KR20210020695A - Self-activatable catalytic electrode for electrochemical CO2 reduction using metal impurities and method for manufacturing the same - Google Patents

Abstract

Provided are an electrochemical carbon dioxide reduction catalyst electrode capable of self-activation using metal impurities and a manufacturing method thereof. The electrode comprises: carbon catalyst particles doped with a heteroelement having a lone pair of electrons; and a binder comprising a non-ionic conductive polymer. Self-activation is possible by selectively adsorbing and stabilizing metal cation impurities present in the electrolyte solution at the level of a single atom, thereby improving catalyst performance and durability.

Description

Self-activatable catalytic electrode for electrochemical CO2 reduction using metal impurities and method for manufacturing the same}

The present invention relates to an electrochemical carbon dioxide reduction catalyst electrode capable of self-activation using metal impurities and a method of manufacturing the same, and more particularly, to improve catalyst performance and durability by suppressing deactivation of the catalyst by metal cation impurities present in an electrolyte solution. It relates to an electrochemical carbon dioxide reduction catalyst electrode and a method for producing the same.

As the demand for sustainable clean energy and compound production increases, the importance of electrochemical reaction systems is emerging. In particular, in the development of an electrochemical catalyst for this, since a high-purity electrolyte prepared using a highly purified salt is used, the effects of trace components that may exist in the actual reaction system on the catalyst performance are mostly devalued or excluded. For example, electrochemical carbon dioxide reduction reactions were also carried out using high purity electrolytes in most laboratory scale experiments. However, even with only a very small amount of metal cation impurities present in the electrolytic solution, it may precipitate on the surface of the catalyst during the reaction, thereby causing a rapid decrease in activity of the catalyst. For example, it is possible to reduce the reactivity of a copper (Cu) catalyst within a few hours with only one part per million (ppm) of iron cation impurities, and gold (Au) and silver (Ag), which are other representative metal catalysts for carbon dioxide reduction reactions. ) The catalyst is also rapidly deactivated by trace metal impurities.

These metal cation impurities may exist in the reaction system through various inflow paths. First, it can be introduced through the water and the electrolyte salt used to prepare the electrolyte. _{For example, when preparing an electrolyte solution of 0.1M concentration using potassium hydrogen carbonate (KHCO 3} ) salt with a purity of 99.7% or higher and ultra-high purity water, iron cation impurities of up to 0.05 ppm exist, which is the activity of the copper catalyst for carbon dioxide conversion. Rapidly inhibited within a few hours. In addition, when potassium hydroxide (KOH) is used, iron cation impurities with a higher concentration of 0.66 ppm based on the 1M concentration of the electrolyte are present. In addition, the amount of residual metal cation impurities in the electrolyte may vary depending on the purity of the water used. Accordingly, in the case of a 0.5M concentration of potassium hydrocarbon electrolyte using ultrapure water (Milli Q water) and deionized water, the copper catalyst loses the activity of the carbon dioxide conversion reaction within 6 hours, and tap-water is used. In the case of an electrolyte prepared using it, it is known that it is rapidly deactivated within 2 hours.

Second, metal cation impurities may be introduced through an external path. For example, iron cation impurities may be eluted from a reaction tank made of stainless steel and parts constituting the same and supplied to the electrolyte. However, considering the commercialization aspect of the electrochemical catalytic reaction, it is inevitable to use a pipeline made of stainless steel, a connection part, and a storage tank for large-scale production.

Therefore, the design of a catalyst having high resistance to metal cation impurities, especially iron cation impurities, remains an essential prerequisite for the commercialization of electrochemical catalytic reactions.

Previous studies reported as part of an effort to prevent catalyst deactivation by metallic impurities focused on preventing deposition of metallic impurities. For example, an improvement plan through electrochemical pretreatment through pulsed electro-reduction has been proposed. However, this approach temporarily regenerates the catalyst to mitigate the effects of metal cation impurities, and its effectiveness decreases as the number of treatments increases. Another approach is to remove metallic impurities by introducing a chelating agent into the electrolyte. In this case, catalyst durability of up to 30 hours can be secured, but additional costs are involved in the use of a chelating agent.

