JPWO2017158832A1 - Electrode for electrolysis, electrode unit, and electrolyzed water generator - Google Patents

Abstract

  An electrode for electrolysis according to an embodiment has an electrode substrate having a first surface, a second surface facing the first surface, and a plurality of through holes penetrating from the first surface to the second surface, and an opening in the first surface A plurality of first recesses, a plurality of second recesses that are open on the second surface and have a larger opening area than the first recess, and a catalyst layer provided on the first surface, At least a part of the first recess communicates with the second recess, the first recess has a larger number than the second recess, and the plurality of through holes have the shortest first distance between the first through hole and the first through hole. At least a second through hole adjacent to the first through hole and a third through hole adjacent to the first through hole at a second distance longer than the first distance, and between the second through hole and the third through hole. The third distance is longer than the second distance, and the catalyst layer has a first thickness in the first region between the first through hole and the second through hole. Greater than the second thickness at hole and a second region between the third through hole.

Description

  Embodiments described herein relate generally to an electrode for electrolysis, an electrode unit, and an electrolyzed water generating apparatus.

  2. Description of the Related Art In recent years, electrolyzers have been provided that generate electrolyzed water having various functions by electrolyzing water, such as alkali ion water, ozone water, or hypochlorous acid water. Among electrolyzed water, hypochlorous acid water has an excellent sterilizing power and is safe for the human body and approved as a food additive. Electrolyzers are also used for hydrogen production and the like.

  As an electrolysis apparatus, for example, an electrolyzed water generation apparatus having a three-chamber electrolysis tank has been proposed. The inside of the electrolytic cell is divided into three chambers, an intermediate chamber, and an anode chamber and a cathode chamber located on both sides of the intermediate chamber, by a cation exchange membrane and an anion exchange membrane. The anode chamber and the cathode chamber are provided with an anode and a cathode, respectively. As an electrode, a porous electrode is used in which a large number of holes are processed by expanding, etching, or punching on a metal plate base material.

  In such an electrolysis apparatus, for example, salt water is passed through the intermediate chamber, and water is circulated through the anode chamber and the cathode chamber, respectively. By electrolyzing the salt water in the intermediate chamber at the cathode and the anode, hypochlorous acid water and chlorine are generated at the anode, and sodium hydroxide water and hydrogen are generated at the cathode chamber. The generated hypochlorous acid water is used as sterilizing / disinfecting water, and sodium hydroxide water is used as washing water. Hydrogen is used as hydrogen water or fuel. In particular, when chlorine and hydrogen are mainly produced, electrolysis is performed with a larger current.

  In these electrolysis, high production efficiency of hypochlorous acid is necessary in the standing to produce hypochlorous acid. If the generation efficiency is low, a considerable part of the input electric power is consumed for oxygen gas generation or the like. Therefore, in order to obtain the required amount of hypochlorous acid, it is necessary to increase the current and voltage. This increases energy consumption and shortens the life of the electrolytic electrode and electrode unit.

JP 2014-101549 A JP 2013-194323 A

  An object of an embodiment of the present invention is to provide an electrolytic electrode, an electrode unit, and an electrolytic device having a long life.

An electrode for electrolysis according to an embodiment includes a first surface, a second surface facing the first surface, and an electrode substrate having a plurality of through holes penetrating from the first surface to the second surface;
A plurality of first recesses opening in the first surface;
A plurality of second recesses opening in the second surface and having an opening area wider than the first recess;
A catalyst layer provided on the first surface;
At least a part of the through hole communicates the first recess and the second recess,
The first recess has a larger number than the second recess,
The plurality of through holes are:
A first through hole;
A second through hole adjacent to the first through hole at the shortest first distance;
The first through hole includes at least a third through hole adjacent to the first through hole at a second distance longer than the first distance, and the third distance between the second through hole and the third through hole is greater than the second distance. long,
The catalyst layer has a first thickness in a first region between the first through hole and the second through hole, and a second thickness in a second region between the first through hole and the third through hole. Bigger than that.

FIG. 1 is a diagram schematically illustrating an example of an electrolysis apparatus according to an embodiment. FIG. 2 is a diagram illustrating an example of an electrode having a diamond-shaped through hole with rounded corners according to the embodiment.

The
FIG. 3 is a diagram illustrating an example of an electrode having a rectangular through hole with rounded ends according to the embodiment. FIG. 4 is a diagram illustrating an example of an electrode having an elliptical through hole according to the embodiment. FIG. 5 is a diagram schematically illustrating another example of the electrolysis apparatus according to the embodiment. Drawing 6A is a figure showing an example of the manufacturing method of the electrode used for an embodiment. Drawing 6B is a figure showing an example of the manufacturing method of the electrode used for an embodiment. Drawing 6C is a figure showing an example of the manufacturing method of the electrode used for an embodiment. FIG. 6D is a diagram illustrating an example of an electrode manufacturing method used in the embodiment. Drawing 6E is a figure showing an example of the manufacturing method of the electrode used for an embodiment. Drawing 6F is a figure showing an example of the manufacturing method of the electrode used for an embodiment. FIG. 7 is a schematic diagram illustrating an example of the configuration of electrodes and diaphragms used in the embodiment. FIG. 8 is a diagram schematically illustrating another example of the electrode device according to the embodiment.

  The electrode for electrolysis according to the embodiment includes an electrode base material and a catalyst layer provided on the electrode base material.

  The electrode substrate includes a first surface, a second surface facing the first surface, and a plurality of through holes penetrating from the first surface to the second surface.

  The electrode base material includes a plurality of first recesses that open to the first surface and a plurality of second recesses that open to the second surface and have an opening area wider than the first recess.

  At least a part of the through hole communicates the first recess and the second recess, and the first recess has a larger number than the second recess.

  In the electrode for electrolysis according to the first embodiment, the plurality of through holes are formed in the first through hole, the second through hole adjacent to the first through hole at the shortest first distance, and the first through hole. And a third through hole adjacent to each other at a second distance longer than the first distance. The third distance between the second through hole and the third through hole is longer than the second distance.

  In the electrode for electrolysis according to the second embodiment, the plurality of first recesses include three recesses adjacent to each other, for example, the third recess, the fourth recess, and the fifth recess, and the plurality of second recesses are adjacent to each other. Two recesses such as a sixth recess and a seventh recess adjacent to the sixth recess. The plurality of through holes include a first through hole communicating with the third recess and the sixth recess, a second through hole communicating with the fourth recess and the sixth recess, the fifth recess, and the seventh recess. And a third through hole communicating with each other.

  In the electrode for electrolysis according to the third embodiment, the plurality of first recesses include a third recess and a fourth recess adjacent to the third recess, and the plurality of second recesses are formed in the fifth recess and the fifth recess. A plurality of through-holes including an adjacent sixth recess, the first through-hole communicating with the third recess and the fifth recess, the second through-hole communicating with the fourth recess and the fifth recess, and a third A recess and a third through hole communicating with the sixth recess.

  In the electrode for electrolysis according to the first to third embodiments, the first thickness in the first region provided on the first surface of the electrode base material and between the first through hole and the second through hole is equal to It is larger than the second thickness in the second region between the first through hole and the third through hole.

  An electrode unit according to an embodiment is an electrode unit using the above-described electrode for electrolysis as a first electrode, and is disposed so as to face a first electrode having a first surface and a second surface, and the first surface of the first electrode. The second electrode, the porous membrane provided on the first surface of the first electrode, and the electrolyte solution holding structure provided between the porous membrane and the second electrode.

  An electrolysis apparatus according to the embodiment is an example of an electrolysis apparatus to which the above-described electrolysis electrode and an electrode unit using the electrolysis electrode are applied. This electrolysis apparatus has an electrolytic cell, an electrode unit incorporated in the electrolytic cell, a first electrode chamber and a second electrode chamber partitioned by the electrode unit. The electrode unit can be equipped with a mechanism for applying a voltage, for example, a power source for applying a voltage to the electrode, a control device, and the like.

