This application claims the benefit of priority based on Korean Patent Application No. 10-2018-0078916 dated July 06, 2018, and all contents disclosed in the documents of the Korean patent application are incorporated as a part of this specification.
[3]
[4]
technical field
[5]
The present invention relates to a cathode for electrolysis and a method for manufacturing the same, and to a cathode for electrolysis in which the standard deviation of the composition of ruthenium between a plurality of equally divided pixels is 0.4 or less, and a method for manufacturing the same.
[6]
background
[7]
A technique for producing hydroxide, hydrogen and chlorine by electrolyzing inexpensive brine such as seawater is widely known. This electrolysis process is usually called a chlor-alkali process, and it can be said that it is a process whose performance and reliability of technology have been proven through commercial operation for several decades.
[8]
In this electrolysis of brine, an ion exchange membrane is installed inside the electrolyzer to divide the electrolyzer into a cation chamber and an anion chamber, and the ion exchange membrane method that uses brine as an electrolyte to obtain chlorine gas from the anode and hydrogen and caustic soda from the cathode is currently used. This is the most widely used method.
[9]
On the other hand, the electrolysis process of brine is made through a reaction as shown in the following electrochemical reaction formula.
[10]
Oxidation electrode reaction: 2Cl - → Cl 2 + 2e - (E 0 = +1.36 V)
[11]
Reduction electrode reaction: 2H 2 O + 2e - → 2OH - + H 2 (E 0 = -0.83 V)
[12]
Overall reaction: 2Cl - + 2H 2 O → 2OH - + Cl 2 + H 2 (E 0 = -2.19 V)
[13]
[14]
In carrying out the electrolysis of brine, the electrolytic voltage is the theoretical voltage required for electrolysis of the brine, the overvoltage of each of the oxidizing electrode (anode) and the reducing electrode (cathode), the voltage due to the resistance of the ion exchange membrane, and the voltage between the electrodes. All voltages due to distance must be considered, and among these voltages, overvoltage due to electrodes is an important variable.
[15]
Accordingly, a method for reducing the overvoltage of the electrode is being studied. For example, a noble metal-based electrode called DSA (Dimensionally Stable Anode) has been developed and used as an anode, and an excellent material with a low overvoltage and durability for the cathode. development is required.
[16]
Stainless steel or nickel has been mainly used as such a cathode, and recently, to reduce overvoltage, the surface of stainless steel or nickel is coated with nickel oxide, an alloy of nickel and tin, a combination of activated carbon and oxide, ruthenium oxide, platinum, etc. How to use it is being studied.
[17]
In addition, in order to increase the activity of the cathode by controlling the composition of the active material, a method of adjusting the composition using a platinum group element such as ruthenium and a lanthanide group element such as cerium is also being studied. However, an overvoltage phenomenon occurred and deterioration due to reverse current occurred.
[18]
[19]
[Prior art literature]
[20]
[Patent Literature]
[21]
(Patent Document 1) JP2003-2977967A
[22]
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[23]
It is an object of the present invention to provide a cathode for electrolysis in which an overvoltage phenomenon and lifespan characteristics are improved while exhibiting high efficiency by uniformly distributing an active material in an active layer.
[24]
means of solving the problem
[25]
The present invention is a metal substrate; and an active layer positioned on at least one surface of the metal substrate, wherein the active layer includes ruthenium oxide, platinum oxide and cerium oxide, and when the active layer is equally divided into a plurality of pixels, the equally divided plurality of pixels The standard deviation of the composition of inter-ruthenium is 0.4 or less, and the N atom in the active layer provides a cathode for electrolysis that is present in 20 to 60 mol% compared to ruthenium.
[26]
[27]
In addition, the present invention includes a coating step of applying, drying, and heat treatment of a catalyst composition for a cathode for electrolysis on at least one surface of a metal substrate, wherein the application is performed by an electrostatic spray deposition method, and the active layer composition for a cathode comprises: a metal precursor mixture including a ruthenium-based compound, a platinum-based compound, and a cerium-based compound; and an organic solvent including an alcohol-based compound and an amine-based compound.
[28]
Effects of the Invention
[29]
Since the cathode for electrolysis according to the present invention is manufactured by the electrostatic spray deposition method, the active material in the active layer can be uniformly distributed, thereby reducing the overvoltage phenomenon while exhibiting high efficiency and improving the lifespan characteristics.
[30]
Modes for carrying out the invention
[31]
Hereinafter, the present invention will be described in more detail to help the understanding of the present invention.
[32]
[33]
The terms or words used in the present specification and claims should not be construed as being limited to their ordinary or dictionary meanings, and the inventor may properly define the concept of the term in order to best describe his invention. Based on the principle that there is, it should be interpreted as meaning and concept consistent with the technical idea of ​​the present invention.
