JP4832063B2 - Electrolysis cell and electrolysis method using the same - Google Patents

Description

  The present invention relates to an electrolysis cell capable of causing electrolysis of an electrolytic solution and an electrolysis method using the same.

  When performing the electrolysis reaction, it is considered that by reducing the distance between the pair of electrodes, electric resistance is reduced and generation of useless Joule heat can be suppressed, so that power consumption is reduced. However, in the reaction in which gas is generated by electrolysis, the gas generated by bringing a pair of electrodes closer to each other adheres to the electrode, making it difficult for current to flow, reducing the power consumption reduction effect, and increasing voltage fluctuation. There was a problem that the amount of generated gas decreased. In addition, by bringing the electrodes close to each other, the gas generated at the anode and the cathode is easily mixed, which is not preferable. If partition walls are provided for the purpose of preventing mixing, the electrical resistance increases, so it is better not to do so.

  For example, hydrogen generated by electrolysis of water has attracted attention from the viewpoint of effective energy utilization. In other words, it is considered that water is electrolyzed and stored as hydrogen in regions and times where power is abundant and supplied to regions and times where power is required. In more detail, abundant electricity produced by large dams in a large river basin far from a large city produces hydrogen by electrolysis of water and supplies it to factories and large cities through pipelines. It can be consumed as a raw material, or used as a fuel for hydrogen automobiles or fuel cells. In addition, electrolysis of water is performed using surplus power at midnight when power demand is low and stored as hydrogen, and the stored hydrogen is used as fuel for fuel cells, gas turbines, etc. during the time when power demand increases. Is also possible.

  On the other hand, oxygen generated by electrolysis of water has many industrial uses and medical uses.

  There are many reports on water electrolysis devices (see, for example, Patent Documents 1 to 3). In particular, Patent Document 3 reports a gas-liquid separation device used for a water electrolysis device of an oxygen / hydrogen generator, which includes an anode chamber and a cathode chamber and uses a solid electrolyte membrane as a diaphragm. However, the gas-liquid separation device is provided outside the electrolysis cell, and no effect can be exhibited with respect to the gas staying between the electrodes when the distance between the electrodes is shortened.

By the way, as a method for gas-liquid separation in a micro flow path, a method using a shallow gas channel having a hydrophobic surface along a deep liquid channel having a hydrophilic surface is reported in Patent Document 4.
Japanese Patent Laid-Open No. 9-176885 JP-A-8-333694 JP-A-8-144078 JP 2005-169386 A

  The method for gas-liquid separation in the microchannel disclosed in Patent Document 4 is suitable as a method for gas-liquid separation in the microchannel. However, this structure has been shown to be applied to separation of gas mixed in liquid and gas-liquid extraction, but there is no description of application to electrolysis reaction. Of course, the electrode to which gas generated by electrolysis is attached The present situation is that nothing is said about removing the gas from the gas.

  In the electrolysis reaction, if the gas generated by electrolysis remains attached to the electrode, there is a problem that the electric resolution by the electrode is lowered, and improvement is desired.

  Accordingly, an object of the present invention is to solve the conventional problems and achieve the following object. That is, an object of the present invention is to provide an electrolysis cell capable of quickly removing gas generated by electrolysis from the electrode surface, and an electrolysis method using the same.

The above problem is solved by the following means. That is,
The electrolysis cell of the present invention comprises:
A liquid flow path through which the electrolyte flows,
A gas flow path disposed in contact with a width direction end of the liquid flow path, wherein an electrolyte and a gas-liquid interface flowing in the liquid flow path in the vicinity of a boundary surface with the liquid flow path A gas flow path for forming;
A pair of electrodes arranged to constitute at least a part of an inner wall of the liquid flow path and / or the gas flow path, and for causing electrolysis of the electrolytic solution, at least a part of which is the electrolyte and A pair of electrodes that are in contact with each other and the entire contact area with the electrolytic solution is located within 100 μm from the boundary surface of the liquid channel and the gas channel;
It is characterized by comprising.

  In the electrolysis cell of the present invention, even if the gas generated by the electrolysis of the electrolytic solution adheres to the electrode, the entire contact area with the electrolytic solution is located within the above range from the boundary of the liquid channel and the gas channel. By doing so, since the gas adhering to the electrode comes into contact with the gas-liquid interface, the gas generated by electrolysis can be quickly removed from the electrode surface.

