This application claims the benefit of priority based on Korean Patent Application No. 10-2018-0078915 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 an active layer composition of a reduction electrode for electrolysis and a reduction electrode for electrolysis derived therefrom.
[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 is a process whose performance and reliability of technology have been proven through commercial operation for several decades.
[8]
For the 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, which uses brine as an electrolyte to obtain chlorine gas from the anode and hydrogen and caustic soda from the reducing electrode, is currently the most It is widely used.
[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 oxidizing electrode, and an excellent material with low overvoltage and durability for the reduction electrode development is required.
[16]
Stainless steel or nickel has been mainly used as such a reduction electrode, 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 reduction electrode by controlling the composition of the active material, a method of adjusting the composition using a platinum group metal such as ruthenium and a lanthanide group metal such as cerium is 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]
An object of the present invention is to improve the overvoltage phenomenon of the reduction electrode for electrolysis, and to provide a reduction electrode for electrolysis with excellent performance stability and excellent durability due to small variations in initial performance and performance after activation of the electrode.
[24]
means of solving the problem
[25]
The present invention provides an active layer composition of a reducing electrode for brine electrolysis, comprising: a metal precursor mixture including a ruthenium precursor, a platinum precursor, and a lanthanide metal precursor; and an organic solvent including an amine-based compound; provides an active layer composition for a reduction electrode comprising.
[26]
In addition, the present invention is a metal substrate; And located on the metal substrate, it provides a reduction electrode for electrolysis comprising an active layer derived from the composition of the active layer of the reduction electrode.
[27]
Effects of the Invention
[28]
The reduction electrode for electrolysis derived from the active layer composition of the reduction electrode of the present invention can improve durability by increasing the needle-like structure of the lanthanide metal on the electrode surface, and can improve the overvoltage phenomenon, and the difference in performance before and after activation of the electrode Since there is almost no , it is possible to increase the reliability of the electrode performance evaluation without an activation process.
[29]
Modes for carrying out the invention
[30]
Hereinafter, the present invention will be described in more detail to help the understanding of the present invention.
[31]
[32]
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.
[33]
[34]
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.
[35]
Chlorine oxidation reaction: 2Cl - → Cl 2 + 2e - (E 0 = +1.36 V)
[36]
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.
[37]
Hydrogen reduction reaction: 2H 2 O + 2e - → 2OH - + H 2 (E 0 = -0.83 V)
[38]
[39]
1. Active layer composition of reduction electrode for electrolysis
[40]
The active layer composition of the reduction electrode for electrolysis according to an embodiment of the present invention is an active layer composition of the reduction electrode of the brine electrolysis, a metal precursor mixture; and an organic solvent, wherein the metal precursor mixture includes a ruthenium precursor, a platinum precursor, and a lanthanide metal precursor.
[41]
[42]
metal precursor mixture
[43]
The active layer composition according to an embodiment of the present invention includes a metal precursor mixture as an active component, and the ruthenium precursor may be a material that provides a ruthenium component as an active material to the active layer of the reduction electrode for electrolysis.
[44]
The ruthenium precursor 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) 1 selected from the group consisting of bromide hydrate (RuBr 3 ·xH 2 O), ruthenium (III) iodide (RuI 3 ), ruthenium (III) iodide hydrate (RuI 3 ·xH 2 O) and ruthenium acetate salt more than one species, of which ruthenium(III) chloride hydrate is preferable.
[45]
The ruthenium is a metal having excellent electrical conductivity and excellent catalytic activity as well as significant advantages in terms of economy, and has a property that corrosion does not occur well even in extreme conditions, so it can be a metal that can be usefully applied to a reduction electrode for electrolysis have.
[46]
The platinum precursor may be a material that provides a platinum component as an active component to the active layer of the reduction electrode for electrolysis.
[47]
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.
[48]
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.
[49]
The platinum precursor 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.
