KR20200084261A - Electrode for electrolysis and preparation method thereof - Google Patents

Abstract

The present invention relates to an electrolytic electrode which comprises: a metal substrate; and an active layer formed on the metal substrate, wherein the metal substrate is a structure having a three-dimensional porous grid shape, and the active layer comprises a platinum group metal and a lanthanum group metal.

Description

Electrolytic electrode and manufacturing method therefor{ELECTRODE FOR ELECTROLYSIS AND PREPARATION METHOD THEREOF}

The present invention relates to an electrode for electrolysis with improved overvoltage and a method for manufacturing the same.

The chlor-alkali process is a process for producing chlorine (Cl ₂ ) and caustic soda (NaOH) by electrolysis of brine, which can mass-produce two materials widely used as basic materials in the petrochemical field. Is an industrially useful process.

The chlor-alkali process is performed in a chlor-alkali membrane or diaphragm electrolysis cell having an electrolytic electrode comprising an electrolytic catalyst. In the chlor-alkali process, overvoltage must be applied to overcome various intrinsic resistances in the cell in addition to the theoretically necessary voltage. Since reducing the overvoltage significantly reduces the energy costs associated with cell operation, it is desirable to develop a method to minimize the overvoltage requirement.

As one of the methods for reducing the overvoltage requirement of the electrolytic cell, a number of methods for reducing the overvoltage of the electrode have been proposed. For example, an electrode called DSA ^ㄾ (Dimensionallly Stable Anode) has been developed and used as an anode, and in the case of a cathode, mild steel, nickel, or stainless steel, which is conventionally used, has an overvoltage of 300 to 400 mV. Various materials have been developed, such as a method of reducing an overvoltage by forming an alloy on the surface or covering the surface with ruthenium oxide to activate the surface.

However, since the electrode currently being developed still exhibits a high overvoltage, it is essential to further reduce the overvoltage of the electrode in order to reduce the electrolytic voltage, and if the electrolysis process continues, the plating deteriorates, and the active material coating falls off, resulting in overvoltage. Can be elevated.

Therefore, there is a need to develop an electrode capable of increasing the activity and durability of the electrode to increase the efficiency of electrolysis.

An object of the present invention is to provide an electrode for electrolysis that can reduce the overvoltage demand of the electrolysis cell due to low overvoltage.

In addition, another object of the present invention is to provide a method of manufacturing the electrode for electrolysis.

The present invention to solve the above problems,

Metal substrates; And an active layer formed on the metal substrate.

The metal substrate is a structure having a three-dimensional porous lattice shape,

The active layer provides an electrode for electrolysis, comprising a platinum group metal and a lanthanide metal.

In one embodiment of the invention, the structure having the three-dimensional porous lattice shape,

A plurality of channels each elongated along the first direction; And

A plurality of riblet elements provided to connect side walls of two adjacent channels along a second direction orthogonal to the first direction, and spaced apart at predetermined intervals along the first direction;

An opening positioned between two adjacent riblet elements of the riblet elements;

It may include.

In one embodiment of the present invention, the platinum group metal may be at least one selected from the group consisting of ruthenium, platinum, rhodium, iridium, osmium, and palladium, and in detail, may be ruthenium, or ruthenium and platinum. . That is, the active layer, as a platinum group metal, may include one metal of ruthenium, or both metals of ruthenium and platinum.

In one embodiment of the present invention, the lanthanide metal may be one or more selected from the group consisting of cerium and yttrium.

In this case, the active layer may include the platinum group metal and the lanthanide metal in an oxide form.

In one embodiment of the present invention, the platinum group metal and the lanthanide metal may be included in a molar ratio of 30:1 to 2:1. Here, when each metal is two or more, it is calculated based on the total number of moles of each metal.

In addition, the present invention is a method for manufacturing an electrode for electrolysis,

(A) a process for obtaining a metal substrate by manufacturing a thin metal plate as a structure having a three-dimensional porous lattice shape;

(b) preparing a coating solution for an active layer comprising a platinum group metal precursor, a lanthanide metal precursor, and a solvent;

(c) forming an active layer by applying the coating liquid for the active layer on a metal substrate; And

(d) drying and heat-treating the active layer;

It provides a method for producing an electrode for electrolysis comprising.

In one embodiment of the invention,

The process (a),

(a-1) a process of forming an opening of a two-dimensional pattern by etching or punching on a thin metal plate;

(a-2) a process of manufacturing a mold having a straight molded flow path; And

(a-3) a process of performing a stamping operation on a metal thin plate on which a two-dimensional pattern is formed using the mold;

It may include.