[34]
[35]
As used herein, the term “oxidation electrode” refers to an electrode in which chlorine gas is generated by oxidation of chlorine in electrolysis of brine, and an electrode having a positive potential while giving away electrons and undergoing an oxidation reaction In that sense, it may be referred to as an anode.
[36]
Chlorine oxidation reaction: 2Cl - → Cl 2 + 2e - (E 0 = +1.36 V)
[37]
As used herein, the term "reduction electrode" refers to an electrode in which a reduction reaction of hydrogen occurs to generate hydrogen gas in the electrolysis of brine, and an electrode that receives electrons and undergoes a reduction reaction and has a negative potential. In this respect, it may be referred to as a cathode.
[38]
Hydrogen reduction reaction: 2H 2 O + 2e - → 2OH - + H 2 (E 0 = -0.83 V)
[39]
[40]
1. Cathode for electrolysis
[41]
The cathode for electrolysis according to an embodiment of the present invention includes a metal substrate; and an active layer positioned on at least one surface of the metal substrate.
[42]
[43]
The metal substrate may be nickel, titanium, tantalum, aluminum, hafnium, zirconium, molybdenum, tungsten, stainless steel, or an alloy thereof, of which nickel is preferable.
[44]
The shape of the metal substrate may be a rod, sheet or plate shape, and the thickness of the metal substrate may be 50 to 500 μm, and is not particularly limited as long as it can be applied to an electrode that is generally applied to a chlorine-alkali electrolysis process. , the shape and thickness of the metal substrate may be proposed as an example.
[45]
The metal substrate may have irregularities formed on its surface.
[46]
[47]
The active layer includes ruthenium oxide, platinum oxide and cerium oxide, and when the active layer is equally divided into a plurality of pixels, the standard deviation of the composition of ruthenium between the equally divided plurality of pixels is 0.4 or less, and N in the active layer The atoms are present in 20 to 60 mole % relative to ruthenium.
[48]
[49]
The standard deviation of the composition of the ruthenium is preferably 0.35 or less, and more preferably 0.30 or less.
[50]
The standard deviation of the composition of ruthenium indicates the uniformity of the active material in the active layer, that is, the degree of uniform distribution of the active material in the active layer. it means. If the active material is not uniformly distributed, the flow of electrons from the electrode is concentrated to a region with low resistance, so that the thin portion of the active layer may be rapidly etched. In addition, electrons penetrate into pores in the active layer, so that the inactivation proceeds quickly and the life of the electrode may be shortened. In addition, the concentration of the cathode electrolyte is lowered around the place where the flow of electrons is concentrated, and the oxygen selectivity, that is, the amount of oxygen generated increases, and the overvoltage may increase due to the non-uniform current distribution. In addition, as the flow of electrons is ubiquitous, the load of the separator may be non-uniform when the cell is driven, thereby reducing the performance and durability of the separator.
[51]
[52]
Here, the standard deviation of the composition of the ruthenium is calculated by equally dividing the electrolysis cathode into a plurality of pixels, measuring the weight % of ruthenium in each equally divided pixel, and substituting the measured value into the following formula will be.
[53]
Specifically, the cathode for electrolysis was manufactured in a width of 0.6 m and a length of 0.6 m (width × length = 0.6 m × 0.6 m), and after equally divided into 16 pixels, XRF (X-ray fluorescence) Measure the weight % of ruthenium in each pixel using a component analyzer. Then, by using the weight % of each measured ruthenium, the dispersion (V(x)) is calculated through Equation 1 below, and the standard deviation (σ) is calculated through Equation 2 below using this.
[54]
[Equation 1]
[55]

[56]
[Equation 2]
[57]

[58]
In Equation 1, E(x 2 ) represents the average value of the square of the weight % of ruthenium in 16 pixels, and [E(x)] 2 represents the square of the average value of the weight % of ruthenium in 16 pixels.
[59]
[60]
The ruthenium is an active material of the cathode for electrolysis, and may include 3 to 7 mol% of ruthenium, preferably 4 to 6 mol%, based on 100 mol% of the total amount of metal components in the active layer. .
[61]
If the above-described range is satisfied, durability can be improved without affecting the performance of the cathode for electrolysis. In addition, since ruthenium is not excessively coated on the active layer of the cathode for electrolysis, process costs and reagent costs can be reduced, and the loss of ruthenium during activation or electrolysis can be minimized.
[62]
[63]
The active layer may include the cerium and ruthenium in a weight ratio of 1:1 to 1:1.5, and preferably includes the cerium and ruthenium in a weight ratio of 1:1 to 1:1.3.
[64]
If the above-described range is satisfied, durability can be improved without affecting the performance of the cathode for electrolysis.
