Method for manufacturing platinum oxide electrode

Abstract

According to an embodiment of the present application, the present invention relates to a method for coating platinum on an electrode matrix by using a thermal oxidation process without a plating bath, and provides a method for manufacturing a platinum oxide electrode with the desired physical properties by utilizing an electrospray technique and optimizing a coating solution.

Description

Method for manufacturing platinum oxide electrode

[0001] The present application relates to a method for manufacturing a platinum oxide electrode, and more specifically, to a method for manufacturing a platinum oxide electrode by coating platinum on an electrode base material using a thermal oxidation method without a plating bath, which can increase the surface area of ​​the electrode, the activity of the electrode, the lifespan of the electrode, and the reproducibility of electrode manufacturing by blasting and etching the electrode base material, sintering the electrode base material to form an oxide film, and then coating platinum and sintering at high temperature.

[0002] Platinum is highly stable in electrolytes such as strong acids and alkalis, possesses excellent electrical properties, and is environmentally friendly and biocompatible. These advantages have led to its use as an electrode in various battery systems, including water electrolysis electrodes, fuel cell electrodes, seawater electrolysis electrodes, and wastewater treatment device electrodes.

[0003] In addition, it is attracting attention as an alternative electrode to the DSA electrode (dimensionally stable anode) used in water treatment systems due to its excellent polar conversion efficiency in electrochemical reactions.

[0004] However, since platinum electrodes are expensive, electrodes plated with platinum using a metal support are widely used.

[0005] Typically, platinum-plated electrodes require a plating reactor, incur significant costs due to the large volume of platinum plating solution, and present challenges with plating solution management. Furthermore, because the metal support must fit within the reactor, its size and shape are limited. Furthermore, the plating thickness is typically less than 3 ㎛, and the platinum is not evenly coated on the surface.

[0006] Therefore, it is time to study a method for manufacturing a platinum oxide electrode that can overcome these problems and increase the surface area of ​​the electrode, the activity of the electrode, the lifespan of the electrode, and the reproducibility of electrode manufacturing.

[0007] According to one embodiment of the present application, a method for coating platinum on an electrode base body using a thermal oxidation method without a plating bath is provided, and a method for manufacturing a platinum oxide electrode providing required physical properties is provided by utilizing an electrospray method and optimizing a coating solution.

[0008] One aspect of the present application relates to a method for manufacturing a platinum oxide electrode.

[0009] In one example, a method for manufacturing a platinum oxide electrode may include the steps of: blasting a metal base material; etching the surface of the metal base material; coating the metal base material with platinum by thermal oxidation sintering by applying a coating solution containing platinum chloride to the metal base material; performing a first sintering step until the coating amount of the coating layer reaches a preset reference coating amount; and performing a second sintering step when the coating amount of the coating layer satisfies the reference coating amount.

[0010] In one example, the blasting step may include sandblasting and / or shot blasting.

[0011] In one example, the etching step may include immersing the metal base material in an etching solution containing 5 to 15 wt% of sulfuric acid and 5 to 15 wt% of hydrofluoric acid at a temperature of 20 to 60° C. for 5 to 480 minutes.

[0012] In one example, the step of washing the etched metal base material after the etching step is further included, and the washing step may include an ultrasonic washing step and / or a high-pressure washing step.

[0013] In one example, the platinum coating step can be performed by electrostatic spraying, brushing or dipping methods.

[0014] In one example, the primary sintering step may include drying and heat treatment steps of drying at a temperature of 50 to 100°C for 5 to 30 minutes and heat treating at a temperature of 200 to 450°C for 10 to 40 minutes.

[0015] In the 18-day example, the standard coating amount is 0.5 to 80 g / m 2 , and the drying and heat treatment steps can be repeated until the above standard coating amount is satisfied.

[0016] In one example, the secondary sintering step can be performed at a temperature of 200 to 600 °C for 30 to 90 minutes.

[0017] One aspect of the present application relates to a platinum oxide electrode.

[0018] In one example, the platinum oxide electrode is a platinum oxide electrode manufactured by the above-described manufacturing method, and includes a metal base material and a coating layer, and the thickness of the coating layer may be 0.1 to 5 ㎛.

[0019] According to one embodiment of the present application, a method for manufacturing a platinum oxide electrode having superior economic efficiency compared to a pure platinum electrode can be provided by thermally oxidizing platinum using a metal base material.

[0020] According to one embodiment of the present application, since the size and shape of the metal base material are not limited to the plating bath, a method for manufacturing a platinum oxide electrode capable of producing electrodes of various sizes and shapes can be provided.

[0021] According to one embodiment of the present application, an economical method for manufacturing a platinum oxide electrode can be provided that utilizes a coating solution without wasting the coating solution.

[0022] According to one embodiment of the present application, a method for manufacturing a platinum oxide electrode can be provided that enables rapid production through a continuous process and thus has excellent process efficiency.

