KR20060025079A - Ph sensing electrode having a solid-state electrolyte layer and ph measuring system containing same - Google Patents

Abstract

The present invention relates to an integrated hydrogen ion sensor electrode and a pH measurement system using the same, and more particularly, a conductive current collector, at least one metal / metal oxide composite layer and at least one oxygen ion conductive solid electrolyte layer. It relates to a hydrogen ion sensor electrode and a pH measurement system using the same. A metal / metal oxide composite layer is positioned on the conductive current collector, and an oxygen ion conductive solid electrolyte layer is positioned thereon.

Hydrogen ion sensor electrode according to the present invention is configured as described above is a solid electrolyte layer and a metal / metal oxide layer is made of a thin film, the electron transfer is smooth and the impedance is low, the electrode reaction rate is improved, wide temperature range of high temperature aqueous solution In particular, accurate pH measurements are possible even at relatively low temperatures (eg 150 ° C). In particular, since the diameter of the hydrogen ion sensor electrode can be significantly reduced, it can be utilized in a micro space of 2 mm or less, and the manufacturing cost is low.

Integrated hydrogen ion sensor, pH sensor, pH measuring system, oxygen ion conductive solid electrolyte

Description

Hydrogen ion sensor electrode having a solid electrolyte layer and pH measurement system using the same {pH sensing electrode having a solid-state electrolyte layer and pH measuring system containing same}

1 is a schematic diagram of a pH sensor electrode according to the present invention,

2 is a graph showing a result of measuring pH using a sensor electrode and a conventional sensor electrode according to an embodiment of the present invention,

3 is a graph showing an electrochemical impedance measurement result of a sensor electrode according to an exemplary embodiment of the present invention.

Figure 4 is a graph comparing the electrochemical impedance measurement results of the sensor electrode and the conventional sensor electrode according to an embodiment of the present invention.

 The present invention relates to a novel hydrogen ion sensor electrode having a solid electrolyte layer and a pH measuring system using the same, and more particularly, to a metal / metal oxide composite layer and an oxygen ion conductive solid electrolyte layer. The present invention relates to a new concept of hydrogen ion sensor electrode and pH measuring system using the same, which has high reliability as a result of pH measurement in a wider temperature range, is applicable to pH measurement of a solution in a microcavity, and is also advantageous in terms of manufacturing cost.

Conventionally, various pH electrodes for measuring pH, such as aqueous solution, have been developed. For example, Korean Patent Application No. 1978-1723 discloses a composite electrode for measuring pH, etc., which can measure ions, ORP, pH, etc., and Korean Patent Application No. 1980-3262 discloses pH and pH of a chemical copper plating solution. Disclosed is a main electrode for pH measurement, in which a reducing agent concentration can be converted into a pH value and measured accurately continuously for a long time.

However, the above-described conventional inventions and the like only disclose a pH electrode for measuring pH at a normal temperature.

Meanwhile, the pH (-log [H ⁺ ]) measuring electrode developed for application to high temperature aqueous solution includes hydrogen electrode, palladium-hydrogen (Pd-H) electrode, metal / metal oxide electrode, and oxygen ion conductivity. Metal / metal oxide electrodes based on ceramic films.

First, the electrode reaction and potential of the hydrogen electrode are expressed as follows.

Electrode reaction: 2H ^{+ _{(solution) + 2e - → H 2 (}} Pt)

Potential: E =-(2.303RT / 2F) log ( f _H2 )-(2.303RT / F) pH

Application temperature range for pH measurement of the hydrogen electrode is known to be 25 ~ 300 ℃. However, the electrode is a hydrogen, and the molecule has to be present in solution, the need to know in order to have a restriction that it can only work with a stable system to the reduction by hydrogen, and further calculates the exact potential hydrogen bankrupt capacity (fugacity (f _H2)) It is also not easy to measure, which is disadvantageous in actual use.

Second, the electrode reaction of the palladium-hydrogen (Pd-H) electrode is expressed as follows.

Electrode reaction: H ^{+ (solution) + e - → H (Pd} )

The practical application temperature range of the electrode is known to be 25 to 200 ° C. However, in general, in the measurement of pH of a high temperature aqueous solution, at least 300 ° C. of the applicable temperature is required, the electrode may not be preferably used for measuring a pH of a high temperature aqueous solution because the application temperature range is narrow. Moreover, a more fundamental limitation of the electrode is that the sensor electrode cannot be used as a pH measuring electrode in a solution containing an oxidizing agent such as dissolved oxygen.

