technical field
[One]
Cross-Citation with Related Applications
[2]
This application claims the benefit of priority based on Korean Patent Application No. 10-2019-0119109 dated September 26, 2019, and all contents disclosed in the literature of the Korean patent application are incorporated as a part of this specification.
[3]
[4]
technical field
[5]
The present invention relates to a composition for forming tin oxide capable of forming tin oxide with high yield, and a method for forming tin oxide using 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 chlor-alkali process, 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 cathode, is currently the most widely used is being used
[9]
On the other hand, the chlor-alkali process is made through a reaction as shown in the following electrochemical reaction formula.
[10]
Anode reaction: 2Cl - → Cl 2 + 2e - (E 0 = +1.36 V)
[11]
Cathode reaction: 2H 2O + 2e - → 2OH - + H 2 (E 0 = -0.83 V)
[12]
Overall reaction: 2Cl - + 2H 2O → 2OH - + Cl 2 + H 2 (E 0 = -2.19 V)
[13]
[14]
In carrying out the electrolysis of brine, the electrolysis voltage must consider all of the voltages required for the electrolysis of the brine in theory, the overvoltage of the anode, the overvoltage of the cathode, the voltage due to the resistance of the ion exchange membrane, and the voltage due to the distance between the anode and the cathode, Among these voltages, the overvoltage by the electrode is acting as an important variable.
[15]
Accordingly, a method for reducing the overvoltage of the electrode is being researched. 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 low overvoltage and durability for the anode is also developed. this is being requested
[16]
Stainless steel or nickel has been mainly used as such anode, and recently, in order 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]
However, among the methods for introducing a coating layer on the electrode surface as described above, when a coating layer containing tin is introduced, the tin yield in the coating layer is low due to the high volatility of intermediate products that may occur during the coating layer introduction process, and the coating layer composition is also not uniform. There is a problem, and the scattered coating layer may cause equipment contamination. In order to solve this problem, there is a case where a tin precursor having complex ions is used, but in this case, since a complex synthesis process is required, there is a problem in that it is difficult to prepare the precursor and the cost is increased.
[18]
[19]
Prior art literature
[20]
(Patent Document 1) KR 2017-0086104A
[21]
(Patent Document 2) KR 2006-0052940A
[22]
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[23]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a composition for forming tin oxide capable of forming tin oxide with a high yield while being simple to manufacture, and a method for forming tin oxide using the same.
means of solving the problem
[24]
In order to solve the above problems, the present invention provides a composition for forming tin oxide comprising a tin precursor, a sulfate ion and a solvent, wherein the molar ratio of sulfate ion to tin (sulfate ion/tin) is 1 or more.
[25]
In addition, the present invention provides a tin oxide forming method comprising the step (S1) of sintering the composition for forming tin oxide at a temperature of 480 ℃ or higher.
Effects of the Invention
[26]
The composition for forming tin oxide according to the present invention is economical because it is easy to manufacture, can form tin oxide with a high yield, and can be applied in the same manner to the conventional electrode manufacturing process.
Brief description of the drawing
[27]
1 shows an XRD graph when the composition for forming tin oxide according to an embodiment of the present invention is calcined at different temperatures.
Modes for carrying out the invention
[28]
Hereinafter, the present invention will be described in more detail.
[29]
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.
[30]
[31]
Composition for forming tin oxide
[32]
The inventors of the present invention can suppress volatilization of an intermediate product in the process of forming tin oxide from a tin precursor when the tin precursor and the sulfate ion exist simultaneously, and the molar ratio of the sulfate ion and the tin in the composition is 1 or more, Accordingly, it was discovered that the yield of finally formed tin oxide can be dramatically increased, thereby completing the present invention.
[33]
[34]
Specifically, the present invention provides a composition for forming tin oxide comprising a tin precursor, a sulfate ion, and a solvent, wherein the molar ratio of sulfate ion to tin (sulfate ion/tin) is 1 or more.
[35]
[36]
Tin oxide is formed from the tin precursor, and any tin precursor that can be converted into tin oxide under high temperature conditions may be used. For example, the tin precursor may be an ion of tin itself, that is, a tin ion, or a tin halide compound including tin (II or IV) chloride (including hydrates of tin halide compounds), tin isopropoxide It may be a compound selected from the group consisting of tin alkoxide compound, tin acetate, tin sulfate, and tin 2-ethylhexanoate. When such a tin precursor is used, it is easy to form tin oxide thereafter, and the tin precursor can be uniformly distributed in the solvent, so that tin oxide having uniform physical properties can be formed.