[0023] According to one embodiment of the present application, a method for manufacturing a platinum oxide electrode can be provided that can uniformly produce a desired coating thickness by using a metal base material having excellent adhesion and a large unit surface area.

[0024] According to one embodiment of the present application, a method for manufacturing a platinum oxide electrode that can be used as an electrode for electroplating, an electrode for an automobile battery, a commercial fuel cell, an electrode for electropainting, an electrode for seawater electrolysis, and an electrode for sterilization and water treatment can be provided.

[0025] Figure 1 is a flow chart for explaining a method for manufacturing a platinum oxide electrode according to the present application.

[0026] Figure 2 is an SEM image for each sample.

[0027] Figure 3 is a graph showing the durability evaluation results for each sample.

[0028] Figure 4 is a graph showing the electrochemical analysis results for each sample.

[0029] Figures 6 and 7 are graphs of XRD evaluation results for each sample.

[0030] Figure 8 is a graph showing the durability life of a platinum electrode according to the secondary sintering temperature.

[0031] Fig. 9(a) is a test result graph that can confirm the decrease in unit weight of the metal base material according to the hydrofluoric acid content, Fig. 9(b) is a test result graph that can confirm the change in residual Al content of the metal base material (titanium) according to the hydrofluoric acid content, and Fig. 9(c) is a test result graph that can confirm the change in surface brightness (L*) of the metal base material (titanium) according to the hydrofluoric acid content.

[0032] The terminology used in this application is solely for the purpose of describing specific embodiments and is not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as "comprise" or "have" indicate the presence of features, components, etc. described in the specification, but do not imply that one or more other features, components, etc. are not present or cannot be added.

[0033] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0034] The term "nano" in this application may mean a size in nanometers (nm), for example, but not limited to, a size of 1 to 1,000 nm. In addition, the term "nanoparticle" in this specification may mean a particle having an average particle diameter in nanometers (nm), for example, but not limited to, a particle having an average particle diameter of 1 to 1,000 nm.

[0035] Hereinafter, the method for manufacturing a platinum oxide electrode of the present application will be described in detail with reference to the attached drawings. However, the attached drawings are exemplary only, and the scope of the method for manufacturing a platinum oxide electrode of the present application is not limited by the attached drawings.

[0036] Figure 1 is a flow chart for explaining a method for manufacturing a platinum oxide electrode according to the present application.

[0037] As illustrated in FIG. 1, the method for manufacturing a platinum oxide electrode of the present application may include a step of blasting a metal base material (S110); a step of etching the surface of the metal base material (S120); a step of coating the metal base material with platinum using a thermal oxidation sintering method by applying a coating solution containing platinum chloride to the metal base material (S130); a step of performing primary sintering until the platinum coating amount reaches a preset reference coating amount (S140); and a step of performing secondary sintering when the platinum coating amount satisfies the reference coating amount (S150).

[0038] Hereinafter, the method for manufacturing the platinum oxide electrode of the present application is described step by step.

[0039] The electrode base material is preferably a material that has conductivity that can be used as an electrode and does not react with the catalyst (platinum coating layer), and specifically, it is preferable to include at least one selected from the group consisting of titanium, tantalum, ruthenium, zinc, zirconium, vanadium, aluminum, iron, chromium, tin, nickel, molybdenum, tungsten, and stainless steel, and titanium is more preferable because of its high heat resistance, acid resistance, and durability. The metal base material may be in the form of a sheet, mesh, wire, blade, tube, perforated plate, porous metal sheet, etc. In addition, a desired coating thickness can be uniformly produced by using a metal base material with a large unit surface area and excellent adhesion. In addition, since platinum is thermally oxidized using a metal base material, it is economical compared to a pure platinum electrode. In addition, compared to an electrode coated using a plating solution in a conventional plating bath, the size and shape of the metal base material are not limited to the plating bath, so electrodes of various sizes and shapes can be produced, and there is no waste of the coating solution, making it economical.

[0040] S110: Blasting process

[0041] First, the prepared metal substrate is blasted. This is a pretreatment process for the electrode substrate to enhance the adhesion between the electrode substrate and the electrode catalyst.

[0042] In particular, the blasting treatment step is a primary surface treatment step that physically forms the roughness of the base material surface to between 2 and 10 ㎛ using, for example, alumina ceramic particles to improve adhesion between the catalyst and the metal base material.

[0043] In one example, the blasting step may include sandblasting and / or shot blasting.

[0044] The method of removing black scale and the like by spraying quartz sand or cast iron grit onto an object with compressed air is called sandblasting (grit blasting), and the method of applying centrifugal force to shot made of cast iron or the like is called shot blasting. The device performing this blasting process is not particularly limited; any device that can exhibit the blasting effect as intended in the present application may be used.

[0045] In one embodiment, the particles used for blasting may be alumina particles or steel cut wire particles. The alumina particles are characterized in that the size of the alumina particles is one selected from alumina particles of #20 to #120. In addition, the size of the steel cut wire particles may be one selected from particles of 0.5 mm to 3 mm.

