Catalytic electrode body for zero-gap type water electrolysis apparatus, and ozone water generating method using the same

Abstract

To form an efficient flow of water on an electrode surface, and to improve an ozone generation efficiency by increasing contact points between a diamond catalytic electrode and an SPE membrane.SOLUTION: A catalytic electrode body is used for a water electrolysis apparatus, in which a waterway network is arranged on a flat working surface of a substrate made of a conductive material; and water to be treated is moved along the waterway network. On the catalytic electrode body, the waterway network includes multiple waterways which are formed as dents in the thickness direction; the waterway network has inlets for allowing water to flow in on the upstream side and outlets for allowing water to flow out on the downstream side regarding the movement of water; and a water flow path is assembled from the inlet to the outlet by a collaborative connection of the inclusive waterways.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a highly efficient electrode body for an electrolysis device, and in particular to an electrode body for a contact (zero-gap) type water electrolysis device for producing ozone water using an SPE (solid polymer electrolyte) membrane. [Background technology]

[0002] Ozone water, an aqueous solution of ozone gas, has a high bactericidal effect but also has low impact on the human body, as it does not irritate the skin when touched or cause problems if it gets into the eyes or mouth. Therefore, it is used for sterilization and infection control in various facilities around the world, including medical institutions, food factories, and daycare centers.

[0003] Ozone gas can be easily produced by the anodic reaction in a water electrolysis cell. 3H 2 O → O 3 + 6H + +6e - 2H 2 O → O 2 + 4H + + 4e - O 2 + H 2 O → O 3 + 2H + + 2e - Various electrode materials, electrolytic cell configurations, and methods have been developed with the aim of optimizing the current efficiency in this electrolytic reaction, improving the efficiency of ozone generation, and increasing the electrode life.

[0004] As a catalytic electrode material to promote the above reaction, diamond that has been made conductive by adding boron (boron-doped diamond, BDD) is preferred because of its excellent chemical and dimensional stability. It is often used as an anode material by coating it in the form of a film on a corrosion-resistant metal substrate that is not easily electrolyzed, or by adhering particles to the metal.

[0005] For example, there are known examples of electrode structures in which BDD is coated onto a titanium plate or mesh by chemical vapor deposition (CVD), or BDD particles are fixed between titanium meshes, but due to ease of handling and the reliability of ozone generation, it is more common to form a thin film of BDD by chemical vapor deposition (CVD) on a flat metal plate with multiple holes (Non-Patent Documents 1 and 2).

[0006] On the other hand, a method has also been developed in which an electrolytic cell is made by placing an anode and a cathode facing each other in close contact (zero-gap) with an SPE membrane such as Nafion (trade name) between them, immersing the cell in water, and applying a potential (Patent Document 1). This cell structure has the advantage that the reaction space is narrow, so the diffusion length of substances is short and the reaction proceeds quickly. In other words, since ozone, hydrogen peroxide, and various water electrolysis intermediate products (ions, radicals) are present near the electrode surface, anodic oxidation proceeds efficiently, and it is known that, for example, during wastewater purification, the reaction between pollutants in the water and the oxidizing agent proceeds quickly, achieving high purification efficiency.

[0007] The electrode reaction that generates ozone proceeds in the part of the electrode that contacts water, particularly near the boundary between the BDD and SPE membrane, where a three-phase interface of gas, liquid, and solid is formed. In some cases, multiple small holes are formed in the electrode plate to allow water to penetrate or pass through, thereby expanding the contact area. There are also reports of high current efficiency being achieved in the ozone generation reaction using an electrolysis device constructed by closely contacting a BDD-coated Ti plate anode with an SPE membrane. (Non-Patent Document 2) [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Re-Tabled Publication No. 2020 / 171238 (Patent No. 7010529) [Non-patent literature]

[0009] [Non-Patent Document 1] K. Arihara, et al. ElectroChem. Solid-State Lett., 9, D17 (2006) [Non-Patent Document 2] R&D Kobe Steel Technical Review 60 (1)Apr. 2010 Summary of the Invention [Problem to be solved by the invention]

[0010] In the electrolytic generation of ozone and other gases using a zero-gap electrolysis device that uses a BDD catalytic electrode and an SPE membrane, maximizing the area in which the diamond electrode and the SPE membrane come into contact with water is an important factor in optimizing operating conditions such as current efficiency. However, it cannot be said that this is sufficiently achieved with conventional electrode configurations, and there is room for improvement.