In the electrolysis cell of the present invention, the cross section of the gas passage and the liquid passage is constituted by a rectangular, if the gas flow path has a thin thickness than the liquid flow path, wherein in the gas passage inner wall The contact angle with respect to the electrolytic solution is preferably 90 ° or more. Meanwhile, the cross-section of the gas passage and the liquid passage is constituted by a rectangular, if the gas flow path has a thickness thicker than the liquid flow path, the contact angle with respect to the electrolytic solution in the liquid flow passage inner wall 90 It is good that it is below.

  In the electrolysis cell of the present invention, the pair of electrodes may have a width of 100 μm or less. The electrolysis reaction may be a reaction in which water is decomposed into oxygen and hydrogen.

  On the other hand, the electrolysis method of the present invention is characterized in that the electrolytic solution of the present invention is used to electrolyze the electrolytic solution with the pair of electrodes.

  ADVANTAGE OF THE INVENTION According to this invention, the electrolysis cell which can remove rapidly the gas produced by electrolysis from the electrode surface, and the electrolysis method using the same can be provided.

  Hereinafter, the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is provided to the member which has the substantially same function through all the drawings, and the overlapping description may be abbreviate | omitted. Further, in the plan view in the drawing, the internal structures such as the flow paths and the electrodes are drawn with solid lines for easy understanding.

  FIG. 1 is a plan view showing an electrolysis cell according to the embodiment. FIG. 2 is a cross-sectional view showing the electrolysis cell according to the embodiment. FIG. 3 is a partially enlarged cross-sectional view showing electrode positions in the electrolysis cell according to the embodiment. FIG. 4 is a cross-sectional view showing an electrolysis cell according to another embodiment. 2 to 4 are cross-sectional views corresponding to the AA cross-sectional view of FIG.

  As shown in FIGS. 1 and 2, the electrolysis cell according to the embodiment includes a liquid flow path 10 through which an electrolytic solution 18 flows. An inlet 10A for introducing the electrolytic solution 18 communicates with one end of the liquid channel 10, and a discharge port 10B for discharging the electrolytic solution 18 communicates with the other end.

  At both ends in the width direction of the liquid flow path 10, two gas flow paths 12 are formed to form an air-liquid interface with an electrolyte solution 18 that is in contact with an arbitrary region across the flow path and flows into the flow path. It is installed. The gas flow path 12 is for discharging the gas 14 generated by electrolysis of the electrolytic solution 18. As shown in FIG. 2, the gas flow path 12 is configured to be shallower than the liquid flow path 10. Further, as shown in FIG. 4, the gas channel 12 may be configured to be deeper than the liquid channel 10. Here, the channel depth indicates the thickness of the channel. The gas passage 12 communicates with a discharge port 12B through a gas discharge passage 12A.

  Here, the gas-liquid interface between the electrolyte 18 and the gas 14 is not necessarily formed on the same plane as the boundary 20 between the liquid flow path 10 and the gas flow path 12, but the boundary is approximately in the vicinity of the boundary 20. It is formed at a position within 15 μm (preferably within 10 μm) from the boundary surface at a distance along the direction orthogonal to the surface formed by 20.

  The formation of this gas-liquid interface utilizes the difference in interfacial tension. That is, as shown in FIG. 2, when the gas channel 12 is shallower than the liquid channel 10, if the contact angle of the inner wall of the gas channel 12 with respect to the electrolyte 18 is 90 ° or more, the electrolyte 18 A situation that does not enter the gas flow path 12 can be created, and a gas-liquid interface can be formed.

  As shown in FIG. 4, when the gas flow path 12 is deeper than the liquid flow path 10, if the contact angle of the inner wall of the liquid flow path 10 with respect to the electrolyte 18 is 90 ° or less, the electrolyte 18 A situation that does not enter the gas flow path 12 can be created, and a gas-liquid interface can be formed.

  More specifically, if the pressure of the electrolytic solution 18 does not exceed the pressure necessary for the electrolytic solution 18 to enter the gas channel 12, the electrolytic solution 18 cannot enter the gas channel 12, A gas-liquid interface can be formed in the vicinity of the boundary 20 between the liquid channel 10 and the gas channel 12.