[0046] In one example, the first surface treatment step preferably uses an alumina spray to form a surface roughness of between 2 and 10 μm.

[0047] S120: Etching process step

[0048] The surface of the metal substrate is etched. This is a pretreatment process for the electrode substrate to increase the adhesion between the electrode substrate and the electrode catalyst.

[0049] This is a secondary surface treatment step that forms a microstructure on the primary surface-treated metal base material using acid or alkali.

[0050] The secondary surface treatment step involves treating the metal base material by immersing it in a mixture of a strong acid solution (sulfuric acid, hydrofluoric acid, hydrochloric acid, etc.) and an organic acid (carboxylic acid, sulfinic acid, sulfonic acid, etc.) at a mixing ratio of 0.1:99.9 wt% to 99.9:0.1 wt% at a temperature ranging from room temperature to 100 degrees Celsius for a treatment time of 5 to 480 minutes.

[0051] In one example, the etching step may include immersing the metal base material in an etching solution containing 5 to 15 wt% of sulfuric acid and 5 to 15 wt% of hydrofluoric acid at a temperature of 20 to 60° C. for 5 to 480 minutes. The etching solution may be distilled water with the remainder other than sulfuric acid and hydrofluoric acid.

[0052] The reason for etching after blasting is to remove invisible impurities on the surface of the base material and to provide a uniform and deep roughness at the same time, thereby increasing the bonding strength between the coating material and the electrode base material, and to allow the overall cracks of the electrode base material to maintain a lattice shape.

[0053] Hydrochloric acid can be used as an etching solution, but etching with hydrochloric acid produces Cl2 gas, which is toxic to workers. To overcome this problem, the present application utilizes etching solutions of sulfuric acid and hydrofluoric acid.

[0054] The reason for performing etching is to remove impurities (AL2O3, SiO2, etc.) on the surface of the metal base material and to provide uniform roughness (Ra 1-3μm) to increase the strength of the coating material and electrode base material.

[0055] However, when a sulfuric acid solution is used alone, there are problems with the surface roughness and hydrophobicity. To solve this problem, a hydrofluoric acid solution is added and used. If sulfuric acid and hydrofluoric acid are used in amounts less than 5 wt%, the etching time of the electrode takes too long and impurities are not easily removed, which causes the surface appearance to be contaminated after thermal sintering. On the other hand, if they are used in amounts greater than 15 wt%, over-etching of the electrode base material surface may occur, exceeding the domestic Toxic Chemicals Management Act standards. Therefore, it is preferable to use them in the range of 5 wt% to 15 wt%. In particular, it is preferable to use sulfuric acid in amounts less than 9 wt%.

[0056] The lower limit of the temperature range of the above etching treatment step may be 20, 25, 30, 35, 40, 45, 50, or 55°C, and the upper limit of the temperature range may be 60, 55, 50, 45, 40, 35, 30, or 25°C. If the upper limit is exceeded, there are economic problems such as uneven surface roughness due to over-etching of the electrode base material surface, difficulty in the working process due to high-temperature etching solution, and increased equipment installation costs. If the temperature is lower than the lower limit, the etching time takes a long time, increasing the process time, and there are problems such as difficulty in removing impurities from the metal base material.

[0057] The lower limit of the range of the holding time of the above etching treatment step may be 5, 30, 60, 90, 120, 150, 180, 210, 240, or 270 minutes, and the upper limit of the time range may be 480, 450, 420, 390, 360, 330, or 300 minutes. If the upper limit is exceeded, there is a problem that the surface roughness of the electrode base material is not uniform due to over-etching of the surface, and if the lower limit is less than the lower limit, there is a problem that impurities in the metal base material are not removed and fine roughness is not generated on the surface of the metal base material.

[0058] In one example, the step of washing the etched metal base material after the etching step is further included, and the washing step may include an ultrasonic washing step and / or a high-pressure washing step.

[0059] Specifically, ultrasonic cleaning can be performed at a temperature range of 25 to 80°C for 10 to 60 minutes. The ultrasonic cleaning can be repeated 1 to 3 times.

[0060] Additionally, after washing in an ultrasonic cleaner, the surface can be cleaned with distilled water, then cleaned with a high-pressure washer, and then a final finish wash with distilled water can be performed.

[0061] Specifically, the step of washing the treated metal base material after the secondary surface treatment step may be additionally included, and the washing method may be a step of removing attached impurities using ultrasonic washing and / or high-pressure water including an alkali-alcohol-distilled water step.

[0062] S130: Platinum coating step

[0063] A coating solution containing platinum chloride is applied to a metal base material, and the metal base material is coated with platinum using a thermal oxidation sintering method.

[0064] This is a step of forming a thin film by thermal oxidation by applying a catalyst-forming coating solution containing platinum chloride or platinum chloride to a metal base material that has been surface-treated in step 2.