Third, in the case of the metal / metal oxide electrode, except for the W / WO ₃ system, there is a disadvantage in that accurate pH cannot be measured because Nernstian pH behavior is not exhibited. On the other hand, the electrode reaction and the potential of the W / WO ₃ system showing the Nernian pH behavior of the metal / metal oxide electrode is expressed as follows.

Electrode reaction: WO ₃ ⁺ 6H + ^{(solution) + 6e - → W + 3H} 2 O

Potential: E = E ^o _{W /} WO3-(2.303RT / F) pH

However, since the practical application temperature range of the electrode is known to be 25 to 200 ° C., it cannot be preferably used for pH measurement of a high temperature aqueous solution as in the case of the palladium-hydrogen (Pd-H) electrode. In addition, there are disadvantages in that the chemical form of tungsten oxide is very diverse and difficult to use due to its poor durability.

Finally, the metal / metal oxide electrode based on the oxygen ion conductive ceramic film is currently used most because the ceramic film has chemical resistance and thus can be applied to various chemical environments. The yttria-stabilized zirconia (YSZ) sensor electrode (M / MO | YSZ | H ⁺ , H ₂ O) having excellent oxygen ion conductivity and good mechanical strength is most widely used as the ceramic membrane.

The total electrode reaction and potential of the electrode are as follows.

The electrode ^{reaction: MO x + 2 x H +} ( solution) x 2 + e ^- → M x + H ₂ O

Potential: E = E ^o _{M / MO x-} (2.303RT / F) pH

Looking at the total electrode reaction equation and the potential equation, the potential does not seem to have anything to do with the ceramic film. However, the actual measured potential may vary depending on the type of ceramic film. Oxygen ion conduction occurs in the ceramic membrane, and the potential measured only depends on the pH of the solution if the conductivity is high enough. In other words, the potential measured in the ceramic membrane with poor oxygen ion conductivity does not accurately reflect the pH of the solution.

Conventional technologies for metal / metal oxide electrodes based on the oxygen ion conductive ceramic membranes include US Pat. Nos. 4,264,424 and 6,551,478.

The U.S. Patent No. 4,264,424 (GE, USA) relates to a metal / metal oxide hydrogen ion sensor electrode based on an oxygen ion conductive ceramic film. The main components of the ceramic film are zirconium oxide, thorium oxide, Cerium oxide, lanthanum oxide, etc. are used, yttria, scandia, calcia, magnesia, etc., are used as additives, and internal electrodes are also used. A hydrogen ion sensor electrode using copper / copper oxide, iron / ferrous oxide + magnetite, or the like is disclosed as a material.

In addition, U. S. Patent No. 6,551, 478 (U.S. Department of Energy) discloses a sensor electrode consisting of a flexible tube, an oxygen ion conductive ceramic plug located at the end of the tube, and a metal / metal oxide electrode reaction system. In this patent, Teflon is described as the material of the tube, and stabilized zirconia is described as the material of the ceramic plug. In addition, as the electrode reaction system, copper / copper oxide, iron / iron oxide, silver / silver oxide, nickel / nickel oxide, mercury / mercury oxide, and the like are described.

The conventional ceramic membrane-based hydrogen ion sensor electrode is the most widely used at present because of the applicability to various chemical environments, high precision and excellent durability due to chemical inertness of the ceramic membrane.

However, hydrogen ion sensor electrodes known to date have some problems as follows.

First, the YSZ membrane-based sensor electrode, which has a relatively high performance among ceramic membrane-based hydrogen ion sensor electrodes, tends to increase the impedance of the sensor electrode at a relatively low temperature region of less than 180 ° C except for the Hg / HgO system. Because of this, the sensor electrode does not show the Nernstian pH behavior, and as a result, a large error occurs in pH measurement of the solution, and thus cannot be used preferably. On the other hand, in the Hg / HgO system, which can measure pH more accurately even at a relatively low temperature range due to the relatively wide application temperature range, Hg, which is a material used, is not an environmentally friendly material. .

Second, the conventional ceramic membrane-based hydrogen ion sensor electrode has a disadvantage that it is difficult to measure pH in a micro space due to the large size of the sensor.

