WO2023128244A1

WO2023128244A1 - Organic-based electrochemical system for removing unreacted ammonia

Info

Publication number: WO2023128244A1
Application number: PCT/KR2022/017519
Authority: WO
Inventors: 김용태; 신해용; 정상문
Original assignee: 포항공과대학교 산학협력단
Priority date: 2021-12-27
Filing date: 2022-11-09
Publication date: 2023-07-06
Also published as: KR102681537B1; KR20230099268A

Abstract

The present invention relates to an organic-based electrochemical system for removing unreacted ammonia. More specifically, the present invention lowers, during extraction of hydrogen from ammonia, the activation energy required for an ammonia removal reaction through an organic-based electrochemical system, so that a catalytic reaction rapidly proceeds, and thus improved activity is exhibited. The present invention comprises a working electrode, a counter electrode, and a reference electrode, and an electrolyte and a support electrolyte, which connect same, and the working electrode comprises a non-noble metal-based catalyst and platinum applied to the surface thereof so that the use of noble metals is reduced by the interaction between a catalyst and a support, and thus an economic effect superior to that of a catalyst having, deposited thereon, approximately 15 times more platinum, which is a noble metal, is implemented, and the problem of high maintenance and incidental expenses of a conventional PSA method can be solved.

Description

Organic based electrochemical system for removing unreacted ammonia

The present invention relates to an organic-based electrochemical system for removing unreacted ammonia. More specifically, the present invention lowers the activation energy required for the ammonia removal reaction during ammonia hydrogen extraction, so that the catalytic reaction proceeds quickly and shows improved activity, and the use of precious metals is reduced due to the interaction between the catalyst and the support, so that the precious metal platinum is about 15 times or more It relates to an organic-based electrochemical system for removing unreacted ammonia that can solve the problems of the conventional PSA method by realizing better economic effects than deposited catalysts.

A fuel cell is a device that converts chemical energy generated by oxidation-reduction of fuel into electrical energy. However, unreacted ammonia generated during hydrogen extraction causes deterioration of the electrode and separator of the fuel cell, and thus an ammonia removal process is additionally required.

At this time, pressure swing adsorption (PSA) technology is widely used to separate gas species from a gas mixture according to molecular characteristics of the gas species and affinity for an adsorbent material for hydrogen purification. However, since ammonia is selectively recovered and removed as a large-capacity plant, there is a problem of high maintenance and additional costs, such as the use of a large-scale device with a scale of tens of thousands of Nm ³ /h.

Therefore, this problem can be solved by an electrochemical system that converts ammonia into other compounds by an electrochemical cell through a cathode, anode, and diaphragm configuration, rather than a pressure circulation method in the existing PSA.

However, currently used electrochemical systems for removing unreacted ammonia are mostly water-based systems, and in this case, there is a disadvantage in that they cannot be applied due to a competitive reaction, HOR (Hydrogen Oxidation Reaction).

Therefore, there is an urgent need for technology development to meet the needs for low-cost, highly active catalysts and fuel cells, which have rapidly increased in recent years. can't see

Accordingly, while the inventors of the present invention continue to make efforts to improve the above problems, the working electrode includes a working electrode, a counter electrode, a reference electrode, an electrolyte connecting them and a supporting electrolyte, and the working electrode is a non-noble metal-based catalyst and applied to the surface thereof. By including platinum, the activation energy required for the ammonia removal reaction is lowered, so the catalytic reaction proceeds quickly, resulting in improved activity. The present invention, which can solve the problems of the conventional PSA method by implementing the effect, has been completed.

(Prior art literature)

(patent literature)

Prior Patent 1 : Korea Patent Registration No. 10-1150843

Prior Patent 2: Korea Patent Registration No. 10-1763382

An object of the present invention is to provide an organic-based electrochemical system for removing unreacted ammonia that exhibits improved activity by rapidly progressing the catalytic reaction by lowering the activation energy required for the ammonia removal reaction.

Another object of the present invention is to reduce the use of precious metals due to the interaction between the catalyst and the support, thereby realizing an economic effect superior to that of a catalyst deposited with about 15 times more precious metal platinum, thereby solving the problems of the conventional PSA method, which was expensive for maintenance and additional costs. It is to provide an organic-based electrochemical system for removing unreacted ammonia.