[65]
[66]
The platinum can improve the overvoltage phenomenon of the cathode for electrolysis, and can minimize the performance deviation from the initial performance of the cathode for electrolysis after a certain time has elapsed, and as a result, separate It is possible to minimize the activation process, and furthermore, it is possible to guarantee the performance of the cathode even if it is not performed.
[67]
[68]
The cerium may minimize the loss of ruthenium in the active layer of the electrode for electrolysis during activation or electrolysis by improving the durability of the cathode for electrolysis. Specifically, during the activation or electrolysis of the cathode for electrolysis, the ruthenium oxide particles containing ruthenium in the active layer become metallic Ru (metallic Ru) or partially hydrated without changing the structure to become active species (active species). ) is returned to And, the structure of the cerium oxide particles containing cerium in the active layer is changed to form a network with the particles containing ruthenium in the active layer, and as a result, the durability of the cathode for electrolysis is improved to prevent the loss of ruthenium in the active layer. can In addition, when a reverse current occurs, cerium is eluted at a lower potential than ruthenium, thereby preventing the noble metal from eluting.
[69]
[70]
The N atom included in the active layer may mean that it is derived from an amine-based compound included in the active layer composition when the cathode is manufactured. At this time, the N atom may be included in about 20 to 60 mol% based on the mole of the ruthenium component of the active layer, preferably 30 to 55 mol%, more preferably 35 to 50 mol%.
[71]
By the presence of N atoms in the active layer within the above range, the acicular structure of the cerium oxide particles derived from the cerium-based compound can be expanded more in the initial driving process to form a solid network in the active layer, and as a result, the durability of the cathode is improved. can be improved
[72]
The amine-based compound may be at least one selected from the group consisting of n-octylamine, t-octylamine, isooctylamine, trioctylamine, oleylamine, tributylamine, and cetyltrimethylammonium bromide, of which n - At least one selected from the group consisting of octylamine, t-octylamine and isooctylamine is preferable.
[73]
[74]
The cathode for electrolysis according to an embodiment of the present invention may further include a hydrogen adsorption layer comprising at least one selected from the group consisting of tantalum oxide, nickel oxide and carbon positioned on the active layer.
[75]
The hydrogen adsorption layer is a layer that improves the activity of generating hydrogen gas of the reduction electrode for electrolysis, and may be present in an amount sufficient not to interfere with the redox reaction of hydrogen ions or water in the hydrogen layer.
[76]
The hydrogen adsorption layer may include pores.
[77]
The hydrogen adsorption layer may be positioned so that at least one selected from the group consisting of tantalum oxide, nickel oxide, and carbon is 0.1 to 10 mmol/m 2 .
[78]
When the above conditions are satisfied, hydrogen adsorption can be promoted without disturbing the electrolysis.
[79]
[80]
The cathode for electrolysis according to an embodiment of the present invention can be used as an electrode for electrolysis of an aqueous solution containing chloride, specifically, as a cathode. The aqueous solution containing the chloride may be an aqueous solution containing sodium chloride or potassium chloride.
[81]
[82]
2. Manufacturing method of cathode for electrolysis
[83]
The method for manufacturing a cathode for electrolysis according to an embodiment of the present invention includes a coating step of coating, drying and heat treatment of a catalyst composition for a cathode for electrolysis on at least one surface of a metal substrate.
[84]
[85]
Before performing the coating step, it may further include the step of pre-treating the metal substrate.
[86]
The pretreatment may be to form irregularities on the surface of the metal substrate by chemical etching, blasting, or thermal spraying of the metal substrate.
[87]
The pretreatment may be performed by sandblasting the surface of the metal substrate to form fine irregularities, and performing salt treatment or acid treatment. For example, the surface of the metal substrate may be sandblasted with alumina to form irregularities, immersed in an aqueous sulfuric acid solution, washed, and dried to pre-treat to form fine irregularities on the surface of the metal substrate.
[88]
[89]
The application is performed by electrostatic spray deposition.
[90]
The electrostatic spray deposition method is a method in which fine coating solution particles charged through a constant current are applied to a substrate, the spray nozzle is mechanically controlled, and the composition for forming an active layer on at least one surface of a metal substrate can be sprayed on at least one surface of the metal substrate at a constant speed, The composition for forming an active layer may be uniformly distributed on the substrate.
[91]
The application is performed through an electrostatic spray deposition method, and the composition for forming an active layer on a metal substrate is sprayed in an amount of 30 to 80 ml, preferably 40 to 70 ml, 0.4 to 1.2 ml/min, preferably 0.6 to 1.0 ml/min. It can be sprayed at a speed of min, and in this case, an appropriate amount of the composition for forming an active layer on the metal substrate can be more uniformly applied.