[50]
[51]
The active layer composition of the reduction electrode for electrolysis according to an embodiment of the present invention may include 0.01 to 0.7 or 0.02 to 0.5 mol of the platinum precursor with respect to 1 mol of the ruthenium precursor, of which 0.02 to 0.5 mol. it is preferable
[52]
If the above-described range is satisfied, the overvoltage phenomenon of the reduction electrode for electrolysis can be significantly improved. In addition, since the initial performance of the reduction electrode for electrolysis and the performance after activation can be kept constant, the activation process is unnecessary in the performance evaluation of the reduction electrode for electrolysis, and accordingly, for the performance evaluation of the reduction electrode for electrolysis The time required for the activation process and cost due to consumption of the test electrode can be greatly reduced. In addition, it may be more preferable in terms of durability to include the platinum precursor in an amount of 0.1 to 0.5 moles relative to 1 mole of the ruthenium precursor.
[53]
[54]
The lanthanide group metal precursor is a material that provides a lanthanide group metal component to the active layer of the reduction electrode for electrolysis.
[55]
The lanthanide element improves the durability of the reduction electrode for electrolysis, thereby minimizing the loss of a platinum group metal, such as ruthenium, in the active layer of the electrode during activation or electrolysis. Specifically, during activation or electrolysis of the reduction electrode for electrolysis, particles containing ruthenium in the active layer become metallic Ru or partially hydrated to be reduced to an active species without changing the structure. . And, the particles containing the lanthanide element in the active layer are changed in structure to form a network with the particles containing ruthenium in the active layer, and as a result, the durability of the reduction electrode for electrolysis is improved to prevent the loss of ruthenium in the active layer. can
[56]
The lanthanide metal may be at least one selected from the group consisting of cerium, neodymium, promedium, samarium, europum, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium, of which cerium-based compounds This is preferable. When the cerium-based compound is present in the active layer of the final reduction electrode in the form of cerium oxide, the fine structure of the particle can form a fairly stable structure as a needle-like structure, and the durability of the electrode can be improved. can be applied.
[57]
The cerium precursor 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) chloride. At least one selected from the group consisting of heptahydrate (CeCl 3 ·7H 2 O), of which cerium (III) nitrate hexahydrate is preferable.
[58]
The active layer composition of the reduction electrode for electrolysis may include 0.01 to 0.5 moles or 0.05 to 0.35 moles of the lanthanide metal precursor, with respect to 1 mole of the ruthenium precursor, of which it is preferable to include 0.05 to 0.35 moles.
[59]
If the above-described range is satisfied, the durability of the reduction electrode for electrolysis may be improved, and thus, the loss of ruthenium in the active layer of the electrode for electrolysis may be minimized during activation or electrolysis.
[60]
[61]
Amine-based compounds contained in organic solvents
[62]
The amine-based compound included in the active layer composition according to an embodiment of the present invention 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.
[63]
The active layer composition of the reduction electrode for electrolysis may include 0.5 to 10 parts by volume of the amine compound, preferably 1 to 8 parts by volume, of which, based on 100 parts by volume of the organic solvent, 2 It is preferable to include to 6 parts by volume. 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 reduction electrode and the fixing mechanism of the platinum group metal oxide particles according to the structure formation can be optimized, as a result, durability improvement and peeling phenomenon Mitigation can be taken more effectively.
[64]
The amine-based compound is preferably at least one selected from the group consisting of n-octylamine, t-octylamine, isooctylamine, trioctylamine, oleylamine, tributylamine, and cetyltrimethylammonium bromide, of which It is preferable that at least one selected from the group consisting of n-octylamine, t-octylamine and isooctylamine.
[65]
[66]
Alcoholic compounds contained in organic solvents
[67]
The active layer composition of the reduction electrode for electrolysis according to an embodiment of the present invention may further include an alcohol-based compound as an organic solvent.
[68]
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. .
[69]
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.
[70]
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.
[71]
[72]
When the active layer composition of the reduction electrode for electrolysis according to an embodiment of the present invention includes an amine-based compound and an alcohol-based compound as an organic solvent included in addition to the metal precursors serving as an active ingredient, lanthanum in preparation for not being used together Since the network structure of the group metal oxide can be formed more firmly, the effect of improving durability can be maximized.
