KR20230145954A - Carbon electrode with multiple dimples and method for manufacturing the same - Google Patents

Abstract

The present invention relates to a carbon electrode that can improve chemical reaction efficiency and MEA performance by improving the surface area and a method of manufacturing the same. In the present invention, the surface area is increased by forming a plurality of grooves on the surface of the carbon electrode, and irregularly shaped catalyst material is evenly coated on the surface of the carbon electrode to the inside of the electrode. Accordingly, the catalytic activity can be improved and the electrochemical reactivity of the carbon electrode can be improved. The surface is coated with a coating solution containing a catalyst, isopropyl alcohol, distilled water, and Nafion solution.

Description

Carbon electrode with multiple dimples and method for manufacturing the same}

The present invention relates to a carbon electrode having multiple grooves to improve electrochemical reactivity and a method of manufacturing the same.

At a time when environmental problems and fuel depletion are emerging due to the use of fossil fuels, the need for alternative energy to fossil fuels is increasing due to increased energy demand due to population growth, industrial technology development, and improved living standards.

Research on next-generation power sources using eco-friendly fuels is continuously being conducted, and fuel cells, which produce almost no pollutants and noise and can produce electrical energy through a one-step energy conversion process, are attracting attention. Additionally, green hydrogen production technology is attracting attention as hydrogen is emerging as a potential energy carrier for renewable energy sources.

In order to produce green hydrogen through water electrolysis technology, electrolysis using a polymer electrolyte membrane electrolyzer cell is a technology that is attracting attention for future hydrogen production. In general, the performance of such a system is determined by the reaction rate at the electrode on which the catalyst is formed and the proton flow through the electrolyte membrane. It is determined by the speed of movement and mass transfer, etc.

Membrane Electrode Assembly (MEA) is a key component that can increase the energy efficiency and electrochemical reaction performance of these systems. Among these components, electrodes cause structural modification of the surface through a simple process, resulting in increased catalytic activity. The performance of the electrode assembly (MEA, Membrane Electrode Assembly) can be improved.

However, despite the development of various electrodes for the development of promising fuel cell or water electrolysis technologies, efforts to improve efficiency through electrode surface treatment are insufficient, and technology for this is needed.

Registered Patent No. 10-1071778 (2011.10.04.)

The problem to be solved by the present invention is to provide a carbon electrode and a method of manufacturing the same that can improve chemical reaction efficiency and MEA performance by improving the surface area.

One embodiment of the present invention is a carbon electrode with a plurality of grooves formed on the surface.

The density of the grooves may be less than 0.8cm ² _dimple /cm ² _electrode .

The carbon electrode may have a surface with multiple grooves coated with a catalyst.

The catalyst may be a transition metal dichalcogenide or a platinum group element, and the particle size of the catalyst may be 0.5 to 2 μm.

The catalyst may be coated in an amount of 0.01 to 0.03 g per 1 cm ² of the carbon electrode.

Another embodiment of the present invention includes forming a plurality of grooves on the surface of a carbon electrode using laser plasma; And a step of coating the surface of the carbon electrode on which the plurality of grooves are formed by spraying a coating solution.

The power of the laser plasma may be 80 to 120 mJ, and the frequency may be 5 to 15 Hz.

The laser plasma may be generated from a light source, pass through a convex lens, and be irradiated to the carbon electrode.

The density of the grooves may be less than 0.8cm ² _dimple /cm ² _electrode .

The coating solution may contain a catalyst.

The catalyst may be a transition metal dichalcogenide or a platinum group element, and the particle size of the catalyst may be 0.5 to 2 μm.

The catalyst may be coated in an amount of 0.01 to 0.03 g per 1 cm ² of the carbon electrode.

In the present invention, the surface area is increased by forming a large number of grooves on the surface of the carbon electrode, and the irregularly shaped catalyst material is evenly coated on the surface of the carbon electrode to the inside of the electrode, thereby improving the catalytic activity and increasing the electrochemical reactivity of the carbon electrode. It can be improved.

Figure 1 is a photograph showing a carbon electrode according to an embodiment of the present invention.
Figure 2 is a photograph taken by SEM of the surface of the coated carbon electrode of the present invention.
Figure 3 is a flow chart showing the carbon electrode manufacturing method of the present invention.
Figure 4 is a diagram showing a device for forming grooves on the surface of a carbon electrode of the present invention.
Figure 5 is a graph showing current density and resistance values according to the groove density of the carbon electrode.