[92]
In this case, per injection per time is an amount required to spray both surfaces of the metal substrate once, and the application may be performed at room temperature.
[93]
[94]
When performing the electrostatic spray deposition method, the voltage of the nozzle has a great influence on the particle shape and coating efficiency, so it should be conducted under an appropriate voltage condition. If the voltage condition is too low, the particles are split into small pieces, so spraying is not possible, and the coating behavior is almost similar to spray coating. In addition, when too high a voltage is applied, the coating efficiency on the metal substrate rapidly decreases, so an appropriate voltage condition is required.
[95]
The voltage of the nozzle may be 10 kV to 30 kV, preferably 15 kV to 25 kV. In this case, it is possible to coat with a uniform content, so that the coating performance can be further improved.
[96]
In general, a cathode for electrolysis is prepared by forming an active layer containing a cathode reaction active material on a metal substrate, wherein the active layer is coated with a composition for forming an active layer containing the active material on a metal substrate and dried and heat treatment.
[97]
At this time, the application is usually performed through doctor blade, die casting, comma coating, screen printing, spray spraying, roll coating, and brushing, in this case, it is difficult to uniformly distribute the active materials on the metal substrate, The active materials in the active layer of the cathode may not be uniformly distributed, and as a result, the activity of the cathode may be reduced or a problem may occur that the lifespan is reduced.
[98]
In addition, in the past, electrostatic spray deposition has not been applied for reasons such as coating efficiency, and it is difficult to actually satisfy various aspects such as uniformity of the active layer and coating efficiency through the electrostatic spray deposition method.
[99]
However, in the method for producing a cathode for electrolysis according to another embodiment of the present invention, the active material in the active layer is uniformly applied by applying the composition for forming an active layer on the metal substrate by electrostatic spray deposition rather than a conventional method. It is possible to manufacture a distributed cathode, and the cathode for electrolysis produced through this can reduce overvoltage, as well as improve lifespan characteristics, and suppress oxygen generation. Furthermore, the electrostatic spray deposition method can be particularly suitably applied as described above due to the optimization of the voltage of the nozzle and the coating spray amount during electrostatic spraying, and may be a method optimized for the manufacturing method according to an embodiment of the present invention.
[100]
[101]
The active layer composition for the cathode includes a metal precursor mixture including a ruthenium-based compound, a platinum-based compound, and a cerium-based compound; and an organic solvent including an alcohol-based compound and an amine-based compound.
[102]
The ruthenium-based compound is ruthenium hexafluoride (RuF 6 ), ruthenium (III) chloride (RuCl 3 ), ruthenium (III) chloride hydrate (RuCl 3 ·xH 2 O), ruthenium (III) bromide (RuBr 3 ), ruthenium (III) may be at least one member selected from the group consisting of bromide hydrate (RuBr 3 ·xH 2 O), ruthenium iodide (RuI 3 ), ruthenium iodide (RuI 3 ) and ruthenium acetate salt, of which ruthenium (III) ) chloride hydrate is preferred.
[103]
The platinum-based compound is chloroplatinic acid hexahydrate (H 2 PtCl 6 .6H 2 O), diamine dinitro platinum (Pt(NH 3 ) 2 (NO) 2 ) and platinum (IV) chloride (PtCl 4 ), platinum ( II) chloride (PtCl 2 ), potassium tetrachloroplatinate (K 2 PtCl 4 ), potassium hexachloroplatinate (K 2 PtCl 6 ) may be at least one selected from the group consisting of, of which chloroplatinic acid hexahydrate is desirable.
[104]
The platinum can improve the overvoltage phenomenon of the reduction electrode for electrolysis, and can minimize the performance deviation from the initial performance of the reduction electrode for electrolysis and the performance after a certain time has elapsed, and as a result, separate It is possible to minimize the activation process, and furthermore, it is possible to guarantee the performance of the reduction electrode even if it is not performed.
[105]
As such, the effect of further including the platinum precursor may be more than just adding platinum as an active ingredient, but may be an effect of including ruthenium and platinum, that is, two or more kinds of platinum group metals as active ingredients, in this case From the point that the performance of the reduction electrode is improved and the difference between the initial performance and the performance after activation is small, it can be seen that the performance of the electrode driven in the actual field is stable and the reliability of the electrode performance evaluation result is high.
[106]
The platinum-based compound may be included in 0.01 to 0.7 mol or 0.02 to 0.5 mol with respect to 1 mol of the ruthenium-based compound, and preferably in an amount of 0.02 to 0.5 mol, more preferably 0.1 to 0.5 mol. can
[107]
If this is satisfied, the overvoltage phenomenon of the cathode for electrolysis can be remarkably improved. In addition, since the initial performance of the cathode for electrolysis and the performance after a certain period of time can be maintained constant, the activation process of the cathode for electrolysis is unnecessary. Accordingly, it is possible to reduce the time and cost required for the activation process of the cathode for electrolysis.