As mentioned above, in a general metal-based electrochemical carbon dioxide reduction catalyst, deposition of metal impurities is detrimental to the selective production of a desired product. Accordingly, there is a need for a new method capable of overcoming the problem of deactivation of the catalyst by metal cation impurities and further improving the reaction activity.

Removal of impurity phases from the electrochemical device (Korean Patent Registration No. 10-1192701)

Pulsed Electroreduction of CO2 on Silver Electrodes, J. Electrochem. Soc., 143, 582, (1996). “Deactivation of Copper Electrode” in Electrochemical Reduction of CO2, Electrochim. Acta, 50, 5354, (2005). Pulsed Electroreduction of CO2 on Copper Electrodes, J. Electrochem. Soc., 140, 3479, (1993). Stabilizing Copper for CO2 Reduction in Low-Grade Electrolyte., Inorg. Chem., 57, 14624, (2018). Impurity Ion Complexation Enhances Carbon Dioxide Reduction Catalysis., ACS Catal., 5, 4479, (2015).

An aspect of the present invention is to provide an electrochemical carbon dioxide reduction catalyst electrode capable of improving reaction activity and preventing deactivation of a catalyst by metal cation impurities in an electrolyte solution.

Another aspect of the present invention is to provide a method of manufacturing the electrochemical carbon dioxide reduction catalyst electrode.

In one aspect of the present invention,

Carbon catalyst particles doped with heterogeneous elements having unshared electron pairs; And

A binder containing a nonionic conductive polymer;

An electrochemical carbon dioxide reduction catalyst electrode comprising a is provided.

In another aspect of the invention,

Dispersing a binder including carbon catalyst particles and nonionic conductive polymers doped with heteroelements having a non-shared electron pair in a solvent to provide a mixed solution; And

Applying the mixed solution on a substrate to provide a catalyst electrode;

There is provided a method of manufacturing the electrochemical carbon dioxide reduction catalyst electrode comprising a.

The electrochemical carbon dioxide reduction catalyst electrode according to an embodiment may be self-activated by selectively adsorbing and stabilizing metal cation impurities present in an electrolyte solution at a single atom level, thereby improving catalyst performance and durability.

1 is a schematic diagram illustrating an electrochemical carbon dioxide reduction catalyst electrode according to an embodiment.
2 is a graph showing the theoretical calculation value of interaction energy with metal impurities according to the types of catalysts and conductive polymer binders used in manufacturing a catalyst electrode.
3 is a schematic diagram showing the adsorption point of ^{Fe 2+} ions when a nonionic conductive polymer is used and when an ionic conductive polymer is used.
4A to 4E are results of catalytic performance for carbon dioxide reduction reactions of the catalytic electrodes prepared in Comparative Examples 1 and 1 to 4, respectively, showing partial current densities of carbon monoxide and hydrogen generation according to voltage.
5 is a graph comparing partial current densities of _{CO and H 2} in carbon dioxide reduction products in -0.63 V vs RHE of the catalyst electrodes prepared in Comparative Example 1 and Examples 1 to 4. FIG.
6 shows a scanning transmission electron microscope (STEM) and STEM Elemental Mapping analysis results after the catalyst performance evaluation of the catalyst electrode prepared in Comparative Example 1.
7 shows STEM and STEM Elemental Mapping analysis results after catalytic performance evaluation of the catalyst electrode prepared in Example 1.
8 shows the results of analyzing the X-ray absorption wide area microstructure of the catalyst electrode prepared in Example 1.
9 shows the results of X-ray photoelectron spectroscopy analysis of the catalyst electrode prepared in Example 1.
10 shows long-term stability evaluation results for carbon dioxide conversion reaction of the catalyst electrode prepared in Example 1.
11 and 12 show catalyst performance evaluation results for nickel and zinc cation impurities of the catalyst electrode prepared in Example 1, respectively.

The present inventive concept described below may apply various transformations and may have various embodiments. Specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present creative idea to a specific embodiment, it is to be understood as including all transformations, equivalents or substitutes included in the technical scope of the present creative idea.

The terms used below are only used to describe specific embodiments, and are not intended to limit the present inventive idea. Singular expressions include plural expressions unless the context clearly indicates otherwise. Hereinafter, terms such as "comprises" or "have" are intended to indicate the existence of features, numbers, steps, actions, components, parts, components, materials, or a combination thereof described in the specification. It is to be understood that the above other features, or the possibility of the presence or addition of numbers, steps, actions, components, parts, components, materials, or combinations thereof, are not excluded in advance. "/" used below may be interpreted as "and" or "or" depending on the situation.

