, a platinum wire was fixed to the reducing phase 3 and the oxidizing phase 5 as a lead wire, connected to a DC power supply, and a DC voltage was applied to flow a current. The evaluation was performed at 600 ° C. when the system was energized, and at 350 ° C. when no current was applied. As a gas to be treated, a model combustion exhaust gas of 1000 ppm of nitrogen monoxide, 2% of oxygen and helium balance was flowed at a flow rate of 50 ml / min. The nitrogen oxide concentration in the gas to be treated before and after flowing into the chemical reaction system was measured by a chemiluminescence NOx meter, and the nitrogen and oxygen concentrations were measured by gas chromatography. The nitrogen oxide purification rate was determined from the nitrogen oxide reduction amount, and the current density and the power consumption when the purification rate became 50% were measured.
[0028]
That is, at the start of measurement, the chemical reactor was heated to a reaction temperature of 600 ° C., and electricity was supplied to the chemical reaction section. At this time, the purification rate of nitrogen oxides increased as the amount of current increased, and the nitrogen oxides decreased to about 50% when the current density was 31 mA / cm ² and the power consumption was 61 mW / cm ² .
[0029]
In this chemical reaction system, the energization was further stopped one hour after the start of energization, and the measurement of the decomposition rate of nitrogen oxides was continued as it was. Although it decreased, it showed a gradual decreasing tendency after that, and the continuous measurement for a total of 5 days (120 hours) showed a decrease of 5% or less, and a reduction in the purification rate was recognized as time passed. As a result, when the amount of power required for the nitrogen oxide purification reaction for a total of 120 hours is compared with the calculated value at a purification rate of 35%, the power consumption is reduced to at least about 1/84 or less of the case of continuous energization according to the present invention. It was confirmed that.
[0030]
Example 2
Under the same chemical reaction system configuration conditions as in Example 1, the amount of oxygen was increased from 2% to 10% and the concentration of nitrogen oxide was reduced from 1000 ppm to 500 ppm in order to examine suitability for practical conditions. The removal performance of nitrogen oxides was examined. The energization of the system was repeated three times for 10 minutes under the same temperature and power conditions as in Example 1. As shown in FIG. 3, the decomposition rate of nitrogen oxides decreased by 15% or more immediately after the start of the measurement, and reached a level lower than 30% by about 20 hours after the start of the measurement. Gradually decreased, and almost reached an equilibrium state from around 100 hours. After a lapse of 200 hours, the same energization treatment was performed again, and the change in the nitrogen oxide decomposition rate due to substantially the same lapse of time as the first time was shown.
[0031]
Example 3
Under the same chemical reaction system configuration conditions as in Example 1, activation of the system by a reducing atmosphere treatment was evaluated. At a co-existing oxygen content of 2%, a system operating temperature of 650 ° C., and a nitrogen oxide concentration of 1000 ppm, a chemical reaction system having a required power of about 68 mW / cm ² when decomposing 50% nitrogen oxide was supplied for 48 hours after stopping power supply (nitrogen When the oxide decomposition rate was reduced to about 38%), the temperature was increased to 800 ° C., and a reducing gas containing 5% of hydrogen and 95% of argon was allowed to flow for 10 hours. A performance improvement of about 2% was observed.
[0032]
【The invention's effect】
As described above, according to the present invention, the following effects can be obtained.
(1) It is possible to provide a chemical reaction system that can efficiently process a substance to be treated with low power consumption even when oxygen that interferes with a chemical reaction of the substance to be treated is excessively present.
(2) Nitrogen oxides can be purified with high efficiency by low power consumption.
(3) The chemical reaction system can be reactivated.
(4) It is possible to provide an energy-saving electrochemical reaction system capable of activating and using a chemical reaction section by applying a current or applying an electric field at intervals of time.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a chemical reaction system according to one embodiment of the present invention.
FIG. 2 is an example of a local structure desirable as an internal structure of the working electrode layer.
FIG. 3 is a view showing a state in which the purification performance of nitrogen oxides is restored by an energization process.
[Explanation of symbols]
1 barrier layer 2 working electrode layer 3 cathode (reducing phase)
4 Ion conductive phase 5 Anode (oxidation phase)
6 Chemical reaction section 7 Chemical reaction system