Here, as shown in FIG. 2, when the gas channel 12 is shallower than the liquid channel 10, the pressure required for the electrolyte 18 to enter the gas channel 12 is the following Young-Laplace. It is calculated by the following formula.
Formula 1: ΔP = 2γ [sin (θ−90 °) / r]
(In the formula, ΔP is a pressure (Pa) necessary to enter the gas flow path 12, γ is an interfacial tension (N / m) of the electrolytic solution 18, and θ is a contact of the inner wall of the gas flow path 12 with the electrolytic solution 18). Angle (°), r is the depth of the gas flow path 12 (m)

Similarly, as shown in FIG. 4, when the gas channel 12 is deeper than the liquid channel 10, the pressure required for the electrolyte solution 18 to enter the gas channel 12 is -It is determined by the Laplace formula.
Formula 2: ΔP = 2γcos (θ) / r
(Where ΔP is the pressure (Pa) required to enter the gas flow path 12, γ is the interfacial tension (N / m) of the electrolytic solution 18, and θ is the contact of the inner wall of the liquid flow channel 10 with the electrolytic solution 18) Angle (°), r is the depth of the gas flow path 12 (m)

  That is, the condition that the pressure difference between the electrolyte 18 and the gas does not exceed the pressure obtained from the Young-Laplace equation is the condition that the electrolyte 18 does not enter the gas flow path 12.

  As shown in FIG. 2, when the gas flow path 12 is shallower than the liquid flow path 10, the contact angle of the inner wall of the gas flow path 12 with respect to the electrolyte 18 is 90 as is clear from (Equation 1). If it is less than 0 °, the pressure at which the electrolytic solution 18 enters the gas flow path 12 becomes negative and the electrolytic solution 18 enters the gas flow path 12, so that the contact angle of the inner wall of the gas flow path 12 with respect to the electrolytic solution 18 is It can be seen that the angle is preferably 90 ° or more.

  On the contrary, as shown in FIG. 4, when the gas flow path 12 is deeper than the liquid flow path 10, the contact angle of the inner wall of the liquid flow path 10 with respect to the electrolytic solution 18 is apparent from (Equation 2). If the angle exceeds 90 °, the pressure at which the electrolytic solution 18 enters the gas flow path 12 becomes negative, and the electrolytic solution 18 enters the gas flow path 12, so that the inner wall of the liquid flow path 10 contacts the electrolytic solution 18. It can be seen that the angle is preferably 90 ° or less.

The pressure difference between the electrolytic solution 18 and the gas 14 is obtained by actual measurement using a Bourdon pressure gauge, a bell pressure gauge, a ring pressure gauge, a weight pressure gauge, a semiconductor pressure sensor in which a diaphragm and a strain gauge are integrated, or the like. Alternatively, the pressure loss of the fluid can be calculated from the following Hagen-Poiseuille equation in the case of laminar flow.
Formula: ΔP = ² μvl ² L / S ²
(In the above formula, ΔP is the pressure loss (Pa) of the electrolytic solution at the flow path length L, μ is the viscosity of the electrolytic solution (Pa · sec), v is the flow rate of the electrolytic solution (m / sec), and l is the flow rate. The circumference of the path (m), L is the length of the flow path (m), and S is the cross-sectional area (m ² ) of the flow path)

  As shown in FIG. 2, when the gas channel 12 is shallower than the liquid channel 10, the contact angle of the inner wall of the gas channel 12 with respect to the electrolyte 18 is preferably 90 ° or more, but 110 ° or more. More preferably, 120 ° or more is particularly preferable. The upper limit of this contact angle is 180 ° which is geometrically possible. In order to satisfy such a contact angle, a material having a contact angle with respect to the electrolytic solution 18 of 90 ° or more may be used as a member (substrate) constituting the gas flow path 12, and the contact angle of the material is less than 90 °. Even if it exists, it can be used if the contact angle can be 90 ° or more by surface treatment.

  The surface treatment method mentioned here is not particularly limited, but for example, treatment with a water-repellent spray using commercially available Teflon (registered trademark) or silicone, or fluorine-based gas such as tetrafluoromethane or tetrafluoroethane was used. Examples thereof include plasma treatment, treatment with chemical modification using octadecylsilane, and the like, which can be appropriately selected according to the material of the substrate forming the gas flow path 12 and the properties of the electrolytic solution 18. Further, the contact angle with respect to the electrolytic solution 18 may be devised to increase the contact angle by providing fine irregularities on the surface of the member of the gas flow path 12 having a contact angle of 90 ° or more.