In one embodiment of the present invention, the process (b) may be performed by immersing the metal substrate in an aqueous sulfuric acid solution.

In one embodiment of the invention, the platinum group metal precursor, ruthenium chloride hydrate (RuCl ₃ · nH ₂ O), chloroplatinic acid hydrate (H ₂ PtCl ₆ · nH ₂ O), platinum chloride (PtCl ₄ ), tetraamine platinum (II) Chloride hydrate (Pt(NH ₃ ) ₄ Cl ₂ ㆍH ₂ O), rhodium chloride (RhCl ₃ ), rhodium nitrate hydrate (Rh(NO ₃ ) ₃ ㆍnH ₂ O), iridium chloride hydrate (IrCl ₃ ㆍ nH ₂ O), palladium nitrate (Pd(NO ₃ ) ₂ ) It may be at least one selected from the group consisting of, in detail, ruthenium chloride hydrate (RuCl ₃ · nH ₂ O), or, ruthenium chloride hydrate (RuCl ₃ ㆍ nH ₂ O) and tetraamine platinum(II) chloride hydrate (Pt(NH ₃ ) ₄ Cl ₂ ㆍH ₂ O).

In one embodiment of the present invention, the lanthanide metal precursor is cerium(III) nitrate (Ce(NO ₃ ) ₃ ), cerium(III) carbonate (Ce ₂ (CO ₃ ) ₃ ), cerium(III) chloride (CeCl) ₃ ), yttrium oxide (Y ₂ O ₃ ) and yttrium carbonate (Y ₂ (CO ₃ ) ₃ ).

In this case, the platinum group metal precursor and the lanthanide metal precursor may be included so that the number of moles of the metal contained in each precursor is in a ratio of 30:1 to 2:1.

When two types of metal precursors are included in each of the precursor types, the total number of moles is calculated.

In one embodiment of the present invention, the solvent may be a C1 to C6 alcohol, a C4 to C8 glycol ether, or a mixed solvent thereof, wherein the mixing ratio may be 10: 1 to 1:2 by volume ratio. .

The concentration of the coating solution for the active layer may be 50 to 150 g/L,

The drying temperature may range from 70 to 200°C, and the heat treatment temperature may range from 300 to 600°C.

Electrolytic electrode of the present invention, by processing the shape of the electrode in three dimensions to have a three-dimensional porous lattice shape, thereby facilitating the flow of liquid reactants and generated gases, thereby lowering the overvoltage of the cathode in the electrolysis process Bar, it can exhibit an excellent overvoltage improvement effect.

Further, according to the method of manufacturing an electrode for electrolysis of the present invention, an electrode for electrolysis having the above-described effect can be manufactured without introducing additional materials.

1 is a plan view of a metal substrate according to the present invention;
2 is a perspective view of a metal substrate according to the present invention;
3 to 4 are plan views for explaining a method of manufacturing a metal substrate according to the present invention.
5 is a photograph of a metal substrate according to the present invention;
6 is a cell voltage graph according to Experimental Example 1;
7 is a cell voltage graph according to Experimental Example 2.

The terms used in this specification are only used to describe exemplary embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, the terms "include", "have" or "have" are intended to indicate that an implemented feature, step, component, or combination thereof exists, one or more other features or steps, It should be understood that the existence or addition possibilities of the components, or combinations thereof, are not excluded in advance.

The present invention can be applied to various changes and may have various forms, and specific embodiments will be illustrated and described in detail below. However, this is not intended to limit the present invention to a specific disclosure form, and it should be understood that all modifications, equivalents, and substitutes included in the spirit and scope of the present invention are included.

Hereinafter, the present invention will be described in detail.

The present invention is a metal substrate; And an active layer formed on the metal substrate.

The metal substrate is a structure having a three-dimensional porous lattice shape,

The active layer provides an electrode for electrolysis, comprising a platinum group metal and a lanthanide metal.

The electrode for electrolysis of the present invention uses a structure having a three-dimensional porous lattice shape as a metal substrate, so it is easy to supply liquid reactants at the electrode and to release gas generated during liquid electrolysis, so that the overvoltage of the cathode in the electrolysis process Can lower it.

On the other hand, the material of the metal substrate, a metal substrate having electrical conductivity, which is commonly used in the technical field of the present invention can be used without limitation. For example, nickel, nickel alloys, stainless steel, copper, cobalt, iron, steel, or alloys thereof are possible, and nickel or nickel alloys are preferred in terms of electrical conductivity and durability.

The shape of the metal substrate is not limited as long as it has a three-dimensional porous lattice shape, and the shape can be adjusted according to the conditions under which the cathode is driven. That is, as a porous body, if it is a shape having a plurality of openings, it is not limited.