[0011] Conventional anodes include electrodes with a structure in which BDD is supported on a titanium mesh or substrate. In the structure using a mesh, the raw water supply is ensured because the water to be treated passes through the mesh, but the metal mesh structure poses a problem in the adhesion between the BDD and the SPE membrane. On the other hand, in the case of a BDD supported on a metal substrate, although adhesion with the SPE membrane is ensured, there is a problem in the amount of raw water that can be supplied through the narrow gaps. Therefore, although the substrate is provided with many small holes to supply raw water, the formation of a three-phase interface is mainly limited to the circumferential area of ​​the small holes that contact the SPE membrane.

[0012] Therefore, an object of the present invention is to improve the efficiency of ozone generation per electrode area in such an electrolytic cell by expanding the reaction area that contributes to ozone generation. In particular, in the present invention, an effective and clear water channel network is provided on the anode surface to form an efficient flow of water on the working surface and increase the number of contact points between the diamond catalyst electrode and the SPE membrane where a three-phase interface is formed, thereby improving the efficiency of ozone generation. [Means for solving the problem]

[0013] The present invention relates to an electrode body for an electrolytic cell for water treatment, in which a water channel network is provided on the flat working surface of a substrate made of a conductive material and the water to be treated is moved along the water channel network. The main feature of the present invention is that the water channel network includes continuous water channels formed as grooves in the thickness direction, and has an inlet for allowing water to flow in on the upstream side and an outlet for allowing water to flow out on the downstream side, enabling water to flow from the inlet to the outlet.

[0014] The electrode body of the present invention is intended to be mounted in a zero-gap type electrolytic device and used for electrolytic generation of ozone water, etc. The manufacturing method basically includes the following steps. (1) The anode body, which is a corrosion-resistant metal substrate with boron-doped diamond (BDD) bonded thereto, is placed face-to-face with the SPE membrane in intimate contact with it, a cathode is placed on the back of the SPE membrane and immersed in water, and a water flow is generated along the electrode working surface; (2) Applying a potential between the two electrodes that is capable of generating ozone, ionizing the water in contact with the SPE membrane; (3) An anodic reaction is induced by the BDD to generate ozone. (4) The generated ozone is dissolved in the surrounding water and collected. Effect of the Invention

[0015] In the present invention, a wide water channel network is provided on the anode working surface, which is composed of many water channels connecting the inlet and outlet of the raw water, and the edges of both banks of the water channels that contact the SPE membrane are used as the three-phase interface forming region, so that the entire anode working surface can effectively act as an ozone generation starting point. For example, parallel grooves (water channels) with a width of 0.1 mm and a depth of 0.1 mm are formed at 0.1 mm intervals on the entire surface of the metal plate of the electrode substrate such as titanium or niobium, and a BDD thin film is formed on top of them to use the grooves as water channels, so that a three-phase interface is generated at the contact points with the diamond film, particles, and polymer electrolyte membrane present at the edge of the groove, and substantially the entire surface of the electrode can be used as the functional surface for ozone generation.