  The first electrode chamber is, for example, an anode chamber, the second electrode chamber is, for example, a cathode chamber, a line for introducing an electrolytic solution containing chloride ions into an electrolytic cell, a line for taking out acidic electrolyzed water from the anode chamber, and a cathode chamber A line for taking out alkaline electrolyzed water from can be further provided.

  When the electrode for electrolysis according to the embodiment is used, the thickness of the catalyst layer in the region between the short-distance through holes where current tends to concentrate is larger than the thickness of the catalyst layer in the region between the through-holes of longer distance. Since it is large, consumption of the catalyst layer is made uniform, and the catalyst life of the electrode for electrolysis can be extended.

  Here, the distance between the through holes refers to the shortest distance from one end of the through hole to one end of the through hole.

  Further, adjoining means that a part of another through hole does not exist on the line segment indicating the distance between the two through holes.

  Hereinafter, embodiments will be described in more detail with reference to the drawings.

  In addition, the same code | symbol shall be attached | subjected to a common structure through embodiment, and the overlapping description is abbreviate | omitted. In addition, each drawing is a schematic diagram for promoting the embodiment and its understanding, and its shape, dimensions, ratio, etc. are different from the actual device, but these are considered in consideration of the following description and known techniques. The design can be changed as appropriate. For example, in the drawing, the electrode is drawn on a plane, but it may be bent according to the shape of the electrode unit or may be cylindrical.

  FIG. 1 is a diagram schematically showing an example of the electrolysis apparatus according to the first embodiment.

  The electrolysis apparatus 10 includes a three-chamber electrolytic cell 11 and an electrode unit 12. The electrolytic cell 11 is formed in a flat rectangular box shape, and the inside thereof is partitioned into three chambers by a partition wall 14 and an electrode unit 12, an anode chamber 16, a cathode chamber 18, and an intermediate chamber 19 formed between the electrodes. It has been.

  The electrode unit 12 includes a first electrode 20 positioned in the anode chamber 16, a second electrode (counter electrode) 22 positioned in the cathode chamber 18 and having a plurality of predetermined through holes, and a first electrode 20. A catalyst layer 28 is formed on one surface 21a, and a diaphragm 24 is provided thereon. Another diaphragm 27 can be provided on the first surface 23 a of the second electrode 22. The first electrode 20 and the second electrode 22 face each other in parallel with a gap therebetween, and an intermediate chamber (electrolyte chamber) 19 that holds the electrolyte is formed between the diaphragms 24 and 27. A holding body 25 that holds the electrolytic solution may be provided in the intermediate chamber 19. The first electrode 20 and the second electrode 22 may be connected to each other by a plurality of bridges 60 having insulating properties.

  The electrolysis apparatus 10 includes a power supply 30 for applying a voltage to the first and second electrodes 20 and 22 of the electrode unit 12 and a control device 36 for controlling the power supply 30. An ammeter 32 and a voltmeter 34 may be provided.

  As shown in the figure, the first electrode 20 has a porous structure in which a large number of through holes are formed in a base material 21 made of, for example, a rectangular metal plate. The substrate 21 has a first surface 21a and a second surface 21b that faces the first surface 21a substantially in parallel. The distance between the first surface 21a and the second surface 21b, that is, the plate thickness is formed at T1. The first surface 21 a faces the diaphragm 24, and the second surface 21 b faces the anode chamber 16. An anodic oxide film (not shown) may be formed on the surface 21a.

  A plurality of first recesses 40 are formed on the first surface 21a of the base material 21 and open to the first surface 21a. A plurality of second recesses 42 are formed on the second surface 21b and open to the second surface 21b. The opening diameter R1 of the first recess 40 on the side of the diaphragm 24 is smaller than the opening diameter R2 of the second recess 42, and the number of recesses is such that the first hole 40 is larger than the second hole 42. ing. The depth of the first hole 40 is T2, the depth of the second hole 42 is T3, and T2 + T3 = T1. In the embodiment, for example, T2 <T3. In the figure, a through hole in which the first recess 40 and the second recess 42 are connected is formed, but there may be a recess that is not connected or a part of which is connected. The substrate 21 is preferably the same substrate. When different base materials are laminated, hypochlorous acid tends to stay on the base material contact surface, and the generation efficiency decreases. In addition, current concentration tends to concentrate at the junction, and catalyst deterioration tends to occur.

  The opening diameter R1 of the first recess 40 on the side of the diaphragm 24 is smaller than the opening diameter R2 of the second recess 42, and the number of the recesses is such that the first hole 40 is larger than the second hole 42. Stress due to the edge of the recess from the diaphragm to the diaphragm is relieved and the life of the diaphragm is increased. In addition, since the number of second recesses can be reduced, the electrical resistance can be reduced, which is advantageous in place of wiring and mechanical holding.

  At least one of the first electrode 20 and the second electrode 22 used in the electrolysis apparatus 10 according to the embodiment has a plurality of predetermined through holes.

  FIG. 2 is a schematic diagram showing an example of an electrode that can be used as the first electrode 20 of FIG.

  FIG. 2 is a view of the first electrode 20 as viewed from the second surface 21b.

  In the drawing, the plurality of through holes are formed by connecting the first recess 40 and the second recess 42.

  The plurality of through holes include a first through hole 51, a second through hole 52 adjacent to the first through hole 51 with a first distance D1, and a second through hole 51 longer than the first distance D1. And a third through hole 53 adjacent to each other at a distance D2. The second through hole 52 and the third through hole 53 are arranged in different directions with respect to the first through hole 51. The third distance D3 between the second through hole 52 and the third through hole 53 is longer than the second distance D2.

  The catalyst layer 28 is provided on the first surface 21a facing the second surface 21b of the electrode substrate.

  When the first distance D1 is the shortest and the second distance D2 is greater than the distance D1 among the distances between the adjacent through holes of the plurality of through holes, the first distance between the first through hole 51 and the second through hole 52 is When the maximum thickness of the catalyst layer in the first region C1 is the first thickness H1, and the maximum thickness of the catalyst layer in the second region C2 between the first through hole 51 and the third through hole 53 is the second thickness H2, The first thickness H1 is larger than the second thickness H2.

  In the plurality of through holes, the distance between adjacent through holes can be set to 0.1 mm or more and 2.5 mm or less.

  When the thickness is less than 0.1 mm, chloride ions do not sufficiently stay and the efficiency tends to decrease. When the thickness exceeds 2.5 mm, the generated hypochlorous acid tends to be difficult to be discharged.

  In electrolysis, the current tends to concentrate in a region where the distance between adjacent through holes is the shortest. For this reason, the catalyst between the shortest penetrations is most easily consumed. When the maximum thickness of the catalyst layer in the first region between the through holes having the shortest adjacent distance is larger than the maximum thickness of the catalyst layer in the second region between the through holes having the long adjacent distance, consumption of the catalyst layer is made uniform. As a result, the catalyst life is extended, and the electrode life, the electrode unit life, and the electrolysis device life can be extended.

  The ratio of the maximum thickness of the catalyst layer in the first region to the maximum thickness of the catalyst layer in the second region is preferably 1.2 times or more and 7 times or less. More preferably, it is 1.5 times or more and 5 times or less, more preferably 2 times or more and 4 times or less. If the ratio is too large, the amount of catalyst between the shortest through-holes becomes too large, and the cost becomes high, or stress is concentrated and peeling tends to occur. The absolute thickness of the catalyst layer is preferably 0.5 μm or more and 20 μm or less. If it is less than 0.5 μm, the catalyst layer tends to be non-uniform and the life tends to be shortened. If it is larger than 20 μm, the process for producing the catalyst layer tends to be long and the cost tends to be high. The absolute thickness of the catalyst layer is preferably 1 μm or more and 10 μm or less, and more preferably 2 μm or more and 4 μm or less. The thickness of the catalyst layer can be measured by cross-sectional SEM.