Among these structures, for example, a structure having the three-dimensional porous grid shape,

A plurality of channels each elongated along the first direction; And

A plurality of riblet elements provided to connect side walls of two adjacent channels along a second direction orthogonal to the first direction, and spaced apart at predetermined intervals along the first direction;

An opening positioned between two adjacent riblet elements of the riblet elements;

It may include.

Here, the riblet element and the openings may have a parallelogram shape, that is, a pair of long sides may be provided to be inclined with respect to the first direction and the second direction, respectively.

In order to more clearly describe the above structure, it will be described with reference to FIGS. 1 to 2.

1 is a plan view of a metal substrate according to an embodiment of the present invention, and FIG. 2 is a perspective view of the metal substrate.

Referring to FIGS. 1 to 2, the metal substrate 100 according to the present invention includes a plurality of channels 110 each extending elongated along a first direction (x-axis direction or a longitudinal direction) and an orthogonal to the first direction It includes a plurality of riblet elements 120 provided to connect side walls 112 of two adjacent channels 110 along two directions (y-axis direction or width direction). The channel 110 has a structure open toward the riblet element 120. The channel 110 includes a bottom portion and a side wall, and the bottom portion and each side wall may be provided to be orthogonal. Further, the bottom part of the channel 110 and the riblet element may be provided in parallel.

The plurality of riblet elements 120 connecting the side walls of the two adjacent channels 110 are spaced apart at predetermined intervals along the first direction, and between the two adjacent riblet elements 120 along the first direction. The opening 130 is provided.

Here, the opening 130 may have various shapes, for example, may have a circular, elliptical, or polygonal shape. In one embodiment, the opening 130 may be provided to have a parallelogram shape. Specifically, the opening 130 may be provided such that a pair of long sides of the stool is inclined with respect to the first direction and the second direction, respectively.

Similarly, the riblet element 120 may have a shape determined by the shape of adjacent openings 130, and in one embodiment, the riblet element 120 may have a polygonal shape, specifically, The riblet element 120 may be provided to have a parallelogram shape. That is, the riblet element 120 may be provided such that a pair of long sides of the stool is inclined with respect to the first direction and the second direction, respectively.

In addition, the two riblet elements 120 adjacent along the second direction may be provided to have a symmetrical shape with respect to the channel 110 as a reference (first direction).

When using a metal substrate having such a structure, the liquid reactant or the gas to be generated does not form a straight flow path through the openings arranged in the second direction, and forms a vortex by forming a wave-like flow path. This can facilitate mass transfer.

Meanwhile, the active layer may include a platinum group metal and a lanthanide metal.

In this case, the platinum group metal may be at least one selected from the group consisting of ruthenium (Ru), platinum (Pt), rhodium (Rh), iridium (Ir), osmium (Os), and palladium (Pd). The platinum group metal has catalytic activity, and is included in the electrode for electrolysis to reduce overvoltage and improve life characteristics. Specifically, the platinum group metal may be ruthenium, or ruthenium and platinum. That is, the active layer is a platinum group metal, and may include only ruthenium or platinum together with ruthenium. More specifically, it may be ruthenium and platinum.

When ruthenium is used as the platinum group metal, ruthenium oxide is not only stably present in the electrolytic solution, but also exhibits a lower electrode overvoltage than other metal species, and when platinum is used, activation of ruthenium oxide is promoted for a short time. It is more preferable to use ruthenium or, in addition, platinum together, since it leads to a low electrode overvoltage within.

Further, the lanthanide metal may be one or more selected from the group consisting of cerium and yttrium. Specifically, it may be cerium.

The platinum group metal and the lanthanide group metal may include a molar number of metals in a molar ratio of 30:1 to 2:1. Here, when two or more platinum group metals or lanthanide metals are included, the above range may be satisfied based on the total number of moles of each metal combined. That is, for example, when ruthenium and platinum are included together as the platinum group metal and cerium is included as the lanthanide metal, the number of moles of ruthenium + the number of platinum moles: the number of moles of cerium may satisfy the above range.

If, if the content of the platinum group metal is out of the above range in the active layer and is included too little, there may be a problem that the electrode performance is deteriorated because the platinum group metal content that catalyzes the electrode is not sufficient. Economics may drop.

In addition, when the platinum group metal includes ruthenium and platinum, the ruthenium and platinum may be included in a molar ratio of 100:1 to 2:1.

The platinum exhibits a very good catalytic action, but is expensive and economically inefficient. Therefore, if the content of platinum outside the above range is too large, the economic efficiency is significantly reduced, and it is preferable to be included in the above range. In addition, when the platinum content is too small, the effect of promoting activation of ruthenium oxide by platinum decreases, making it difficult to lower the electrode overvoltage in a short time.