[0016] Furthermore, since the electrode body of the present invention can pass a large current at a low voltage, it is optimal as an electrode for producing ultra-high concentration ozone water, and can be expanded to various applications in semiconductor processes. In addition, since it is possible to produce ultra-high concentration ozone water using tap water without causing electrolytic deposition of minerals, it can also be used to produce industrial treated water, such as in the pretreatment process for plating, and can be used in a variety of equipment and processes involving water treatment. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is an explanatory diagram showing an example of an electrode assembly having a rectangular substrate and an active surface produced according to the present invention. [Diagram 2] FIG. 2 is an explanatory diagram showing an example of an electrode body having a circular substrate and a working surface produced according to the present invention. [Diagram 3] FIG. 3 is an enlarged explanatory view showing the shape of a water channel network (part) on the surface of an electrode body produced according to the present invention. [Figure 4] FIG. 4 is an explanatory diagram of the water channel network of the electrode body of the present invention used in an example of comparative operation with a conventional configuration. [Diagram 5] FIG. 5 is a graph showing current-voltage comparison in an example of operation using an electrode assembly of the present invention and a conventional configuration. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] It is known that the ozone gas generation reaction on the anode surface proceeds in a three-phase interface region of approximately 0.05 mm in width where the reaction field water, the catalytic BDD electrode, and the SPE membrane meet. Therefore, in the present invention, a water channel network consisting of many water channels is provided on the working surface of the anode, and the BDD on both sides of the water channels that contact the SPE membrane are used as the starting points for ozone generation.

[0019] Such an increase in the three-phase interface makes it possible to reduce the resistance of the BDD catalyst portion, which has the following advantages, particularly in the ozone generation process, and is therefore of great practical value. - When operating at the same current density, the voltage can be lowered, suppressing the deposition of minerals at the cathode. As a result, long-term operation is possible. -When operating at the same voltage, the current density can be increased, so the amount of ozone and hydrogen peroxide produced can be increased. In other words, a large amount of ozone water can be produced with a small device. The actual electrodes will take on various shapes depending on the structure of the electrolysis device, but in any case, by providing a large number of water channels connecting the inlet and outlet of the water to be treated, it is possible to increase the amount of functional water such as ozone water and reduce the flow resistance.

[0020] In the operation of a zero-gap type water electrolysis cell, water to be treated is generally introduced between the closely attached working surface and the SPE membrane surface, and a gentle flow is provided so that the generated ozone and hydrogen are dissolved and pass through. In particular, the electrode body of the present invention is provided with an electrode body having a water channel network that maximizes the three-phase interface reaction area where the reaction proceeds and can guide the water to be treated and efficiently guide and discharge it outside the electrode body.

[0021] The water channel network of the present invention includes linear (straight or curved) open recesses or grooves formed on the surface, i.e., working surface, of an electrode substrate made of a metal such as titanium, niobium, or silicon that has excellent corrosion resistance and has the ability to fix a precipitated diamond layer via carbide. The substrate can be distributed with through holes to expand the reaction area or to allow the water to be treated to flow from the opposite surface (back surface) of the substrate. The distribution of through holes in a substrate is known per se, but they can be used as a component of the water channel network of the present invention by connecting them with water channels as described below. The water channel network can be said to provide a flow path that guides the movement of the water to be treated on the working surface of the electrode body, and the flow path can be variously configured by functionally connecting the water channels and the through holes as described in detail below.

[0022] The shape of the electrode substrate varies depending on the design of the electrolytic cell, such as annular, polygonal, or the like, and whether or not there is a through hole. However, the water channel network of the present invention can be used for any substrate with a flat surface. The water channel network pattern is designed according to the geometric shape of the working surface, and is constructed by combining and arranging long and short water channels. Each water channel is formed on the working surface as a groove with a width of 0.1 mm or more and a depth of 0.05 mm or more by laser processing or other existing methods. That is, this groove must be designed to have a sufficient width and depth compared to the anchor groove for preventing the diamond film deposited on the substrate from falling off, and to ensure the function of the water channel. In the case of a quadrilateral substrate such as a rectangle or square, it is convenient to form multiple parallel straight water channels between the outer end of the upstream side of the substrate and the outer end of the downstream side opposite to the substrate, especially on the working surface without a through hole, but in this case, cutting a straight groove by machining is preferable in terms of accuracy and processing time.