[0065] The platinum coating step can be performed by producing a thin film using various methods such as electro-spray, brushing, dipping, and similar methods.

[0066] In one example, the platinum coating step may be performed by electrostatic spraying, brushing, or dipping. While no specific limitations are imposed on the method, any device capable of forming the coating layer intended by the present application may be used.

[0067] The present application preferably utilizes electrostatic spraying. This method offers the advantages of being able to produce electrodes utilizing metal substrates of various sizes and shapes, and its continuous production allows for rapid mass production. Compared to plating, it offers a competitive edge in cost, low electrode surface resistance, and a uniform coating of the electrode surface.

[0068] The coating solution may consist of platinum chloride, a binder and a solvent.

[0069] Specifically, the coating solution may include 2 to 20 parts by weight of platinum chloride, 0.1 to 10 parts by weight of binder, and 70 to 97 parts by weight of solvent.

[0070] The platinum chloride comprises at least one selected from the group consisting of H2PtCl6, (NH4)2(PtCl6), K2PtCl6, and Na2PtCl6.

[0071] Platinum chloride can be prepared as an aqueous platinum chloride solution using distilled water or alcohol as a solvent. The concentration of the platinum chloride solution is preferably 0.01 to 1 M. If the concentration is less than 0.01 M, there is a problem with the insufficient formation of a platinum catalyst layer, and if it exceeds 1 M, there is a problem with the uneven formation of the catalyst layer.

[0072] Additionally, the platinum chloride may be used with an added binder, and the coating solution may be used individually or as a mixed solution. When used with an added binder, the adhesive bonding between the electrode matrix and the platinum catalyst on the surface is increased, mud cracks are formed on the electrode surface, and the activity and lifespan of the electrode are improved.

[0073] The binder may be a metal chloride (such as a chloride of Ti, Ta, Ru, Sn, Ir, etc.) or a substance that can withstand high temperatures and further increase the bonding between the electrode material and platinum. Preferably, using titanium chloride (TiCl3) as the binder can increase the bonding between the metal matrix and the platinum catalyst.

[0074] It is desirable to use a binder with a concentration of less than 1M.

[0075] In one example, the solvent may be distilled water or an alcohol. Alcohol may be preferred for rapid evaporation, and examples of alcohols include ethanol, butanol, and 2-propanol.

[0076] S140: First sintering stage

[0077] The first sintering is performed until the platinum coating amount reaches the preset standard coating amount.

[0078] This is a first aging and heat treatment step until the platinum metal content in the above catalyst coating layer reaches a metal content of 1.0 to 80 g / m2. For example, the first heat treatment step can be performed using an oven that maintains a temperature of 50 to 150°C to remove solvent remaining in the catalyst coating layer.

[0079] In one example, the primary sintering step may include drying and heat treatment steps of drying at a temperature of 50 to 100°C for 5 to 30 minutes and heat treating at a temperature of 200 to 450°C for 10 to 40 minutes.

[0080] The lower limit of the drying time range of the above drying step may be 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 minutes, and the upper limit of the drying time range may be 30, 29, 28, 28, 27, 26, 25, 24, 23, 22, or 21 minutes. If the upper limit is exceeded, the process time may be prolonged, which may lead to an increase in working costs, and if the lower limit is lower, there may be a problem that the bonding strength between the catalyst of the dried coating liquid and the metal base material may be weakened.

[0081] The lower limit of the temperature range of the above drying step may be 50, 55, 60, 65, 70, or 75°C, and the upper limit of the temperature range may be 100, 95, 90, 85, 80, or 75°C. If the temperature exceeds the upper limit, a high-temperature heating furnace is required, which reduces economic feasibility and makes the work difficult. If the temperature is below the lower limit, the solvent may not volatilize, which may result in a long drying time and solvent stains may appear on the surface, which may cause problems with the electrode quality.

[0082] The lower limit of the range of heat treatment time in the above heat treatment step may be 10, 12, 14, 16, 18, 20, 22, or 24 minutes, and the upper limit of the range of heat treatment time may be 40, 38, 36, 34, 32, 30, 28, or 26 minutes. If the upper limit is exceeded, there is an economic problem due to an increase in the process time, and if the lower limit is lower, there is a problem that the durability of the electrode may be reduced due to a weak adhesive force between the platinum catalyst and the metal base material.

[0083] The lower limit of the temperature range of the above heat treatment step may be 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, or 300°C, and the upper limit of the temperature range may be 450, 440, 430, 420, 410, 400, 390, 380, 370, 360, or 350°C. If the upper limit is exceeded, there may be problems of increased process time and risk due to high temperature, and if the lower limit is lower, there may be problems of reduced durability of the electrode due to weak adhesive strength of the platinum catalyst.

[0084] In one example, the reference coating weight is 0.5 to 80 g / m 2 , and the drying and heat treatment steps can be repeated until the above standard coating amount is satisfied.