Finally, in the case of the conventional ceramic membrane-based hydrogen ion sensor electrode, there is a disadvantage that the manufacturing cost is too expensive.

Thus, the inventors of the present invention show the pH behavior of Nernstian at a low temperature in the hydrogen ion sensor electrode, so that it is possible to measure pH more accurately in the entire temperature range of the high temperature aqueous solution, and also to reduce the size and manufacturing cost of the sensor electrode. As a result of intensive studies to provide a hydrogen ion sensor electrode, the present invention has been completed by developing a sensor electrode having a new structure capable of reducing the electrochemical impedance and reducing the size of the sensor electrode by an appropriate method.

Therefore, the object of the present invention is to solve the problems of the conventional hydrogen ion electrode sensor shows a high accuracy even at a low temperature of the high-temperature aqueous solution to be measured, can be applied to the pH measurement of the solution in the microcavity, and further the low manufacturing cost It is to provide a hydrogen ion sensor electrode of the structure.

Another object of the present invention is to provide a pH measurement system using the hydrogen ion sensor electrode.

In order to achieve the above object, the present invention;

In the hydrogen ion sensor electrode, the hydrogen ion sensor electrode provides a hydrogen ion sensor electrode is formed by sequentially forming a conductive current collector, a metal / metal oxide composite layer and an oxygen ion conductive solid electrolyte layer. .

In addition, the present invention;

i) a hydrogen ion sensor electrode comprising a conductive current collector, a metal / metal oxide composite layer and an oxygen ion conductive solid electrolyte layer;

ii) high temperature reference electrode; And

iii) providing a pH measuring system comprising a voltage measuring device having a high input impedance.

In the hydrogen ion sensor electrode according to the present invention, the metal / metal oxide composite layer of the electrode is located on the conductive current collector, and the oxygen ion conductive solid electrolyte layer is located on the metal / metal oxide composite layer.

In the hydrogen ion sensor electrode according to the present invention, the conductive current collector is copper, iron, silver, platinum, gold, nickel, cobalt, zinc, tungsten, titanium (Ti), iridium (Ir), rhodium (Rh), zirconium (Zr), palladium (Pd), tin (Sn), metals surface-treated with them, combinations thereof, and alloys thereof.

In the hydrogen ion sensor electrode according to the present invention, the main metal of the metal / metal oxide composite layer is specifically copper, iron, silver, platinum, gold, nickel, cobalt, zinc, tungsten, titanium (Ti), iridium ( Ir), rhodium (Rh), zirconium (Zr), palladium (Pd), tin (Sn), combinations thereof, and alloys thereof.

In the hydrogen ion sensor electrode according to the present invention, the oxygen ion conductive solid electrolyte is a main component and yttrium selected from the group consisting of zirconium (Zr) oxide, thorium (Th) oxide, bismuth (Bi) oxide and cerium (Ce) oxide And one or more dopants selected from the group consisting of (Y) oxides, magnesium (Mg) oxides, calcium (Ca) oxides, scandium (Sc) oxides, erbium (Er) oxides, and samarium (Sm) oxides.

The high temperature reference electrode may be one of a silver / silver chloride (Ag / AgCl) electrode, a platinum / hydrogen (Pt / H ₂ ) electrode, and a palladium / hydrogen (Pd-H) electrode.

The input impedance of the electrometer measuring the voltage between the hydrogen ion sensor and the reference electrode is preferably 10 ⁸ ohm or more, more preferably 10 ¹⁰ ohm or more and most preferably 10 ¹² ohm. That's it.

Hereinafter, the present invention will be described in more detail.

The present invention can more accurately measure the pH of a solution in a wider temperature range, especially in a relatively low temperature region, in high temperature pH measurement such as 100 to 300 ° C., and therefore can be applied over a wide range of temperature ranges. In order to provide a pH measurement system that is applicable to pH measurement and particularly advantageous in terms of manufacturing cost, the pH measurement system, as described above, comprises: i) a conductive current collector, a metal / metal oxide composite layer and an oxygen ion conductivity; A hydrogen ion sensor electrode comprising a solid electrolyte layer; ii) high temperature reference electrode; And iii) a voltage meter with a high input impedance.