  Specifically, for example, if the electrolytic solution 18 is an aqueous solution, a contact angle of 90 ° or more with the electrolytic solution can be obtained without surface treatment if the substrate material is Teflon (registered trademark). Further, for example, plasma treatment using a fluorine-based gas such as tetrafluoromethane can be applied to a plus chip such as acrylic, polycarbonate, or polyimide as a substrate material. A chemical modification method using octadecylsilane or the like can be applied to glass, quartz, silicon, or the like as a substrate material. Further, treatment with a Teflon (registered trademark) coating agent can be applied to a metal such as platinum, stainless steel, or nickel as a substrate material.

  On the other hand, as shown in FIG. 4, when the gas channel 12 is deeper than the liquid channel 10, the contact angle of the inner wall of the liquid channel 10 with respect to the electrolyte 18 is preferably 90 ° or less, but 70 ° or less. Further preferred is 30 ° or less. The lower limit of the contact angle is 0 ° which is geometrically possible. In order to satisfy such a contact angle, a material having a contact angle with respect to the electrolytic solution 18 of 90 ° or less may be used as a member (substrate) constituting the liquid flow path 10, and the contact angle of the material exceeds 90 °. Even if it can be used, it can be used if the contact angle can be reduced to 90 ° or less by surface treatment.

The surface treatment method referred to here is not particularly limited, but can be appropriately selected according to the material of the member (substrate) constituting the liquid flow path 10 and the properties of the electrolytic solution. Specifically, for example, if the electrolytic solution 18 is an aqueous solution, a contact angle of 90 ° or less with respect to the electrolytic solution 18 can be obtained without surface treatment if the substrate material is glass or titanium oxide. Plastics such as acrylic and polycarbonate can be hydrophilized by plasma treatment using oxygen gas, UV ozone treatment, or the like. Further, the surface of the member of the gas flow path 12 having a contact angle with respect to the electrolytic solution 18 of 90 ° or less may be devised so as to reduce the contact angle by providing fine irregularities on the surface.

  Here, the contact angle with respect to the electrolytic solution 18 was measured by a droplet method for measuring a contact angle between a stationary droplet and a substrate. For the measurement, use a “contact angle meter CA-X type” manufactured by Kyowa Interface Science Co., Ltd., and enter the two points of contact between the droplet and the substrate and the vertex of the droplet on the computer screen. The “click method” was used. Moreover, the droplet was set so that it might become a droplet volume of 1.8 microliters using "auto dispenser AD-21 type" by Kyowa Interface Science Co., Ltd.

  As shown in FIG. 4, when the gas flow path 12 is deeper than the liquid flow path 10, the depth of the liquid flow path 10 is preferably 50 μm or less, preferably 30 μm or less, and particularly preferably 15 μm or less. From the viewpoint of processing accuracy, the lower limit is 0.1 μm. When the depth of the gas flow path 12 is 50 μm or less, the generated gas 14 is difficult to exist in the liquid flow path 10 and is easily removed by the gas flow path 12. On the other hand, when the depth of the liquid flow path exceeds 50 μm, the generated gas 14 tends to enter the liquid flow path 10 and may be difficult to remove to the gas flow path 12.

  Here, the channel length of the liquid channel 10 is not particularly limited, and may be appropriately designed in consideration of the reaction solution concentration, the reaction solution flow rate, the current density, the current efficiency, and the like.

  Further, the inlet 10A for introducing the electrolytic solution 18 into the liquid flow path 10 may be connected to a supply means for introducing fluid into the flow path from the outside, although not shown. A supply means such as a small pump may be built in the flow path. The supply means for introducing the electrolytic solution 18 from the outside into the liquid flow path 10 is not particularly limited. For example, various pumps, a method of pumping, a method of using a difference in gravity, and a high pressure compressed For example, a method of supplying from a separate container can be used. Specific examples of pumps include 1) a syringe pump that pushes fluid in a cylinder with a piston, and 2) a reciprocating pump that increases pressure using a reciprocating motion of a piston or plunger, such as a piston pump or a diaphragm pump, 3) Rotating pumps that rotate gears and rollers such as gear pumps and peristaltic pumps, confine the fluid in a gap and push it to transport, 4) Rotary fluids such as volute pumps and diffuser pumps, which rotate by rotating blades and pressurize by centrifugal force Centrifugal pumps that increase the pressure, and other generally known pumps.