Meanwhile, the active layer may include the platinum group metal and the lanthanide metal in an oxide form.

The catalyst loading of the active layer may be 0.1 mg/cm ² to 20 mg/cm ² , specifically, 0.5 mg/cm ² to 15 mg/cm ² , or 1 mg/cm ² to 10 mg/cm ² days Can. When the above range is satisfied, excellent electrode activity can be ensured, which is preferable.

The present invention,

(A) a process for obtaining a metal substrate by manufacturing a thin metal plate as a structure having a three-dimensional porous lattice shape;

(b) preparing a coating solution for an active layer comprising a platinum group metal precursor, a lanthanide metal precursor, and a solvent;

(c) forming an active layer by applying the coating liquid for the active layer on a metal substrate; And

(d) drying and heat-treating the active layer;

It provides a method for producing an electrode for electrolysis comprising.

The electrode for electrolysis produced according to the present invention is excellent in the degree of improvement in the overvoltage of the cathode by smoothing the fluidity of the liquid reactant and the product gas.

Specifically, the process (a),

(a-1) a process of forming an opening of a two-dimensional pattern by etching or punching on a thin metal plate;

(a-2) a process of manufacturing a mold having a straight molded flow path; And

(a-3) a process of performing a stamping operation on a metal thin plate on which a two-dimensional pattern is formed using the mold;

It may include.

For more specific description, it will be described with reference to FIGS. 3 to 4.

3 and 4 are plan views illustrating a method of manufacturing a metal substrate.

First, in order to manufacture a metal substrate having a three-dimensional porous lattice structure, a metal thin plate 200 is prepared.

Referring first to FIG. 3, the method of manufacturing the metal substrate includes forming a pair of opening 210 patterns having a symmetrical shape along the longitudinal direction on the metal thin plate 200. The pair of openings 210 are spaced at a predetermined interval, and the region therebetween is formed of the aforementioned channel 110. The opening 210 pattern means that the plurality of openings 210 are arranged to have a certain rule. The opening 210 illustrated in FIG. 3 may correspond to the opening 130 of the metal substrate 100.

On the other hand, the opening 210 may have a circular, elliptical, polygonal (eg, parallelogram) shape. The opening 210 pattern may be formed through etching or punching.

Next, the metal thin plate including the opening of the two-dimensional pattern is stamped by using a mold having a linearly formed flow path.

Referring to FIG. 4, the manufacturing method may include, specifically, a riblet element 120 (see FIG. 1) corresponding to the opening 210 region and a channel 110 (see FIG. 1) corresponding to the region adjacent to the opening 210. ) Is stamped along the longitudinal direction of the thin metal plate 200 so as to have a stepped structure.

As shown in Figure 3, by forming the opening pattern through an etching or punching process, it is possible to form a 2D flow path on a metal thin plate, and a metal substrate having a final 3D riblet shape through a stamping process as in FIG. 4 using a mold (100) can be molded. In particular, as the shape of the simple straight forming flow path is applied in the stamping process, the mold manufacturing cost can be reduced, the influence of sensitivity of the mold manufacturing tolerance can be minimized, and the molding difficulty can be reduced.

5 is a photograph of the metal substrate manufactured as described above.

Meanwhile, the platinum group metal precursor included in the coating solution for the active layer may be a salt or oxide of the platinum group metal. At this time, the salt or oxide may be used in the form of a hydrate.

For example, the platinum group metal precursor includes ruthenium chloride hydrate (RuCl ₃ ㆍ nH ₂ O), chloroplatinic acid hydrate (H ₂ PtCl ₆ ㆍnH ₂ O), platinum chloride (PtCl ₄ ), tetraamine platinum (II) chloride Hydrate (Pt(NH ₃ ) ₄ Cl ₂ ㆍH ₂ O), Rhodium chloride (RhCl ₃ ), Rhodium nitrate hydrate (Rh(NO ₃ ) ₃ ㆍnH ₂ O), Iridium chloride hydrate (IrCl ₃ ㆍnH ₂ O) , Palladium nitrate (Pd(NO ₃ ) ₂ ) One or more selected from the group consisting of.

The platinum group metal precursor is calcined by a heat treatment step to be converted into catalytically active particles, that is, metal or compound particles that are catalytic for the electroreduction of water. When such a platinum group metal or compound is included in the electrode, an effect that the electrode overvoltage is improved can be obtained.

Specifically, the platinum group metal precursor is, ruthenium chloride hydrate (RuCl ₃ · nH ₂ O), or ruthenium chloride hydrate (RuCl ₃ · nH ₂ O) and platinum chloride (PtCl ₄ ) or chloroplatinic acid hydrate (H ₂ PtCl ₆ ㆍnH ₂ O).