  The distance 2 is preferably 1.5 times the distance 1 or more. If the ratio is less than 1.5 times, chloride ions are difficult to stay and the efficiency is lowered, and it is difficult to increase the thickness of the catalyst layer in the first region. Also, the electric resistance tends to increase and the voltage tends to increase. Preferably it is 4 times or more. More preferably, it is 5 times or more. However, when it becomes larger than 10 times, hypochlorous acid tends to be difficult to discharge.

  The predetermined plurality of through holes provided in the first electrode 20 are, for example, rhombuses with rounded corners. The aperture can be measured using an optical microscope. In this case, the shape of the first recess 40 is also a rhombus with rounded corners like the through hole. The concave section can be tapered or curved so that the inside is narrowed.

  Further, in the first electrode 20 having a porous structure, the contact angle between the opening of the through hole and the porous diaphragm 24 is obtuse by forming the through hole with a tapered surface or a curved surface in which the opening on the first surface side becomes wide. Thus, stress concentration on the porous diaphragm 24 can be reduced. Thereby, the opening of the through hole is smaller than the opening of the first recess 40 on the first surface 21a.

  The 1st recessed part may be produced in the whole surface of the 1st surface. In this case, the 1st recessed part which does not penetrate to the 2nd surface exists. The first recess not penetrating is excellent in holding chloride ions, so that the condition where the chloride ion concentration is low, for example, the concentration of chloride held in the intermediate chamber 19 is low, or the pressure in the intermediate chamber 19 is the anode chamber 16. When the pressure is lower than the pressure, it is effective for improving the generation efficiency of hypochlorous acid and lowering the driving voltage.

  As the shape of the second recess 42, a diamond shape in which a plurality of first recesses 40 can be used.

Alternatively, other shapes in which a plurality of first recesses 40 can be used. It is possible to prevent current concentration if the apex of the taper or curve is rounded.

  As shown in FIG. 2, the plurality of first recesses 40 have substantially the same size, but the plurality of first recesses 40 provided in the electrode substrate have a minimum opening diameter passing through the center of the opening of the first recess 40 constituting the through hole. Of the through holes, the aperture ratio of the through hole located at the center of the electrode substrate can be different from the aperture ratio of the through hole located at the peripheral edge of the electrode substrate. When the aperture ratio of the through hole located at the center is smaller than that at the periphery, the electrical resistance at the center is reduced, and current supply to the center is facilitated. On the other hand, if the opening ratio of the through hole located in the central portion is larger than that in the peripheral portion, gas can be easily released. Which is preferred depends on the size of the electrode, the operating conditions, and the relationship with other members, but can be selected.

  FIG. 3 schematically shows an exploded perspective view showing an example of an electrode unit using the electrode according to the present embodiment. The two electrodes 220 and 222 have the same structure.

  Among the distances between adjacent through holes of the plurality of through holes, the maximum thickness of the catalyst layer in the region C4 between the first and second through holes where the adjacent distance 1 is the shortest, the adjacent distance 2 is greater than the distance 1. It is larger than the maximum thickness of the catalyst layer in the region C5 between the large through holes. Further, the distance 3 of the region C6 between the second and third through holes is larger than the distance 2.

  As shown in the drawing, each of the six first recesses 63 has a rectangular shape that reaches from the right end to the left end of the electrode 223 excluding the seal portion 224, and the first recess 63 does not communicate with the second surfaces 221b and 223b. It has a recessed part and the opening part (through-hole) 61 connected to 2nd surface 221b, 223b. The depth of the 1st recessed part in which the through-hole 61 is arrange | positioned in the 1st recessed hole part 63 at intervals 3 each is shallow compared with the 2nd recessed part 62. FIG. Reference numeral 64 denotes a voltage application port, and the thick beam 65 faces the voltage application direction.

  Each of the three second recesses 62 has a rectangular shape that reaches from the upper end to the lower end of the electrode 221 excluding the seal portion. Six through holes respectively arranged in the six first recesses communicate with one second recess 62. The number density of the first recesses 61 on the first surface 221a is sufficiently larger than the number density of the second recesses 62 on the second surface 221b. In FIG. 3, the number of openings is reduced for easy understanding, but the number of openings is larger.

  In the embodiment, any shape can be used as the shape of the through hole. However, a rectangular shape with a round end, or an ellipse with rounded corners is preferable. FIG. 3 shows a part of the electrode. In such a shape, since the end is round, stress concentration on the porous diaphragm hardly occurs. Further, if the opening interval can be made dense, the opening ratio can be increased.

  In the electrode shape of FIG. 3, hypochlorous acid generated due to the first recess 63 is easy to move, and therefore easily flows out from the through hole. If hypochlorous acid does not flow out, chlorine gas is generated or diffuses to the diaphragm side, resulting in a low efficiency. This is likely to occur when the chloride ion concentration is high, and is likely to occur when the chloride concentration in the intermediate chamber 19 is high or the pressure in the intermediate chamber 19 is higher than that in the anode chamber 16. Therefore, the electrode structure as shown in FIG. 3 is particularly effective when the chloride concentration in the intermediate chamber 19 is high or the pressure in the intermediate chamber 19 is higher than that in the anode chamber 16.

The opening area of the through hole can be from 0.01 mm ² to 4 mm ² . If it is smaller than 0.01 mm ^2, it will be difficult to discharge reaction products such as gas and hypochlorous acid to the outside, and deterioration of the members will easily occur. When it is larger than 4 mm ² , the electrical resistance increases, and the electrode reaction efficiency tends to decrease. The thickness is preferably 0.1 mm ² to 1.5 mm ² . More preferably, it is 0.2 mm ² to 1 mm ² .

The opening area of the second recess can be ¹ to 1600 mm ² . The thickness is preferably 4 mm ² to 900 mm ² , more preferably 9 mm ² to 400 mm ² . A concave portion that is elongated in one direction and is connected to the end of the electrode excluding the seal portion, such as a rectangle or an ellipse, is also possible.

  The opening of the second recess 42 can have various shapes such as a square, a rectangle, a rhombus, a circle, and an ellipse. A larger opening diameter of the second recess 42 can improve hypochlorous acid and outgassing, but it cannot be increased because the electrical resistance increases. As illustrated, the opening of the second recess 62 may be a recess that is elongated in one direction, such as a rectangle or an ellipse, and is connected to the end of the electrode excluding the seal portion.

  Also, the opening of the first recess 63 can be various shapes such as a square, a rectangle, a rhombus, a circle, an ellipse, and the like. As shown in the figure, an opening that extends in one direction, such as a rectangle or an ellipse, and is connected to the end of the electrode excluding the seal portion is also possible.

  Two recesses that connect from end to end of the first recess and the second recess may be orthogonal or parallel to each other. If it goes straight, gas diffusion is easy. If parallel, chloride ions are easy to collect. Orthogonal means intersecting at an angle of 87 to 93 degrees, and parallel means that the intersecting angle is within 3 degrees.

  In FIG. 3, openings 61 are arranged in the direction of the voltage application port 64. As a result, since the beams 65 having a large electrode thickness and a small electrical resistance are arranged in the voltage application direction, power supply is facilitated, and the drive voltage can be reduced.

  FIG. 4 schematically shows an exploded perspective view showing another example of the electrode unit using the electrode according to the embodiment.

  The two electrodes 220 'and 222' have the same structure.

  In FIG. 4, openings 61 ′ are arranged in the direction of the voltage application port 64 ′. As a result, the beams 65 'having a large electrode thickness and a small electrical resistance are arranged in the voltage application direction, so that power supply is facilitated and the driving voltage can be reduced.

  Among the distances between adjacent through holes of the plurality of through holes, the maximum thickness of the catalyst layer in the region C7 between the first and second through holes where the adjacent distance 1 is the shortest is the first where the adjacent distance 2 is long. And larger than the maximum thickness of the catalyst layer in the region C8 between the third through holes. Further, the distance 3 of the region C9 between the second and third through holes is larger than the distance 2.

  As illustrated, in the electrode 221 'and the electrode 223', the first recess 61 'constituting the through hole has an elliptical shape. In addition, two recesses, that is, the first recess 62 ′ and the second recess 63 that are connected from end to end of the electrode excluding the seal portion are parallel to each other.