In the drawings, the thickness is enlarged or reduced in order to clearly express various layers and regions. The same reference numerals are assigned to similar parts throughout the specification. Throughout the specification, when a part such as a layer, film, region, plate, etc. is said to be "on" or "on" another part, this includes not only the case directly above the other part, but also the case where there is another part in the middle. . Throughout the specification, terms such as first and second may be used to describe various components, but the components should not be limited by terms. The terms are used only for the purpose of distinguishing one component from another.

Hereinafter, an electrochemical carbon dioxide reduction catalyst electrode and a method of manufacturing the same according to exemplary embodiments will be described in more detail.

Electrochemical carbon dioxide reduction catalyst electrode according to an embodiment,

Carbon catalyst particles doped with heterogeneous elements having unshared electron pairs; And

It includes; a binder containing a nonionic conductive polymer.

1 is a schematic diagram for explaining an electrochemical carbon dioxide reduction catalyst electrode according to an embodiment.

As shown in FIG. 1, the electrochemical carbon dioxide reduction catalyst electrode mixes the carbon catalyst particles 10 doped with heterogeneous elements having a non-shared electron pair with a binder 20 containing a nonionic conductive polymer to form a substrate 30. It can be prepared by applying.

The carbon catalyst particles may include at least one selected from graphite, graphene, carbon nanotubes, carbon nanofibers, activated carbon, carbon black, acetylene black, and fullerene as a carbon-based support, but is limited thereto. No, any carbon-based material that can be used for a carbon dioxide reduction catalyst electrode in the art can be used without limitation.

The heteroelement having a non-shared electron pair doped on the carbon catalyst particles may be at least one element selected from a group 15 element, a group 16 element, and a group 17 element. According to an embodiment, the heteroelement having an unshared electron pair may include at least one element selected from nitrogen, phosphorus, sulfur, and fluorine. For example, the heteroelement having the unshared electron pair may be nitrogen.

The doping amount of the heterogeneous element may range from 1 to 10 atomic% based on the total number of carbon atoms of the carbon catalyst particles and the heterogeneous element. Compared to the undoped carbon catalyst particles in the above range, carbon dioxide reduction performance can be improved and metal cation impurities present in the electrolyte can be effectively adsorbed.

Carbon catalyst particles doped with heteroelements having an unshared electron pair may exhibit better reduction of _{CO 2 than non-doped carbon catalyst particles.} For example, doping of nitrogen atoms in graphite, graphene, CNT, etc., forms graphitic, pyridinic, and pyrrolic nitrogen.In these nitrogen sites, _{the activation energy required to reduce CO 2} to *COOH is lower than that of pure undoped carbon sites. The reduction of CO ₂ can occur better. In addition, these nitrogen sites are strongly bonded to *COOH, but have low bonding strength with *CO, so that CO is selectively generated. In particular, when -0.3 eV is applied, a spontaneous reduction reaction can occur in pyridinic nitrogen, so that the part becomes the most effective reaction point. In addition, nitrogen-doped carbon can block a competitive reaction for _{CO 2} reduction because the overvoltage of the hydrogen generation reaction is about -0.82 eV.

In addition, in the carbon catalyst particles doped with a heteroelement having an unshared electron pair, a heterogeneous element site having an electron-rich unshared electron pair may provide an active point. When carbon catalyst particles doped with a heterogeneous element having a non-shared electron pair are used in a carbon dioxide reduction reaction with a binder containing a nonionic conductive polymer, metal cation impurities in the electrolyte can be selectively adsorbed to the site of the electron-rich heteroelement, thereby self-activating. (self-activation) can be implemented.

The electrochemical carbon dioxide reduction catalyst electrode includes a nonionic conductive polymer as a binder, together with carbon catalyst particles doped with heteroelements having a non-shared electron pair. The nonionic conductive polymer not only improves the physical strength and conductivity of the catalyst electrode, but also restricts the adsorption point of metal cation impurities in the catalyst electrode to only heteroelement sites having non-shared electron pairs. Accordingly, the electrochemical carbon dioxide reduction catalyst electrode may implement self-activation through selective adsorption of metal cation impurities present in the electrolyte solution.