[73]
[74]
2. Reduction electrode for electrolysis
[75]
Reduction electrode for electrolysis according to another embodiment of the present invention is a metal substrate; and an active layer located on the metal substrate and derived from the active layer composition of the reduction electrode described above.
[76]
[77]
The metal substrate may be nickel, titanium, tantalum, aluminum, hafnium, zirconium, molybdenum, tungsten, stainless steel, or an alloy thereof, of which nickel is preferable.
[78]
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 suggested as an example.
[79]
[80]
The active layer is derived from the active layer composition of the reduction electrode for electrolysis according to an embodiment of the present invention, and is prepared using a coating step of applying, drying and heat-treating the active layer composition of the reduction electrode on at least one surface of a metal substrate can do.
[81]
In the coating, drying, and heat treatment process, the mixing ratio of the metal precursor applied when the active layer composition is mixed, that is, the molar ratio between the metals may be removed by removing only the organic compound such as an organic solvent without substantially changing, but in the case of an amine compound may exist as N atoms in the active layer of the reduction electrode, and the metal precursors may be present in the active layer in the form of oxides.
[82]
[83]
It may include the step of pre-treating the metal substrate before performing the coating step. 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.
[84]
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 unevenness, immersed in an aqueous sulfuric acid solution, washed and dried, and thus pre-treated to form fine unevenness on the surface of the metal substrate.
[85]
[86]
The coating step may be a coating step of applying, drying and heat treatment of the active layer composition on at least one surface of the metal substrate. The application is not particularly limited as long as the active layer composition can be evenly applied on the metal substrate and may be performed by a method known in the art.
[87]
The application may be performed by any one method selected from the group consisting of doctor blade, die casting, comma coating, screen printing, spray spraying, electrospinning, roll coating, and brushing.
[88]
[89]
The drying may be performed at 50 to 300° C. for 5 to 60 minutes, and preferably at 50 to 200° C. for 5 to 20 minutes. When the above conditions are satisfied, the solvent can be sufficiently removed and energy consumption can be minimized.
[90]
[91]
The heat treatment may be performed at 400 to 600° C. for 1 hour or less, and is preferably performed at 450 to 550° C. for 5 to 30 minutes. When the above-described conditions are satisfied, impurities in the active layer may be easily removed and the strength of the metal substrate may not be affected.
[92]
On the other hand, the coating may be performed by sequentially repeating application, drying and heat treatment so as to be 10 g or more based on ruthenium per unit area (m2) of the metal substrate. That is, in the manufacturing method according to another embodiment of the present invention, after coating, drying and heat treatment of the active layer composition on at least one surface of the metal substrate, the first active layer composition is applied again on one surface of the metal substrate, drying and Coating with heat treatment may be repeatedly performed.
[93]
[94]
The reduction electrode for electrolysis according to another embodiment of the present invention may further include a hydrogen adsorption layer, wherein the hydrogen adsorption layer is located on the active layer and is selected from the group consisting of tantalum oxide, nickel oxide and carbon. It may include more than one species.
[95]
The hydrogen adsorption layer is a layer that improves the activity of the reduction electrode so that hydrogen gas can be generated more smoothly in the reduction electrode for electrolysis, and in an amount not to interfere with the redox reaction of hydrogen ions or water in the hydrogen layer. may exist.
[96]
The hydrogen adsorption layer may include pores. 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 . When the above conditions are satisfied, hydrogen adsorption can be promoted without disturbing the electrolysis.
[97]
[98]
The hydrogen adsorption layer may be 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 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.
[99]
[100]
The reduction electrode for electrolysis according to an embodiment of the present invention may be used to electrolyze brine, and specifically may be used for electrolysis of an aqueous solution containing chloride. The aqueous solution containing the chloride may be an aqueous solution containing sodium chloride or potassium chloride.
[101]
[102]
Hereinafter, examples and experimental examples will be described in more detail to describe 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.