[37]
[38]
The concentration of the tin precursor in the composition for forming tin oxide may vary depending on the type of the tin precursor, the type of the solvent, and the solubility of the tin precursor in the solvent, but generally 0.01 to 10 M, based on the tin ion; Preferably, it may be 0.05 to 5M. When the concentration of the tin precursor is lower than this, the amount of tin oxide formed is small, so it may not be economical in terms of cost. It is difficult to handle and, in some cases, deposits may occur and the formation of tin oxide may not be uniform.
[39]
[40]
The sulfate ion (SO 4 2-) serves to suppress the volatilization of an intermediate product generated in the process from the tin precursor to the formation of tin oxide, thereby increasing the yield of finally produced tin oxide. The sulfate ion may be dissolved in the solvent and added to the solvent in the form of a compound capable of generating sulfate ions, for example, sulfuric acid (H 2SO 4 ), sodium sulfate (Na 2SO 4 ), calcium sulfate (CaSO 4 ), sulfuric acid It may be produced by dissolving at least one compound selected from the group consisting of potassium (K 2SO 4) and ammonium sulfate ((NH 4) 2SO 4) in a solvent.
[41]
The concentration of sulfate ions in the composition for forming tin oxide may vary depending on the type and concentration of the tin precursor in the composition or the type of solvent, but may be generally 0.01 to 10M, preferably 0.05 to 5M. If the concentration of sulfate ions is less than this, the function of sulfate ions is not sufficiently exhibited, and the yield of tin oxide is lowered.
[42]
[43]
Meanwhile, the molar ratio of sulfate ion to tin in the composition provided by the present invention (sulfate ion/tin) may be 1 or more, preferably 3 or more. Also, it may be 20 or less or 15 or less, preferably 10 or less. If the molar ratio of the sulfate ion component to the tin component in the composition is less than this, the function of the sulfate ion described above may not be sufficiently realized, and the yield of tin oxide formed from the composition of the present invention may be low. Conversely, if the molar ratio of the sulfate ion component to the tin component in the composition is greater than this, a problem such as excessively present sulfate ion remains as an impurity even after the formation of tin oxide may occur.
[44]
[45]
The solvent serves to uniformly dissolve the tin precursor and the sulfate ion, and as the solvent, the tin precursor and the sulfate ion have solubility, but do not adversely affect the tin oxide production in the subsequent tin oxide production step. It can be used without any particular limitation as long as it can be easily removed. In particular, one or more selected from the group consisting of water, alcohols (eg, ethanol, isopropanol or n-butanol), and ketones (eg, dimethyl ketone, diethyl ketone or methyl ethyl ketone) may be used as a solvent, In particular, at least one selected from the group consisting of water, ethanol, isopropanol, n-butanol and methyl ethyl ketone is preferable. When such a solvent is used, the stability of the composition for forming tin oxide can be ensured, and the subsequent uniform tin oxide formation is possible.
[46]
[47]
On the other hand, the solvent may further include an additional component to improve the dispersibility of the dissolved solute or to improve solubility. For example, ethoxy ethanol or butoxy ethanol may be further included to improve the dispersibility of the solute, and hydrochloric acid or hydrogen peroxide may be further included to improve solubility.
[48]
[49]
In the present invention, the composition for forming tin oxide may further include a platinum group precursor.can When the composition for forming tin oxide further includes a platinum group precursor, a composite metal oxide including tin oxide and platinum group oxide may be finally formed.
[50]
As the platinum group precursor, a ruthenium precursor and/or an iridium precursor may be used. Specifically, when the platinum group precursor is a ruthenium precursor, ruthenium hexafluoride (RuF 6), ruthenium (III) chloride (RuCl 3), ruthenium (III) ) chloride hydrate (RuCl 3 ×H 2O), ruthenium (III) nitrosyl chloride (Ru (NO) Cl 3), hexaammine ruthenium (III) chloride (Ru (NH 3) 6Cl 3), ruthenium (III) bromide ( At least one compound selected from the group consisting of RuBr 3), ruthenium (III) bromide hydrate (RuBr 3·xH 2O), ruthenium iodide (RuI 3), and ruthenium acetate may be used as a platinum group precursor, preferably ruthenium (III) chloride hydrate (RuCl 3·xH 2O), ruthenium (III) nitrosyl chloride (Ru(NO)Cl 3), hexaammine ruthenium (III) chloride (Ru(NH 3) 6Cl 3) and ruthenium acetate One or more selected from the group may be used. When the above-listed ruthenium precursor is used, there is an advantage in that the composite metal oxide including ruthenium oxide and tin oxide can be easily formed and the yield is high.