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Throughout the specification, similar parts are given the same reference numerals.

Figure 1 is a photograph showing a carbon electrode according to an embodiment of the present invention.

Referring to Figure 1, one embodiment of the present invention is a carbon electrode 100 with a plurality of grooves 110 formed on the surface.

In the present invention, a plurality of grooves 110 are formed on the surface of the carbon electrode 100 to increase the surface area of the carbon electrode 100, and thus the catalyst 120 material is evenly coated on the surface of the carbon electrode 100. In addition, the irregularly shaped catalyst 120 material is evenly coated on the surface of the carbon electrode 100 to the inside of the electrode, thereby improving catalytic activity and thereby improving the electrochemical reactivity of the carbon electrode 100.

The density of the groove 110 is 0.8cm ² _dimple /cm ² _electrode It may be less than or equal to 0.01~0.8cm ² _dimple /cm ² _electrode , more preferably 0.12~0.3cm ² _dimple /cm ² _electrode , and most preferably 0.16cm ² _dimple /cm ² It could be _{an electrode} .

In the present invention, if the density of the grooves 110 exceeds 0.8 cm ² _dimple / cm ² _electrode , the shape of the grooves 110 in the electrochemical reaction region is not independent and may be formed as a connected line, thereby reducing electrochemical reactivity. can do. Additionally, if the density of the grooves 110 is less than 0.01 cm ² _dimple /cm ² _electrode , the current value may be low due to increased resistance, which may reduce electrochemical reactivity.

Figure 2 is a photograph taken by SEM of the surface of the coated carbon electrode of the present invention.

Referring to FIG. 2, the surface of the carbon electrode 100 of the present invention on which a plurality of grooves 110 are formed may be coated with a catalyst 120, and the catalyst 120 may be a transition metal dichalcogenide or a platinum group element. It may be a transition metal dichalcogenide. Additionally, the particle size of the catalyst may be 0.5 to 2 μm.

In the present invention, the transition metal dichalcogenide is a material having semiconductor properties based on a combination of transition metal elements and chalcogen elements, specifically MoS ₂ , MoTe ₂ , WS ₂ , InS ₂ , InSe ₂ , and MoSe ₂ Or it may be WSe ₂ , and preferably MoS ₂ (molybdenum sulfur dioxide).

Additionally, the platinum group element may be ruthenium, rhodium, palladium, osmium, iridium, or platinum, but is not limited thereto.

The catalyst 120 can be coated on the surface of the carbon electrode 100, and the electrochemical reactivity of the carbon electrode 100 can be improved by coating the surface of the carbon electrode 100 with the catalyst 120.

The particle size of the catalyst 120 may be 0.5 to 2 ㎛, and the average particle size may be 0.8 to 1.2 ㎛. Since the catalyst 120 particles have a geometrically irregular size and shape, if it is outside the above range, uneven catalyst coating may occur even inside the porous carbon electrode.

Additionally, 0.01 to 0.03 g of catalyst 120 may be coated per 1 cm ² of the carbon electrode. If the catalyst 120 is coated with less than 0.01 g per 1 cm ² of the carbon electrode or overcoated with more than 0.03 g per 1 cm ² of the carbon electrode, the catalyst 120 is not evenly coated on the surface of the carbon electrode and the catalyst particles agglomerate with each other. Poor catalyst coating may reduce the improvement in electrochemical reactivity.

Figure 3 is a flow chart showing the carbon electrode manufacturing method of the present invention.

Referring to FIG. 3, another embodiment of the present invention includes forming a plurality of grooves 110 on the surface of a carbon electrode 100 using laser plasma 220, and forming a plurality of grooves 110 on the surface of the carbon electrode 110. (100) This is a carbon electrode manufacturing method that includes the step of spraying and coating the surface with a coating solution.

Referring to FIG. 3, in the present invention, the step of forming a plurality of grooves 110 on the surface of the carbon electrode 100 is performed using laser plasma 220.

The power of the laser plasma 220 may be 80 to 120 mJ, preferably 90 to 110 mJ, and the frequency of the laser plasma 220 may be 5 to 15 Hz, preferably 8 to 12 Hz. there is. If the power of the laser plasma 220 is less than 80 mJ or the frequency is less than 5 Hz, it is not easy to form a groove on the carbon electrode surface 100, and if the power of the laser plasma 220 exceeds 120 mJ or the frequency is If exceeds 15Hz, the depth of the groove on the surface of the carbon electrode may increase, resulting in loss of catalyst or loss of the effect of improving electrochemical reactivity.