[103]
[104]
Example 1
[105]
1) Preparation of active layer composition of reduction electrode for electrolysis
[106]
Ruthenium chloride hydrate (RuCl 3 · xH 2 O) (manufacturer: Heraeus) 2.169 mmol, chloro platinum acid hexahydrate (H 2 PtCl 6 · 6H 2 O) (manufacturer: Heesung 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: Daejung Hwageum) 2.375 ml, and 2-butoxyethanol (manufacturer: Daejeonghwageum) 2.375 ㎖ was sufficiently dissolved, and 0.25 mL of n-octylamine (manufacturer: Daejeonghwageum) was added and mixed to prepare an active layer composition for a reduction electrode for electrolysis.
[107]
[108]
2) Preparation of coating solution
[109]
The active layer composition of the reduction electrode for electrolysis was stirred at 50° C. for 24 hours to prepare a coating solution containing 100 g of ruthenium per 1 liter of the solution.
[110]
[111]
3) Preparation of reduction electrode for electrolysis
[112]
The surface of the nickel substrate (thickness: 200 μm, purity: 99% or more) was sandblasted with aluminum oxide (120 mesh) under 0.4 MPa 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.
[113]
The coating solution was coated on the pre-treated nickel substrate using a brush, dried for 10 minutes in a convection drying oven at 180° C., and heat-treated in an electric heating furnace at 500° C. for 10 minutes. After performing this coating, drying and heat treatment 9 more times, heat treatment was performed at 500 ° C. for 1 hour to prepare a reduction electrode for electrolysis.
[114]
[115]
Example 2
[116]
Electrolysis was carried out in the same manner as in Example 1, except that 1.928 mmol of ruthenium chloride hydrate, 0.482 mmol of chloroplatinic acid hexahydrate, and 0.482 mmol of cerium (III) nitrate hexahydrate were dissolved to prepare an active layer composition of a reducing electrode for electrolysis. A reduction electrode for decomposition was prepared.
[117]
[118]
Example 3
[119]
Electrolysis was carried out in the same manner as in Example 1, except that an active layer composition of a reducing electrode for electrolysis was prepared by dissolving 1.687 mmol of ruthenium chloride hydrate, 0.723 mmol of chloroplatinic acid hexahydrate, and 0.482 mmol of cerium (III) nitrate hexahydrate. A reduction electrode for decomposition was prepared.
[120]
[121]
Example 4
[122]
Electrolysis was carried out in the same manner as in Example 1, except that 2.41 mmol of ruthenium chloride hydrate, 0.0482 mmol of chloroplatinic acid hexahydrate, and 0.482 mmol of cerium (III) nitrate hexahydrate were dissolved to prepare an active layer composition of a reducing electrode for electrolysis. A reduction electrode for decomposition was prepared.
[123]
[124]
Example 5
[125]
Electrolysis was carried out in the same manner as in Example 1, except that an active layer composition of a reducing electrode for electrolysis was prepared by dissolving 2.41 mmol of ruthenium chloride hydrate, 0.241 mmol of chloroplatinic acid hexahydrate, and 0.482 mmol of cerium (III) nitrate hexahydrate. A reduction electrode for decomposition was prepared.
[126]
[127]
Example 6
[128]
Electrolysis was carried out in the same manner as in Example 1, except that an active layer composition of a reducing electrode for electrolysis was prepared by dissolving 2.41 mmol of ruthenium chloride hydrate, 0.482 mmol of chloroplatinic acid hexahydrate, and 0.482 mmol of cerium (III) nitrate hexahydrate. A reduction electrode for decomposition was prepared.
[129]
[130]
Example 7
[131]
Electrolysis was carried out in the same manner as in Example 1, except that an active layer composition of a reducing electrode for electrolysis was prepared by dissolving 2.41 mmol of ruthenium chloride hydrate, 0.723 mmol of chloroplatinic acid hexahydrate, and 0.482 mmol of cerium (III) nitrate hexahydrate. A reduction electrode for decomposition was prepared.
[132]
[133]
Example 8
[134]
It is sufficiently dissolved in 2.45 ml of isopropyl alcohol (manufacturer: Daejung Hwageum) and 2.45 ml of 2-butoxyethanol (manufacturer: Daejung Hwageum), 0.1 ml of n-octylamine (manufacturer: Daejung Hwageum) is added and mixed A reduction electrode for electrolysis was prepared in the same manner as in Example 6 except that it was prepared.