[0085] Standard coating amount 0.5 to 80 g / m 2 When this happens, it can help form a uniform catalyst layer, increase the adhesion defects between the metal substrate and the platinum catalyst, and improve the activity and durability of the electrode.

[0086] The upper limit of the standard coating amount is 80 g / m 2 It can be 70, 60, 50, 40 g / m 2 It can be, and the standard coating amount is preferably 20 to 30 g / m 2 may be. As an additional example, 1.0 to 80 g / m 2 or 1.0 to 40 g / m 2 It could be.

[0087] If the upper limit of the above coating amount is exceeded, there is a problem that the process takes longer and the economic feasibility is reduced.

[0088] S150: Secondary sintering stage

[0089] If the platinum coating amount satisfies the above-mentioned standard coating amount, a secondary sintering process is performed. This is a secondary heat treatment step for forming a crystal phase when the metal content of the catalyst coating layer satisfies the standard value. For example, this includes a step of forming a catalyst crystal phase using a sintering furnace (muffle furnace) that maintains a temperature of 200 to 500°C, and all of these conditions can be achieved by using an oven and sintering furnace that are elevated and maintained at room temperature for a period of time or in a pre-elevated and maintained state.

[0090] In one example, the second heat treatment step is a step for determining the crystal phase of the catalyst and can be performed at a temperature of 200 to 600°C for 30 to 300 minutes.

[0091] In one example, the secondary sintering step can be performed at a temperature of 200 to 600 °C for 30 to 90 minutes.

[0092] The reason for performing secondary sintering is to increase the adhesive strength between the coating material and the electrode, thereby improving the durability of the electrode, and to grow thermally oxidized catalyst particles to improve the performance of the electrode and increase the surface strength.

[0093] The lower limit of the sintering time range of the above sintering step may be 30, 35, 40, 45, 50, 55, or 60 minutes, and the upper limit of the sintering time range may be 90, 85, 80, 75, 70, 65, or 60 minutes. If the upper limit is exceeded, there is a problem that the process time is prolonged without affecting the improvement of the durability of the electrode, which is not economical, and if the lower limit is lower, there is a problem that the durability of the electrode is reduced.

[0094] The lower limit of the temperature range of the above heat treatment step may be 200, 220, 240, 260, 280, 300, 320, 340, 360, 380, or 400°C, and the upper limit of the temperature range may be 600, 580, 560, 540, 520, 500, 480, 460, 440, or 420°C. If the upper limit is exceeded, there is a problem of reduced electrode durability due to deformation of the metal base material by heat, and a problem of the metal base material becoming an insulator (the titanium component is transformed into anatase and becomes an insulator) and not having the characteristics of the electrode, and if the temperature is below the lower limit, there is a problem of reduced electrode durability due to reduced adhesion between the coating material and the metal base material.

[0095] One aspect of the present application relates to a platinum oxide electrode.

[0096] In one example, the platinum oxide electrode is a platinum oxide electrode manufactured by the above-described manufacturing method, and includes a metal base material, an oxide film, and a platinum coating, and the thickness of the platinum oxide electrode may be 0.05 to 10 μm, and the thickness of the platinum coating may be 0.1 to 5 μm.

[0097] The coating layer contains the metal as the base metal and its oxide. For example, if the base metal is platinum, the coating layer is primarily composed of platinum and platinum oxide. The coating layer may also include a binder component.

[0098] The lower limit of the thickness of the coating layer may be 0.1, 0.5, 1, 1.5, 2, 2.5, or 2.5 ㎛, and the upper limit of the thickness may be 5, 4.5, 4, 3.5, 3, or 2.5 ㎛. Since industrial electrodes typically have a thickness of less than 3 ㎛, if the upper limit is exceeded, there is an economic problem due to increased work process time, and if the lower limit is less than the lower limit, the catalyst layer is easily peeled off due to the thin coating layer, which reduces the durability of the electrode and causes poor electrode performance due to low conductivity.

[0099] As an example, a platinum catalyst electrode in which the metal matrix is ​​platinum may be an insoluble catalyst electrode that includes a mixture of platinum and platinum oxide in a ratio of 0.5:9.5 to 9.5:0.5.

[0100] As a further embodiment of the present application, a method for manufacturing a platinum oxidation electrode may include a first surface treatment step of physically forming a roughness of 2 to 10 μm on the surface of a base material using alumina ceramic to improve adhesion between a catalyst and a metal base material; a second surface treatment step of forming a microstructure on the first surface-treated metal base material using an acid or an alkali; a step of forming a thin film by thermal oxidation by applying a catalyst-forming coating solution containing platinum chloride or chloroplatinic acid to the second surface-treated metal base material; a step of performing first aging and heat treatment until the content of platinum metal in the catalyst coating layer becomes a metal content of 1.0 to 80 g / m2; and a second heat treatment step for forming a crystal phase when the metal content of the catalyst coating layer satisfies a reference value.