2 is a graph showing the theoretical calculation value of the interaction energy with metal impurities according to the type of the conductive polymer binder used in manufacturing the catalyst electrode. As shown in FIG. 2, in the case of the ionic conductive polymer binder, the interaction energy with the Fe impurity is high, whereas in the case of the nonionic conductive polymer binder, the interaction energy with the Fe impurity is lower than that of nitrogen-doped carbon. Therefore, even when mixed and used with carbon catalyst particles doped with heterogeneous elements having the same unshared electron pair, the adsorption point of the metal cation impurity may vary.

3 is a schematic diagram showing the adsorption point of ^{Fe 2 +} ions when a nonionic conductive polymer is used and when an ionic conductive polymer is used. As shown in FIG. 3, for example, even if nitrogen-doped carbon catalyst particles are used in the same manner, in the case of using a nonionic conductive polymer, Fe ^{2 +} ions can be adsorbed to the nitrogen site of the carbon catalyst particles. When an ionic conductive polymer such as pion is used, Fe ^{2 +} ions are adsorbed to the sulfonic acid group of Nafion.

Therefore, when a catalyst electrode is prepared using a nonionic conductive polymer as a binder with carbon catalyst particles doped with a heterogeneous element having a lone pair of electrons, the adsorption point of metal cation impurities such as Fe can be limited to the site of a heterogeneous element having a lone pair of electrons. I can.

According to an embodiment, as the nonionic conductive polymer, for example, polyphenylene vinylene, polynaphthalene vinylene, polymethyl methacrylate, polystyrene, polycaprolactone, polyvinyl alcohol, polyethylene glycol, polypropylene glycol, Polyethylene oxide, polypropylene oxide, polyalkyl oxide, polyoxyethylene oxide, polyethylene oxide-propylene oxide copolymer, cellulose, methyl cellulose, ethyl cellulose, methyl hydroxyethyl cellulose, methyl hydroxypropyl cellulose, hydroxyethyl cellulose, carboxy It may include at least one selected from methylcellulose, carboxymethylhydroxyethylcellulose, and derivatives thereof, but is not limited thereto.

The nonionic conductive polymer can be used in a backbone structure, including a double bond chain or a single bond chain, or both, and it is better to use one containing a double bond chain in the electrochemical carbon dioxide reduction. It is preferable in that it can exhibit performance. As the nonionic conductive polymer having a double bond chain in the backbone structure, for example, polyphenylene vinylene and its derivatives, polynaphthalene vinylene and its derivatives, or a mixture thereof may be used.

In the electrochemical carbon dioxide reduction catalyst electrode, a weight ratio of the carbon catalyst particles and the nonionic conductive polymer may range from 1:100 to 100:1. For example, the weight ratio of the carbon catalyst particles and the nonionic conductive polymer may range from 1:50 to 50:1, specifically, from 1:10 to 10:1. In the above range, not only the physical strength and conductivity of the catalyst electrode may be improved, but also the electrochemical carbon dioxide reduction catalyst performance and durability may be improved.

According to an embodiment, the electrochemical carbon dioxide reduction catalyst electrode may further include a metal cation impurity adsorbed to a site in which the heteroelement having the unshared electron pair exists. The metal cation impurity may include at least one metal cation selected from iron (Fe), nickel (Ni), zinc (Zn), and copper (Cu).

The metal cation impurities are derived from impurities present in the electrolyte, and may be stabilized in a highly dispersed state by being adsorbed at the level of a single atom at a site where a hetero element having a non-shared electron pair exists during a carbon dioxide reduction reaction. Self-activation and long-term stability of the electrochemical carbon dioxide reduction catalyst electrode can be secured through selective adsorption of such metal cation impurities.

As described above, since the electrochemical carbon dioxide reduction catalyst electrode can selectively adsorb metal cation impurities in the electrolyte solution during the electrochemical carbon dioxide reduction reaction, it prevents deactivation of the catalyst by metal cation impurities, thereby improving catalyst performance and durability. In addition to being able to, it has the effect of reducing the cost of refining the electrolyte. In addition, since the electrochemical carbon dioxide reduction catalyst electrode can be applied to various metal cation impurities and has an effect induced based on adsorption of metal ion cation during the reaction, it can be applied to various electrochemical reactions.