In the structure of the hydrogen ion sensor electrode according to the present invention, a metal / metal oxide composite layer is present on the conductive current collector, and an oxygen ion conductive solid electrolyte layer is present thereon. Thus, only the oxygen ion conductive solid electrolyte layer is exposed to the solution. Looking at the principle that the hydrogen ion concentration is detected by the hydrogen ion sensor electrode according to the present invention configured as described above are as follows. First, there is a reaction (A) in which water is generated by the reaction of hydrogen ions in the solution with oxygen ions in the ceramic lattice at the solution-side interface of the solid electrolyte made of ceramic material, and then the concentration of oxygen ions in the solid electrolyte. The migration phenomenon (B) due to the diffusion due to the slope appears, and the electrode reaction (C) of the metal / metal oxide occurs at the metal / metal oxide composite layer interface of the solid electrolyte. Looking at the detailed reaction occurring in the hydrogen ion sensor electrode as follows.

A. Solution-side interface: 2 x H ⁺ (solution) + O ^2- (solid electrolyte) → H ₂ O

B. Solid electrolyte interior: Oxygen ion migration

C. The solid electrolyte inside ^{interface: MO x + 2 x e -} → M + O 2- ( solid electrolyte)

When the three reactions (A to C) are combined, the following overall reaction formula can be obtained.

The electrode reaction ^{scheme: MO x + 2 x H +} ( solution) x 2 + e ^- → M x + H ₂ O

As a result, the hydrogen ion concentration of the solution affects the oxygen ion concentration of the solid electrolyte layer, and the oxygen ion concentration of the solid electrolyte layer affects the electrode reaction of the metal / metal oxide.

The Nernst equation of the total electrode reaction is as follows.

Potential: E = E ^o _{M / MO x-} (2.303RT / F) pH

Thus, as can be seen from the above potential equation, since the potential depends only on the concentration of hydrogen ions in the solution, the pH of the solution can be calculated from the potential measured at the hydrogen ion sensor electrode.

In order for the sensor electrode to show the Nernian pH behavior even at a low temperature, the electrochemical impedance of the sensor electrode should be lowered. The main components of the sensor electrode impedance are impedance due to oxygen ion movement inside the solid electrolyte and impedance due to electrode reaction of the internal electrode material. In order to lower the impedance due to oxygen ion migration even at a low temperature, it may be proposed to reduce the thickness of the ceramic film or to change the type of the ceramic film. As described above, in the present invention, oxygen ions, among the main impedances of the hydrogen ion sensor electrode, may be proposed. Improving the electrochemical reaction rate by greatly reducing the impedance due to the movement.

That is, in the conventional ceramic film-based sensor electrode, the thickness of the ceramic film has a problem such that the impedance due to the movement of oxygen ions is very high in a relatively low temperature range of 200 ° C. or less, but the present invention constituted as described above. The electrode sensor significantly improves the rate of electrode reaction by using the method of remarkably reducing the thickness of solid electrolyte to reduce the impedance caused by oxygen ion migration.

Hereinafter, a detailed manufacturing process of the hydrogen ion sensor electrode according to the present invention will be described in detail.

Fabrication of the hydrogen ion sensor electrode according to the present invention can be divided into two types depending on whether or not the conductive current collector participates as an oxidized species or reduced species in the electrochemical redox reaction. have. The shape of the conductive current collector may include a wire, plate, or rod shape.

First, the conductive current collector participates in an electrochemical redox reaction as well as a lead wire of simple electron transfer. In this case, the conductive current collector and the metal of the metal / metal oxide composite are the same. The metal / metal oxide composite layer is positioned on the current collector metal surface using a variety of methods. The method of manufacturing the metal / metal oxide composite layer includes a method of oxidizing a metal surface, a method of attaching a metal oxide to the surface of metal particles, and the like. Metal surface oxidation methods include oxidation in air, oxidation by heat under oxygen atmosphere, chemical oxidation by solution under various chemical conditions, and the like. Physical chemical bonding methods include plasma spray coating, deposition by active sputtering, spin coating, pressing, and the like. The conductive current collector may be copper, iron, silver, platinum, gold, nickel, cobalt, zinc, tungsten, titanium (Ti), iridium (Ir), rhodium (Rh), zirconium (Zr), palladium (Pd), tin ( Sn), metals surface-treated with them, combinations thereof, and alloys thereof. A solid electrolyte layer through which oxygen ions selectively pass is formed on the metal / metal oxide composite layer of the conductive current collector. The solid electrolyte layer may be formed by a known method such as plasma spray coating, deposition by active sputtering, spin coating, or pressing. Can be used. In addition, the oxygen ion conductive solid electrolyte is a main component selected from the group consisting of zirconium (Zr) oxide, thorium (Th) oxide, bismuth (Bi) oxide and cerium (Ce) oxide and yttrium (Y) oxide, magnesium (Mg) One or more dopants selected from the group consisting of oxides, calcium (Ca) oxides, scandium (Sc) oxides, erbium (Er) oxides and samarium (Sm) oxides.