Claims (13)

1) Oxygen ion conductor (ion conduction phase) and cathode (reduction phase) and anode (oxidation phase) opposed to each other with the oxygen ion conductor (2) oxidation and / or In a chemical reaction system in which a chemical reaction unit is configured with a reduction catalyst as a basic unit, a current is applied or an electric field is applied to the chemical reaction unit, or a reduction or heat treatment is performed under reduced pressure, so that the chemical reaction unit is adsorbed and reacted. A chemical reaction system characterized by activating the ability to ionize and remove the inhibiting oxygen. As the chemical reaction section, a reduced phase having selectivity for each of oxygen and the substance to be treated, and pores of micrometer or less required for efficiently supplying and treating the substance to be treated to the reduced phase. The chemical reaction system according to claim 1, wherein a chemical reaction unit having the chemical reaction unit is used. As the chemical reaction part, an ion conductor, an electron conductor, and a contact point between an electron conduction phase and an ion conduction phase formed by combining any one of a mixed conductor, energization, application of an electric field, or reduction or under reduced pressure A chemical reaction system characterized by using a chemical reaction part in which a minute reaction region in which a redox reaction is performed on a substance to be treated is introduced into a part of the chemical reaction part by heat treatment. As the minute reaction region, an interface composed of a metal phase portion of the electron conduction phase, an oxygen deficient portion of the ion conduction phase, and a minute space (void) around the contact point is formed at the contact point between the electron conduction phase and the ion conduction phase. The chemical reaction system according to claim 3, wherein the formed chemical reaction section is used. 4. The chemical reaction system according to claim 3, wherein a chemical reaction unit having a minute reaction region in which the oxidation-reduction reaction is performed is introduced into a cathode as the chemical reaction unit. As the chemical reaction part, a chemical electrode having a working electrode layer that controls an oxidation-reduction reaction above a cathode, and a micro-reaction region having a size of nanometer to micrometer in which the oxidation-reduction is performed is introduced in the same layer. The chemical reaction system according to claim 1, wherein a reaction unit is used. 2. The chemical reaction system according to claim 1, wherein the substance to be treated is a nitrogen oxide. 7. The chemical reaction system according to claim 6, wherein the chemical reaction is a reductive decomposition of nitrogen oxide. A method using a chemical reaction system for performing a chemical reaction of a substance to be treated according to any one of claims 1 to 8, wherein the temperature is maintained at 400 to 700 ° C in the chemical reaction system. A method for using a chemical reaction system, comprising raising or lowering the temperature in a region, energizing or applying an electric field at intervals of time, and activating a chemical reaction part. A method for activating a chemical reaction system for performing a chemical reaction of a substance to be treated according to any one of claims 1 to 8, wherein the temperature is maintained at 400 to 700 ° C in the chemical reaction system. A method for activating a chemical reaction system, comprising raising or lowering the temperature in a temperature range, and applying a current or applying an electric field for 1 minute to 3 hours between a cathode and an anode. The method for activating a chemical reaction system according to claim 10, wherein an electrochemical reaction is caused by applying a current of 5mA to 1A or an applied voltage of 0.5V to 2.5V. The method for activating a chemical reaction system according to claim 10, wherein the energization or electric field treatment is performed at an oxygen partial pressure of 0% to 21% (in the atmosphere). A method for activating a chemical reaction system for performing a chemical reaction of a substance to be treated according to any one of claims 1 to 8, wherein the temperature of the chemical reaction system is maintained at 500 ° C or higher. A method for activating a chemical reaction system, comprising raising or lowering the temperature in a region, and performing heat treatment under reduction or reduced pressure.

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