Hereinafter, a method of manufacturing an electrochemical carbon dioxide reduction catalyst electrode according to an embodiment will be described.

According to an embodiment, the method of manufacturing the electrochemical carbon dioxide reduction catalyst electrode,

Dispersing a binder including carbon catalyst particles and nonionic conductive polymers doped with heteroelements having a non-shared electron pair in a solvent to provide a mixed solution; And

And applying the mixed solution on a substrate to provide a catalyst electrode.

The binder including the carbon catalyst particles doped with heterogeneous elements and the nonionic conductive polymer is as described above.

As a solvent for dispersing the binder including the carbon catalyst particles doped with heterogeneous elements and the nonionic conductive polymer, for example, water, alcohol, carbonate, glycol, acetone, or a mixed solvent thereof may be used. Non-limiting examples of such solvents include water; Alcohols such as ethanol and isopropyl alcohol; Acetone, and the like or mixtures thereof. Specifically, for example, one or a combination of water, ethanol, and isopropyl alcohol may be used.

In the case of a solvent, for example, it may be adjusted in the range of 0.1 ml to 10 ml based on 1 mg of catalyst mass.

For the dispersion, a stirring method or a sound wave treatment method may be used. Microwave processing can be processed at an output in the range of 50W to 700W, and preferably about 200W can be used.

A mixed solution in which a binder including carbon catalyst particles doped with heterogeneous elements having a non-shared electron pair and a nonionic conductive polymer is dispersed is prepared, and then the mixed solution is applied on a substrate to provide a catalyst electrode.

The substrate may be used without limitation as long as it is a conductive electrode substrate commonly used in the art. For example, as a substrate, carbon paper, glassy carbon, or the like may be used.

As a method of applying the mixed solution on the substrate, the mixed solution is directly dropped or sprayed using a gaseous phase such as nitrogen, argon, helium, air, spin coating in which the mixed solution is dropped while the substrate is rotated, After the mixed solution is dropped on the substrate, a coating method or the like in which the mixed solution is developed with a pusher can be used. The active area of the catalyst electrode ^{may be in the range of 0.2 to 10 cm 2} , for example, in the range of 0.3 to 1 cm ² , and specifically, for example, may be ^{about 0.5 cm 2.}

After applying the mixed solution, it is dried at room temperature to remove the solvent, thereby providing a catalyst electrode.

The method of manufacturing the electrochemical carbon dioxide reduction catalyst electrode may further include contacting the catalyst electrode with an electrolyte solution and performing a carbon dioxide reduction reaction.

In the carbon dioxide reduction reaction, the electrolyte solution may be used by saturating carbon dioxide gas with a potassium hydrogen carbonate solution having a concentration of 0.1 to 0.5 M, for example.

The electrolyte solution may contain metal cation impurities. While the carbon dioxide reduction reaction proceeds, metal cation impurities present in the electrolyte solution may be selectively adsorbed to the sites of heterogeneous elements having non-shared electron pairs of the carbon catalyst particles. Through the selective adsorption of metal cation impurities to heterogeneous sites, metal-heterogeneous interactions can be induced and highly dispersed metal sites can be stabilized. Through this, self-activation and long-term stability of the carbon catalyst particles doped with a heteroelement having an unshared electron pair can be secured.

Exemplary embodiments are described in more detail through the following examples and comparative examples. However, the Examples and Comparative Examples are for illustrative purposes only, and the scope of the present invention is not limited thereto.

Example 1: Preparation of a catalyst electrode using polyphenylene vinylene (PPV)

First, a nitrogen-doped carbon catalyst (containing 5 at% nitrogen) was prepared by the following procedure.

As a precursor, 0.5 g of 1,10-phenanthroline and 2 g of zinc (II) zeolitic imidazolate framework (ZIF-8) were mixed, and mixed and pulverized four times for 30 minutes at 400 RPM using a zirconia ball mill. . The obtained mixture powder was pyrolyzed for 1 hour at 1050° C. in an argon gas phase to synthesize a nitrogen-doped carbon catalyst. Then, the obtained catalyst was dissolved and washed with residual metals using sulfuric acid having a pH of 1.