Second, the conductive current collector is an electrochemically inert material, and merely serves as a lead wire for electron transfer. The conductive current collector necessarily includes a metal / metal oxide composite layer that participates in the electrochemical reaction. A preferred example of the method of forming the metal / metal oxide composite layer is a method of first coating a metal on a conductive current collector and then forming a metal oxide on the current collector surface-treated with metal. As a method of coating the metal on the conductive current collector, a known method such as an electrochemical plating method or a vacuum deposition method can be used. The metal oxide forming method includes a method of oxidizing a metal surface, a method of attaching a metal oxide to the surface of a metal particle, and the like. Metal surface oxidation methods include oxidation in air, oxidation by heat under oxygen atmosphere, chemical oxidation by solution under various chemical conditions, and the like. The physicochemical bonding method may include plasma spray coating, deposition by active sputtering, spin coating, pressing, or the like. The conductive current collector may be copper, iron, silver, platinum, gold, nickel, cobalt, zinc, tungsten, titanium (Ti), iridium (Ir), rhodium (Rh), zirconium (Zr), palladium (Pd), tin ( Sn), metals surface-treated with them, combinations thereof, and alloys thereof. Examples of the metal that is the main component of the metal / metal oxide composite layer include copper, iron, silver, platinum, gold, nickel, cobalt, zinc, tungsten, titanium (Ti), iridium (Ir), rhodium (Rh), and zirconium (Zr). ), Palladium (Pd), tin (Sn), combinations thereof, and alloys thereof. A solid electrolyte layer through which oxygen ions selectively pass is formed on the metal oxide layer of the conductive current collector. The solid electrolyte layer may be formed by a known method such as plasma spray coating, deposition by active sputtering, spin coating, or pressing. Can be used. The oxygen ion conductive solid electrolyte includes a main component selected from the group consisting of zirconium (Zr) oxide, thorium (Th) oxide, bismuth (Bi) oxide and cerium (Ce) oxide, yttrium (Y) oxide, magnesium (Mg) oxide, One or more dopants selected from the group consisting of calcium (Ca) oxide, scandium (Sc) oxide, erbium (Er) oxide and samarium (Sm) oxide.

Examples of the high temperature reference electrode of the pH measurement system include silver / silver chloride (Ag / AgCl) electrodes, platinum / hydrogen (Pt / H ₂ ) electrodes, and palladium / hydrogen (Pd-H) electrodes. In the case of the silver / silver chloride electrode, it is preferable to take an external reference electrode method because the life is shortened due to the thermal hydrolysis of silver chloride, which is commonly occurring in a high temperature reducing environment.

The voltage between the hydrogen ion sensor and the reference electrode of the pH measurement system is measured using a suitable electrometer. Since the current amount of the sensor electrode is very small, if more current flows toward the electrometer, the equilibrium reaction of the sensor electrode is impaired, and the measured potential does not accurately reflect the pH of the solution. For this reason, an electrometer with a large input impedance should be used so that little current flows toward the electrometer. The higher the input impedance of the electrometer, which measures the voltage between the hydrogen ion sensor and the reference electrode, is preferred, and should be at least 10 ⁸ ohms or more. In general, it is desirable to use an electrometer with a high input impedance of more than 10 ¹² ohms.