[51]
[52]
Meanwhile, in the present invention, when the platinum group precursor is an iridium precursor, one selected from the group consisting of iridium chloride hydrate (IrCl 3·xH 2O) and hydrogen hexachloroiridate hexahydrate (H 2IrCl 6·6H 2O) The above compounds may be used as a platinum group precursor. As in the case of the ruthenium precursor, when the above-listed iridium precursors are used, the formation of a composite metal oxide including iridium oxide and tin oxide is easy, and the yield is high.
[53]
[54]
How to form tin oxide
[55]
The present invention provides a method for forming tin oxide using the above-described composition for forming tin oxide. Specifically, the present invention provides a tin oxide forming method comprising the step (S1) of calcining the above-described composition for forming tin oxide at a temperature of 480 ℃ or higher.
[56]
Due to the high-temperature calcination in this step, the tin precursor is converted to tin oxide in the presence of sulfate ions, and the calcination temperature may be 480°C or higher, preferably 550°C or higher in order to supply sufficient energy for conversion. If the calcination temperature is lower than this, sufficient energy for conversion to oxide may not be supplied, so uniform tin oxide formation may not be achieved. Sulfate ions contained in the composition for forming can be smoothly removed.
[57]
Firing in this step may be carried out for 30 minutes or more, preferably for 60 minutes or more. If the firing time is shorter than this, sufficient tin oxide may not be formed.
[58]
Firing in this step may be performed immediately in the state of the composition, or may be performed after the composition is applied to another object. For example, the composition for forming tin oxide may be coated on a metal substrate and then fired to form a coating layer including tin oxide on the surface of the metal substrate. The application may be performed, for example, 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. In the case of firing the composition after coating as described above, the process of coating and firing may be repeated a plurality of times.
[59]
[60]
The method for forming tin oxide of the present invention may further include drying (S0) at a temperature of 50 to 300° C., preferably 50 to 200° C., before firing. When the drying step is performed before firing, tin oxide may be more easily formed. The drying may be performed for 5 to 60 minutes, preferably 5 to 30 minutes.
[61]
[62]
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.
[63]
[64]
Example 1
[65]
A composition for forming tin oxide was prepared by dissolving tin(II) chloride dihydrate and sulfuric acid (H 2SO 4 ) in deionized water as a solvent. The molar ratio of sulfate ions (SO 4 2-) to the tin component in the composition was set to 3.
[66]
[67]
Example 2
[68]
A composition for forming tin oxide was prepared in the same manner as in Example 1 except that tin 2-ethylhexanoate was dissolved as a tin precursor.
[69]
[70]
Example 3
[71]
A composition for forming tin oxide was prepared in the same manner as in Example 1 except that tin sulfate (SnSO 4) was directly dissolved.
[72]
[73]
Example 4
[74]
A composition for forming tin oxide was prepared by dissolving ruthenium chloride trihydrate, iridium chloride trihydrate and tin(II) chloride dihydrate in an excess of 1M aqueous sulfuric acid so that the molar ratio of Ru:Ir:Sn was 35:20:45. . The molar ratio of sulfate ion (SO 4 2-) to the tin component in the composition was set to 8
[75]
[76]
Example 5
[77]
A composition for forming tin oxide was prepared in the same manner as in Example 4 except that tin sulfate was directly dissolved as a tin precursor.
[78]
[79]
Comparative Example 1
[80]
A composition for forming tin oxide was prepared in the same manner as in Example 1, except that sulfuric acid was not dissolved.
[81]
[82]
Comparative Example 2
[83]
A composition for forming tin oxide was prepared in the same manner as in Example 2, except that sulfuric acid was not dissolved.
[84]
[85]
Comparative Example 3
[86]
A composition for forming tin oxide was prepared in the same manner as in Example 1, except that the molar ratio of sulfate ions (SO 4 2-) to the tin component in the composition was 0.7.
[87]
[88]
Comparative Example 4
[89]
A composition for forming tin oxide was prepared in the same manner as in Example 4 except that n-butanol was used as a solvent.