9 mg of the prepared nitrogen-doped carbon catalyst (containing 5 at% nitrogen) was mixed with 3 mg of polyphenylene vinylene (PPV), a nonionic conductive polymer as a binder, and then dispersed in 3 ml of isopropyl alcohol using a sonication method. Using carbon paper as an electrode substrate, the dispersed mixed solution was sprayed and coated with ^{nitrogen gas to have an active area of 0.5 cm 2.} The electrode substrate coated with the mixed solution was dried at room temperature to prepare a catalyst electrode.

Example 2: Preparation of a catalyst electrode using polynaphthalene vinylene (PNV)

A catalyst electrode was manufactured in the same manner as in Example 1, except that polynaphthalene vinylene (PNV) was used instead of polyphenylene vinylene (PPV) in Example 1.

Example 3: Preparation of a catalyst electrode using ethyl cellulose (EC)

Except for using ethyl cellulose (EC) instead of polyphenylene vinylene (PPV) in Example 1, the same procedure as in Example 1 was performed to prepare a catalyst electrode.

Example 4: Preparation of a catalyst electrode using polyvinyl alcohol (PVA)

A catalyst electrode was manufactured in the same manner as in Example 1, except that polyvinyl alcohol (PVA) was used instead of polyphenylene vinylene (PPV) in Example 1.

Comparative Example 1: Preparation of a catalyst electrode using Nafion

In Example 1, a catalyst electrode was manufactured in the same manner as in Example 1, except that Nafion, an ionic conductive polymer was used instead of polyphenylenevinylene (PPV) as a binder.

Evaluation Example 1: Evaluating the catalyst performance of an electrode by iron cations

The catalyst performance was evaluated by performing a carbon dioxide reduction reaction as follows using the catalyst electrodes prepared in Examples 1 to 4 and Comparative Example 1.

The carbon dioxide reduction reaction was performed using a 0.5M potassium hydrogencarbonate electrolyte saturated with carbon dioxide, and a three-electrode system using the prepared catalyst electrode as a working electrode, a platinum plate as a counter electrode, and an Ag/AgCl electrode as a reference electrode was used. Here, in the electrochemical method, catalytic performance was evaluated by applying a potential in the range of -0.33 to -0.83 V based on a reversible hydrogen electrode (RHE) electrode using chronoamperometry.

In addition, electrochemical measurements were performed in a two-room electrochemical cell using a CHI potentiostat, and 38 ml of catholyte and anolyte were separated using a selemion anion exchange membrane. The electrolyte solution was purged with high purity carbon dioxide gas for at least 30 minutes, and the pH after saturation was approximately 7.2. Current was measured with time at each fixed potential, and gaseous products (ie, H ₂ , CO) were analyzed by a gas chromatograph equipped with a pulsed discharge detector.

To investigate the effect of metal cations, first evaluate the performance in the absence of metal impurities, and then re-evaluate the performance under the condition of 2.5 ppm concentration in the entire electrolyte by injecting an aqueous solution in which _{iron chloride (FeCl 2) is dissolved as a metal cation impurity.} I did.

The results of analyzing the catalyst performance of the catalyst electrodes prepared in Comparative Example 1 and Examples 1 to 4 are shown in FIGS. 4 and 5. Specifically, FIGS. 4A to 4E show partial current densities of _{carbon monoxide (CO) and hydrogen (H 2} ) produced according to the carbon dioxide reduction reaction according to the voltage of the catalyst electrodes prepared in Comparative Examples 1 and 1 to 4, respectively. 5 is a graph comparing partial current densities of carbon monoxide (CO) and hydrogen (H _{2) in -0.63 V vs. RHE of each catalyst electrode.}

As shown in FIGS. 4A to 5, in the case of the catalyst electrode using Nafion, an ionic conductive polymer in Comparative Example 1, the production of carbon monoxide (CO), which is a desired product, was reduced in the presence of metal cation impurities, The production of phosphorus hydrogen (H ₂ ) increased.