Figure 5 is a diagram showing a device for forming grooves 110 on the surface of the carbon electrode 100 of the present invention. Referring to FIG. 5, in the present invention, the laser plasma 220 is generated from a light source 210, passes through a convex lens 240, and can be irradiated to the carbon electrode 100.

Specifically, the laser plasma 220 is generated from the light source 210, is reflected from one or more line mirrors 230, passes through the plano-convex lens 240, and then reaches the surface of the carbon electrode 100. And, accordingly, a plurality of grooves 110 are formed on the surface of the carbon electrode 100.

The density of the groove 110 is 0.8cm ² _dimple /cm ² _electrode It may be less than or equal to 0.01~0.8cm ² _dimple /cm ² _electrode , more preferably 0.12~0.3cm ² _dimple /cm ² _electrode , and most preferably 0.16cm ² _dimple /cm ² It could be _{an electrode} .

In the present invention, if the density of the grooves 110 exceeds 0.8 cm ² _dimple / cm ² _electrode , the shape of the grooves 110 in the electrochemical reaction region is not independent and may be formed as a connected line, thereby reducing electrochemical reactivity. can do. Additionally, if the density of the grooves 110 is less than 0.01 cm ² _dimple /cm ² _electrode , the current value may be low due to increased resistance, which may reduce electrochemical reactivity.

In the present invention, the step of spraying and coating the surface of the carbon electrode 100 on which the plurality of grooves 110 are formed is a step to improve the electrochemical reactivity of the carbon electrode 100. The coating solution may include a catalyst 120, and the catalyst 120 may be a transition metal dichalcogenide or a platinum group element, preferably a transition metal dichalcogenide. Additionally, the particle size of the catalyst may be 0.5 to 2 μm.

In the present invention, the transition metal dichalcogenide is a material having semiconducting properties depending on the combination of transition metal elements and chalcogen elements, specifically MoS ₂ , MoTe ₂ , WS ₂ , InS ₂ , InSe ₂ , MoSe ₂ Or it may be WSe ₂ , and preferably MoS 2 (molybdenum sulfur dioxide).

Additionally, the platinum group element may be ruthenium, rhodium, palladium, osmium, iridium, or platinum, but is not limited thereto.

The catalyst 120 can be coated on the surface of the carbon electrode 100, and the electrochemical reactivity of the carbon electrode 100 can be improved by coating the surface of the carbon electrode 100 with the catalyst 120.

The particle size of the catalyst 120 may be 0.5 to 2 ㎛, and the average particle size may be 0.8 to 1.2 ㎛. Since the catalyst 120 particles have a geometrically irregular size and shape, if it is outside the above range, uneven catalyst coating may occur even inside the porous carbon electrode.

Additionally, 0.01 to 0.03 g of catalyst 120 may be coated per 1 cm ² of the carbon electrode. If the catalyst 120 is coated with less than 0.01 g per 1 cm ² of the carbon electrode or overcoated with more than 0.03 g per 1 cm ² of the carbon electrode, the catalyst 120 is not evenly coated on the surface of the carbon electrode and the catalyst particles agglomerate with each other. Poor catalyst coating may reduce the improvement in electrochemical reactivity.

The coating solution can be prepared by mixing a catalyst, alcohol, distilled water, and Nafion solution.

In the present invention, when the carbon electrode is coated, silicon can be applied to the uncoated side, thereby preventing unnecessary electrochemical effects.

Hereinafter, specific embodiments according to the present invention will be described.

Example

The effective area (0.75 cm) is measured using laser plasma generated from a light source on a carbon electrode (1 cm ² carbon gas diffusion electrode (GDE, Toray TGP-H-090)) located on a plate controlled by a micrometer. ² ), finely processed at regular intervals, the density of 15 different grooves (0.80 cm ² _dimple /cm ² _electrode A carbon electrode with (hereinafter) was manufactured.

At this time, the laser plasma is generated from a light source (Q-Switched 1064nm Nd:YAG pulse laser (Quantel, Brilliant b)), passes through a number of line mirrors, and is directed to the carbon electrode through a block lens (Plano convex lens). was investigated.