The above and other objects of the present invention can all be achieved by the present invention described below.

One aspect of the present invention is a working electrode, a counter electrode, a reference electrode, and an electrolyte and a supporting electrolyte connecting the working electrode, the counter electrode, and the reference electrode. ), wherein the working electrode relates to an organic-based electrochemical system for removing unreacted ammonia including a non-noble metal-based catalyst and platinum applied on the surface of the non-noble metal-based catalyst.

In one embodiment, the working electrode may include a rotating disk electrode, the counter electrode may include a graphite rod, and the reference electrode may include Ag/AgCl.

In one embodiment, the electrolyte is 1-methyl-2-pyrrolidone (NMP), acetone, ethanol, n-propanol, n- Butanol (n-butanol), n-hexane, cyclohexanol, acetic acid, ethyl acetate, diethyl ether, dimethylformamide ( dimethyl formamide: DMF), dimethylacetamide: DMAc, dioxane, tetrahydrofuran: THF, dimethyl sulfoxide: DMSO, cyclohexane, benzene, It may include at least one selected from the group consisting of toluene, xylene, water, and derivatives or mixtures thereof.

In one embodiment, the supporting electrolyte may include an amide-based or ammonium-based compound.

In one embodiment, the amide-based compound is melamine (2-amino-4,6-dichlorotriazine), cyanuric chloride, calcium cyanamide, sodium amide, melem (2 ,5,8-triamino-tri-s-triazine), cyanamide, dicyandiamide, and derivatives or mixtures thereof.

In one embodiment, the ammonium compound is ammonium fluoride (NH ₄ F), ammonium fluoborate (NH ₄ BF ₄ ), ammonium acetate (Ammonium Acetate, CH ₃ COONH ₄ ), ammonium Ammonium sulfamate (NH ₄ SO ₃ NH ₂ ), Ammonium hexafluorophosphate (NH ₄ PF ₆ ), Ammonium hexafluoroaluminate ((NH ₄ ) ₃ AlF ₆ ), Ammonium nitrite nitrite, NH ₄ NO ₂ ), Ammonium perchlorate (NH ₄ ClO ₄ ), Ammonium Sulfite (NH ₄ ) ₂ SO ₃ ), Ammonium carbonate (NH ₄ ) ₂ CO ₃ , Diammonium molybdate (NH ₄ ) ₂ MoO ₄ ), ammonium phosphate (Ammonium phosphate, (NH ₄ ) ₂ PO ₄ ), ammonium permanganate (NH ₄ MnO ₄ ), ammonium di Chromate (Ammonium dichromate (NH ₄ ) ₂ Cr ₂ O ₇ ), Ammonium sulfate (NH ₄ SO ₄ ), Ammonium persulfate ((NH ₄ ) ₂ S ₂ O ₈ ) and Ammonium hexachloroflame At least one selected from the group consisting of tinate (Ammonium hexachloroplatinate, (NH ₄ )PtCl ₆ ) may be included.

In one embodiment, the non-noble metal-based catalyst is graphene, carbon black, graphite, acetylene black, Denka black, Catcheon black, activated carbon, mesoporous carbon, carbon nanotube, carbon nanofiber, carbon nanohorn, carbon nanoring , Carbon nanowires and fullerene (C ₆₀ ) It may be supported on any one of the carbon-based support selected from the group consisting of.

In one embodiment, the non-noble metal-based catalyst is any one or more selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sn, Mo, W, Rh, Nb and Ru. can include

In one embodiment, the platinum may be applied on the surface of the non-noble metal-based catalyst in an amount of 1.5 to 2.5 nm.

In one embodiment, the electrochemical system is a group consisting of voltammetry, amperometry, potentiometry, conductometry, coulometry and electrogravimetry. At least one electrochemical detection signal selected from may be measured.