[90]
[91]
The components and content ratios of the compositions for forming tin oxide prepared in Examples and Comparative Examples are summarized in Table 1 below.
[92]
[Table 1]
Metal Precursor Solvent Sulfate Ion/Tin Molar Ratio
Example 1 Tin Chloride Dihydrate Water 3
Example 2 Tin Ethylhexanoate Water 3
Example 3 Tin Sulfate Water 3
Example 4 Ruthenium Chloride Trihydrate/Iridium Chloride Trihydrate/Tin Chloride Dihydrate (35:20:45) Water 8
Example 5 Ruthenium chloride trihydrate/iridium chloride trihydrate/tin sulfate (35:20:45) water 8
Comparative Example 1 Tin Chloride Dihydrate Water 0
Comparative Example 2 Tin Ethylhexanoate Water 0
Comparative Example 3 Tin Chloride Dihydrate Water 0.7
Comparative Example 4 Ruthenium chloride trihydrate/iridium chloride trihydrate/tin chloride dihydrate (35:20:45) n-butanol 0
[93]
[94]
Experimental Example 1. Confirmation of yield of the prepared composition for forming tin oxide
[95]
The compositions for forming tin oxide prepared in Examples 1 to 4 and Comparative Examples 1 to 2 were calcined, and the yield was calculated from the weight of the tin oxide obtained as a result of calcination. The yield was calculated using Equations 1 and 2 below, and the results are shown in Table 2.
[96]
[Equation 1]
[97]
Yield = {(weight of sample after firing)/(number of moles of Sn in sample before firing X molecular weight of SnO 2)} X 100
[98]
In Examples 1 to 3 and Comparative Examples 1 to 2 including only a tin precursor as a metal precursor, the yield was calculated by Equation 1 above.
[99]
[Equation 2]
[100]
Yield = (weight of sample after firing)/{(number of moles of Ru in sample before firing X molecular weight of RuO 2)+(number of moles of Ir in sample before firing X molecular weight of IrO 2)+(number of moles of Sn in sample before firing X Molecular weight of SnO 2)} X 100
[101]
In the case of Example 4 including ruthenium and iridium precursors in addition to the tin precursor as the metal precursor, the yield was calculated by Equation 2 above.
[102]
[103]
[Table 2]
Metal sample weight (g) Sample weight after firing (g) Yield (%) Firing temperature (℃) Firing time (min)
Example 1 1.2063 0.7977 99.0 550 60
Example 2 1.1554 0.4238 98.6 550 60
Example 3 1.0898 0.7344 100.9 550 60
Example 4 1.7180 1.0050 97.0 550 60
Comparative Example 1 1.0189 0.2634 43.8 480 60
Comparative Example 2 1.0922 0.2026 53.5 480 60
Comparative Example 3 0.8375 0.4580 81.9 550 60
[104]
From the above results, a higher yield is shown when the composition for forming tin oxide of Examples of the present invention containing both a tin precursor and a sulfate ion is calcined. If not, it was confirmed that a sufficient degree of yield could not be obtained.
[105]
[106]
Experimental Example 2. Confirmation of XRD and yield change according to calcination temperature
[107]
In addition, XRD was confirmed by changing the firing temperature to 450°C, 480°C, 530°C, 550°C and 580°C, and it is shown in FIG. 1 using pure SnO 2 as a control.
[108]
As shown in FIG. 1 , it was confirmed that tin oxide was not easily formed when calcined at a temperature of less than 480° C., and it was confirmed that most tin precursors were converted to tin oxide at a temperature of 480° C. or higher.
[109]
[110]
In addition, the composition for forming tin oxide of Example 1 was different from each other. The yield was calculated by calcination at two temperatures. The results are shown in Table 3 below.
[111]
[112]
[Table 3]
Firing temperature (℃) Metal sample weight (g) Sample weight after firing (g) Yield (%)
550 1.2063 0.7977 99.0
480 1.0922 0.9774 134.0
[113]
[114]
From Table 3, when the calcination temperature was less than 550 °C, it was confirmed that the yield exceeded 100%, which was confirmed because sulfate ions were not completely removed. In relation to this, as a result of elemental analysis of the results obtained when the yield exceeds 100%, the sulfur content was calculated to be 7.6%.