In the hydrogen ion sensor electrode according to the present invention constituted as described above, a conductive current collector, a metal / metal oxide composite layer and an oxygen ion conductive solid electrolyte layer are sequentially coated, and the metal / metal oxide composite The layer uses a metal / metal oxide integrated composite in which the metal oxide is applied to the surface of the metal, and thus, the electron reaction is smooth and the impedance is low, thereby improving the electrode reaction rate. Accurate pH can be measured at low temperature, and the metal / metal oxide composite layer is sequentially coated on the conductive current collector, and the oxygen ion conductive solid electrolyte layer is sequentially coated on the conductive current collector, so that the size of the electrode can be reduced and utilized in microcavity. In addition, the production cost is low.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments. The following examples are merely presented to aid the understanding of the present invention, of course, the present invention is not limited to the following examples.

<Example 1>

Ni wire (Nilaco, Japan, purity = 99.99%, diameter = 1.0 mm) was put in an oven where the temperature was kept constant at 150 ° C, and the surface of the Ni wire was partially oxidized under an oxygen atmosphere for at least 20 hours. The surface coating film of the oxidized Ni wire was formed from YSZ (yttria-stabilized zirconia, yttria = 8.5 wt%) powder using plasma spray coating. The electrode was loaded in a properly designed stainless body to secure and protect the electrode.

<Example 2>

A 0.01 MB (OH) ₃ aqueous solution was used as the test solution. The solution was placed in an autoclave of high temperature and high pressure, and argon gas purging was performed for 10 hours or more to completely remove the dissolved CO ₂ and oxygen in the solution. The autoclave was loaded with a hydrogen ion sensor electrode prepared according to Example 1 and an external Ag / AgCl reference electrode. After measuring the potential of the hydrogen ion sensor electrode at four temperature conditions of 140, 180, 220 and 260 ℃, the pH of the test solution was calculated using the Nernst equation. The voltage between the hydrogen ion sensor electrode and the reference electrode was measured using a Keithley 602 electrometer (input impedance = 10 ¹⁴ ohm). The measured pH results are shown in FIG. 2. In particular, the electrochemical impedance was analyzed at 180 ° C. The frequency range was 100 kHz to 10 mHz and the AC amplitude was 50 mV. The impedance analysis results are shown in FIG. 3.

<Example 3>

Copper (Cu) was coated on the platinum wire (Korean Heesung Metal, purity = 99.99%, diameter = 1.0 mm) by vacuum evaporation method over 10 um. The copper coated platinum wire was placed in an oven where the temperature was kept constant at 150 ° C., and the surface copper was partially oxidized under an oxygen atmosphere for at least 10 hours. The surface coating film of the surface-treated platinum wire was formed from YSZ (yttria-stabilized zirconia, yttria = 8.5 wt%) powder using plasma spray coating. The electrode was loaded in a properly designed stainless body to secure and protect the electrode.

Comparative Example 1

Except for using NiO (Alfa, Purity = 99.99%, Particle Size = 5 um) and NiO (Aldrich, Purity = 99.99%, Particle Size = 10 um) instead of NiO surface treated with NiO In the same manner as in Example 1 to prepare a hydrogen ion sensor electrode. Ni powder and NiO powder were mixed evenly using a mixer at a weight ratio of 1 to 1 before entering into the YSZ tube.

Comparative Example 2

Except for using the sensor electrode prepared in Comparative Example 1 and the pH and impedance were measured in the same conditions and methods as in Example 2, the results are shown in Figure 2 and 4, respectively.

2, the pH value measured in Example 2 and Comparative Example 2 is almost similar to the actual pH value in the 180 ~ 260 ℃ temperature range. However, at 140 ° C., in Example 2, there is no significant difference from the actual pH, but in Comparative Example 2, it can be seen that a large error occurs. In addition, looking at the impedance results of FIGS. 3 and 4 measured at 180 ° C., it can be seen that the impedance of the integrated hydrogen ion sensor electrode of the present invention shows much lower impedance than the conventional electrode.

This result shows that when the conventional simple metal / metal oxide mixture is used, the impedance is large at the low temperature of about 140 ° C. of the sensor electrode, and thus an error occurs. Therefore, hydrogen according to the present invention cannot be used properly in the relatively low temperature region of the high temperature aqueous solution. In the case of the electrode, no error occurs even at a low temperature of about 140 ° C., and therefore, the electrode can be preferably used in the whole region including the relatively low temperature region of the high temperature aqueous solution.

Hydrogen ion sensor electrode according to the present invention is configured as described above because the electron transfer is smooth and the impedance is poor, the electrode reaction rate is improved, it is possible to measure the accurate pH even in a wide temperature range of the high temperature aqueous solution, especially at a relatively low temperature, the electrode It can be used in the micro space by reducing the size of the product, and the production cost is low.