The organic-based electrochemical system for removing unreacted ammonia according to the present invention lowers the activation energy required for the ammonia removal reaction through the organic-based electrochemical system during ammonia hydrogen extraction, so that the catalytic reaction proceeds quickly and exhibits improved activity. It has the advantage of solving the problems of the conventional PSA method, which had high maintenance and additional costs, by realizing superior economic effects than catalysts deposited with about 15 times more precious metal platinum by reducing the use of precious metals due to the interaction between supports.

1 is a schematic diagram showing the principle of electricity generation in a conventional fuel cell and problems of an aqueous electrochemical system.

2 is a photograph showing an organic-based electrochemical system for removing unreacted ammonia according to an embodiment of the present invention.

3 is a cyclic voltammetry graph comparing catalytic activity results according to electrolyte types of an organic-based electrochemical system for removing unreacted ammonia according to an embodiment of the present invention.

4 is a cyclic voltammetry graph comparing catalytic activity results according to the type of lipoelectrolyte of an organic-based electrochemical system for removing unreacted ammonia according to an embodiment of the present invention.

5 is a cyclic voltammetry graph comparing the activity of noble metal-based substances in an organic-based electrochemical system for removing unreacted ammonia according to an embodiment of the present invention.

6 is a bar graph comparing non-noble metal-based catalytic activity of an organic-based electrochemical system for removing unreacted ammonia according to an embodiment of the present invention.

7 is a cyclic voltammetry graph comparing non-noble metal-based catalytic activity of an organic-based electrochemical system for removing unreacted ammonia according to an embodiment of the present invention.

Hereinafter, embodiments of the present application will be described in detail with reference to the accompanying drawings. However, the technology disclosed in this application is not limited to the embodiments described herein and may be embodied in other forms. However, the embodiments introduced herein are provided so that the disclosed content can be thorough and complete and the spirit of the present application can be sufficiently conveyed to those skilled in the art. In the drawing, in order to clearly express the components of each device, the size of the components, such as width or thickness, is shown somewhat enlarged.

In addition, although only some of the components are shown for convenience of explanation, those skilled in the art will be able to easily grasp the remaining components. When describing the drawings as a whole, it is described from the observer's point of view, and when one element is referred to as being located above or below another element, this means that the one element is located directly above or below another element, or an additional element is interposed between them. It includes all possible meanings.

In addition, those skilled in the art will be able to implement the spirit of the present application in various other forms without departing from the technical spirit of the present application. Also, like reference numerals in a plurality of drawings denote substantially the same elements.

In addition, singular expressions should be understood to include plural expressions, unless the context clearly dictates otherwise, and terms such as include or have describe features, numbers, steps, operations, components, parts, or combinations thereof. It should be understood that it is intended to specify that one exists, but does not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

In addition, in performing a method or manufacturing method, each process constituting the method may occur in a different order from the specified order unless a specific order is clearly described in context. That is, each process may occur in the same order as specified, may be performed substantially simultaneously, or may be performed in the reverse order.

Hereinafter, the present invention will be described in more detail.

Electrochemical system for removing unreacted ammonia

An electrochemical system for removing unreacted ammonia, which is one aspect of the present invention, includes a working electrode, a counter electrode, a reference electrode, and an electrolyte connecting the working electrode, the counter electrode, and the reference electrode. (Electroyte) and a supporting electrolyte (Supporting Electrode), and the working electrode includes a non-noble metal-based catalyst and platinum coated on the surface of the non-noble metal-based catalyst.

Referring to FIG. 1, a membrane electrode assembly in a fuel cell is a basic unit for generating electricity and is composed of an electrolyte membrane for the movement of hydrogen ions, an anode electrode formed on both sides of the electrolyte membrane, and a cathode electrode. At the anode electrode, an oxidation reaction of fuel occurs to generate hydrogen ions and electrons, the hydrogen ions move to the cathode electrode through an electrolyte membrane, and in the cathode electrode, oxygen and hydrogen ions transferred through the electrolyte membrane react with electrons to form water is generated, and the movement of electrons occurs in the external circuit by this reaction. At this time, unreacted ammonia generated during hydrogen extraction in the fuel cell causes deterioration of the electrode and separator of the fuel cell, so an ammonia removal process is additionally required, and ammonia is removed by an electrochemical cell through the configuration of a cathode, anode, and diaphragm. It can be by an electrochemical system that converts it into other compounds (A). However, most of the electrochemical systems for removing unreacted ammonia, which are currently water-based, have a problem in application due to the competing reaction HOR (Hydrogen Oxidation Reaction) (B).