[135]
[136]
Example 9
[137]
Dissolve sufficiently in 2.25 ml of isopropyl alcohol (manufacturer: Daejung Hwageum) and 2.25 ml of 2-butoxyethanol (manufacturer: Daejung Hwageum) 0.5 mL of n-octylamine (manufacturer: Daejung Hwageum) and mix A reduction electrode for electrolysis was prepared in the same manner as in Example 6 except that it was prepared.
[138]
[139]
Comparative Example 1
[140]
A reduction electrode for electrolysis was prepared in the same manner as in Example 1, except that the active layer composition of the reduction electrode for electrolysis was prepared without adding n-octylamine.
[141]
[142]
Comparative Example 2
[143]
A reduction electrode for electrolysis was prepared in the same manner as in Example 2, except that the active layer composition of the reduction electrode for electrolysis was prepared without adding n-octylamine.
[144]
[145]
Comparative Example 3
[146]
A reduction electrode for electrolysis was prepared in the same manner as in Example 3, except that the active layer composition of the reduction electrode for electrolysis was prepared without adding n-octylamine.
[147]
[148]
Comparative Example 4
[149]
2.41 mmol of ruthenium chloride hydrate and 0.482 mmol of cerium (III) nitrate hexahydrate are sufficiently dissolved in 2.375 ml of isopropyl alcohol and 2.375 ml of 2-butoxyethanol, 0.25 ml of n-octylamine is added and mixed to reduce electrolysis A reduction electrode for electrolysis was prepared in the same manner as in Example 1, except that the active layer composition of the electrode was prepared.
[150]
[151]
Comparative Example 5
[152]
A reduction electrode for electrolysis was prepared in the same manner as in Example 6, except that the active layer composition of the reduction electrode for electrolysis was prepared without adding n-octylamine.
[153]
[154]
The contents of the main components of Examples and Comparative Examples are summarized in Table 1 below.
[155]
[Table 1]
division Ru precursor (mmol) Pt precursor (mmol) Ce precursor (mmol) Ru:Pt Ru:Ce Amine-based compounds 1) Alcohol-based compounds 1)
Example 1 2.169 0.241 0.482 1:0.11 1:0.22 5 95
Example 2 1.928 0.482 0.482 1:0.25 1:0.25 5 95
Example 3 1.687 0.723 0.482 1:0.43 1:0.28 5 95
Example 4 2.41 0.0482 0.482 1:0.02 1:0.20 5 95
Example 5 2.41 0.241 0.482 1:0.10 1:0.20 5 95
Example 6 2.41 0.482 0.482 1:0.20 1:0.20 5 95
Example 7 2.41 0.723 0.482 1:0.30 1:0.20 5 95
Example 8 2.41 0.482 0.482 1:0.20 1:0.20 2 98
Example 9 2.41 0.482 0.482 1:0.20 1:0.20 10 90
Comparative Example 1 2.169 0.241 0.482 1:0.11 1:0.22 0 100
Comparative Example 2 1.928 0.482 0.482 1:0.25 1:0.25 0 100
Comparative Example 3 1.687 0.723 0.482 1:0.43 1:0.28 0 100
Comparative Example 4 2.41 - 0.482 No Pt input 1:0.20 5 95
Comparative Example 5 2.41 0.482 0.482 1:0.20 1:0.20 0 100
[156]
1) As an organic solvent, the amine-based compound and the alcohol-based compound are the amount of the added volume based on 100 parts by volume of the organic solvent.
[157]
[158]
Experimental Example 1: Effect according to whether octylamine was added
[159]
A half cell was prepared by immersing the reduction electrode 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%). The initial voltage of the reduction electrode was measured at a current density of -0.62 A/cm 2 through a linear scanning potential method, and the results are shown in Tables 2 to 5 below.
[160]
Then, the half-cell was treated at a current density of -6 A/cm 2 for 1 hour, and then the voltage of the reduction electrode was measured at a current density of -0.62 A/cm 2 through a linear scanning potential method, and the results are shown below. Tables 2 to 5 are shown.