The lanthanide metal precursor is a salt or oxide containing the above-described lanthanide metal, but is not limited, for example, cerium(III) nitrate (Ce(NO ₃ ) ₃ ), cerium(III) carbonate ( Ce ₂ (CO ₃ ) ₃ ), cerium (III) chloride (CeCl ₃ ), yttrium oxide (Y ₂ O ₃ ) and yttrium carbonate (Y ₂ (CO ₃ ) ₃ ) may be at least one selected from the group consisting of , Specifically, cerium(III) nitrate (Ce(NO ₃ ) ₃ ).

In addition, the salt or oxide may be used in the form of a hydrate (Hydrate). For example, cerium nitrate hexahydrate, cerium carbonate 5, 8, or 9 hydrate, cerium chloride 1, 3, 6, or 7 hydrate, yttrium carbonate trihydrate, and the like can be used, and specifically, cerium nitrate hexahydrate (Ce (NO ₃ ) ₃ ㆍ6H ₂ O) can be used.

The lanthanide metal precursor is calcined in a heat treatment step to be converted to a lanthanide metal oxide. The lanthanide metal oxide lacks hydrogen-producing activity, but changes from a particle form to a needle form under an environment in which hydrogen is generated, and this needle form serves to support the active layer of the platinum group compound, thereby suppressing the fall of the active layer. .

The mixing ratio of the platinum group metal precursor and the lanthanide metal precursor is not particularly limited, as described above, in order to optimize the catalytic activity of the electrode for final electrolysis, the number of moles of the metal contained in the precursor is 30:1 to The mixture may be used in a ratio of 2:1 molar ratio, specifically, in a ratio of 10:1 to 3:1.

At this time, as described above, when two or more platinum group metal precursors or lanthanide metal precursors are included, the above range may be satisfied based on the total number of moles of each metal combined.

Meanwhile, the precursors may be subjected to a pre-treatment process in a vacuum oven to remove crystalline water and the like.

The pretreatment may be performed in a vacuum oven at 50°C to 120°C for 3 hours to 60 hours.

The solvent used in the coating solution for the active layer in the present invention is an organic solvent capable of dissolving a platinum group metal precursor and a lanthanide metal precursor, and a solvent capable of volatilizing 95% or more in a drying and heat treatment step is suitable.

For example, as the organic solvent, an organic polar solvent such as an alcohol-based solvent, a glycol ether-based solvent, an ester-based solvent, or a ketone-based solvent may be used, and one or more of them may be mixed and used. Preferably, the organic solvent may be an alcohol-based solvent, a glycol ether-based solvent, or a combination thereof.

The alcohol-based solvent is preferably an alcohol of C1 to C6, and specifically, one selected from the group consisting of methanol, ethanol, propanol, isopropanol, butanol, ethylene glycol, and propylene glycol may be used, but is not limited thereto.

The glycol ether-based solvent is preferably a C4 to C8 glycol ether, specifically 2-ethoxyethanol, 2-propoxyethanol, 2-isopropoxyethanol, 2-butoxyethanol, and 2-(2-meth One or more selected from the group consisting of ethoxyethoxy)ethanol may be used, but is not limited thereto.

In one embodiment of the present invention, the organic solvent may be a mixed solvent of C1 to C6 alcohol and C4 to C8 glycol ether. When such a mixed solvent is used, peeling and cracking of the prepared electrode is significantly reduced compared to an electrode using only a single alcohol-based solvent, and a more uniform coating is possible with a longer drying time when coating a large area. It is preferred.

In order to secure the above effect, the mixing ratio of C1 to C6 alcohol and C4 to C8 glycol ether is preferably in the range of 10:1 to 1:2 by volume ratio, and more preferably in the range of 4:1 to 1:1. In one embodiment of the present invention, a 1:1 mixed solvent of isopropanol and 2-butoxyethanol was used as the organic solvent, but the combination and mixing ratio of the solvent are not limited thereto.

In addition, the coating solution for the active layer may further include an amine-based solvent as a stabilizer in addition to the organic solvent. When the amine-based solvent is included in the coating solution as described above, the electrode structure that is finally manufactured increases the needle-like structure of the lanthanide metal on the surface while driving the cell, thereby improving the durability of the electrode and further improving the overvoltage reduction effect of the electrode. Can represent.

The amine-based solvent may be a C6 to C30 saturated or unsaturated aliphatic amine, and the type is not particularly limited, for example, octylamine, decylamine, dodecylamine, oleylamine, laurylamine and hexa One or more selected from the group consisting of decylamine may be used. In detail, octylamine, oleylamine, and combinations thereof may be used as the amine-based solvent.