Claims (16)

In the hydrogen ion sensor electrode, the hydrogen ion sensor electrode comprises a conductive current collector, at least one metal / metal oxide composite layer and at least one oxygen ion conductive solid electrolyte layer, Wherein the metal / metal oxide composite layer is on the conductive current collector, wherein a solid electrolyte layer is positioned thereon.  The method of claim 1, wherein the conductive current collector is copper, iron, silver, platinum, gold, nickel, cobalt, zinc, tungsten, titanium (Ti), iridium (Ir), rhodium (Rh), zirconium (Zr), palladium (Pd), tin (Sn), a hydrogen ion sensor electrode, characterized in that at least one selected from the group consisting of metals surface-treated with these, combinations thereof or alloys thereof.  The method of claim 1, wherein the metal of the metal / metal oxide composite layer is chemically the same as the conductive current collector, or copper, iron, silver, platinum, gold, nickel, cobalt, zinc, tungsten, titanium (Ti). ), Iridium (Ir), rhodium (Rh), zirconium (Zr), palladium (Pd), tin (Sn), hydrogen ion sensor electrode, characterized in that at least one selected from the group consisting of a combination or alloys thereof.  The metal oxide of claim 1, wherein the metal oxide of the metal / metal oxide composite layer is copper oxide, iron oxide, silver oxide, platinum oxide, gold oxide, nickel oxide, cobalt oxide, zinc oxide, tungsten oxide, titanium (Ti). ) Hydrogen, iridium (Ir) oxide, rhodium (Rh) oxide, zirconium (Zr) oxide, tin (Sn) oxide and an oxide of aluminum or a hydrogen ion sensor electrode characterized in that at least one selected from the group consisting of a mixture of these oxides. .  The hydrogen ion sensor electrode of claim 1, wherein a thickness of the metal / metal oxide composite layer on the conductive current collector is 0.001 to 500 um.  6. The hydrogen ion sensor electrode as claimed in claim 5, wherein the metal / metal oxide composite layer on the conductive current collector has a thickness of 0.01 to 100 um. 2. The yttrium oxide of claim 1, wherein the oxygen ion conductive solid electrolyte is selected from a group consisting of zirconium (Zr) oxide, thorium (Th) oxide, bismuth (Bi) oxide, and cerium (Ce) oxide. Hydrogen ion sensor comprising one or more dopants selected from the group consisting of magnesium (Mg) oxide, calcium (Ca) oxide, scandium (Sc) oxide, erbium (Er) oxide and samarium (Sm) oxide electrode. 8. The hydrogen ion sensor electrode according to claim 7, wherein the amount of the additive is 3 to 20% by weight. 9. The hydrogen ion sensor electrode according to claim 8, wherein the amount of the additive is 5 to 15% by weight.  The hydrogen ion sensor electrode of claim 1, wherein a thickness of the solid electrolyte layer positioned on the metal / metal oxide composite layer is 0.01 to 100 um. i) a hydrogen ion sensor electrode comprising a conductive current collector, at least one metal / metal oxide composite layer and at least one oxygen ion conductive solid electrolyte layer; ii) high temperature reference electrode; And iii) a pH measurement system, comprising a voltage meter with a high input impedance. The pH measuring system of claim 11, wherein the high temperature reference electrode is one of a silver / silver chloride (Ag / AgCl) electrode, a platinum / hydrogen (Pt / H ₂ ) electrode, and a palladium / hydrogen (Pd-H) electrode. . 12. The pH measurement system of claim 11, wherein an input impedance of an electrometer for measuring the voltage between the hydrogen ion sensor and the reference electrode is 10 ⁸ ohm or more. The pH measurement system of claim 13, wherein an input impedance of an electrometer for measuring the voltage between the hydrogen ion sensor and the reference electrode is 10 ¹⁰ ohm or more. 15. The pH measurement system of claim 14, wherein an input impedance of an electrometer for measuring the voltage between the hydrogen ion sensor and the reference electrode is 10 ¹² ohm or more.  12. The pH measurement system of claim 11, wherein the thickness of the solid electrolyte layer positioned on the metal / metal oxide composite layer of the hydrogen ion sensor electrode is 0.01 to 100 um.

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