  Further, the hydraulic equivalent diameter of the liquid channel 10 is preferably 1 μm or more and 2000 μm or less, and more preferably 10 μm or more and 1000 μm or less. If the hydraulic equivalent diameter of the liquid flow path 10 is 10 μm or less, the pressure loss becomes extremely large and the processing amount may be remarkably reduced, which is not preferable, and if it is 2000 μm or more, temperature control becomes difficult and by-products increase. This is not preferable. The hydraulic equivalent diameter mentioned here can be expressed by (channel cross-sectional area × 4 ÷ wetting side length).

  The pre-treatment method and post-treatment method of the electrolytic solution 18 are not particularly limited, but may be performed using a flow path having a hydraulic equivalent diameter similar to the liquid flow path 10.

  A pair of electrodes 16 is disposed so as to constitute at least a part of the inner wall of the liquid channel 10 and / or the gas channel 12 having such a configuration. The exposed portions 16 </ b> A of the pair of electrodes 16 constitute at least a part of the inner walls of the liquid channel 10 and / or the gas channel 12. Although not shown, the cell is also provided with a terminal that is electrically connected to each of the pair of electrodes 16 and connected to an external power source.

  The pair of electrodes 16 are at least partially in contact with the electrolytic solution 18, and the entire contact region of the electrolytic solution 18 is located within 100 μm (preferably within 50 μm) from the boundary between the liquid channel 10 and the gas channel 12. Is arranged. Thereby, the gas 14 generated by electrolysis can be quickly separated from the electrode 16 into the gas flow path 12.

  Here, the mechanism for separating the gas 14, that is, the mechanism for separating the gas 14 generated and adhered to the electrode 16 from the electrode 16 to the gas flow path 12, is as follows. The phenomenon in which unification occurs is well known, but is an application of this phenomenon. That is, if there is a gas-liquid interface between the electrolytic solution 18 and the gas 14 near the bubble generated at the electrode 16, the bubble will be united when it comes into contact with the gas-liquid interface, and is extracted outside the electrolysis cell. It becomes possible. As a result of designing and experimenting with an electrolysis cell based on such an idea, the gas 14 generated at the electrode 16 becomes a small bubble immediately after the generation and adheres to the electrode 16, but there is a gas-liquid interface near the generated electrode 16. It has been clarified that the gas 14 (bubbles) is drawn to the gas flow path 12 side when the generated bubbles come into contact.

  As a result of detailed examination, the electrode 16 is in contact with the electrolytic solution 18, and the entire contact area with the electrolytic solution 18 is set within 100 μm (preferably within 50 μm) from the boundary 20 between the liquid channel 10 and the gas channel 12. It was revealed that the gas 14 generated by electrolysis can be quickly removed from the surface of the electrode 16.

  Here, “the entire contact area with the electrolytic solution 18 is located within a predetermined range from the boundary 20 between the liquid flow path 10 and the gas flow path 12” means that the electric current is perpendicular to the direction of the electrolytic flow of the liquid flow path 10. When the decomposition cell is cut, the liquid flow path 10 and the gas flow path in the electrolyte solution contact region of the electrode 16 from the portion closest to the electrode 16 in the boundary 20 of the liquid flow path 10 and the gas flow path 12 in the cross section. This means that the distance to the part farthest from the 12 boundaries 20 is within a predetermined range.

  Further, it is obvious that the electrode 16 cannot be electrolyzed unless it is in contact with at least the electrolytic solution, but the electrolytic solution contact region is within the above range from the boundary 20 between the liquid flow channel 10 and the gas flow channel 12. If the distance is greater than the distance, the gas generated by the electrolysis is difficult to contact the gas-liquid interface, and it takes time for the bubbles to increase and contact the gas-liquid interface. It will flow through the flow path. For this reason, it is necessary that the entire electrolyte contact region exists within the above range.

  On the other hand, since the electrode 16 must cause an electrolytic reaction of the electrolytic solution 18, it must be in contact with the electrolytic solution 18, but when the electrode 16 is located only on the gas flow path 12 side, at least the electrode 16 It is preferable that a part is located within 15 μm (preferably within 10 μm) from the boundary 20 between the liquid channel 10 and the gas channel 12, and more preferably within 10 μm. This is because the gas-liquid interface is formed within 15 μm from the boundary surface at a distance along the direction orthogonal to the surface formed by the boundary 20 near the boundary 20. By positioning at least a part of the electrode 16 within this range, the gas-liquid interface covers a part of the electrode and has a contact area with the electrolytic solution.