Referring to FIG. 2, like the organic-based electrochemical system for removing unreacted ammonia according to one embodiment of the present invention, a working electrode, a counter electrode, a reference electrode and the Including an electrolyte and a supporting electrolyte connecting a working electrode, a counter electrode and a 1020180074020 reference electrode, wherein the working electrode includes a non-noble metal catalyst and platinum applied on the surface of the non-noble metal catalyst , it is possible to implement an organic-based electrochemical system with optimal catalytic activity by properly removing ammonia in the cathode reaction.

In one embodiment, the working electrode is an electrode where an electrochemical reaction of metal ions to be analyzed occurs, and can be analyzed by placing an electrode catalyst on glassy carbon having low electrochemical reactivity. In addition, the working electrode includes a non-noble metal-based catalyst and platinum applied on the surface of the non-noble metal-based catalyst, and through this, the activation energy required for the ammonia removal reaction is lowered, so that the catalytic reaction proceeds rapidly and exhibits improved activity. In addition, the working electrode may include, for example, a rotating disk electrode. However, as long as it can implement the object of the present invention, it is not limited thereto.

In one embodiment, the counter electrode is an electrode used to facilitate the current flow of the working electrode and complete the reaction. When oxidation occurs in the working electrode, the counter electrode undergoes a reduction reaction and the working electrode undergoes a reduction reaction. When this occurs, an oxidation reaction may occur in the counter electrode. For example, the counter electrode may include a graphite rod having excellent performance of the counter electrode due to its large surface area. However, as long as it can implement the object of the present invention, it is not limited thereto.

In one embodiment, the reference electrode is a standard for controlling and measuring the potential of the working electrode, is used to measure the voltage of the working electrode as an absolute value, and is made of a material in which the voltage does not change significantly during the electrochemical reaction. can For example, the reference electrode may include Ag/AgCl or Ag/Ag ⁺ .

In one embodiment, the electrolyte connects the working electrode, the counter electrode, and the reference electrode, and may include one having excellent solubility, current density, and the like. For example, the electrolyte is 1-methyl-2-pyrrolidone (NMP), acetone, ethanol, n-propanol, n-butanol (n-butanol), n-hexane, cyclohexanol, acetic acid, ethyl acetate, diethyl ether, dimethylformamide formamide: DMF), dimethylacetamide: DMAc, dioxane, tetrahydrofuran: THF, dimethyl sulfoxide: DMSO, cyclohexane, benzene, toluene (toluene), xylene (xylene), water (water) and any one or more selected from the group consisting of derivatives or mixtures thereof. Preferably, dimethyl formamide (DMF) may be included. However, as long as it can implement the object of the present invention, it is not limited thereto.

Referring to FIG. 3, after fixing the counter electrode and the supporting electrolyte, the organic-based material is screened, and the catalytic activity and solubility vary depending on the type of electrolyte, and in particular, it can be seen that the organic-based DMF has excellent characteristics. .

In one embodiment, the supporting electrolyte is added to compensate for insufficient conductivity because an organic solvent is used as an electrolyte, and may include, for example, an amide-based compound or an ammonium-based compound.

In one embodiment, the amide-based compound is, for example, melamine (2-amino-4,6-dichlorotriazine), cyanuric chloride (cyanuric chloride), calcium cyanamide (calcium cyanamide), sodium amide (sodium amide) , melem (2,5,8-triamino-tri-s-triazine), cyanamide, dicyandiamide, and any one or more selected from the group consisting of derivatives or mixtures thereof. . Preferably, sodium amide (NaNH ₂ ) may be included. However, as long as it can implement the object of the present invention, it is not limited thereto.