[0023] The water channel network of the present invention is designed according to the surface configuration, including the geometric shape of the electrode substrate and the presence or absence of through-holes, and is composed of water channels formed as long or short, straight or curved linear surface recessed grooves. The through-holes also form part of the water channel network. This water channel network has multiple inlets opening at the upstream inlet end and multiple outlets opening at the downstream outlet end, providing multiple routes (flow paths) for guiding the water to be treated from the inlets to the outlets.

[0024] Each flow path can be constructed as a single long waterway with both an inlet and an outlet, but it is also effective to connect a number of shorter waterways with connecting waterways that are formed in the cross direction and open on each of them to form a combined flow path. The former waterway can be called a full waterway, and the latter waterways can be called a partial waterway or a connecting waterway. In this way, the waterway network of the present invention provides a number of flow paths from the inlet end to the outlet end.

[0025] The configuration of the waterway network of the present invention can be designed, for example, as follows. In the case of a simple surface without through holes, in the case of a quadrilateral or polygonal substrate, the water channel network can be composed exclusively of all-through water channels that reach from the upstream end to the downstream end, and in the case of a ring-shaped substrate, they can be composed of all-through water channels that reach from the edge of the central hole (inner circumference) to the outer circumference. It is efficient to form these all-through water channels as a group of parallel straight lines in the former case, and radially in the case of a ring. It is also effective to form connecting water channels in a direction that intersects with these water channels midway through their length, i.e., orthogonal in the former case, and in one or multiple concentric circles with different radii in the case of a ring, and connect the multiple all-through water channels by opening them.

[0026] In the case where it is difficult to extend the entire water passage in a substrate in which many through holes are distributed, the water passage network of the present invention can secure a flow passage from the upstream end to the downstream end of the substrate by connecting each through hole and the through hole with an upstream end and a downstream end with a short water passage. If there is a surface area in which a flow passage that does not pass through the through holes can be formed, there is no problem in using a combined flow passage that connects a full water passage that does not pass through the through holes or a partial water passage and a connecting water passage.

[0027] The connecting water channel can be widely used as a component for connecting all the above-mentioned water channels, connecting the holes in a substrate having through holes, and connecting the holes to the upstream end or downstream end. The supply of the water to be treated is ensured by connecting the through holes to each other, but it is also possible to design it so that the water flow is averaged and the water flow resistance is reduced, thereby increasing the amount of water passing through.

[0028] In the present invention, in the case of a circular or annular substrate having a relatively large through hole (main hole) in the center of the substrate, a typical example of a water channel network is to form a radial full water channel along the direction of the water flow when a water flow is given from the periphery to the center or in the opposite direction. In this case, it is appropriate to connect adjacent full water channels with connecting water channels of full or partial circles (arcs) of multiple concentric circles with different radii. The insertion of connecting water channels increases the amount of water passing by reducing the water flow resistance, and also increases the area of ​​the three-phase interface, which allows for an increase in the amount of ozone generated. Laser or mechanical processing can be used to form the full water channels, as in the case of a quadrilateral substrate.

[0029] In the above, it is convenient to set the intervals between the water channels at equal angles, but since the intervals on the circumference are enlarged on the outer periphery side, it is preferable to make them as small as possible. However, as the angular interval (pitch) becomes smaller, the density increases on the inner diameter side, while the intervals become too large on the outer periphery side, so it is also effective to form a multi-pitch radial water channel configuration in which the main water channel does not reach the entire outer periphery, but rather forms a smaller pitch / full water channel up to the middle of the ring width or from there, and connects both water channels with a connecting water channel.

[0030] The electrode substrate after the water channel formation process is then subjected to a CVD process to deposit or coat the surface of the substrate with boron-doped conductive diamond (BDD) particles or a film for use as an anode plate. If measures are taken to prevent diamond from being altered by heat, groove cutting by laser processing can also be performed as a post-processing of the BDD-coated anode plate. Even in the case of a film, the BDD coating has many gaps, so the water to be treated can also flow in from above the working surface. In the area where the BDD and SPE film on the working surface are close to each other, ozone is generated by an electrolytic reaction and dissolved in the water, which flows toward the outlet along the main water channel and the connecting water channel.