  Here, when the electrode 16 is located only on the gas flow path 12 side, “at least a part of the electrode 16 is located within a predetermined range from the boundary 20 between the liquid flow path 10 and the gas flow path 12” When the electrolysis cell is cut perpendicular to the direction of the electrolyte flowing in the passage 10, the liquid flow in the electrode 16 starts from the portion of the boundary 20 between the liquid flow path 10 and the gas flow path 12 closest to the electrode 16 in the cross section. This means that the distance to the part closest to the boundary 20 between the path 10 and the gas flow path 12 is within a predetermined range.

  In summary, as shown in FIG. 3, when the electrode 16 is located only on the gas flow path 12 side, at least a part of the electrode 16 needs to be in contact with the electrolytic solution 18. The part needs to be located within 15 μm from the boundary 20 between the liquid flow path 10 and the gas flow path 12, and if the position exceeds 15 μm as in the electrode 16-1 drawn with a dotted line, it does not come into contact with the electrolytic solution 18.

  On the other hand, when the electrode 16 is located only on the liquid flow path 10 side, the entire contact area with the electrolytic solution 18 is located within 100 μm (preferably within 50 μm) from the boundary 20 between the liquid flow path 10 and the gas flow path 12 ( The positions of the electrodes 16-2 and 16-3 drawn by dotted lines) are necessary, and when the position is more than 100 μm as in the electrode 16-4 drawn by dotted lines, the attached gas 14 quickly becomes a gas flow path. 12 will not be separated.

  In addition, when the electrode 16 is disposed so as to straddle the boundary 20 between the liquid flow path 10 and the gas flow path 12, it is necessary to satisfy each of the above conditions.

  Therefore, in the present embodiment, at least a part of the pair of electrodes 16 is in contact with the electrolytic solution 18, and the entire contact region of the electrolytic solution 18 is within 100 μm from the boundary between the liquid channel 10 and the gas channel 12 (preferably It is necessary to be disposed so as to be located within 50 μm).

  The width of the electrode 16 is preferably 100 μm or less, more preferably 50 μm or less, and particularly preferably 10 μm or less. Note that the lower limit of the width of the electrode 16 is 0.1 μm from the viewpoint of the limit of fine processing. The width of the electrode 16 refers to the maximum distance of the surface where the electrode 16 and the electrolytic solution 18 are in contact with each other when the electrolysis cell is cut perpendicularly to the direction of flowing of the electrolytic solution in the liquid flow path 10. Specifically, for example, when the end face of the plate-like electrode 16 corresponds to the electrolyte contact region, the thickness of the plate-like body is indicated, and the diameter is indicated for a cylindrical or columnar wire. The width of the electrode 16 correlates well with the diameter of the bubbles adhering to the electrode 16, and if there is no adhering surface other than the surface of the electrode 16, bubbles having a diameter of about 2 to 3 times the electrode width may adhere. It became clear from observation of the surface of the electrode 16. Further, as the width of the electrode 16 was narrower, bubbles could be extracted even when electrolysis was performed at a high current density. This is probably because the bubbles are taken into the gas flow path 12 when the bubbles are small.

  The shape of the electrode 16 is not particularly limited. It may be wire, plate, or thin film. In the present embodiment, a plate-like body having an L-shaped cross section is applied. In addition, the installation form of the electrode 16 is not particularly limited. In this embodiment, the electrode 16 is installed so as to constitute a part of the inner wall of the flow path. For example, an insulating spacer is provided between the pair of electrodes 16. You may install between.

  The method for manufacturing the electrode 16 is not particularly limited. As a preferred method, a wire-shaped conductor is installed on or near the boundary 20 between the liquid flow path 10 and the gas flow path 12, or a plate-shaped (or thin film-shaped) conductor is connected to the liquid flow path 10. You may arrange | position on the boundary 20 of the gas flow path 12, or its vicinity. In the case of using a thin-film conductor as the electrode 16, there is a method of forming a metal by vapor deposition or sputtering technique after covering with a thin plate mask cut into an electrode shape or using a photoresist. Can be mentioned. In the present embodiment, the liquid flow path is formed so that one end face (exposed portion 16A of the electrode 16 exposed from the electrode substrate 24) of the conductor made of a plate-like body having an L-shaped cross section constitutes a part of the inner wall of the flow path. 10 and the gas flow path 12 are arranged along the vicinity of the boundary 20.