  The first recess 62 ′ has a larger area than the second recess 63, and the arrangement of the through holes 61 ′ in the first recess 62 ′ is two rows of the arrangement of the through holes 61 ′ in the second recess 63.

  Although the electrode structure is schematically shown in FIG. 4, the number of first recesses, second recesses, and through holes is actually much larger.

  In the first electrode 220 ′ having a porous structure, the contact angle between the opening of the through hole and the porous diaphragm 24 becomes an obtuse angle by forming the through hole with a tapered surface or a curved surface where the opening on the first surface side becomes wide. Stress concentration on the porous diaphragm 24 can also be reduced.

  Note that at least a portion of the first recess 62 ′ only needs to communicate with the second recess 63, and may include a first recess that is not the through hole 61 ′. The first recess that is not in communication has the effect of increasing the electrode area and the effect of promoting the retention and diffusion of the substance.

  The curvature radius of the edge excluding the catalyst layer on the first surface of the through hole is preferably 0.01 mm or more. Thereby, the current concentration at the edge portion can be relaxed and the catalyst layer can be formed uniformly. Preferably it is 0.05 mm to 1 mm, More preferably, it is 0.1 mm to 0.5 mm.

  FIG. 5 is a diagram schematically illustrating another example of the electrolysis apparatus according to the embodiment.

  As shown in FIG. 5, in addition to the configuration of FIG. 1, a liquid flow path may be provided in the anode chamber 16 and the cathode chamber 18. In some cases, a porous spacer may be provided between the electrode unit 12 and the anode chamber 16 or the cathode chamber 18. Also, a line L1 for introducing an electrolyte containing chloride ions into the electrolytic cell 11, a salt water reservoir 107, lines L2 and L3 for supplying water to the electrolytic cell, a line L4 for extracting acidic electrolytic water from the electrolytic cell, and alkaline electrolysis from the electrolytic cell A line L5 for taking out water may be further provided. Further, a line L7 for circulating an electrolyte containing chloride ions may be provided, or a line for discharging may be provided. Further, the water softener 109 and a line L6 for supplying the water softener 109 with acidic electrolyzed water for adsorbent regeneration from the acidic electrolyzed water reservoir 106 may be further provided. The water softener may be used only for water supplied to the cathode side. Furthermore, a tank for storing alkaline electrolyzed water may be provided. Moreover, you may provide the tank for mixing an acidic liquid and an alkaline liquid and approaching neutrality.

  An example of a method for producing the first electrode 20 and the porous diaphragm 24 having the above-described configuration will be described below.

  6A to 6F are views showing an example of a method for manufacturing the electrode unit according to the embodiment.

  The first electrode 20 can be produced by, for example, an etching method using a mask.

  As shown in FIGS. 6A and 6B, a single flat substrate 21 is prepared.

  Resist films 50 a and 50 b are applied to the first surface 21 a and the second surface 21 b of the substrate 21.

  As shown in FIG. 6C, the resist films 50a and 50b are exposed using an optical mask (not shown) to produce etching masks 52a and 52b, respectively. The aperture area and aperture ratio are defined by the optical mask.

  As shown in FIG. 6D, the first surface 21a and the second surface 21b of the base material 21 are wet-etched with a solution through the masks 52a and 52b, whereby a plurality of first recesses 40 and a plurality of second recesses are obtained. 42 is formed. Thereafter, the first electrode 20 is obtained by removing the masks 52a and 52b. The planar shapes of the first recess 40 and the second recess 42 can be controlled by an optical mask and etching conditions. By designing the mask, the aperture ratio, aperture area, aperture shape, etc. in the electrode can be freely controlled.

  The taper of the first and second recesses 40 and 42 and the shape of the curved surface can be controlled by the material of the substrate 21 and the etching conditions. When the depth of the first recess 40 is T2, and the depth of the second recess 42 is T3, the first and second recesses are formed so that T2 <T3. In the etching, both surfaces of the base material 21 may be etched simultaneously, or one surface may be etched. The type of etching is not limited to wet etching, and dry etching or the like may be used. Further, the first electrode 20 can be manufactured not only by etching but also by an expanding method, a punching method, or processing by laser or precision cutting, but the etching method is most preferable.

  As the base material 21 of the first electrode 20 used in the embodiment, a valve metal such as titanium, chromium, aluminum, or an alloy thereof, or a conductive metal can be used. Of these, titanium is preferred.

  An electrocatalyst (catalyst layer) 28 is formed on at least the first surface 21 a of the first electrode 20. As the anode catalyst, a noble metal catalyst such as platinum or an oxide catalyst such as iridium oxide is preferably used, and an oxide catalyst containing iridium oxide is most preferable. Before the anode catalyst is produced, it is preferable to produce minute oxide film irregularities by anodizing the electrode from the viewpoint of improving the adhesion between the catalyst and the substrate. Moreover, even if a thin tantalum oxide layer is formed on the surface, it is preferable because the adhesion between the catalyst and the substrate is improved.

  The catalyst layer formed on the first surface 21a has a distance in which the maximum thickness of the catalyst layer is adjacent in the region C1 between the through holes having the shortest adjacent distance among the distances between the adjacent through holes of the plurality of through holes. Is larger than the maximum thickness of the catalyst layer in the region C2 between the long through holes. The structure of the catalyst thickness can be prepared by repeating the steps of applying the liquid to the first surface 21a, drying and sintering the electrode substrate easily with the liquid containing the catalyst precursor. Since the opening area of the through hole of the present embodiment is small or the width of the through hole is small, the entire first surface including the through hole is initially covered with the liquid containing the catalyst precursor by coating. During the drying process, the liquid covering the through-holes collects at the electrode part in contact with the through-holes. However, the liquid gathers more between the shortest through-holes. Can be bigger. The thickness ratio can be controlled by the concentration of the liquid containing the catalyst precursor used, the type of liquid, and the drying conditions. The higher the concentration and the greater the surface tension, the greater the ratio of thickness. Moreover, the ratio tends to increase when drying is performed slowly. The catalyst precursor is preferably an alcohol containing an iridium alkoxide, and more preferably a propanol solution containing iridium propoxide or a butanol solution containing iridium butoxide. The catalyst layer preferably contains tantalum oxide from the viewpoint of catalyst life. It is also preferable to produce minute oxide film irregularities by anodic oxidation of the electrode and to form a tantalum oxide layer on the surface because the base material is easily wetted with the alcohol solution containing the catalyst precursor.

  A first catalyst layer made of an electrocatalyst provided between the first electrode and the first diaphragm, and a surface of the first electrode opposite to the first catalyst layer; May further include second catalyst layers having different amounts per unit area.

  You may form so that the average amount per unit area of an electrocatalyst may differ on both surfaces of a 1st electrode. Thereby, a side reaction etc. can be suppressed.

  The surface of the positive electrode on the porous membrane side (first surface) is preferably substantially flat except for the recess. The surface roughness of the flat portion is preferably 0.01 μm to 3 μm. If it is smaller than 0.01 μm, the actual surface area of the electrode tends to decrease, and if it is larger than 3 μm, stress on the diaphragm tends to concentrate on the convex portion of the electrode. More preferably, it is 0.02 μm to 2 μm, and further preferably 0.03 μm to 1 μm.

  For example, the diaphragm 24 is formed in a rectangular shape having substantially the same dimensions as the first electrode 20 and faces the entire surface of the first surface 21a. The diaphragm 27 is formed in a rectangular shape having substantially the same dimensions as the second electrode 22 and faces the entire surface of the first surface 23a.

  As the diaphragms 24 and 27, films having many pores of 1 μm or less can be used. For example, a laminate of a first porous layer having a first pore diameter and a second porous layer having a second pore diameter different from the first pore diameter can be used. As the membrane used for the diaphragm, an ion-selective membrane such as a hydrocarbon polymer ion permeable membrane or a fluorine polymer ion permeable membrane can be used.