[108]
The cerium-based compound is cerium (III) nitrate hexahydrate (Ce(NO 3 ) 3 .6H 2 O), cerium (IV) sulfate tetrahydrate (Ce(SO 4 ) 2 .4H 2 O) and cerium (III) At least one selected from the group consisting of chloride heptahydrate (CeCl 3 ·7H 2 O), of which cerium (III) nitrate hexahydrate is preferable.
[109]
The cerium-based compound may be included in an amount of 0.01 to 0.5 mol or 0.05 to 0.35 mol, preferably 0.05 to 0.35 mol, based on 1 mol of the ruthenium-based compound.
[110]
If the above-described range is satisfied, the durability of the cathode for electrolysis can be improved to minimize the loss of ruthenium in the active layer of the electrode for electrolysis during activation or electrolysis.
[111]
[112]
The organic solvent includes an amine-based compound and an alcohol-based compound, and the amine-based compound may have an effect of reducing the ruthenium oxide crystal phase during electrode coating. In addition, by including the amine compound, the size of the needle structure of the lanthanide metal, specifically cerium oxide, can be increased, and the cerium oxide network structure formed therefrom can serve to more firmly fix the ruthenium oxide particles. Thereby, it is possible to finally improve the durability of the electrode. As a result, even if the electrode is driven for a long time, it is possible to significantly reduce the peeling phenomenon caused by aging and other internal and external factors.
[113]
The active layer composition of the cathode may contain 0.5 to 10 parts by volume of the amine-based compound, preferably 1 to 8 parts by volume, of which 2 to 6 parts by volume, based on 100 parts by volume of the organic solvent. Incorporation by skin is preferred. When the amine compound is included in this range, the formation of the network structure of the lanthanide metal oxide in the active layer of the cathode and the fixing mechanism of the platinum group metal oxide particles according to the structure formation can be optimized, and as a result, durability improvement and peeling phenomenon Mitigation can be taken more effectively.
[114]
The type of the amine-based compound is the same as described above.
[115]
The alcohol-based compound may include one or more, and may be selected from primary alkyl alcohols and alkoxyalkyl alcohols. The primary alkyl alcohol may be an alcohol having an alkyl group having 1 to 4 carbon atoms, for example, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol or tert-butanol. .
[116]
In addition, the alkoxyalkyl alcohol has an alkyl group in which an alkoxy group having 1 to 4 carbon atoms is bonded with a substituent, and the alkyl group may also have 1 to 4 carbon atoms, for example, the alkoxy group is methoxy, ethoxy, n-pro. It may be epoxy, isopropoxy, n-butoxy, sec-butoxy, isobutoxy or tert-butoxy, and the alcohol matrix may be a material exemplified by the primary alkyl alcohol.
[117]
The alcohol-based compound may be selected from two or more of the primary alkyl alcohol and the alkoxyalkyl alcohol, but preferably one or more may be selected from each, for example, isopropanol is selected as the primary alkyl alcohol. and 2-butoxyethanol is selected as the alkoxyalkyl alcohol. As such, when two or more types of alcohol solvents are included, in particular, at least one type for each series, uniformity of the coating can be secured when the active layer is formed, and thus, a uniform composition can be obtained over the entire area of ​​the electrode.
[118]
[119]
In the active layer composition according to an embodiment of the present invention, when an amine-based compound and an alcohol-based compound are included as an organic solvent included in addition to the metal precursors serving as active ingredients, a network structure of a lanthanide metal oxide in case they are not used together Since the formation can be made more firmly, the effect of improving durability can be maximized.
[120]
[121]
The concentration of the active layer composition of the cathode may be 15 to 80 g / ℓ, preferably 20 to 75 g / ℓ. If this is satisfied, not only the standard deviation of the ruthenium composition is lowered, but also the overvoltage phenomenon of the cathode can be significantly reduced.
[122]
[123]
The method of manufacturing a cathode for electrolysis according to an embodiment of the present invention may further include the step of preparing a hydrogen adsorption layer after the coating step.
[124]
The structure of the hydrogen adsorption layer is the same as described above, and it is prepared by thermal decomposition, or by fixing and coating at least one selected from the group consisting of tantalum oxide, nickel oxide and carbon on the surface of the active layer using an appropriate resin, or , can be produced by pressing. In addition, the hydrogen adsorption layer may be prepared by hot-dip plating, chemical vapor deposition, physical vapor deposition, vacuum vapor deposition, sputtering, or ion plating.