  The material of the electrode 16 is not particularly limited as long as it is energized. For example, palladium, platinum, rhodium, iridium, nickel, gold, tungsten, niobium, cadmium, manganese, thallium, lead, mercury and other metals and alloys, glassy carbon, spectroscopic grade graphite, pyrolytic graphite, carbon cloth, etc. Materials and powders thereof dispersed in xylene wax, epoxy resin, silicone rubber, Nujol, etc. can be used. In addition, when the metal is attached by vapor deposition or sputtering, a thin film such as chromium or titanium may be attached as a base in order to improve adhesion to the substrate. Carbon may be coated with a paste in which carbon powder is dispersed in an adhesive material on the surface of the metal electrode. Similarly, a hydrocarbon compound is coated on the surface of the metal electrode and thermally decomposed under reduced pressure. Pyrolytic graphite may be used.

  A technique such as metal plating may be applied to the surface of the electrode 16 so as to widen the electrode surface, and platinum black or palladium black having particularly high catalytic activity may be attached.

  The electrolytic solution 18 is a medium that causes an electrochemical reaction with electrodes. The electrochemical reaction is not particularly limited as long as the reaction generates gas 14. For example, a reaction that generates hydrogen by a reduction reaction of alcohols, a reaction that generates carbon dioxide by an oxidation reaction of carboxylic acids, a reaction that generates hydrogen and oxygen by electrolysis of water, or the electricity of an aqueous solution containing chloride ions Examples include reactions that generate hydrogen and chlorine by decomposition. Among them, since water has a high surface tension, a gas-liquid interface can be created relatively easily by using the structure of the present invention. Therefore, a reaction using an aqueous solution is preferable, and hydrogen and oxygen are generated by electrolysis of water. The reaction to be generated is more preferable.

Further, the electrochemical reaction may be an electrochemical reaction using a supporting electrolyte. The kind and amount of use are not particularly limited as long as they can be dissolved in the reaction solution and have conductivity. Since the supporting electrolyte acts as an ion in the solvent, it is a salt, acid, or alkali combined with an anion and a cation that are easily ionized. Examples of the cation include hydrogen ions, alkali metal ions such as Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , ammonium ions, tetramethylammonium ions, tetraethylammonium ions, tetra (n-propyl) ammonium ions, And quaternary alkyl ammonium such as tetra (i-propyl) ammonium ion, tetra (n-butyl) ammonium ion, tetra (n-hexyl) ammonium ion, and the like. Examples of anions include halogen ions such as Cl ⁻ , Br ⁻ and I ⁻ , hydroxyl ions, acetate ions, sulfate ions, nitrate ions, perchlorate ions, BF ₄ ⁻ , PF ₆ ⁻ , bis (trifluoromethanesulfonyl) imide. Bis (1,1,2,2,3,3,3-heptafluoro-1-propanesulfonyl) imide, bis (1,1,2,2,3,3,4,4,4-nonafluoro-1 -Butanesulfonyl) imide, various sulfonate ions, and the like.

  The electrolysis cell according to the present embodiment includes, for example, a flow path substrate 22 in which a groove serving as each flow path is formed, and an electrode substrate 24 on which the electrode 16 is disposed or embedded. .

  The flow path substrate 22 can be manufactured, for example, by forming a groove that becomes a flow path by etching or machining.

  The electrode substrate 24 can be manufactured, for example, by forming a groove in the substrate and embedding a wire or a plate-like conductor in the groove, or by depositing a thin-film conductor on the substrate by vapor deposition or sputtering. it can. In the present embodiment, the electrode substrate 24 has a convex substrate 28 having an opening substrate 26 provided with an opening 26A and a convex portion 28A provided so as to be fitted into the opening 26A of the opening substrate 26 via the electrode 16. Between the substrate so that the end surface of the electrode 16 having an L-shaped cross section (the exposed portion 16A of the electrode 16 exposed from the electrode substrate 24) and the upper surface of the convex portion 28A are exposed on the inner peripheral portion of the opening 26A of the opening substrate 26. Are stacked via an electrode 16 having an L-shaped cross section.

  Then, by applying heat and pressure such as thermocompression bonding and heat fusion so that the groove corresponding to the flow path and the exposed electrode side face each other, tightening with screws, or bonding with an adhesive, An electrolysis cell can be obtained by bonding the substrate 22 and the electrode substrate 24 together.