[0101] The first surface treatment step can be performed by using an alumina spray to form a surface roughness of between 2 and 10 ㎛.

[0102] The secondary surface treatment step can be performed by treating the metal base material with a mixture of a main treatment solution (strong acid; sulfuric acid, hydrochloric acid, aqua regia, etc.) and a secondary treatment solution (weak acid; hydrofluoric acid, carboxylic acid, other organic acids, etc.) at a mixing ratio of 10:0 vol% to 0:10 vol%, at a temperature ranging from room temperature to 100°C, and for a treatment time of 5 to 480 minutes.

[0103] The cleaning method may further include a step of washing the treated metal base material after the secondary surface treatment step, and may include a step of removing attached impurities using ultrasonic cleaning and / or high-pressure water including an alkali-alcohol-distilled water step.

[0104] The platinum coating step can be performed by producing a thin film using various methods such as electro-spray, brushing, dipping, and similar methods.

[0105] The first heat treatment step of the second stage includes a step of forming a crystal phase of the catalyst using a sintering furnace (muffle furnace) maintained at a temperature of 200 to 500°C after the first stage section of removing the solvent remaining in the catalyst coating layer using an oven maintained at a temperature of 50 to 150°C, and all of these conditions may be maintained at room temperature for a time or may be maintained at a pre-elevated temperature using an oven and sintering furnace.

[0106] The steps can be repeated under the first heat treatment conditions until the above standard platinum metal content is satisfied.

[0107] The second heat treatment step is a step to determine the crystal phase of the catalyst and can be performed at a temperature of 200 to 600°C for 30 to 300 minutes.

[0108] The platinum oxide electrode manufactured by the above manufacturing method can have a thickness of 0.05 to 10 μm.

[0109] The above platinum catalyst electrode may be an insoluble catalyst electrode including a mixed electrode of platinum and platinum oxide in a ratio of 0.5:9.5 to 9.5:0.5.

[0110] Below, the present application is described in more detail through experimental examples.

[0111] [Example]

[0112] A platinum oxide electrode sample was manufactured by sandblasting a titanium base material with #120 size alumina and etching it in a 50°C etching solution for 30 minutes, applying a coating solution by electrostatic spraying, and performing primary and secondary sintering. The examples are described in detail below.

[0113] [Example 1]

[0114] A platinum oxide electrode was manufactured using a titanium substrate that was sandblasted with #120 size alumina and etched and washed for 30 minutes in a 50°C etching solution. A 0.07 M concentration platinum chloride solution (H2PtCl6) was used for coating. The amount of platinum catalyst per coating solution was calculated as 1 g / m. 2 The coating amount was set to this, and after drying at 100℃ for 10 minutes, repeated coating was performed at 400℃ for 15 minutes in an electric furnace, and then secondary heat treatment was performed at 500℃ for 1 hour to form a platinum catalyst layer of 10g / m. 2 A platinum oxide electrode containing was fabricated.

[0115] [Example 2]

[0116] A platinum oxide electrode was manufactured using a titanium substrate that was sandblasted with #120 size alumina and etched and washed for 30 minutes in a 50°C etching solution. A 0.07 M concentration platinum chloride solution (H2PtCl6) was used for coating, and a 0.1 M concentration titanium chloride (TiCl3) solution was used as a binder. The amount of platinum catalyst and binder per coating solution was converted to 1 g / m, respectively. 2 The coating amount is set to this, and after drying at 100℃ for 10 minutes, repeat coating operation is performed at 400℃ for 15 minutes in an electric furnace, and then secondary heat treatment is performed at 500℃ for 1 hour to obtain a platinum catalyst amount of 10g / m 2, The binder layer is 2g / m 2 A platinum oxide electrode containing was fabricated.

[0117] [Example 3]

[0118] A platinum oxide electrode was manufactured using a titanium substrate that was sandblasted with #120 size alumina and etched and washed in a 50°C etching solution for 30 minutes. A 0.07 M platinum chloride solution was used for coating. The amount of platinum catalyst per coating solution was calculated as 1 g / m. 2The coating amount is set to this, and after drying at 100℃ for 10 minutes, repeat coating operation is performed at 400℃ for 15 minutes in an electric furnace, and then secondary heat treatment is performed at 600℃ for 1 hour to obtain 10g / m of platinum. 2 A platinum oxide electrode containing was fabricated.

[0119] [Example 4]

[0120] A platinum oxide electrode was manufactured using a titanium substrate that was sandblasted with #120 size alumina and etched and washed in a 50°C etching solution for 30 minutes. A 0.07 M platinum chloride solution was used for coating. The amount of platinum catalyst per coating solution was calculated as 1 g / m. 2 The coating amount is set to this, and after drying at 100℃ for 10 minutes, repeat coating operation is performed at 400℃ for 15 minutes in an electric furnace, and then secondary heat treatment is performed at 700℃ for 1 hour to obtain 10g / m of platinum. 2 A platinum oxide electrode containing was fabricated.