[0031] In the present invention, by providing many water channels on the anode surface and taking in the water to be treated into the water channels, the water to be treated in the water channels is used in the electrolysis reaction, and the electrical resistance can be reduced by increasing the area of ​​the three-phase interface. Furthermore, the formation of these water channels makes it possible to increase the current density (conduction of H+ ions), and when operating at the same voltage as conventional electrodes, it is possible to improve the water electrolysis rate.

[0032] Furthermore, the reduction in electrical resistance has made it possible to operate the device at a lower voltage when operating at the same current density as conventional electrodes, i.e., at the same water electrolysis rate. As a result, even in areas where the tap water is hard and the electrolysis of minerals during water electrolysis is an obstacle to the introduction of water electrolysis equipment, the electrolysis reaction of minerals on the cathode surface can be suppressed, and the device life can be expected to be extended.

[0033] 1 showing an example of a water channel network configuration in an electrode body according to the present invention, the electrode body shown as a whole 10 has a substrate 11 made of a square (rectangular) metal plate, across its surface, and a large number of linear grooves 12, each of which extends from one end to the other and forms a full-length water channel, are formed in parallel to form a water channel network 13. These full-length water channels reach and intersect with connecting water channels (connecting water channels) 14-18 every few lines along their length, allowing water to flow between them.

[0034] In particular, when the working surface of the electrode substrate is circular, a hole (main hole) is provided at the center of symmetry or at another location that penetrates the entire thickness of the substrate, allowing water (the water to be treated) to pass from the opposite (back) side of the working surface of the substrate to the working surface, and a plurality of water channels that open on the edge of the inner circumference are radially extended from the end of the substrate to the outer circumference. In this case, adjacent pairs of water channels may be connected by a water channel that reaches both of them.

[0035] In the example of the annular electrode body 20 in Fig. 2, the same type of metal plate 21 as above has a circular through hole 22 in the center, and a plurality of linear water passages 23 (24 in the figure) extend radially from this hole to the outer periphery. Connecting water passages 24-26 extend in an annular shape, intersecting with these water passages midway through their lengths. This connection allows water to flow between the radial water passages, and as a whole forms a water passage network 27.

[0036] A detailed configuration example of a water channel network in an electrode substrate having many through holes is shown in Fig. 3. In this figure, each through hole 31 is connected to the adjacent surrounding through holes by connecting water channels 32 extending in six directions, and the treated water is guided to the downstream end by these connections. In this figure, the water channel network is composed only of through holes and connecting water channels, but if there is a blank area on the surface without through holes, it is also possible to provide a main water channel (not shown) that runs from the inlet end on the upstream side to the outlet end on the downstream side.

[0037] This increases the electrolysis current and improves the amount of ozone generated by adding three-phase interface regions formed at the interfaces between both banks of each water channel and the SPE membrane to the three-phase interface region of approximately 0.05 mm width formed by the interaction between the outer edge of the through-hole and the SPE membrane.

[0038] The water channel of the present invention is generally called a microchannel, and since substances generated by water electrolysis (for example, oxidizing agents such as ozone and hydrogen peroxide) diffuse quickly in the water channel, it is possible to promote reactions with other substances contained in the water. For example, if wastewater containing harmful impurities is directly electrolyzed through an electrolysis device incorporating the electrodes of the present invention, the impurities in the wastewater can be efficiently oxidized and decomposed in the microchannel.

[0039] The electrode with a water channel of the present invention is highly effective when used in processes and equipment that require the promotion of reactions between ozone or hydrogen peroxide generated by electrolysis and other substances contained in water. In other words, the electrode with a water channel of the present invention is expected to be even more effective when incorporated into water electrolysis equipment intended for the purposes of purifying wastewater or making river water drinkable. EXAMPLES

[0040] The outer and inner diameters of the tube, which has many fine through holes, are φ35 mm and φ11 mm (area is approximately 8.6 cm). 2 An electrode substrate having a water channel network according to the present invention was prepared using a 0.5 mm thick ring-shaped niobium plate, and for comparison, an electrode substrate having a conventional structure without a water channel network was prepared.