  The diaphragm preferably contains an inorganic oxide. In particular, the positive electrode side diaphragm is preferably an inorganic oxide having a positive zeta potential in a pH range of 2 to 6. Thereby, the transport performance of the diaphragm to anions can be increased in a chemically stable and weakly acidic region.

  Examples of inorganic oxides that can be used include zirconium oxide, titanium oxide, aluminum oxide, tin oxide, zircon, copper oxide, iron oxide, and mixed oxides thereof. Preferably, zirconium oxide, titanium oxide, aluminum oxide, or zircon can be used as the inorganic oxide having good chemical stability. Among these, as the inorganic oxide having good bending resistance, zirconium oxide and aluminum oxide that tends to have a positive zeta potential even when neutral are more preferable. Inorganic oxides can include hydroxides, alkoxides, oxyhalides, and hydrates. When an inorganic oxide is produced through hydrolysis of a metal halide or metal alkoxide, a mixture of these may be formed depending on the post-treatment temperature.

  The abundance ratio of the inorganic oxide in the diaphragm can vary depending on the location. For example, the abundance ratio of the inorganic oxide can be increased around the pores and on the surface.

  As the inorganic oxide, a composite oxide such as zircon or a mixture of different inorganic oxides can be used. The diaphragm may further include two or more different oxides, and the abundance ratio of each oxide may vary depending on the position of the diaphragm. For example, a region containing zirconium oxide having a high bending strength can be present on the surface, and a region containing titanium oxide having a large positive potential can be present inside.

  The zeta potential on the surface of the diaphragm can be greater than −30 mV at pH 4. If it is smaller than −30 mV, chloride ions tend to hardly enter even when a voltage is applied to the diaphragm. Furthermore, the zeta potential on the surface of the diaphragm can be greater than -15 mV.

  In the embodiment, the diaphragm can be arranged on the positive electrode side on the negative electrode.

  The porous diaphragm provided on the negative electrode can contain an inorganic oxide having a negative zeta potential in the region of pH 8 to 10. Thereby, the cation transport performance can be increased in the vicinity of the cathode in the weak alkali region. As such an inorganic oxide, an oxide whose zeta potential tends to be negative in an alkaline region can be used. Examples of such an inorganic oxide include zirconium oxide, titanium oxide, aluminum oxide, tungsten oxide, and zircon. , Silicon oxide, and zeolite can be used. As the inorganic oxide, a mixture of the above oxides can be used. Moreover, the abundance ratio of the inorganic oxide in the diaphragm can vary depending on the location. For example, there may be a region containing zirconium oxide having a high bending strength on the surface, and a region containing silicon oxide having a wide negative potential pH range inside.

  The inorganic oxide diaphragm 24 can have pores irregularly in-plane and three-dimensionally, by applying nanoparticles to form a film, or by producing it with a sol-gel. In this case, the diaphragm 24 is resistant to bending and the like. The diaphragm 24 may contain a polymer in addition to the inorganic oxide. The polymer gives the membrane flexibility. As such a polymer, a chemically stable main chain substituted with a halogen atom can be used, and examples thereof include polyvinylidene chloride, polyvinylidene fluoride, and Teflon (registered trademark). Among these, Teflon is preferable from the viewpoint of chemical and thermal stability. Examples of other polymers include hydrocarbon polymers such as polyethylene and polypropylene. Among these, polyethylene is preferable from the viewpoint of chemical stability and low cost, and high-density polyethylene is more preferable. Also, so-called engineering plastics such as polyimide, polysulfone, polyphenylene sulfide and the like can be used.

  The opening diameter of the diaphragm 24 can be different from the opening diameter on the first electrode 20 side and the opening diameter on the second electrode 22 side. By increasing the opening diameter of the hole on the second electrode 22 side, it is possible to make the movement of ions easier and reduce the stress concentration due to the through hole 40 of the first electrode 20. This is because the larger the opening on the electrode 22 side, the easier the ion movement by diffusion. Anions are attracted to the electrode relatively easily even if the hole diameter on the electrode 20 side is small. Conversely, if the pore diameter on the electrode 20 side is large, the generated chlorine or the like tends to diffuse to the porous diaphragm side.

  The pore diameter on the surface of the diaphragm can be measured by using a high-resolution scanning electron microscope (SEM). The internal holes can be measured by cross-sectional SEM observation.

  In FIG. 7, the schematic diagram showing an example of a structure of the electrode and diaphragm used for embodiment is shown.

  As shown in the drawing, the diaphragm 24 includes a first region 24 a that covers the first surface 21 a portion of the first electrode 20, and a second region 24 b that covers the openings of the plurality of first recesses 40 that communicate with the second hole 42. ,have. In the 21a portion, the generated gas such as chlorine is difficult to be discharged. Therefore, the electrode unit 12 tends to deteriorate. Therefore, in the diaphragm 24, the surface holes in the first region are eliminated, that is, formed without holes, or the diameter of the surface holes in the first region 24a is made smaller than the diameter of the holes in the second region, The electrolytic reaction in the region in contact with the first region 24a can be suppressed, and deterioration of the electrode unit 12 can be prevented. In order to reduce the hole diameter or to make the hole non-porous, a thin non-porous film or a small-diameter diaphragm can be formed on the first surface 21a of the first electrode by screen printing or the like. However, since the reaction area of the electrode is reduced, it is possible to cause a sufficient reaction in the electrode region where gas tends to escape. Further, by covering the second surface 21b of the first electrode 20 opposite to the diaphragm 24 with an electrically insulating film that does not allow liquid to pass through, it is possible to reduce side reactions. FIG. 7 also shows the first recess 40 that is not a through hole. As the diaphragm 24, a multilayer film in which a plurality of porous films having different pore diameters are stacked can be used. In this case, by making the hole diameter of the diaphragm located on the second electrode 22 side larger than the hole diameter of the diaphragm located on the first electrode 20 side, it is easier to move ions and stress concentration due to the through holes of the electrode. Can be reduced.

  By pressing the diaphragm 24 between the first electrode 20 and the second electrode 22 configured as described above, the first electrode 20, the diaphragm 24, and the second electrode 22 are in contact with each other. The electrode unit 12 is obtained.

  As shown in FIG. 1, the electrode unit 12 is disposed in the electrolytic cell 11 and attached to the partition wall 14. The electrolytic cell 11 is partitioned into an anode chamber 16 and a cathode chamber 18 by the partition wall 14 and the electrode unit 12. Thereby, the electrode unit 12 is arrange | positioned in the electrolytic cell 11 so that the arrangement direction of a structural member may turn into a horizontal direction, for example. The first electrode 20 of the electrode unit 12 is disposed facing the anode chamber 16, and the second electrode 22 is disposed facing the cathode chamber 18.

  In the electrolysis apparatus 10, both electrodes of the power supply 30 are electrically connected to the first electrode 20 and the second electrode 22. The power supply 30 applies a voltage to the first and second electrodes 20 and 22 under the control of the control device 36. The voltmeter 34 is electrically connected to the first electrode 20 and the second electrode 22 and detects a voltage applied to the electrode unit 12. The detection information is supplied to the control device 36. The ammeter 32 is connected to the voltage application circuit of the electrode unit 12 and detects the current flowing through the electrode unit 12. The detection information is supplied to the control device 36. The control device 36 controls the application of voltage or the load to the electrode unit 12 by the power supply 30 according to the detection information according to the program stored in the memory. The electrolyzer 10 applies an electric voltage or loads between the first electrode 20 and the second electrode 22 in a state in which the reaction target substance is supplied to the anode chamber 16 and the cathode chamber 18, and performs electrochemistry for electrolysis. Allow the reaction to proceed.

  As an example of forming the diaphragm 24 on the first surface 21a in which the catalyst 28 is formed on the surface of the first electrode 20, first, as shown in FIG. 6E, inorganic oxide particles and / or inorganic oxide precursors are used. The pre-treatment film 24c is prepared by applying the solution containing the first surface 21a. Next, as shown in FIG. 6F, the pretreatment film 24c is sintered to produce a porous diaphragm 24 having porosity.