In the present invention, the amine-based solvent may be included in a range of 3 to 40% by volume, or 5 to 30% by volume relative to 100% by volume of the coating solution for the active layer. If, when the content of the amine-based solvent is less than 3% by volume, the durability improvement effect and the overvoltage reduction effect of the above-described electrode cannot be secured, and if it exceeds 40% by volume, it is difficult to dissolve the metal precursors and the coating solution in which the precursors are uniformly dispersed is used. There is a problem that cannot be obtained.

In the present invention, the method of preparing the coating solution for the active layer is not particularly limited, and for example, it may be by a method of introducing and dissolving a platinum group metal precursor and a lanthanide metal precursor in an organic solvent.

At this time, the final concentration of the coating solution for the active layer may be 50 to 150 g/L, or 80 to 120 g/L. When the concentration range is satisfied, the content of the metal precursor in the coating solution becomes sufficient to ensure electrode performance and durability, and the coating solution can be coated with an appropriate thickness on the substrate to maximize process efficiency.

Next, the active layer coating liquid is applied on a metal substrate to form an active layer, and dried and heat-treated to prepare an electrode for electrolysis.

On the other hand, the metal substrate may be subjected to a cleaning treatment such as degreasing or blasting or a surface roughening treatment before forming the active layer to further improve adhesion to the active layer.

For example, (a') the process of forming the unevenness by sandblasting the metal substrate (sandblasting); And (a'') pre-processing the metal substrate on which the irregularities are formed;

It may further include.

Here, the pre-treatment of the process (a'') may be performed by immersing the metal substrate in an aqueous sulfuric acid solution.

In addition, in order to form an electrode of an appropriate thickness, the steps of applying, drying and heat-treating the coating solution may be repeated several times.

The method of applying the coating solution for the active layer is not particularly limited, and spray coating, paint brushing, doctor blade, immersion-impression method, spin coating method, and other coating methods known in the art may be used.

The drying step is performed to remove the solvent contained in the active layer, and drying conditions are not particularly limited and may be appropriately adjusted according to the solvent used and the thickness of the active layer. For example, the drying step may be performed for 5 minutes to 15 minutes at a temperature of 70 to 200 °C.

Next, a heat treatment step for firing the metal precursor is performed.

In the heat treatment step, thermal decomposition of the platinum group metal precursor and the lanthanide metal precursor in the active layer occurs, and accordingly, it is converted into a platinum group metal having a catalytic activity, a compound thereof, a lanthanide metal oxide, and the like.

Heat treatment conditions may be different depending on the type of metal precursor used, specifically, the heat treatment temperature may be 300 to 600°C or 400 to 550°C, and the heat treatment time may be 10 minutes to 2 hours.

If the electrodes are manufactured by repeating the coating, drying and heat treatment steps one or more times as described above, the heat treatment steps performed after each coating and drying steps are performed as short as 5 to 15 minutes, and after the last drying step The final heat treatment step of 30 minutes or more, or can be used a method performed for a sufficient time of about 1 to 2 hours. When the final heat treatment step is performed for a long time as described above, the metal precursor can be completely thermally decomposed, and the interface of each active layer is minimized to obtain an electrode performance improvement effect, which is preferable.

The thickness of the active layer in the electrolytic electrode manufactured by the above method is not particularly limited, but may be specifically in the range of 0.5 to 10 μm, and in the range of 1 to 3 μm.

The electrode for electrolysis prepared according to the above-described manufacturing method of the present invention can be applied to electrolysis cells of various industrial electrolysis, and can be suitably used as a cathode of a chlor-alkali cell.

Hereinafter, preferred examples are provided to help understanding of the present invention, but the following examples are merely illustrative of the present invention, and it is apparent to those skilled in the art that various changes and modifications are possible within the scope and technical scope of the present invention. It is natural that changes and modifications fall within the scope of the appended claims.

Preparation Example 1

A two-dimensional pattern was formed as shown in FIG. 3 by using an etching method on a nickel thin plate (5 cm x 5 cm x 5 cm thick). By manufacturing a mold having a straight molded flow path, a stamping operation is performed on the nickel substrate on which the 2D pattern is formed (200 tons of pressure is applied by using HKCA-200 press product manufactured by Hanil Knuckle Press Co., Ltd.). As a result, a metal substrate having a three-dimensional porous lattice structure was obtained.

Preparation Example 2

A nickel mesh (monolithic gold mesh, 200 μm) was prepared.