[0121] [Comparative Example 1]

[0122] For the titanium base material, a titanium base material was used that was sandblasted with #120 size alumina and etched and washed in a 50℃ etching solution for 30 minutes. A platinum plating electrode with a 0.3 ㎛ thick platinum coating was manufactured on the titanium base material using the conventional platinum plating method (current 20 A, current applied for 30 minutes) using a plating bath using a PT-500 platinum plating solution.

[0123] [Experimental Example]

[0124] For each sample, colorimetric analysis, XRF content analysis, XRD component analysis, electrochemical analysis, and durability evaluation were performed, and the performance of the electrode was evaluated based on the results, which are shown below.

[0125] [Experimental Example 1]

[0126] Colorimetric analysis and XRF content analysis were performed on Examples 1 and 2 and Comparative Example 1, and the results are shown in Table 1 below. The colorimetric analysis is an experiment to confirm the external color of the electrode (L*: black < white, +a*: red -a: green, +b: yellow -b: blue), and the X-ray fluorescence analysis (XRF) analysis is an experiment to measure the content of each element in the electrode. The colorimetric analysis was performed using a 3nh YS3060 instrument, and the XRF analysis was performed using an X-met 8000 instrument.

[0127] Sample name Color difference XRFL*a*b*Ti (%)Pt(%) Comparative example 176.630.863.6789.879.11 Example 176.151.145.9589.549.98 Example 275.390.863.4789.489.82 Example 376.510.835.5489.899.78 Example 476.861.146.7889.739.65

[0128] According to the results in Table 1, it was found that the appearance color difference values ​​and Pt contents (%) of the Pt plating electrode of Comparative Example 1 and the platinum oxidation electrodes of Examples 1 and 2 were similar.

[0129] [Experimental Example 2]

[0130] In addition, in order to determine the morphological structural characteristics of the electrode surface, the electrode surfaces of the samples of Comparative Example 1, Example 1, and Example 2 were photographed using a scanning electron microscope (SEM, JSM-6010PLUS / LA), and the results are shown in Fig. 2, respectively.

[0131] As illustrated in Fig. 2, the platinum-plated electrode surface of Comparative Example 1 (a) of Fig. 2 can be confirmed. In the case of the plated electrode, it was confirmed that the platinum coating was not uniform, exposing the surface of the metal base material. This may be the cause of the deterioration of the electrode durability of the metal base material.

[0132] In contrast, the platinum oxide electrode surface of Example 1 in Fig. 2 (b) could be confirmed. In the case of the platinum oxide electrode, the surface is uniformly and densely coated with a platinum catalyst, so that the metal base material is not exposed, and thus the electrode has the advantage of excellent durability. In addition, the surface of the platinum oxide electrode including the binder of Example 2 in Fig. 2 (c) could be confirmed. In the case of the platinum oxide electrode including the binder, the electrode activity can be improved by forming certain cracks on the surface of the coating layer of the electrode, thereby increasing the electrode performance and durability of the electrode.

[0133] [Experimental Example 3]

[0134] In addition, a durability evaluation was performed on the sample. The specific durability evaluation was performed using a 1.5 M H2SO4 electrolyte solution at a current density of 500 mA / cm, as shown in Table 2 below. 2 The electrode life was determined at the point when the cell voltage reached 9 V from the initial voltage. The results are shown in Fig. 3.

[0135] Experimental conditions: current density 500 mA / cm 2 Voltage range 0 ~ 9 V Electrolyte 1.5 M H2SO4 solution Electrode spacing 1.5 cm Temperature 25 ℃

[0136] Classification Life Time (hr) Voltage Initial Current ΔV Comparison Example 11594.189.004.85 Example 11653.649.005.35 Example 21693.659.005.35

[0137] As shown in Table 3 and Figure 3, compared to Comparative Example 1, it can be confirmed that Examples 1 and 2 have lower initial voltages and relatively better electrode lifespans.

[0138] [Experimental Example 4]

[0139] Additionally, electrochemical analysis was performed on the samples. For electrochemical analysis, cyclic voltammetry and linear sweep voltammetry were measured using a VersaSTAT device, and the results are shown in Fig. 4.

[0140] As shown in Fig. 4, it can be seen that the platinum catalyst exhibits similar platinum electrode performance even when manufactured by a thermal oxidation method, and it can be confirmed that the activity of Examples 1 and 2 is superior.

[0141] As shown in Fig. 5, it was found that the oxygen evolution reaction (OER) of Examples 1 and 2 was superior to that of Comparative Example 1 in the shape of the LSV graph.

[0142] [Experimental Example 5]

[0143] Platinum peaks were observed using an X-ray diffraction analyzer (XRD, Bruker D8 Advence), and the results are shown in Figs. 6 and 7.