  As a method for producing a solution containing an inorganic oxide precursor, for example, a metal alkoxide is dissolved in alcohol, and a high-boiling solvent such as glycerin is added or sintered to produce a porous structure. A solution can be prepared by mixing organic substances such as fatty acids that easily oxidize into carbon dioxide. Moreover, in order to cover the porosity of an electrode, a solution can raise a viscosity by adding a small amount of water and hydrolyzing a metal alkoxide partially.

  As a method of forming the porous diaphragm 24, a solution containing inorganic oxide particles and / or an inorganic oxide precursor can be applied to another porous film. Alternatively, a porous film having large pores can be formed in advance on the first surface 21a of the first electrode 20, and the surface and pores can be covered with inorganic oxide particles and / or inorganic oxide precursors. Or the diaphragm which has an inorganic oxide can be formed on the holding body 25 which hold | maintains electrolyte solution by the said method. Moreover, these can be combined.

  As a method for applying a solution containing inorganic oxide particles and / or an inorganic oxide precursor, brush coating, spraying, dipping, or the like can be used. In the step of sintering the pretreatment film 24c to produce a porous material, the sintering temperature can be about 100 to 600 ° C.

  With the above configuration and manufacturing method, it is possible to provide a long-life electrode unit capable of maintaining high-efficiency electrolysis performance over a long period of time and an electrolysis apparatus using the electrode unit.

  Hereinafter, examples will be shown and embodiments will be described in detail.

Example (Example 1)
A flat titanium plate having a plate thickness T1 of 0.5 mm is prepared as the substrate 21 of the first electrode.

  The titanium plate is etched in the same manner as in the steps shown in FIGS. 6A to 6D to produce the first electrode 20 of the first embodiment. The electrode is 15 cm long in the water flow direction and 10 cm wide.

  As shown in FIG. 3, of the first electrode 220 and the second electrode 222, the thickness of the region including the first recess 63 having a small area (the depth of the first recess) is 0.1 mm, and the second having a large area. The thickness of the region including the recess 62 (depth of the second recess) is 0.4 mm. The first recess 63 is a rectangle that is connected from end to end excluding the electrode seal portion, and the second recess 62 is also a rectangle that is connected from end to end excluding the electrode seal portion, and is orthogonal to the first recess 63. ing. The through holes 61 are rectangular with round ends as shown in FIG. 3, the average width of the apertures is 0.22 mm, the average length of the apertures is 2.5 mm, and the shorter pitch of the apertures is 0.5 mm on the average. The average pitch is 5 mm.

  The etched electrode substrate 221 is treated at 80 ° C. for 1 hour in a 10 wt% oxalic acid aqueous solution. Furthermore, it is anodized at 10 V for 2 hours in a mixed aqueous solution of 1M ammonium sulfate and 0.5M ammonium fluoride. Next, a solution prepared by adding 1-butanol to iridium chloride and tantalum chloride so that the amount of metal is 0.25 M is applied to the first surface 221 a of the electrode substrate 221, and then dried and fired. A catalyst layer (not shown) is created. In this case, drying is performed at 80 ° C. for 10 minutes, and baking is performed at 450 ° C. for 10 minutes. Two electrode base materials are produced by repeating such coating, drying, and firing five times, and a first electrode (anode) 220 is obtained. The distance between the through holes in the first region C4 shown in FIG. 3 of this electrode is an average of 0.28 mm, and the distance between the through holes in the second region C5 is an average of 2.5 mm. The ratio of the first distance to the second distance is 1: 8.9 on average. The distance between the through holes in the third region C6 is an average of 2.6 mm.

  As a diaphragm, an aqueous dispersion mixture of titanium oxide fine particles having a particle diameter of 100 nm and polyvinylidene fluoride particles is applied to a glass cloth having a thickness of 100 μm and dried. Furthermore, it is immersed in a 5% isopropanol solution of triisopropoxyaluminum and pulled up to the atmosphere. Dry in the atmosphere at 120 ° C. for 1 hour to prepare a diaphragm having a porous structure. The zeta potential of this diaphragm surface at pH 4 is 15 mV.

  Instead of forming the catalyst layer 28 containing iridium oxide, the second electrode (counter electrode, cathode) 22 is formed in the same manner as the first electrode 21 except that platinum is sputtered as the catalyst layer.

  Further, the membrane 27 is immersed in a 5% isopropanol solution of tetraisopropoxyzirconium in a polyethylene porous membrane having a thickness of 30 μm and pulled up to the atmosphere. Subsequently, the membrane is dried in the atmosphere at 90 ° C. for 1 hour to prepare a diaphragm having a porous structure.

  The zeta potential at pH 8 on the diaphragm surface is -30 mV.

  As the holding body 25 for holding the electrolytic solution, porous polystyrene having a thickness of 5 mm is used. The first electrode 20, the diaphragm 24, the porous polystyrene 25, the diaphragm 27, and the second electrode 22 are overlaid and fixed using silicone packing and screws, and the electrode unit 12 is created. The electrode unit 12 is placed in the electrolytic cell 11, and the partition wall 14 and the electrode unit 12 are used to form an anode chamber 16, a cathode chamber 18, and an intermediate chamber 19 provided with a porous polystyrene 25 disposed between the electrodes. Divided into three rooms.

  The anode chamber 16 and the cathode chamber 18 of the electrolytic cell 11 are each formed of a container made of vinyl chloride in which straight channels are formed. A control device 36, a power source 30, a voltmeter 34, and an ammeter 32 are installed. A pipe and a pump for supplying water from the water supply source 106 to the anode chamber 16 and the cathode chamber 18 are connected to the electrolytic cell 11 to secure the water supply lines 104 and 105. Furthermore, a line L4 for extracting hypochlorous acid water from the anode chamber 16 and a line L5 for extracting alkaline water from the cathode chamber 18 can be provided. A saturated saline tank 107 for circulating and supplying a saturated saline solution to the holder (porous polystyrene) 25 of the electrode unit 12, a pipe and a pump are connected to the electrode unit, and an electrolyte containing chloride ions is introduced into the electrolytic cell. A line L1 and a line 108 for collecting excess electrolyte are secured. Thereby, an electrolyzer having the same configuration as that of FIG. 5 is obtained.

  Electrolysis is performed using the electrolyzer 10 at a flow rate of 2 L / min, a voltage of 5.7 V, and a current of 10 A. Hypochlorous acid water is supplied on the first electrode (anode) 20 side, and hydrogen is supplied on the second electrode (cathode) 22 side. And produces aqueous sodium hydroxide. The production efficiency of hypochlorous acid is 73 ± 2%. Here, the production efficiency of hypochlorous acid is obtained from the amount of charge charged by measuring the effective chlorine concentration of the treated water.

  Subsequently, the electrode is removed and the following measurement is performed on 10 through-holes by cross-sectional SEM.

  Among the plurality of through holes, the maximum thickness of the catalyst layer in the first region between the through holes with the shortest adjacent distance is 4 to 5 μm, and the catalyst layer in the second region between the through holes with the longest adjacent distance is The maximum thickness is 2.2 to 3.5 μm, and the ratio of the maximum thickness of the catalyst layer in the first region to the maximum thickness of the catalyst layer in the second region is 1.3 to 2.2 times.

  An electrolysis apparatus is produced using the 1st electrode produced by the same method. The production efficiency of hypochlorous acid is the same. When this device is operated for 2000 hours, the increase in voltage is 10%.

  The obtained results are shown in Table 1 below.

(Comparative Example 1)
Instead of a solution prepared by adding 1-butanol to iridium chloride and tantalum chloride so that the metal amount is 0.25M, respectively, 1-butanol is added to iridium chloride and tantalum chloride so that the metal amount is 0.05M respectively. In addition to using the prepared solution and repeating the application, drying and baking of the solution five times, the same as in Example 1 except that the application, drying and baking of the solution is repeated 25 times. A first electrode and a second electrode are produced.

  The initial characteristics are the same as in the first embodiment. The electrode is removed and a cross-sectional SEM is taken to measure 10 through holes.