On the contrary, in the case of the catalyst electrode using the nonionic conductive polymers PPV, PNV, EC and PVA in Example 1-4, the production of carbon monoxide (CO), a desired product, was increased in the presence of metal cation impurities, and the addition product The production of phosphorus hydrogen (H ₂ ) decreased. From this, it can be seen that the catalyst performance of Example 1-4 was improved by selective adsorption of metal cation impurities by using a nonionic conductive polymer as a binder.

On the other hand, as shown in FIG. 5, among the nonionic conductive polymers used in Example 1-4, PPV and PNV having a double bond in their backbone structure have higher absolute CO generation than EC and PVA consisting of only single bonds. Appeared.

Evaluation Example 2: Characterization of a self-activated catalyst electrode

In order to compare and analyze the characteristics of the self-activated catalyst electrode, scanning transmission electron microscope (STEM) and STEM Elemental Mapping after evaluating the catalyst performance in an environment in which iron cation impurities exist for the catalyst electrodes prepared in Comparative Examples 1 and 1 Analysis was performed, and the results are shown in FIGS. 6 and 7 respectively.

As shown in FIG. 6, in the case of the catalyst electrode using Nafion, which is an ionic conductive polymer in Comparative Example 1, after evaluating the catalyst performance in an environment in which iron cation impurities are present, iron cations are precipitated in the form of large nanoparticles of 100 nm or more. Can be seen.

On the other hand, as shown in FIG. 7, in the case of the catalyst electrode using PPV, which is a nonionic conductive polymer in Example 1, after evaluating the catalytic performance in an environment in which iron cation impurities are present, iron cations are used throughout the carbon catalyst without nanoparticle formation. It can be seen that it is highly dispersed and stabilized at the nitrogen site of the nitrogen doped carbon catalyst throughout.

For the catalyst electrode prepared in Example 1, X-ray absorption broadband microstructure analysis and X-ray photoelectron spectroscopy analysis were performed, and the results are shown in FIGS. 8 and 9, respectively. As shown in FIGS. 8 and 9, it was confirmed that the catalyst electrode prepared in Example 1 developed an interaction between iron and nitrogen.

Evaluation example 3: Self-activation Long-term stability evaluation of the electrochemical carbon dioxide reduction reaction using

In order to evaluate the long-term stability of the carbon dioxide conversion reaction with respect to the catalyst electrode prepared in Example 1, the voltage of -0.63 V vs RHE under the same conditions as in Evaluation Example 1 except that the ^{electrode active area was 0.283 cm 2} The current density was measured while driving for 300 hours by applying, and the results are shown in FIG. 10.

As shown in FIG. 10, in the case of using the catalyst electrode using PPV in Example 1, it can be seen that stable performance for the carbon dioxide conversion reaction was secured during the operation of 300 hours. In the case of long-term stability evaluation, the performance was evaluated by applying a voltage of -0.63 V vs RHE under the same conditions except for Test Example 1. and an electrode active area of 0.283 cm ^2.

Evaluation Example 4: Self-activation by various metal cation impurities

In order to check whether self-activation using nickel and zinc cation impurities other than iron cation impurities, nickel chloride (NiCl ₂ ) and zinc chloride (ZnCl ₂ ) were used _{instead of iron chloride (FeCl 2) for the catalyst electrode prepared in Example 1.} Using the same, the catalyst performance was evaluated in the same manner as in Evaluation Example 1, and the results are shown in FIGS. 11 and 12, respectively.

As shown in FIGS. 11 and 12, it was confirmed that the catalyst electrode prepared in Example 1 is capable of self-activation such as an increase in CO and a decrease in H2 for the metal cation impurities used.

In the above, preferred embodiments according to the present invention have been described with reference to the drawings and embodiments, but these are only exemplary, and various modifications and other equivalent embodiments are possible from those of ordinary skill in the art. You will be able to understand. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims (18)