In one embodiment, the ammonium-based compound is, for example, ammonium fluoride (Ammonium fluoride, NH ₄ F), ammonium fluoborate (NH ₄ BF ₄ ), ammonium acetate (Ammonium Acetate, CH ₃ COONH ₄ ), Ammonium sulfamate (NH ₄ SO ₃ NH ₂ ), Ammonium hexafluorophosphate (NH ₄ PF ₆ ), Ammonium hexafluoroaluminate (NH ₄ ) ₃ AlF ₆ ), Ammonium nitrite (NH ₄ NO ₂ ), Ammonium perchlorate (NH ₄ ClO ₄ ), Ammonium Sulfite (NH ₄ ) ₂ SO ₃ ), Ammonium carbonate (NH ₄ ) ₂ CO ₃ ), Diammonium molybdate (NH ₄ ) ₂ MoO ₄ ), Ammonium phosphate (NH ₄ ) ₂ PO ₄ ), Ammonium Permanganate (NH ₄ MnO ₄ ), ammonium dichromate (NH ₄ ) ₂ Cr ₂ O ₇ ), ammonium sulfate (NH ₄ SO ₄ ), ammonium persulfate (Ammonium persulfate, (NH ₄ ) ₂ S ₂ O ₈ ) and It may include at least one selected from the group consisting of ammonium hexachloroplatinate ((NH ₄ )PtCl ₆ ). Preferably, ammonium hexafluorophosphate (Ammonium hexafluorophosphate, NH ₄ PF ₆ ) may be included. However, as long as it can implement the object of the present invention, it is not limited thereto.

Referring to FIG. 4, the catalytic activity varies depending on the type of supporting electrolyte and the gas atmosphere. In particular, considering the ammonia electrolysis mechanism, metal amide-based compounds and ammonium salt-based compounds such as NaNH ₂ and NH ₄ PF ₆ have excellent performance. It can be seen that the implementation of

In one embodiment, the non-noble metal-based catalyst is, for example, graphene, carbon black, graphite, acetylene black, Denka black, Katchen black, activated carbon, mesoporous carbon, carbon nanotube, carbon nanofiber, carbon nanohorn. , Carbon nanorings, carbon nanowires and fullerenes (C ₆₀ ) It may be supported on any one of the carbon-based support selected from the group consisting of. However, it is not necessarily limited to these, and may include all as long as it can be used as a carbon-based support in the art.

The carbon-based support is a support having a large specific surface area and high crystallinity, and may include a structure such as a sphere, a rod, a tube, a horn, or a plate, for example. However, it is not necessarily limited to this structure and may include any structure that can be used as a catalyst support in the art for the carbon-based support. In addition, the carbon-based support may be a porous support. For example, the carbon-based support may be a porous carbon material having a large specific surface area and pores. In addition, the carbon-based support may be, for example, mesoporous, and part or all of the support having various shapes may be porous.

In one embodiment, the non-noble metal catalyst is selected from the group consisting of, for example, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sn, Mo, W, Rh, Nb and Ru Any one or more may be included. Preferably, the non-noble metal-based catalyst may include, for example, Ti, V, Ni, W, or Nb. However, as long as it can implement the object of the present invention, it is not limited thereto. In addition, the non-noble metal-based catalyst is included in the working electrode together with platinum applied on the surface of the catalyst, and through this, the activation energy required for the ammonia removal reaction is lowered, so that the catalytic reaction proceeds quickly and exhibits improved activity.

In one embodiment, the platinum may be applied on the surface of the non-noble metal-based catalyst in an amount of 1.5 to 2.5 nm. Preferably, 1.7 to 2.3 nm may be applied. When the coating amount of platinum is less than the coating range, platinum is not properly coated on the surface of the non-noble metal catalyst, making it difficult to realize the catalytic activity of the organic-based electrochemical system by the interaction between the catalyst and the support. In this case, since the amount of platinum applied to the surface of the non-noble metal catalyst increases and the cost is excessive, it is difficult to solve the problems of the conventional PSA method, which was expensive for maintenance and management.

In one embodiment, the electrochemical system can be used by, for example, voltammetry, amperometry, potentiometry, conductometry, coulometry and electrogravimetry. ) It is possible to measure at least one electrochemical detection signal selected from the group consisting of. Preferably, cyclic voltammetry (CV) may be measured in the voltammetry method. For example, the oxidation peak or reduction peak value derived by the hydrogen oxidation reaction (HOR) and the oxygen reduction reaction (ORR) may be detected and compared and analyzed. In addition, the measurement of the cyclic voltammetry (CV) may be measured after heating for activation of hydrogen. Further, for example, the cyclic voltammetry signal may be measured by purging at least one gas selected from the group consisting of argon, hydrogen, and oxygen.