  The maximum thickness of the catalyst layer in the first region between the through holes with the shortest adjacent distance is 2.0 to 2.5 μm, and the maximum thickness of the catalyst layer in the second region between the through holes with the longest adjacent distance is The ratio of the maximum thickness of the catalyst layer in the first region to the maximum thickness of the catalyst layer in the second region is 0.9 to 1.1 times.

  The obtained results are shown in Table 1 below.

  The production efficiency of hypochlorous acid is the same as in Example 1. When this device is operated for 2000 hours, the increase in voltage is 25%, which is larger than that in Example 1.

(Examples 2-14 Comparative Examples 2-4)
Hereinafter, the ratio of the first distance in the first region C4 and the second distance in the second region C5 is changed as shown in the following Table 1 in the electrode shape of FIG. And the electrode is produced by changing the number of times of application variously. In any example, the third distance in the third region C6 is longer than the second distance.

  In FIG. 3, the maximum thickness of the catalyst layer in the first region C4 between the through holes with the shortest adjacent distance, the maximum thickness of the catalyst layer in the second region C5 between the through holes with the long adjacent distance, and after 2000 hours of operation The voltage increase rate was measured in the same manner as in Example 1, and the obtained results are shown in Table 1 below.

  Table 1 below shows the result of the measurement and the magnification of the maximum thickness of the catalyst layer in the first region with respect to the maximum thickness of the catalyst layer in the second region.

In Examples 2 to 8, the thickness of the catalyst layer is changed using electrodes having substantially the same opening structure. The initial electrolysis efficiency is 70 to 75%.

  In Examples 9 to 14, the thickness of the catalyst is similarly changed in the opening structure. In Examples 9 and 10, the initial electrolysis efficiency is 72 to 74%, but Example 11 is 68%, Example 12 is 66%, Example 13 is 67%, and Example 14 is 64%. descend. Therefore, the initial drive voltage is slightly high and the voltage increase rate is also slightly high.

  In Comparative Example 2, the number of times the solution is applied, dried, and fired is repeated more than in Comparative Example 1.

In Comparative Examples 3 and 4, after applying the solution, a filter paper is applied to the electrode from the bottom to remove the solution in the through-hole portion and then dried.

(Example 15)
A flat titanium plate having a plate thickness T1 of 0.5 mm is prepared as the substrate 21 of the first electrode.

  The titanium plate is etched in the same manner as in the steps shown in FIGS. 6A to 6D to produce the first electrode 20 of the embodiment. The electrode is 15 cm long in the water flow direction and 10 cm wide.

Of the first electrode 20, the thickness of the region including the first recess 40 having a small area (the depth of the first recess) is 0.1 mm, and the thickness of the region including the second recess 42 having a large area (the second recess). Is 0.4 mm. The first recessed hole portion 40 has a diamond shape with rounded corners (the angles of the apexes of the extrapolated diamond shape are 60 ° and 120 °) similarly to the electrode shown in FIG. Through-holes are also rounded corners diamond, the opening area is 0.08mm ² ~0.10mm ^2. The 2nd recessed part 42 is also a rhombus, and one side of a rhombus is about 3.6 mm.

  An electrode unit and an electrolysis apparatus are produced in the same manner as in Example 1 except that the first electrode and the second electrode are used.

  The average ratio of the first distance and the second distance shown in FIG. 2 is 1: 5.0.

  Using this electrolyzer, electrolysis is performed at a flow rate of 2 L / min, a voltage of 6.2 V, and a current of 10 A. Hypochlorous acid water is supplied on the first electrode (anode) 20 side, and hydrogen is supplied on the second electrode (cathode) 22 side. And produces aqueous sodium hydroxide. The production efficiency of hypochlorous acid is 75 ± 2%. The first electrode is removed from the apparatus, and 10 through holes are measured with a cross-sectional SEM. The maximum thickness of the catalyst layer in the first region between the through holes with the shortest adjacent distance is 5 to 7 μm, and the maximum thickness of the catalyst layer in the second region between the through holes with the longest adjacent distance is 2 to 3 μm. Yes, the ratio of the maximum thickness of the catalyst layer in the first region to the maximum thickness of the catalyst layer in the second region is 2 to 3 times.

  An electrolysis apparatus is similarly manufactured using the 1st electrode produced by the same method. The production efficiency of hypochlorous acid is almost the same. If the device is operated for 2000 hours, the voltage increases by 9%.

(Comparative Example 5)
Instead of a solution prepared by adding 1-butanol to iridium chloride and tantalum chloride so that the metal amount is 0.25M, respectively, 1-butanol is added to iridium chloride and tantalum chloride so that the metal amount is 0.05M respectively. In addition to using the prepared solution and repeating the application, drying and baking of the solution 5 times, the same as in Example 15 except that the application, drying and baking of the solution is repeated 25 times. A first electrode is produced.

  The initial characteristics are the same as in Example 15. The cross section SEM is measured by removing the electrode, and 10 through holes are measured. The maximum thickness of the catalyst layer in the first region between the through holes with the shortest adjacent distance is 2.0 to 2.6 μm, and the maximum thickness of the catalyst layer in the second region between the through holes with the longest adjacent distance is The ratio of the maximum thickness of the catalyst layer in the first region to the maximum thickness of the catalyst layer in the second region is 0.9 to 1.1 times.

  Furthermore, an electrolysis apparatus is produced using the 2nd electrode produced by the same method as the 1st electrode. The production efficiency of hypochlorous acid is the same as in Example 15. When this device is operated for 2000 hours, the increase in voltage is 30%, and the increase rate is large.

(Example 16)
A flat titanium plate having a plate thickness T1 of 0.5 mm is prepared as the substrate 221 ′ of the first electrode.

  This titanium plate is etched except that the first recess, the second recess, and the through hole having the pattern shown in FIG. 4 are formed by etching and punching from both sides in the same manner as in Example 1. The first electrode 220 ′ of the third embodiment is produced. The electrode is 15 cm long in the water flow direction and 10 cm wide.

  The first recess 63 is a rectangle connected from end to end excluding the electrode seal portion, and the second recess 62 ′ is a rectangle connected from end to end excluding the electrode seal portion, and the end of the electrode excluding the seal portion Two recesses that are connected to the end from each other, that is, the first recess 62 ′ and the second recess 63 are parallel.

The through hole of the first electrode is an ellipse as shown in FIG. The rectangular groove is formed by etching, and the elliptical through hole 61 ′ is formed by punching. The area of the through hole is 0.53 mm ^{2 to} 0.55 mm ² .

  The first recess 62 ′ has a larger area than the second recess 63, and the arrangement of the through holes 61 ′ in the first recess 62 ′ is two rows of the arrangement of the through holes 61 ′ in the second recess 63.

  The second electrode 222 'can be formed in the same manner as the first electrode 220'.

  An electrode unit and an electrolysis device are produced in the same manner as in Example 1 except that the first electrode 220 'and the second electrode 222' are used instead of the first electrode 20 and the second electrode 22.

  Using this electrolyzer, electrolysis was performed at a flow rate of 2 L / min, a voltage of 6.0 V, and a current of 10 A. Hypochlorous acid water was used on the first electrode (anode) side, and hydrogen and water were used on the second electrode (cathode) side. Produces sodium oxide water. The production efficiency of hypochlorous acid is 63 ± 3%. The first electrode is removed from the apparatus, and the cross-sectional SEM is measured. The maximum thickness of the catalyst layer in the first region C7 between the through holes with the shortest adjacent distance is 3 to 4 μm, the maximum thickness of the catalyst layer in the second region C8 between the through holes with the long adjacent distance is 2-3 μm, The ratio of the maximum thickness of the catalyst layer in the first region to the maximum thickness of the catalyst layer in the second region is 1.3 to 1.5 times. The average ratio of the first distance and the second distance shown in FIG. 4 is 1: 4.3. The third distance in the third region C9 is greater than the second distance.

  An electrolysis apparatus is similarly manufactured using the 1st electrode produced by the same method. The production efficiency of hypochlorous acid is almost the same. If the device is run for 2000 hours, the voltage increases by 12%.