[115]
[116]
On the other hand, when the calcination temperature was 550° C. or higher, most of the sulfate ions were removed, and it was confirmed that the yield converges to 100%. Accordingly, when the composition for forming tin oxide of the present invention is used, it is necessary to form tin oxide, but in a region unrelated to sulfate ions, calcination is performed at a relatively low temperature to reduce energy consumption in the calcination process. In the region where removal of sulfate ions is important, it was confirmed that most of the sulfate ions could be removed by calcining at a temperature of 550° C. or higher.
[117]
[118]
Experimental Example 3. EDS analysis when electrode is applied
[119]
The titanium extension substrate blasted with white alumina was pretreated in 10% oxalic acid aqueous solution (90° C.) for 2 hours to form irregularities, washed with distilled water and dried to prepare a metal substrate. The compositions for forming tin oxide of Examples 4 and 5 and Comparative Example 3 were applied to the prepared metal substrate, dried at 70° C., and fired at 550° C. for 10 minutes. The coating, drying, and firing were repeated until the amount of the composition was 20 g/m 2 , and then finally fired at 550° C. for 60 minutes to prepare an electrode. EDS analysis of the prepared electrode surface was performed to calculate the molar ratio of each metal component present in the electrode coating layer, which is shown in Table 4.
[120]
[121]
[Table 4]
EDS analysis result (mol%)
Ru Ir Sn
Example 4 34.0 18.0 48.0
Example 5 36.6 18.4 45.0
Comparative Example 4 42.6 24.8 32.6
[122]
[123]
As a result of EDS analysis, in Examples 4 and 5, the ratio of each metal component of the electrode coating layer was similar to the ratio of each metal precursor in the composition for forming tin oxide, so that most of the tin precursor was converted to oxide like ruthenium and iridium, whereas , in Comparative Example 3, the ratio was different, and it was confirmed that the tin precursor was converted to tin oxide in a relatively small amount compared to ruthenium and iridium.
Claims
[Claim 1]
A composition for forming tin oxide comprising a tin precursor, a sulfate ion and a solvent, wherein the molar ratio of sulfate ion to tin (sulfate ion/tin) is 1 or more.
[Claim 2]
The composition for forming tin oxide according to claim 1, wherein the molar ratio of sulfate ion to tin (sulfate ion/tin) is 3 to 10.
[Claim 3]
The composition for forming tin oxide according to claim 1, wherein the tin precursor is at least one selected from the group consisting of tin ions, tin halogenated compounds, tin alkoxide compounds, tin acetate, tin sulfate, and tin 2-ethylhexanoate.
[Claim 4]
The composition for forming tin oxide according to claim 1, wherein the solvent is at least one selected from the group consisting of water, alcohols, and ketones.
[Claim 5]
The composition for forming tin oxide according to claim 1, wherein the concentration of sulfate ions in the composition is 0.01 to 10M.
[Claim 6]
The composition for forming tin oxide according to claim 1, wherein the concentration of tin ions in the composition is 0.01 to 10M.
[Claim 7]
The composition for forming tin oxide according to claim 1, further comprising a platinum group precursor.
[Claim 8]
8. The method of claim 7, wherein the platinum group precursor is ruthenium hexafluoride (RuF 6), ruthenium (III) chloride (RuCl 3), ruthenium (III) chloride hydrate (RuCl 3·xH 2O), ruthenium (III) nitrosyl chloride (Ru(NO)Cl 3), hexaammine ruthenium (III) chloride (Ru(NH 3) 6Cl 3), ruthenium (III) bromide (RuBr 3), ruthenium (III) bromide hydrate (RuBr 3·xH 2O), A composition for forming tin oxide, which is at least one compound selected from the group consisting of ruthenium iodide (RuI 3) and ruthenium acetate.
[Claim 9]
The tin oxide according to claim 7, wherein the platinum group precursor is at least one compound selected from the group consisting of iridium chloride hydrate (IrCl 3·xH 2O) and hydrogen hexachloroiridate hexahydrate (H 2IrCl 6·6H 2O). Forming composition.
[Claim 10]
A method of forming tin oxide comprising a; (S1) calcining the composition for forming tin oxide of claim 1 at a temperature of 480° C. or higher.
[Claim 11]
The method of claim 10 , further comprising: drying (S0) at a temperature of 50 to 300° C. prior to sintering.
[Claim 12]
The method of claim 10 , wherein the sintering is performed for 30 to 120 minutes.
[Claim 13]
The method of claim 10 , wherein the firing temperature is 550° C. or higher.