[161]
[Table 2]
division Ru:Pt:Ce (molar ratio) n-octylamine Initial performance (V) Performance after activation (V)
Example 1 About 4.5:0.5:1.0 input -1.094 -1.102
Comparative Example 1 About 4.5:0.5:1.0 not input -1.103 -1.103
[162]
[Table 3]
division Ru:Pt:Ce (molar ratio) n-octylamine Initial performance (V) Performance after activation (V)
Example 2 About 4.0:1.0:1.0 input -1.087 -1.084
Comparative Example 2 About 4.0:1.0:1.0 not input -1.095 -1.087
[163]
[Table 4]
division Ru:Pt:Ce (molar ratio) n-octylamine Initial performance (V) Performance after activation (V)
Example 3 About 3.5:1.5:1.0 input -1.075 -1.077
Comparative Example 3 About 3.5:1.5:1.0 not input -1.091 -1.085
[164]
[Table 5]
division Ru:Pt:Ce (molar ratio) n-octylamine Initial performance (V) Performance after activation (V)
Example 6 About 5.0:1.0:1.0 input -1.077 -1.079
Example 8 About 5.0:1.0:1.0 input -1.086 -1.087
Example 9 About 5.0:1.0:1.0 input -1.089 -1.087
Comparative Example 5 About 5.0:1.0:1.0 not input -1.095 -1.093
[165]
Referring to Tables 2 to 5, in the case of Example 1 and Comparative Example 1 of Table 2, when n-octylamine is not added, it can be confirmed that both the initial performance and the performance after activation are poor, but n-octylamine In the case of Example 1, it can be seen that there is a significant improvement in initial performance. In addition, in the case of Example 2 and Comparative Example 2 in Table 3, it can be confirmed that there is a significant improvement in initial performance and performance after activation. It can be seen that the degree of this improvement is more markedly shown even in Example 3 and Comparative Example 3 of Table 4.
[166]
In addition, looking at the data in Tables 2 to 4, it is confirmed that when an amine compound such as n-octylamine is added, the overvoltage improvement due to the increase in the Pt content is significant compared to the case where the amine compound is not added. It is confirmed that the increase of Pt and Pt gives a synergistic effect.
[167]
From these results, it could be predicted that when n-octylamine was added during the preparation of the reduction electrode, the performance of the reduction electrode was remarkably improved.
[168]
[169]
Experimental Example 2: Effect of containing two or more platinum group metals
[170]
In the half cell prepared in Experimental Example 1, the initial voltage of the reduction electrode was measured at a current density of -0.62 A/cm 2 through a linear scanning potential method, and the results are shown in Table 3 below. Then, the half-cell was treated for 1 hour at a current density condition of −6 A/cm 2 , and then the voltage of the reduction electrode was measured at a current density of −0.62 A/cm 2 through a linear scanning potential method, and the result is shown below. Table 6 shows.
[171]
[Table 6]
division Ru:Pt:Ce (molar ratio) Initial performance (V) Performance after activation (V)
Example 7 About 5.0:1.5:1.0 -1.071 -1.069
Comparative Example 4 About 5.0:0:1.0 -1.120 -1.094
[172]
In Example 7, it was confirmed that the initial performance and the performance after activation were at the same level or superior to that of Comparative Example 4. From these results, it was predicted that when platinum was added during the production of the cathode, the performance of the cathode was significantly improved. .
[173]
[174]
Experimental Example 3: Effect according to the ratio of two types of platinum group metals
[175]
In the half cell prepared in Experimental Example 1, the initial voltage of the reduction electrode was measured at a current density of -0.62 A/cm 2 through a linear scanning potential method, and the results are shown in Table 3 below. Then, the half-cell was treated for 1 hour at a current density condition of −6 A/cm 2 , and then the voltage of the reduction electrode was measured at a current density of −0.62 A/cm 2 through a linear scanning potential method, and the result is shown below. Table 7 shows.