(Example 17)
FIG. 8 is a diagram schematically illustrating another example of the electrolysis apparatus according to the embodiment.

  As shown in FIG. 8, this electrolysis apparatus 310 has a cathode chamber 318 and an anode chamber 316 disposed so as to surround the cathode chamber 318 instead of the electrolytic cell 11, and is free from natural convection without a channel and piping. The configuration is the same as that shown in FIG. 1 except that a batch-type electrolytic cell 311 in which a water flow is formed is used. The capacities of the anode chamber 316 and the cathode chamber 318 are 2 L and 0.1 L, respectively, and electrodes manufactured in the same manner as in Example 15 are used. However, the size of the electrode is 4 × 3 cm.

  Electrolysis is performed at a voltage of 7 V and a current of 2 A for 5 minutes to generate hypochlorous acid water on the first electrode (anode) side and hydrogen and sodium hydroxide water on the second electrode (cathode) side. The production efficiency of hypochlorous acid is 80 ± 2%. The first electrode is removed from the apparatus, and 10 through holes are measured with a cross-sectional SEM. The maximum thickness of the catalyst layer in the first region between the through holes having the shortest adjacent distance is 5 to 7 μm, and the maximum thickness of the catalyst layer in the second region between the through holes having the long adjacent distance is 2 to 3 μm. The ratio of the maximum thickness of the catalyst layer in the first region to the maximum thickness of the catalyst layer in the region is 2 to 3 times.

  An electrolysis apparatus is similarly manufactured using the 1st electrode produced by the same method. The production efficiency of hypochlorous acid is almost the same. If this device is operated intermittently for 2000 hours, the voltage rises by 12%.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 10 ... Electrolytic apparatus, 11 ... Electrolytic cell, 12 ... Electrode unit, 14 ... Partition, 16 ... Anode chamber, 18 ... Cathode chamber, 19 ... Intermediate chamber, 20, ... 1st electrode, 21, 23, ... Base material, 22 , ... 2nd electrode, 21a, 23a, ... 1st surface, 21b, 23b, ... 2nd surface, 24, 27 ... diaphragm, 25 ... holder, 26, 26a, 26b ... diaphragm, 28 ... catalyst layer, 30 ... Power source, 32 ... ammeter, 34 ... voltmeter, 40, 44, 61, 63 ... through hole (first recess), 42, 46, 62 ... second recess, 50 ... resist film, 60 ... bridge, 64 ... voltage Application port, 65 ... Beam

Claims (21)

An electrode base material having a first surface, a second surface facing the first surface, and a plurality of through holes penetrating from the first surface to the second surface;
A plurality of first recesses opening in the first surface;
A plurality of second recesses opening in the second surface and having an opening area wider than the first recess;
A catalyst layer provided on the first surface;
At least a part of the through hole communicates the first recess and the second recess,
The first recess has a larger number than the second recess,
The plurality of through holes are:
A first through hole;
A second through hole adjacent to the first through hole at the shortest first distance;
At least a third through hole adjacent to the first through hole at a second distance longer than the first distance, and a third distance between the second through hole and the third through hole is longer than the second distance. The catalyst layer has a first thickness in a first region between the first through hole and the second through hole, and a second thickness in a second region between the first through hole and the third through hole. Electrode for electrolysis larger than thickness. An electrode base material having a first surface, a second surface facing the first surface, and a plurality of through holes penetrating from the first surface to the second surface;
A plurality of first recesses opening in the first surface;
A plurality of second recesses opening in the second surface and having an opening area wider than the first recess;
A catalyst layer provided on the first surface;
The plurality of first recesses include a third recess, a fourth recess, and a fifth recess adjacent to each other,
The plurality of second recesses include a sixth recess and a seventh recess adjacent to the sixth recess,
The plurality of through holes are
A first through hole communicating the third recess and the six recesses;
A second through hole communicating the fourth recess and the sixth recess;
A third through hole communicating with the fifth recess and the seventh recess;
The catalyst layer has a first thickness in a first region between the first through hole and the second through hole, and a second thickness in a second region between the first through hole and the third through hole. Larger electrode for electrolysis. An electrode base material having a first surface, a second surface facing the first surface, and a plurality of through holes penetrating from the first surface to the second surface;
A plurality of first recesses opening in the first surface;
A plurality of second recesses opening in the second surface and having an opening area wider than the first recess;
A catalyst layer provided on the first surface;
The plurality of first recesses include a third recess and a fourth recess adjacent to the third recess,
The plurality of second recesses include a fifth recess and a sixth recess adjacent to the fifth recess,
The plurality of through holes are
A first through hole communicating the third recess and the fifth recess;
A second through hole communicating the fourth recess and the fifth recess;
A third through hole communicating with the third recess and the sixth recess;
In the catalyst layer, the first thickness in the first region between the first through hole and the second through hole is greater than the second thickness in the second region between the first through hole and the third through hole. Large electrolysis electrode.   The electrode for electrolysis according to any one of claims 1 to 3, wherein the first thickness is 1.5 times or more the second thickness.   The electrode for electrolysis according to claim 1 or 3, wherein the second front distance is 1.5 to 10 times the first distance.   The electrode for electrolysis according to any one of claims 1 to 4, wherein the catalyst layer contains iridium oxide and tantalum oxide.   The electrode for electrolysis according to any one of claims 1 to 5, wherein the through hole has a rectangular shape with a round end, an ellipse, or a rhombus with rounded corners. The second recess of the opening, the electrode for electrolysis according to any one of claims 1 to 6 having an area of 1～1600Mm ^2.   The electrode for electrolysis according to any one of claims 1 to 8, wherein the first recess has a peripheral wall having a tapered surface shape or a curved surface shape in which the first surface side is widened.   The electrode for electrolysis according to any one of claims 1 to 9, wherein the second recess is connected from one end to the other end of the electrode base material excluding a seal portion.   The electrode for electrolysis according to any one of claims 1 to 10, wherein the first recess is connected from one end to the other end of the electrode base material excluding a seal portion.   The electrode for electrolysis according to any one of claims 1 to 11, wherein the first recess and the second recess are orthogonal to each other.   The electrode for electrolysis according to any one of claims 1 to 12, wherein the first recess and the second recess are parallel to each other.   The electrode for electrolysis according to any one of claims 1 to 13, wherein in the plurality of through holes, a distance between adjacent through holes is 0.1 mm or more and 2.5 mm or less.   The aperture ratio of the through-hole located in the center part of the said electrode base material among these through holes differs from the aperture ratio of the through-hole located in the peripheral part of the said electrode base material. The electrode for electrolysis of Claim 1.   The electrode for electrolysis according to any one of claims 1 to 15, wherein the first surface is anodized.   The electrode for electrolysis according to any one of claims 1 to 16, wherein the through holes are arranged in series, and a direction of a thick beam or a wide beam separating rows of the through holes is a direction of a voltage application port of the electrode. . A first electrode comprising the electrode for electrolysis according to any one of claims 1 to 17,
A diaphragm disposed on the first surface;
An electrode unit comprising: a second electrode provided on the first surface side of the first electrode; and an electrolyte solution holding structure provided between the diaphragm and the second electrode.   A porous film provided between the first surface of the first electrode and the second electrode and transmitting at least one of ions and liquid; the porous film being a first electrode of the first electrode; The electrode unit according to claim 18, which is sandwiched between a surface and the diaphragm.   An electrolysis apparatus comprising: an electrolytic cell; and the electrode unit according to claim 18 or 19 incorporated in the electrolytic cell, a first electrode chamber partitioned by the electrode unit, and a second electrode chamber.   The first electrode chamber is an anode chamber, the second electrode chamber is a cathode chamber, a line for introducing an electrolytic solution containing chloride ions into the electrolytic cell, a line for extracting acidic electrolyzed water from the anode chamber, and The electrolysis apparatus according to claim 20, further comprising a line for taking out alkaline electrolyzed water from the cathode chamber.

Images