[125]
[126]
Example
[127]
Hereinafter, examples and experimental examples will be described in more detail to illustrate the present invention in detail, but the present invention is not limited by these examples and experimental examples. Embodiments according to the present invention may be modified in various other forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. The embodiments of the present invention are provided to more completely explain the present invention to those of ordinary skill in the art.
[128]
[129]
Example 1
[130]
1) Preparation of active layer composition of reduction electrode for electrolysis
[131]
Ruthenium chloride hydrate (RuCl 3 ·xH 2 O) (manufacturer: Heraeus) 2.41 mmol, chloroplatinic acid hexahydrate (H 2 PtCl 6 ·6H 2 O) (manufacturer: rare metal) 0.241 mmol and cerium (III) nitrate hexa Hydrate (Ce(NO 3 ) 3 .6H 2 O) (manufacturer: Sigma-Aldrich) 0.482 mmol isopropyl alcohol (manufacturer: Daejeonghwageum) 2.375 ml, and 2-butoxyethanol (manufacturer: Daejeonghwageum) 2.375 ㎖ was sufficiently dissolved, and 0.25 ml of n-octylamine (manufacturer: Daejeong Hwageum) was added and mixed to prepare a catalyst composition for a reduction electrode for electrolysis.
[132]
[133]
2) Preparation of coating solution
[134]
The catalyst composition for the reduction electrode for electrolysis was stirred at 50° C. for 24 hours to prepare a coating solution having a concentration of 33.3 g/L.
[135]
[136]
3) Preparation of cathode for electrolysis
[137]
The surface of the nickel substrate (thickness: 200 µm, purity: 99% or more) was sandblasted with aluminum oxide (120 mesh) under 0.8 kgfcm 2 conditions to form irregularities. The nickel substrate on which the unevenness was formed was immersed in an aqueous solution of sulfuric acid (5M) at 80° C. for 3 minutes to form fine unevenness. Then, it was washed with distilled water and dried sufficiently to prepare a pre-treated nickel substrate.
[138]
The coating solution was applied to the pre-treated nickel substrate. At this time, for the application, the active layer composition was applied by an electrostatic spray deposition method at a nozzle voltage of 20 kV, a spray rate of 50 ml per time, a spray rate of 0.8 ml / min, and room temperature conditions, and put in a convection drying oven at 170 ° C. and dried for 10 minutes. and put into an electric heating furnace at 480 ℃ and heat-treated for 10 minutes. This coating, drying and heat treatment were repeatedly performed until the ruthenium in the active layer became 5 wt %, and then heat treatment was performed at 500 ° C. for 1 hour to prepare a cathode for electrolysis.
[139]
[140]
Example 2
[141]
A cathode for electrolysis was prepared in the same manner as in Example 1, except that a coating solution having a concentration of 52 g/L was used in the preparation of the coating solution.
[142]
[143]
Example 3
[144]
A cathode for electrolysis was prepared in the same manner as in Example 1, except that a coating solution having a concentration of 70 g/L was used in the preparation of the coating solution.
[145]
[146]
Example 4
[147]
Electrolysis was carried out in the same manner as in Example 1, except that a coating solution having a concentration of 52 g/L was used in the preparation of the coating solution and the molar ratios of Ru, Pt and Ce were changed as shown in Table 1 below. A cathode was prepared.
[148]
[149]
Example 5
[150]
Electrolysis was carried out in the same manner as in Example 1, except that a coating solution having a concentration of 52 g/L was used in the preparation of the coating solution and the molar ratios of Ru, Pt and Ce were changed as shown in Table 1 below. A cathode was prepared.
[151]
[152]
Comparative Example 1
[153]
A cathode for electrolysis was prepared in the same manner as in Example 1, except that the brush method was applied in the preparation of the cathode for electrolysis.
[154]
[155]
Comparative Example 2
[156]
A cathode for electrolysis was prepared in the same manner as in Example 2, except that the brush method was applied in the preparation of the cathode for electrolysis.
[157]
[158]
Comparative Example 3
[159]
A cathode for electrolysis was prepared in the same manner as in Example 2, except that the electroless spray deposition method was applied in the manufacture of the cathode for electrolysis.
[160]
[161]
Comparative Example 4
[162]
A cathode for electrolysis was prepared in the same manner as in Example 2, except that no amine was added in the preparation of the cathode for electrolysis.
[163]
[164]
Comparative Example 5
[165]
A cathode for electrolysis was prepared in the same manner as in Comparative Example 2, except that no amine was added in the preparation of the cathode for electrolysis.
[166]
[167]
Comparative Example 6
[168]
A cathode for electrolysis was prepared in the same manner as in Example 2, except that platinum was not applied in the manufacture of the cathode for electrolysis.