The organic-based electrochemical system for removing unreacted ammonia according to one embodiment of the present invention shows improved activity as the catalytic reaction proceeds quickly by lowering the activation energy required for the ammonia removal reaction through the organic-based electrochemical system when ammonia hydrogen is extracted. In addition, it includes a working electrode, a counter electrode, a reference electrode, an electrolyte connecting them and a supporting electrolyte, and the working electrode includes a non-noble metal-based catalyst and platinum applied on its surface, thereby using a noble metal as an interaction between the catalyst and the support. It is characterized in that it can solve the problems of the conventional PSA method, which was high in maintenance and additional costs, by realizing an economic effect superior to that of a catalyst deposited with about 15 times more precious metal platinum.

Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, this is presented as a preferred example of the present invention and cannot be construed as limiting the present invention by this in any sense.

Contents not described herein can be technically inferred by those skilled in the art, so descriptions thereof will be omitted.

(Example 1)

Using a Rotating Disk Electrode (RDE) as the working electrode, Ag/AgCl as the reference electrode, a graphite rod as the counter electrode, and dimethyl formamide (DMF) as the electrolyte , And, an ammonium compound (Ammonium salt) and an amide compound (Metal amide) are used as supporting electrolytes, and at this time, the working electrode is Ti, which is a non-noble metal catalyst supported on a carbon-based support, and an island-and-type method on the Ti surface An organic-based simulated electrochemical three-electrode system for removing unreacted ammonia including about 2 nm of Pt was completed.

(Example 2)

In Example 2, an electrochemical system was completed in the same manner as in Example 1, except that V was used instead of Ti as a non-metallic catalyst.

(Example 3)

In Example 3, an electrochemical system was completed in the same manner as in Example 1, except that Nb was used instead of Ti as a non-metallic catalyst.

(Example 4)

In Example 4, the electrochemical system was completed in the same manner as in Example 1, except that W was used instead of Ti as a non-metallic catalyst.

(Example 5)

In Example 5, an electrochemical system was completed in the same manner as in Example 1, except that Ni was used instead of Ti as a non-metallic catalyst.

(Comparative Example 1)

In Comparative Example 1, an electrochemical system was completed in the same manner as in Example 1, except that Pd was used instead of Pt as a material applied to the non-metallic catalyst.

(Comparative Example 2)

In Comparative Example 2, an electrochemical system was completed in the same manner as in Example 1, except that Ir was used instead of Pt as a material applied to the non-metallic catalyst.

(Comparative Example 3)

In Comparative Example 3, an electrochemical system was completed in the same manner as in Example 1, except that Ru was used instead of Pt as a material applied to the non-metallic catalyst.

(Comparative Example 4)

In Comparative Example 4, an electrochemical system was completed in the same manner as in Example 1, except that Au was used instead of Pt as a material applied to the non-metallic catalyst.

(Comparative Example 5)

In Comparative Example 5, an electrochemical system was completed in the same manner as in Example 1, except that Ni was used instead of Pt as a material applied to the non-metallic catalyst.

(Comparative Example 6)

In Comparative Example 6, an electrochemical system was completed in the same manner as in Example 1, except that Ag was used instead of Pt as a material applied to the non-metallic catalyst.

(Comparative Example 7)

In Comparative Example 7, the electrochemical system was completed in the same manner as in Example 1, except that 30 nm of platinum was applied to the GC instead of Ti as a non-metallic catalyst.

(Comparative Example 8)

In Comparative Example 8, the electrochemical system was completed in the same manner as in Example 1, except that 2 nm of platinum was applied to the GC instead of Ti as a non-metallic catalyst.

(experimental example)

The catalyst was evaluated by the following method.

A three-electrode cell for RDE experiment was constructed using the fabricated catalyst, and the polarization curve of Ammonia Reduction Reaction was measured under normal pressure conditions at 80 °C. The potential at a constant current density (10 mA/cm ² ) was read from the polarization curve obtained at this time.