[0041] First, on the electrode substrate of the present invention, seven rows of through holes (small holes) with a diameter of 1.0 mm were formed at intervals of about 0.5 mm on the entire surface, with 28 rows of 4 rows radially formed from the center hole (Figure 4). Next, 56 main water channels, each 0.1 to 0.2 mm in width and depth, were formed between each row of through holes, extending from the central hole to the outer periphery, and connecting water channels were formed from each through hole to four adjacent through holes, thereby connecting the adjacent through holes to the main water channels. On the other hand, the electrode substrate for comparison was used as it was, without providing the above water channels.

[0042] A BDD film with a thickness of about 5 μm was deposited on the substrates of the present invention and the comparative example by the hot filament method. The area that mainly contributes to ozone generation is the area of ​​the three-phase interface where the BDD as the catalytic material on the anode side, the polymer electrolyte membrane (Nafion membrane), and water meet, with a width of about 0.05 mm. Therefore, the three-phase interface area per hole was calculated as 0.16 mm. 2 (π × 1mm × 0.05mm), plus the sum of the three-phase interface areas on both sides of each channel, approximately 0.15 mm 2 By adding grooves to the catalyst, the area of ​​the three-phase interface has been increased to approximately twice that of conventional products without grooves, thereby improving catalytic activity.

[0043] These electrodes were attached to the mixer-equipped accelerated oxidation water production device described in Publication No. 2020-171238, and an ozone water generation test was conducted using tap water. This device is a household ozone water generation device that has a circular water electrolysis device for generating ozone gas at the bottom of an acrylic container with an inner diameter of 50 mm and a length of 170 mm, and a mixer for dissolving ozone gas in water at the top. FIG. 5 shows the current-voltage characteristics in electrolysis using the electrode of the present invention in comparison with a conventional electrode.

[0044] In the conventional ozone water generator equipped with a boron-doped diamond electrode without a water channel, the current density was 0.2 A / cm 2 It was found that a voltage application of about 7.2 V was sufficient for the electrode of the present invention, whereas a voltage application of 9 V was required to pass a current of 1.72 A.

[0045] By lowering the operating voltage to about 7V, the amount of minerals electrolytically deposited on the cathode could be reduced to as close to zero as possible, and the possibility of improving the electrode life and electrolysis of hard water was confirmed. - The amount of ions becomes noticeable at an applied voltage of about 8 V. - It is known that ions can trigger problems such as the deposition of Ca, Mg, and other ions in the water on the cathode surface in the form of hydroxides or carbonates, and therefore water electrolysis at an applied voltage of 8 V or less has led to a wide range of applications.

[0046] On the other hand, in water electrolysis at an applied voltage of 8 V, the current density with conventional electrodes is 0.15 A / cm 2 (current value 1.25A), whereas the electrode of the present invention had a current density of 0.3A / cm 2 (current value 2.5A). In other words, it became possible to generate twice the amount of ozone with an applied voltage of 8V using an anode plate of the same apparent area. From another point of view, the dissolved ozone concentration in ozone water obtained by water electrolysis at 9 V, at which the problem of electrodeposition on the cathode surface becomes significant with a conventional electrode, is 0.48 mg / L. By lowering the applied voltage by 1 V to 8 V with the electrode of the present invention, it is possible to obtain an ozone concentration of 0.75 mg / L, which is about 1.5 times higher, while avoiding the problem of electrodeposition. This is a clear advantage. [Explanation of symbols]

[0047] 10 Electrode body 11 Substrate 12 Connecting canal (straight line) 13 Waterway network 14~18 Connecting Canals 20 Annular electrode body 21 Metal plate 22 Through hole 23 (radial) waterway 24~26 Connecting waterway (circular) 27 Waterway network 31 Through hole 32 Connecting Canal

Claims

1. A catalyst electrode body for a water electrolysis device in which a water channel network is provided on the flat working surface of a substrate made of a conductive material and water to be treated is moved along the water channel network, the water channel network containing a plurality of water channels formed as depressions in the thickness direction, the water channel network having an inlet for allowing water to flow in on the upstream side and an outlet for allowing water to flow out on the downstream side with respect to the movement of the water, and the electrode body having a water flow path from the inlet to the outlet by the interconnection of the contained water channels.