[169]
[170]
Comparative Example 7
[171]
A cathode for electrolysis was prepared in the same manner as in Comparative Example 2, except that platinum was not applied in the preparation of the cathode for electrolysis.
[172]
[173]
The contents of the main components of Examples and Comparative Examples are summarized and shown in Table 1 below.
[174]
[Table 1]
division Ru:Pt:Ce Amine-based compound 1) (n-octylamine) Application method
Example 1 5:0.5:1 5 electrostatic spray deposition
Example 2 5:0.5:1 5 electrostatic spray deposition
Example 3 5:0.5:1 5 electrostatic spray deposition
Example 4 6:0.5:1 5 electrostatic spray deposition
Example 5 4:0.5:1 5 electrostatic spray deposition
Comparative Example 1 5:0.5:1 5 brush method
Comparative Example 2 5:0.5:1 5 brush method
Comparative Example 3 5:0.5:1 5 Uninterruptible Spray Deposition
Comparative Example 4 5:0.5:1 not input electrostatic spray deposition
Comparative Example 5 5:0.5:1 not input brush method
Comparative Example 6 5:0:1 (without Pt input) 5 electrostatic spray deposition
Comparative Example 7 5:0:1 (without Pt input) 5 brush method
[175]
1) 100 parts by volume of the organic solvent compared to 100 parts by volume of the amine compound (n-octylamine)
[176]
[177]
Experimental Example 1
[178]
The distribution degree of metal in the active layer of the cathode for electrolysis of Examples and Comparative Examples was analyzed, and the number of required coating repetitions was counted until the content of ruthenium in each Example and Comparative Example was about 5% by weight, The results are shown in Table 2 below.
[179]
Specifically, each cathode was manufactured to have a size of 0.6 m in width and 0.6 m in height, and after evenly dividing it into 16 pixels, 3 points for each pixel were measured using an XRF (X-ray fluorescence) component analyzer for each pixel. The weight ratio of ruthenium and cerium was measured. Then, the dispersion (V(x)) was calculated through Equation 1 using the weight% of each obtained ruthenium, and the standard deviation (σ) was calculated through Equation 2 using this.
[180]
[Table 2]
division Ru content (mol%) Weight ratio of Ru and Ce N/Ru (mol%) in the active layer standard deviation of Ru number of coatings Coating solution concentration (g/L)
Example 1 5.41 1.25:1 43 0.27 16 33.3
Example 2 5.30 1.14:1 42 0.24 10 52.0
Example 3 5.29 1.09:1 46 0.21 9 70.0
Example 4 5.54 1.29:1 38 0.21 10 52.0
Example 5 5.08 0.89:1 46 0.27 10 52.0
Comparative Example 1 5.72 1.36:1 43 0.42 21 33.3
Comparative Example 2 5.50 1.16:1 44 0.63 14 52.0
Comparative Example 3 4.57 0.94:1 49 1.00 12 52.0
Comparative Example 4 5.23 1.12:1 13 0.25 10 52.0
Comparative Example 5 5.13 1.20:1 15 0.69 13 52.0
Comparative Example 6 5.26 1.12:1 46 0.26 10 52.0
Comparative Example 7 5.22 1.05:1 44 0.75 13 52.0
[181]
In the case of Examples 1 to 5, it can be confirmed that the standard deviation of the ruthenium content is as low as 0.4 or less, and through this, it can be confirmed that the active materials are uniformly distributed in the active layers of the Examples. In the case where the spray deposition method is not applied, it can be seen that the uniformity is significantly lowered as a value exceeding 0.4 is derived. It can be seen that it can be distributed fairly evenly over the entire area.
[182]
In addition, looking at Example 1 and Comparative Example 1 to which the same coating solution concentration is applied, it is confirmed that the desired ruthenium content can be reached even though Example 2 was coated 5 times less, and uniformity can be secured at the same time. , which can be clearly confirmed through Example 2 and Comparative Examples 2 and 3.
[183]
[184]
Experimental Example 2
[185]
A half cell was prepared by immersing the cathode of Examples and Comparative Examples, a Pt wire as a counter electrode, and an Hg/HgO electrode as a reference electrode in an aqueous NaOH solution (32 wt%).
[186]
voltage measurement
[187]
After the half-cell was treated for 1 hour at a current density condition of −6 A/cm 2 , the voltage of the cathode was measured at a current density of −0.44 A/cm 2 through a linear ambient scanning method , and the results are shown in Table 3 below. described.
[188]
Durability measurement
[189]
The change in Ru content before and after electrolysis was measured for the half cell using Portable XRF (Olympus, Delta-professional XRF (X-ray fluorescence spectrometry)), and the results are shown in Table 3 below.