- Overall experimental conditions

a. Working electrode - Rotating Disk Electrode (RDE)

Reference electrode - Ag/AgCl

Counter electrode - Graphite rod

b. Electrolyte: DMF (Dimethyl formamide),

Supporting electrolyte: Ammonium salt, Metal amide

c. Temperature: 80℃

- ARR activity evaluation experiment

a. Purging the electrolyte with ammonia for 30 minutes

b. Rotate the working electrode at 1600 rpm to remove the products on the electrode surface in the ARR

c. Scan rate: 10 mV/s

d. Scan range : -1.4 V(vs RHE) ~ 0.3 V(vs RHE)

샘플명sample name	과전압overvoltage
실시예 1 (Pt 2nm on Ti)Example 1 (Pt 2nm on Ti)	0.253 V0.253V
실시예 2 (Pt 2nm on V)Example 2 (Pt 2nm on V)	0.26 V0.26V
실시예 3 (Pt 2 nm on Nb)Example 3 (Pt 2 nm on Nb)	0.268 V0.268V
실시예 4 (Pt 2nm on W)Example 4 (Pt 2nm on W)	0.276 V0.276V
실시예 5 (Pt 2nm on Ni)Example 5 (Pt 2nm on Ni)	0.28 V 0.28V
비교예 7 (Pt 30nm on GC)Comparative Example 7 (Pt 30nm on GC)	0.26 V0.26V
비교예８ (Pt 2nm on GC)Comparative Example 8 (Pt 2 nm on GC)	0.40 V 0.40V

As described above, the catalyst property evaluation experiment was conducted, and the experimental results are disclosed in Table 1 and FIGS. 5 to 7.

Referring to FIG. 5, as a result of catalyst screening using a noble metal pallet, when platinum is applied as in Example 1, the optimal activity can be realized in the Ammonia Reduction Reaction compared to Comparative Examples 1 to 6 where other metals are applied. can know

6 is a bar graph comparing non-noble metal-based catalytic activity of an organic-based electrochemical system for removing unreacted ammonia according to an embodiment of the present invention, and FIG. 7 is a cyclic voltammetry graph related thereto.

Referring to Figures 6 to 7 and Table 1, as in Examples 1 to 5, at a current density of 10 mA / cm ² , the overvoltage was measured in the order of Ti, V, Nb, W, and Ni, which is necessary for the ammonia removal reaction. It can be seen that by lowering the activation energy, the catalytic reaction proceeds more rapidly, indicating improved activity. In particular, in the case of the above catalysts, as in Comparative Example 8, they show better activity than the catalyst (Pt on GC (30 nm)) in which precious metal platinum is deposited on GC more than twice as much. It can be seen that the catalyst (Pt on GC (30 nm)) in the form of bulk platinum deposited above shows equal or improved activity. Through this, in the case of the present invention, by the interaction between the catalyst and the support It can be confirmed that a significant noble metal saving effect can be implemented.

As described above, the organic-based electrochemical system for removing unreacted ammonia according to the present invention through the physical property evaluation experiment example is the activation energy required for the ammonia removal reaction through the organic-based electrochemical system when extracting ammonia hydrogen compared to the conventional invention. It lowers the catalytic reaction and shows improved activity. In addition, it includes a working electrode, a counter electrode, a reference electrode, an electrolyte connecting them, and a supporting electrolyte, and the working electrode includes a non-noble metal-based catalyst and platinum applied on its surface. By doing this, the interaction between the catalyst and the support reduces the use of precious metals, realizing superior economic effects than catalysts deposited with about 15 times more precious metal platinum, thereby solving the problems of the conventional PSA method, which had high maintenance and additional costs. there is.

On the other hand, although the present invention has been described with limited embodiments and drawings, the present invention is not limited to the above embodiments, and various modifications and variations from these descriptions can be made by those skilled in the art in the field to which the present invention belongs. possible.

Therefore, the scope of the present invention should not be limited to the described embodiments and should not be defined, and should be defined by not only the claims to be described later, but also those equivalent to the claims.