Afterwards, 240 mg of MoS ₂ catalyst (particle size 0.8-1.2 μm, average particle size 1 μm) was mixed with 14.4 mL of isopropyl alcohol, 14.4 mL of distilled water, and 240 μL of Nafion solution (Dupont, 1100EW 5w%) to form a coating solution (0.15 mol%). MoS ₂ ) was prepared. 0.1 mL of the prepared coating solution was sprayed on the surface of the grooved carbon electrode, and then dried five times under a 300W high-temperature halogen lamp. Afterwards, silicon was applied to the opposite side where the groove was not formed to a thickness of 1 μm and dried at room temperature for 5 hours to prepare a carbon electrode (MoS ₂ content, 0.02 g per 1 cm ² of carbon electrode).

Experiment example

To confirm the current density change rate according to the groove density of the carbon electrode prepared in the above example, a linear scanning potential method was used at a scan rate of 50 mV/s and a reduction potential window of 1.5 V, and charge transfer from the catalyst layer and the double layer To determine the relationship between capacitances, the charge transfer resistance of the molybdenum sulfur dioxide catalyst coated on the surface of the carbon electrode was measured using electrochemical impedance spectroscopy in the frequency range of 0-10 ⁶ Hz, and the results are shown in Figure 5. It was.

Referring to Figure 5, it can be seen that the current density increased rapidly by about 8 mA/cm ² from _the groove density of the electrode surface of 0.02 cm ² _dimple /cm ² to the 0.16 cm ² _dimple /cm ² _electrode , and 0.8 cm ² _dimple . It can be seen that _{the electrode} has increased irregularly to /cm ² .

However, at groove densities exceeding 0.16 cm ² _dimple /cm ² _electrode , the current no longer increased significantly, indicating that the groove density had reached a critical value. The charge transfer resistance tends to decrease inversely up to the groove density threshold, but remains almost constant after that threshold without significant change.

In addition, it can be seen that the current density is highest at the groove density of the 0.6 cm ² _dimple /cm ² _electrode , but it can be seen that the current density of the groove density per area is relatively high at the 0.16 cm ² _dimple /cm ² _electrode .

In this way, in the case of the carbon electrode according to the present invention, as can be seen in the above experimental example, the surface area is increased by forming a large number of grooves on the surface of the carbon electrode, and the irregularly shaped catalyst material is spread evenly to the inside of the electrode. It is coated, and as a result, the catalytic activity can be improved and the electrochemical reactivity of the carbon electrode can be improved.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims are also possible. falls within the scope of rights.

100: carbon electrode 110: groove
120: catalyst 210: light source
220: Laser Plasma 230: Line Mirror
240: convex lens

Claims (6)

A carbon electrode with a plurality of grooves formed on the surface.
The density of the groove is 0.12~0.3cm ² _dimple /cm ² _electrode ,
The surface is coated with a coating solution containing a catalyst, isopropyl alcohol, distilled water, and Nafion solution,
A carbon electrode, characterized in that the amount of catalyst applied to the surface of the carbon electrode is 0.01 to 0.03 g per 1 cm ² of the surface of the carbon electrode. According to paragraph 1,
The catalyst is a transition metal dichalcogenide or a platinum group element, and the catalyst has a particle size of 0.5 to 2㎛. Forming a plurality of grooves on the surface of the carbon electrode using laser plasma; and
Coating the surface of the carbon electrode on which the plurality of grooves are formed by spraying a coating solution;
A carbon electrode manufacturing method comprising:
The density of the groove is 0.12~0.3cm ² _dimple /cm ² _electrode ,
The coating solution includes a catalyst, isopropyl alcohol, distilled water, and Nafion solution,
A method of manufacturing a carbon electrode, characterized in that the amount of catalyst applied to the surface of the carbon electrode is 0.01 to 0.03 g per 1 cm ² of the surface of the carbon electrode. According to paragraph 3,
A method of manufacturing a carbon electrode, characterized in that the power of the laser plasma is 80 to 120 mJ and the frequency is 5 to 15 Hz. According to paragraph 3,
A method of manufacturing a carbon electrode, characterized in that the laser plasma is generated from a light source, passes through a convex lens, and is irradiated to the carbon electrode. According to paragraph 3,
The catalyst is a transition metal dichalcogenide or a platinum group element, and the particle size of the catalyst is 0.5 to 2㎛.