Example 1

The surface of the metal substrate of the three-dimensional porous lattice structure prepared in Preparation Example 1 was sandblasted at 0.8 kgf/cm ² with aluminum oxide (White alumina, F120) to process a structure with irregularities. The pretreatment process of the metal substrate was completed by adding it to a 5M H ₂ SO ₄ aqueous solution at room temperature and further processing for 3 minutes.

In addition, before manufacturing the metal substrate, the ruthenium chloride precursor was pretreated through a process of removing crystalline water by placing the ruthenium chloride hydrate in a vacuum oven and drying at 70° C. for 20 hours.

200 ml of pretreated ruthenium chloride precursor, 84 mg of cerium nitrate hexahydrate precursor, and 32 mg of platinum chloride were added to 1 ml of isopropanol and 1 ml of 2-butoxyethanol mixed solvent. The mixture was stirred at 50°C for 1.5 hours. Then, 0.1 ml of n-octylamine was additionally added, and further stirred at 50° C. for 18 hours to obtain a coating solution.

The coating solution obtained above was coated on the metal substrate of the surface-treated three-dimensional porous lattice structure, placed in a convection drying oven at 180°C, dried for 10 minutes, and then placed in an electric heating furnace at 500°C for heat treatment for 10 minutes. After the coating, drying, and heat treatment were additionally performed 9 times, finally, a cathode for electrolysis was obtained by heat treatment at 500° C. for 1 hour.

Example 2

After adding 200 mg of pretreated ruthenium chloride precursor and 68 mg of cerium nitrate hexahydrate precursor to 1 ml of isopropanol and 1 ml of 2-Butoxyethanol mixed solvent, 1.5 at 50°C Stir for hours. Subsequently, 0.1 ml of n-octylamine was additionally added, followed by further stirring at 50° C. for 18 hours to obtain a cathode for electrolysis in the same manner as in Example 1.

Comparative Example 1

In Example 1, the metal substrate of Preparation Example 2 was used as the metal substrate, and the pretreatment process of the metal substrate and the pretreatment process of the precursor were performed in the same manner to obtain a cathode for electrolysis.

Comparative Example 2

In Example 1, the metal substrate of Preparation Example 2 was used as the metal substrate, and the pretreatment process of the metal substrate and the pretreatment process of the precursor were performed in the same manner, except that the coating solution of Example 2 was used. A cathode was obtained.

Experimental Example 1: Overvoltage improvement evaluation

In order to confirm the cathode performances of Examples 1 and 2 and Comparative Examples 1 and 2, voltage measurement experiments were performed in a salt-water electrolysis (Chlor-Alkali Electrolysis). A 30.7% NaOH aqueous solution was used as the negative electrode electrolyte, and a 350 g/L NaCl aqueous solution was used as the positive electrode electrolyte, and the flow rate was set to 15 ml/min, respectively. The cell temperature was maintained at 90°C, and the voltage at a current density of 0.62 A/cm ² was measured.

The area of each electrode used in the experiment was 5*5 cm ² , and the electrodes of Example 1 and Comparative Example 1 were used as the cathode, and commercial DSA (Dimensionally Stable Anode) of Asahi-Kasei was used as the anode, as a separator. Asahi-Kasei commercial Aciplex F6808 was used. The results are shown in FIGS. 6 and 7 below.

6 and 7, it can be seen that, in the current density condition, the embodiment shows a lower cell voltage than the comparative example. That is, compared to the case of manufacturing a cathode using a nickel mesh as a substrate, when manufacturing a cathode using a metal substrate of a three-dimensional porous lattice structure as a substrate, the cathode overvoltage can be lowered to reduce power consumption during electrolysis. have. These results are due to the aspect in which the three-dimensional porous lattice structure has a different shape from the existing nickel mesh, thereby facilitating the mass transfer of liquid reactants and gaseous products.

In addition, referring to FIGS. 6 and 7, it can be confirmed that when platinum is used together than when only ruthenium is used as a platinum group metal, the overvoltage of the cathode can be lowered. Therefore, when using the metal substrate according to the present invention, and coating an active layer containing ruthenium and platinum as a platinum group metal, it is possible to exhibit the best reduction of the cathode overvoltage.