[176]
[Table 7]
division Ru:Pt:Ce (molar ratio) Initial performance (V) Performance after activation (V)
Example 4 About 5.0:0.1:1.0 -1.098 -1.096
Example 5 About 5.0:0.5:1.0 -1.087 -1.082
Example 6 About 5.0:1.0:1.0 -1.077 -1.079
Example 7 About 5.0:1.5:1.0 -1.071 -1.069
[177]
Looking at the reduction electrode voltage measurement values ​​of Examples 4 to 7, it was confirmed that the initial performance of the reduction electrode and the performance after activation were improved as the amount of platinum increased. From these results, it could be predicted that when platinum was added at an optimal ratio during the production of the cathode, the performance of the cathode was significantly improved.
[178]
[179]
Experimental Example 6: Durability evaluation
[180]
For the half cell prepared in Experimental Example 1, using Portable XRF (Olympus Co., Delta-professional XRF (X-ray Fluorescence spectrometry)), changes in Ru and Ce contents before and after electrolysis were measured, and the results are shown in the table below 8 as described.
[181]
[Table 8]
division Ru before electrolysis Ru after electrolysis Ru Residual Rate Ce before electrolysis Ce after electrolysis Ce residual rate
Example 1 3.07 2.94 95.7 3.61 3.62 100.3
Example 2 3.53 3.48 98.6 3.11 3.29 105.8
Example 3 2.10 2.08 99.0 2.77 2.70 97.5
Example 4 3.09 2.76 89.3 3.32 2.32 69.9
Example 5 3.82 3.75 98.2 3.08 3.07 99.7
Example 6 3.59 3.79 105.5 3.50 3.32 94.8
Example 7 3.75 3.55 94.7 3.31 2.85 86.1
Example 8 3.48 3.41 98.0 3.05 3.00 98.4
Example 9 3.65 3.80 104.1 3.24 3.19 98.5
Comparative Example 1 2.79 2.67 95.7 3.01 2.29 76.1
Comparative Example 2 2.57 2.96 115.2 3.02 2.88 95.4
Comparative Example 3 2.67 1.86 69.6 3.05 2.55 83.6
Comparative Example 4 3.07 2.94 95.7 3.10 2.61 84.2
Comparative Example 5 3.35 3.21 95.8 3.21 2.58 80.4
[182]
Referring to Table 8, it can be seen that Examples 1 to 9 showed significantly higher residual ratios of Ru and Ce before and after electrolysis compared to Comparative Examples 1 to 5. That is, it was confirmed that, as in the present invention, an electrode having excellent durability can be manufactured by including platinum as a catalyst metal together with ruthenium and applying an amine compound during the preparation of the active layer composition.
Claims
[Claim 1]
An active layer composition of a brine electrolysis reduction electrode, comprising: a metal precursor mixture including a ruthenium precursor, a platinum precursor, and a lanthanide metal precursor; and an organic solvent including an alcohol-based compound and an amine-based compound;
[Claim 2]
The active layer composition according to claim 1, wherein the amine-based compound is included in an amount of 0.5 to 10 parts by volume based on 100 parts by volume of the organic solvent.
[Claim 3]
The active layer composition of claim 1, wherein the metal precursor mixture contains 0.01 to 0.7 moles of the platinum precursor based on 1 mole of the ruthenium precursor.
[Claim 4]
The active layer composition of claim 1, wherein the metal precursor mixture contains 0.01 to 0.5 moles of the lanthanide metal precursor based on 1 mole of the ruthenium precursor.
[Claim 5]
The method according to claim 1, 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. phosphorus active layer composition.
[Claim 6]
The method according to claim 1, wherein the lanthanide metal comprises at least one selected from the group consisting of cerium, neodymium, promedium, samarium, europum, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. The active layer composition.
[Claim 7]
The active layer composition according to claim 1, wherein the lanthanide metal comprises cerium.
[Claim 8]
The group of claim 1, 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. An active layer composition comprising at least one selected from
[Claim 9]
The method according to claim 1, 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 10]
metal substrates; And located on the metal substrate, the active layer derived from the active layer composition of claim 1; A reduction electrode comprising a.
[Claim 11]
The reduction electrode of claim 10, further comprising a hydrogen adsorption layer on the active layer, wherein the hydrogen adsorption layer comprises at least one selected from the group consisting of tantalum oxide, nickel oxide, and carbon.