Carbon catalyst particles doped with heterogeneous elements having unshared electron pairs; And
A binder containing a nonionic conductive polymer;
Electrochemical carbon dioxide reduction catalyst electrode comprising a. The method of claim 1,
An electrochemical carbon dioxide reduction catalyst electrode comprising at least one element selected from a group 15 element, a group 16 element, and a group 17 element in the hetero element having the unshared electron pair. The method of claim 1,
An electrochemical carbon dioxide reduction catalyst electrode comprising at least one element selected from nitrogen, phosphorus, sulfur, and fluorine as the heteroelement having the unshared electron pair. The method of claim 1,
The carbon catalyst particle is an electrochemical carbon dioxide reduction catalyst electrode comprising at least one selected from graphite, graphene, carbon nanotubes, carbon nanofibers, activated carbon, carbon black, acetylene black, and fullerene. The method of claim 1,
The electrochemical carbon dioxide reduction catalyst electrode in which the doping amount of the heterogeneous element is in the range of 1 to 10 atomic% based on the total number of carbon atoms of the carbon catalyst particles and the heterogeneous element. The method of claim 1,
The nonionic conductive polymer is polyphenylene vinylene, polynaphthalene vinylene, polymethyl methacrylate, polystyrene, polycaprolactone, polyvinyl alcohol, polyethylene glycol, polypropylene glycol, polyethylene oxide, polypropylene oxide, polyalkyl oxide , Polyoxyethylene oxide, polyethylene oxide-propylene oxide copolymer, cellulose, methylcellulose, ethylcellulose, methylhydroxyethylcellulose, methylhydroxypropylcellulose, hydroxyethylcellulose, carboxymethylcellulose, carboxymethylhydroxyethylcellulose, And electrochemical carbon dioxide reduction catalyst electrode comprising at least one selected from derivatives thereof. The method of claim 1,
The electrochemical carbon dioxide reduction catalyst electrode wherein the nonionic conductive polymer includes a double bond chain in a backbone structure. The method of claim 1,
The weight ratio of the carbon catalyst particles and the nonionic conductive polymer is in the range of 1:100 to 100:1 electrochemical carbon dioxide reduction catalyst electrode. The method of claim 1,
Electrochemical carbon dioxide reduction catalyst electrode further comprising a metal cation impurity adsorbed at the site where the hetero element having the unshared electron pair is present. The method of claim 9,
The metal cation impurity is an electrochemical carbon dioxide reduction catalyst electrode comprising at least one metal cation selected from iron (Fe), nickel (Ni), zinc (Zn), and copper (Cu). An electrochemical carbon dioxide reduction apparatus comprising the electrochemical carbon dioxide reduction catalyst electrode according to any one of claims 1 to 10. An electrochemical carbon dioxide reduction method using the electrochemical carbon dioxide reduction catalyst electrode according to any one of claims 1 to 10. Dispersing a binder including carbon catalyst particles and nonionic conductive polymers doped with heteroelements having a non-shared electron pair in a solvent to provide a mixed solution; And
Applying the mixed solution on a substrate to provide a catalyst electrode;
The method of manufacturing an electrochemical carbon dioxide reduction catalyst electrode according to claim 1 comprising a. The method of claim 13,
The method of manufacturing an electrochemical carbon dioxide reduction catalyst electrode comprising at least one element selected from a group 15 element, a group 16 element, and a group 17 element as the hetero element having the lone pair. The method of claim 13,
The method of manufacturing an electrochemical carbon dioxide reduction catalyst electrode comprising at least one element selected from nitrogen, phosphorus, sulfur, and fluorine as the heteroelement having the unshared electron pair. The method of claim 13,
The nonionic conductive polymer is polyphenylene vinylene, polynaphthalene vinylene, polymethyl methacrylate, polystyrene, polycaprolactone, polyvinyl alcohol, polyethylene glycol, polypropylene glycol, polyethylene oxide, polypropylene oxide, polyalkyl oxide , Polyoxyethylene oxide, polyethylene oxide-propylene oxide copolymer, cellulose, methylcellulose, ethylcellulose, methylhydroxyethylcellulose, methylhydroxypropylcellulose, hydroxyethylcellulose, carboxymethylcellulose, carboxymethylhydroxyethylcellulose and A method for producing an electrochemical carbon dioxide reduction catalyst electrode comprising at least one selected from derivatives thereof. The method of claim 13,
A method of manufacturing an electrochemical carbon dioxide reduction catalyst electrode further comprising the step of contacting the catalyst electrode with an electrolyte solution and performing a carbon dioxide reduction reaction. The method of claim 17,
The electrolyte solution is a method of manufacturing an electrochemical carbon dioxide reduction catalyst electrode containing metal cation impurities.

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