Claims (20)

Metal substrates; And an active layer formed on the metal substrate.
The metal substrate is a structure having a three-dimensional porous lattice shape,
The active layer includes a platinum group metal and a lanthanide metal, an electrode for electrolysis. According to claim 1,
The structure having the three-dimensional porous grid shape,
A plurality of channels each elongated along the first direction; And
A plurality of riblet elements provided to connect side walls of two adjacent channels along a second direction orthogonal to the first direction, and spaced apart at predetermined intervals along the first direction;
An opening positioned between two adjacent riblet elements of the riblet elements;
The electrode for electrolysis containing. The electrode for electrolysis according to claim 1, wherein the platinum group metal is at least one selected from the group consisting of ruthenium, platinum, rhodium, iridium, osmium and palladium. The electrode for electrolysis according to claim 3, wherein the platinum group metal is ruthenium, or ruthenium and platinum. The electrode for electrolysis according to claim 1, wherein the lanthanide metal is at least one selected from the group consisting of cerium and yttrium. The electrode for electrolysis of claim 1, wherein the active layer contains the platinum group metal and the lanthanide metal in an oxide form. According to claim 1,
The platinum group metal and the lanthanide group metal are included in a molar ratio of 30:1 to 2:1, the electrode for electrolysis. As a method for manufacturing the electrode for electrolysis according to claim 1,
(A) a process for obtaining a metal substrate by manufacturing a thin metal plate as a structure having a three-dimensional porous lattice shape;
(b) preparing a coating solution for an active layer comprising a platinum group metal precursor, a lanthanide metal precursor, and a solvent;
(c) forming an active layer by applying the coating liquid for the active layer on a metal substrate; And
(d) drying and heat-treating the active layer;
The manufacturing method of the electrode for electrolysis containing. The method of claim 8,
The process (a),
(a-1) a process of forming an opening of a two-dimensional pattern by etching or punching on a thin metal plate;
(a-2) a process of manufacturing a mold having a straight molded flow path; And
(a-3) a process of performing a stamping operation on a metal thin plate on which a two-dimensional pattern is formed using the mold;
The manufacturing method of the electrode for electrolysis containing. According to claim 8, Before forming an active layer on the metal substrate, (a') sandblasting the metal substrate (sandblasting) to form irregularities; And (a'') pre-processing the metal substrate on which the irregularities are formed;
Further comprising, a method of manufacturing an electrode for electrolysis. The method of claim 10, wherein the process (a'') is performed by immersing a metal substrate in an aqueous sulfuric acid solution. The platinum group metal precursor is ruthenium chloride hydrate (RuCl ₃ ㆍ nH ₂ O), chloroplatinic acid hydrate (H ₂ PtCl ₆ ㆍnH ₂ O), platinum chloride (PtCl ₄ ), tetraamine platinum (II) ) Chloride hydrate (Pt(NH ₃ ) ₄ Cl ₂ ㆍH ₂ O), rhodium chloride (RhCl ₃ ), rhodium nitrate hydrate (Rh(NO ₃ ) ₃ ㆍnH ₂ O), iridium chloride hydrate (IrCl ₃ ㆍnH ₂ O), Palladium nitrate (Pd (NO ₃ ) ₂ ) At least one selected from the group consisting of, the method of manufacturing an electrode for electrolysis. According to claim 12, The platinum group metal precursor, ruthenium chloride hydrate (RuCl ₃ · nH ₂ O), or ruthenium chloride hydrate (RuCl ₃ · nH ₂ O) and platinum chloride (PtCl ₄ ) or chloroplatinic acid hydrate (H ₂ PtCl ₄ H ₂ O), a method of manufacturing an electrode for electrolysis. The method of claim 8, wherein the lanthanide metal precursor is cerium(III) nitrate (Ce(NO ₃ ) ₃ ), cerium(III) carbonate (Ce ₂ (CO ₃ ) ₃ ), cerium(III) chloride (CeCl ₃ ) , Yttrium oxide (Y ₂ O ₃ ) And yttrium carbonate (Y ₂ (CO ₃ ) ₃ ) At least one selected from the group consisting of, the method of manufacturing an electrode for electrolysis. The method of claim 8,
The solvent is a C1 to C6 alcohol, a C4 to C8 glycol ether, or a mixed solvent thereof, a method for producing an electrode for electrolysis. The method of claim 15,
The mixing ratio of the alcohol of C1 to C6 and the glycol ether of C4 to C8 is 10: 1 to 1:2 in a volume ratio, the method of manufacturing an electrode for electrolysis. The method of claim 8,
The platinum group metal precursor and the lanthanide metal precursor are included so that the molar number of metals contained in the precursor is in a ratio of 30:1 to 2:1, the method of manufacturing an electrode for electrolysis. The method of claim 8,
The concentration of the coating solution for the active layer is 50 to 150 g/L, a method of manufacturing an electrode for electrolysis. The method of claim 8,
The drying temperature is 70 to 200 ℃, the method of manufacturing an electrode for electrolysis. The method of claim 8,
The heat treatment temperature is 300 to 600 ℃, the manufacturing method of the electrode for electrolysis.

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