2. 2. The electrode assembly according to claim 1, wherein the water channel network includes a plurality of water channels arranged in parallel in the same direction, and at least one water channel has an inlet opening outwardly at an upstream end of the working surface.

3. 3. The electrode assembly according to claim 1, wherein the water channel network includes a plurality of water channels arranged in parallel in the same direction, and at least one water channel has an outlet port that opens outward at a downstream end of the working surface.

4. The electrode body described in claim 1, wherein the water channel network includes a plurality of linear first water channels extending from the upstream side to the downstream side of the substrate, and at least a pair of adjacent water channels are connected by a second water channel formed as a recess in the thickness direction and reaching both water channels to form a flow path.

5. 5. The electrode assembly of claim 1 or 4, wherein the substrate is quadrilaterally shaped and adjacent pairs of the first channels extend at least partially parallel to each other.

6. 5. The electrode assembly according to claim 1, wherein the substrate is annular and a plurality of the first water channels are provided radially extending from a central hole.

7. 7. The electrode assembly according to claim 6, wherein the second water passage extends circumferentially about a center of the annulus, and reaches and is connected to a plurality of first water passages to form a flow path.

8. 2. The electrode assembly according to claim 1, wherein the substrate has a plurality of through holes penetrating the entire thickness of the substrate, and one or more of the through holes are connected to the water channels to form part of a water channel network.

9. 2. The electrode assembly according to claim 1, wherein the substrate has a plurality of through holes penetrating the entire thickness of the substrate, and adjacent through holes and the through holes are connected to their inlet ends and outlet ends by water channels to form flow paths.

10. The electrode assembly according to claim 1 , wherein the planar shapes of the substrate and the working surface are quadrilateral or polygonal.

11. 2. The electrode assembly of claim 1, wherein said substrate is made of Ti, Nb, or Si and has a conductive diamond deposited on a working surface of said substrate.

12. 2. The electrode body according to claim 1, wherein said working surface is coated with a conductive diamond by deposition.

13. 13. The electrode body according to claim 1 or 12, wherein conductive diamond is deposited along the edges of the water network.

14. 14. The electrode body according to claim 1, 12 or 13, wherein the diamond is in the form of particles and is fixed to the substrate in a dispersed manner.

15. 13. The electrode body according to claim 1 or 12, wherein the electrical conductivity of the diamond is due to boron contained therein.

16. 2. The electrode assembly according to claim 1, wherein the width of the water channel is 0.1 mm or more.

17. 2. The electrode assembly according to claim 1, wherein the depth of the water channel is 0.05 mm or more.

18. A method for using the electrode body according to claim 1, in which an electrode body having an electrode catalyst made of boron-doped diamond (BDD) bonded to a corrosion-resistant metal substrate is placed in close contact with a solid polymer electrolyte (SPE membrane) as a zero-gap type water electrolysis device and used as an anode material.

19. (1) The electrode body according to claim 1, which has an electrode catalyst made of boron-doped diamond (BDD) bonded to a corrosion-resistant metal substrate, is placed face-to-face with an SPE (solid polymer electrolyte) membrane, a cathode is placed on the back of the SPE membrane, and the SPE membrane is immersed in water, and a water flow is generated along the working surface. (2) A potential capable of generating ozone is applied between the two electrodes to ionize the water in contact with the SPE membrane. (3) An anodic reaction is induced by the BDD to generate ozone. (4) The generated ozone is dissolved in the surrounding water and collected. A method for producing ozone water.

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