[0144] Through Figs. 6 and 7, peaks of platinum catalyst crystals with an FCC structure having (111), (200), and (220) planes were detected at 2 theta 39.84, 46.33, and 67.6, respectively. In addition, in Fig. 7, peaks of platinum catalyst crystals (PtO2) obtained by thermal oxidation having (100), (101), (110), and (111) planes were detected at 2 theta 35.09, 39.94, 64.06, and 67.19, respectively. In addition, in the case of Fig. 7, peaks of TiO2 obtained by high-temperature oxidation were detected.

[0145] [Experimental Example 6]

[0146] To predict the durability life of platinum electrodes according to secondary sintering temperature, additional experiments were conducted as follows. Durability evaluations were conducted under the conditions shown in Table 2 above, and the results are shown in Table 4 and Figure 8.

[0147] Classification Secondary sintering temperature (℃) Life time (hr) Voltage Initial current ΔV Example 1500 1653.64 9.00 5.35 Example 3600 763.85 9.00 5.15 Example 4700 513.79 9.00 5.21

[0148] As shown in Table 4 and Fig. 8, it can be confirmed that the life time of the electrode tends to increase as the secondary sintering temperature increases, and in one embodiment, it may be preferable that the secondary final sintering temperature be less than 600°C.

[0149] Through these experimental examples, the characteristics of the present application were confirmed as follows. Specifically, compared to conventional platinum electrodes, the XRF content, electrochemical (CV LSV) properties, and XRD peaks of the platinum electrode manufactured by the thermal oxidation method of the present application were observed to be similar, confirming that it can replace platinum plating electrodes using conventional plating baths.

[0150] [Experimental Example 7]

[0151] To confirm the reactivity according to the hydrofluoric acid concentration, the decrease in the unit weight of the metal base material according to the hydrofluoric acid concentration, the change in the residual Al content as an impurity, and the change in the surface brightness (L*) of the metal base material (titanium) were measured.

[0152] Fig. 9(a) is a test result graph that can confirm the decrease in unit weight of the metal base material according to the hydrofluoric acid content, Fig. 9(b) is a test result graph that can confirm the change in residual Al content of the metal base material (titanium) according to the hydrofluoric acid content, and Fig. 9(c) is a test result graph that can confirm the change in surface brightness (L*) of the metal base material (titanium) according to the hydrofluoric acid content.

[0153] As illustrated in Fig. 9, it was confirmed that the surface appearance of the metal base material (titanium) was bright, the residual Al was low, and the weight loss of titanium did not occur excessively when HF was 5 to 15 wt%. When HF was 15 wt% or more, the weight loss of titanium increased rapidly and the surface turned dark.

[0154] Although the above has been described with reference to preferred embodiments of the present application, it will be understood by those skilled in the art that various modifications and changes can be made to the present application without departing from the spirit and scope of the present invention as set forth in the claims below.

Claims

1. Step of blasting the metal substrate; A step of etching the surface of a metal substrate; A step of platinum-coating a metal base material by applying a coating solution containing platinum chloride to the metal base material using a thermal oxidation sintering method; A step of first sintering until the coating amount of the above coating layer reaches a preset standard coating amount; and A method for manufacturing a platinum oxide electrode, comprising a step of performing secondary sintering when the coating amount of the coating layer satisfies the standard coating amount.

2. In paragraph 1, A manufacturing method wherein the blasting step includes a sand blasting and / or shot blasting step.

3. In paragraph 1, A manufacturing method comprising the step of etching the metal base material in an etching solution containing 5 to 15 wt% of sulfuric acid and 5 to 15 wt% of hydrofluoric acid at a temperature of 20 to 60° C. for 5 to 480 minutes.

4. In paragraph 1, An additional step of washing the etched metal base material after the etching step is included. A manufacturing method wherein the washing step includes an ultrasonic washing step and / or a high pressure washing step.

5. In paragraph 1, A manufacturing method in which the platinum coating step is performed by electrostatic spraying, brushing or dipping methods.

6. In paragraph 1, A manufacturing method including a drying and heat treatment step in which the first sintering step is drying at a temperature of 50 to 100° C. for 5 to 30 minutes and heat treating at a temperature of 200 to 450° C. for 10 to 40 minutes.

7. In paragraph 6, A manufacturing method in which the standard coating amount is 0.5 to 80 g / m2, and the drying and heat treatment steps are repeated until the standard coating amount is satisfied.

8. In paragraph 1, A manufacturing method in which the secondary sintering step is performed at a temperature of 200 to 600°C for 30 to 90 minutes.

9. A platinum oxide electrode manufactured by the manufacturing method of Article 1, A platinum oxide electrode comprising a metal substrate and a coating layer, wherein the thickness of the coating layer is 0.1 to 10 ㎛.

10. In paragraph 9, The above coating layer is a platinum oxide electrode containing a metal and a metal oxide.

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