Claims

Working electrode (Working Electrode);

Counter Electrode;

Reference Electrode and

Including an electrolyte and a supporting electrolyte connecting the working electrode, the counter electrode and the reference electrode,

The organic-based electrochemical system for removing unreacted ammonia, wherein the working electrode includes a non-noble metal catalyst and platinum applied on a surface of the non-noble metal catalyst.
The method of claim 1,

The working electrode is a rotating disk electrode,

The counter electrode is a graphite rod and

The reference electrode is an organic-based electrochemical system for removing unreacted ammonia, characterized in that it comprises Ag / AgCl.
The method of claim 1,

The electrolyte is 1-methyl-2-pyrrolidone (NMP), acetone, ethanol, n-propanol, n-butanol ), n-hexane, cyclohexanol, acetic acid, ethyl acetate, diethyl ether, dimethyl formamide (DMF) , dimethylacetamide (DMAc), dioxane, tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), cyclohexane, benzene, toluene, An organic-based electrochemical system for removing unreacted ammonia, characterized in that it includes at least one selected from the group consisting of xylene, water, and derivatives or mixtures thereof.
The method of claim 1,

The organic-based electrochemical system for removing unreacted ammonia, characterized in that the supporting electrolyte includes an amide-based compound or an ammonium-based compound.
The method of claim 4,

The amide compound is melamine (2-amino-4,6-dichlorotriazine), cyanuric chloride, calcium cyanamide, sodium amide, melem (2,5,8- Organic-based unreacted ammonia removal characterized by comprising at least one selected from the group consisting of triamino-tri-s-triazine), cyanamide, dicyandiamide, and derivatives or mixtures thereof for electrochemical systems.
The method of claim 4,

The ammonium-based compound is ammonium fluoride (NH4F), ammonium fluoborate (NH 4 BF 4 ), ammonium acetate (Ammonium Acetate, CH 3 COONH 4 ), ammonium sulfamate (Ammonium sulfamate, NH 4 SO 3 NH 2 ), Ammonium hexafluorophosphate (NH 4 PF 6 ), Ammonium hexafluoroaluminate ((NH 4 ) 3 AlF 6 ), Ammonium nitrite (NH 4 NO 2 ) , Ammonium perchlorate (NH 4 ClO 4 ), Ammonium Sulfite ((NH 4 ) 2 SO 3 ), Ammonium carbonate (NH 4 ) 2 CO 3 ), Diammonium molybdate ( Diammonium molybdate, (NH 4 ) 2 MoO 4 ), Ammonium phosphate (Ammonium phosphate, (NH 4 ) 2 PO 4 ), Ammonium Permanganate (NH 4 MnO 4 ), Ammonium dichromate, (NH 4 ) 2 Cr 2 O 7 ), Ammonium sulfate (NH 4 SO 4 ), Ammonium persulfate (NH 4 ) 2 S 2 O 8 ) and Ammonium hexachloroplatinate, ( An organic-based electrochemical system for removing unreacted ammonia, characterized in that it comprises at least one selected from the group consisting of NH 4 )PtCl 6 ).
The method of claim 1,

The non-noble metal-based catalyst is graphene, carbon black, graphite, acetylene black, Denka black, Katchen black, activated carbon, mesoporous carbon, carbon nanotube, carbon nanofiber, carbon nanohorn, carbon nanoring, carbon nanowire, and An organic-based electrochemical system for removing unreacted ammonia, characterized in that supported on any one carbon-based support selected from the group consisting of fullerene (C 60 ).
The method of claim 7,

The non-noble metal-based catalyst comprises at least one selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sn, Mo, W, Rh, Nb, and Ru. An organic-based electrochemical system for removing unreacted ammonia.
The method of claim 1,

The organic-based electrochemical system for removing unreacted ammonia, characterized in that the platinum is applied on the surface of the non-noble metal catalyst by 1.5 to 2.5 nm.
The method of claim 1,

The electrochemical system is at least one selected from the group consisting of voltammetry, amperometry, potentiometry, conductometry, coulometry, and electrogravimetry. An organic-based electrochemical system for removing unreacted ammonia, characterized in that it measures one electrochemical detection signal.