[190]
[Table 3]
division Ru content (mol%) Weight ratio of Ru and Ce Voltage (V) Ru Residual Rate (%)
Example 1 5.41 1.25:1 -1.075 99.8
Example 2 5.30 1.14:1 -1.083 99.6
Example 3 5.29 1.09:1 -1.087 98.4
Example 4 5.54 1.29:1 -1.095 99.5
Example 5 5.08 0.89:1 -1.101 99.6
Comparative Example 1 5.72 1.36:1 -1.115 99.3
Comparative Example 2 5.50 1.16:1 -1.131 99.8
Comparative Example 3 4.57 0.94:1 -1.155 78.4
Comparative Example 4 5.23 1.12:1 -1.120 94.6
Comparative Example 5 5.13 1.20:1 -1.122 93.7
Comparative Example 6 5.26 1.12:1 -1.136 99.6
Comparative Example 7 5.22 1.05:1 -1.142 99.5
[191]
Referring to Table 2, Examples 1 to 5 not only contained ruthenium in an appropriate amount, but also had a low standard deviation of ruthenium, so it was confirmed that the overvoltage phenomenon of the cathode for electrolysis was improved. However, compared Although Examples 1 to 3, Comparative Examples 5 and 7 contain ruthenium in an appropriate amount, since the standard deviation of ruthenium is high, it is confirmed that the overvoltage phenomenon of the cathode for electrolysis is not improved compared to Examples 1 to 5 could
[192]
In addition, in the case of Comparative Examples 6 and 7 in which Pt was not added, it can be seen that the overvoltage was larger than in Example 2 and Comparative Example 2 which became the respective standards, and Comparative Examples 4 and 5 prepared without adding an amine were It can be seen that there is a loss in terms of durability, and it can be seen that the durability of Comparative Example 3 to which the uninterruptible spray deposition method is applied is greatly reduced.
[193]
Claims
[Claim 1]
metal substrate; and an active layer positioned on at least one surface of the metal substrate, wherein the active layer includes ruthenium oxide, platinum oxide and cerium oxide, and when the active layer is equally divided into a plurality of pixels, the equally divided plurality of pixels The standard deviation of the composition of inter-ruthenium is 0.4 or less, and the N atoms in the active layer are present in an amount of 20 to 60 mol% compared to ruthenium.
[Claim 2]
The method according to claim 1, wherein the standard deviation of the composition of the ruthenium is 0.35 or less for the reduction electrode for electrolysis.
[Claim 3]
The reduction electrode for electrolysis of claim 1, wherein the active layer contains 3 to 7 mol% of the ruthenium with respect to 100 mol% of the total of the metal components in the active layer.
[Claim 4]
The reduction electrode for electrolysis of claim 1, wherein the active layer contains the cerium and ruthenium in a molar ratio of 1:1 to 1:1.5.
[Claim 5]
The method according to claim 1, wherein the reduction electrode for electrolysis is located on the active layer, tantalum oxide, nickel oxide, and further comprising a hydrogen adsorption layer comprising at least one selected from the group consisting of carbon and electrolysis reduction electrode.
[Claim 6]
a coating step of applying, drying, and heat treating the active layer composition for a cathode on at least one surface of a metal substrate, wherein the application is performed by electrostatic spray deposition, and the active layer composition for a cathode is a ruthenium-based compound, a platinum-based compound, and a metal precursor mixture including a cerium-based compound; and an organic solvent including an alcohol-based compound and an amine-based compound;
[Claim 7]
The method according to claim 6, wherein the metal precursor mixture is based on 1 mole of the ruthenium-based compound, 0.01 to 0.7 moles of the platinum-based compound; And 0.01 to 0.5 moles of the cerium-based compound: a method for producing a cathode comprising a.
[Claim 8]
The method according to claim 6, wherein the amine-based compound is at least one selected from the group consisting of n-octylamine, t-octylamine, isooctylamine, trioctylamine, oleylamine, tributylamine, and cetyltrimethylammonium bromide. A method for manufacturing a phosphorus cathode.
[Claim 9]
The group of claim 6, wherein the alcohol-based compound is a primary alkyl alcohol having an alkyl group having 1 to 4 carbon atoms and an alkoxyalkyl alcohol having an alkyl group having 1 to 4 carbon atoms in which an alkoxy group having 1 to 4 carbon atoms is bonded as a substituent. A method for producing a cathode comprising at least one selected from
[Claim 10]
The method according to claim 6, wherein the alcohol-based compound is a primary alkyl alcohol having an alkyl group having 1 to 4 carbon atoms; and an alkoxyalkyl alcohol having an alkyl group having 1 to 4 carbon atoms bonded to an alkoxy group having 1 to 4 carbon atoms as a substituent.
[Claim 11]
The method according to claim 6, wherein the manufacturing method of the cathode further comprises the step of preparing a hydrogen adsorption layer after the coating