  In addition, it is preferable that the material of the flow path substrate 22 and the electrode substrate 24 has an insulating surface at least. This is because the electrode 16 is incorporated in the electrolysis cell, so that insulation between the electrodes 16 is ensured. On the other hand, even a conductive material such as silicon or metal can be used as long as the surface is insulated.

  In the electrolysis cell according to the present embodiment described above, even if the gas 14 generated by the electrolysis of the electrolytic solution 18 adheres to the electrode 16, the entire contact area of the electrolytic solution 18 is the liquid channel 10 and the gas channel 12. Since the gas 14 adhering to the electrode 16 contacts the gas-liquid interface, the gas 14 generated by electrolysis can be quickly removed from the surface of the electrode 16. .

  As a result, for example, the distance between the electrodes 16 can be reduced, the area where the gas 14 adheres to the electrodes 16 and the adhesion time can be suppressed, the voltage during electrolysis can be stabilized, Consumption can be suppressed. Further, in the case of electrolysis in which the gas 14 is generated at both electrodes, there is an effect that a partition for suppressing the mixing of the gas 14 becomes unnecessary.

  The present invention is not limited to the structure of the electrolysis cell according to the present embodiment, and can be appropriately applied to other forms, for example, the forms shown in FIGS. In addition, for the purpose of increasing the electrolysis processing capability, the electrolysis cells of the present invention may be arranged in parallel on the same substrate, or a plurality of substrates can be used in an overlapping manner.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited at all by these Examples.

(Example 1-1)
The electrolysis cell shown in FIGS. 5 and 6 was produced as follows. In addition, FIG. 5 is a top view which shows the electrolysis cell produced in Example 1-1. 6 is a cross-sectional view taken along the line 1-1 in FIG.

1) A polycarbonate plate (30 mm × 70 mm, 2 mmt) as the flow path substrate 22 is machined, and the two gas flow paths 12 are sandwiched between the liquid flow path 10 and the liquid flow path 10 so that the cross section is rectangular. A groove was formed. The dimensions of the liquid channel 10 were a width of 1.0 mm, a depth of 500 μm, and a length applied to the electrode 16 (a length in contact with the electrode) of 20 mm. The dimensions of the gas channel 12 were a width of 1.0 mm, a depth of 100 μm, and a length applied to the electrode 16 of 20 mm. In this manner, a flow path substrate 22 in which the gas flow path 12 was shallower than the liquid flow path was obtained.
2) A polycarbonate plate (30 mm × 70 mm, 1 mmt) as the opening substrate 26 of the electrode substrate 24 is machined so that the convex portion 28A processed into the polycarbonate plate as the opening substrate 26 and the polycarbonate plate as the convex substrate 28 is accommodated. A shaped opening 26A was formed. The dimensions of the opening 26A were 1.02 mm in width and 20 mm in length.
3) An acrylic plate (polymethyl methacrylate) plate (30 mm × 70 mm, 2 mmt) as the convex substrate 28 of the electrode substrate 24 was machined to form a convex portion 28A having a width of 1 mm, a length of 20 mm, and a height of 1 mm.

  4) A platinum foil having a thickness of 10 μm is processed, and the end portion is bent to form an electrode 16 having an L-shaped cross section, which is sandwiched between the opening substrate 26 and the convex substrate 28, and within the opening 26 </ b> A of the opening substrate 26. The overlapping gap was filled with an adhesive and bonded so that the end face of the electrode 16 having an L-shaped cross section and the upper surface of the convex portion 28A were exposed on the periphery. After the adhesive was cured, the surface was polished and the unevenness was processed to 10 μm or less. In this way, an electrode substrate 24 having a pair of electrodes 16 was produced.

5) The flow path substrate 22 was subjected to plasma treatment using tetrafluoromethane. Similarly, the electrode substrate 24 was subjected to plasma treatment using tetrafluoromethane after masking the surface constituting the inner wall of the liquid flow path 10 with a polyimide tape. Plasma treatment conditions were as follows: each substrate was set on the cathode, and a tetrafluoromethane flow rate of 50 sccm, a vacuum degree of 150 mTorr, a power density of 1.78 W / cm ² , and treatment was performed for 30 seconds. At this time, the contact angle with respect to the electrolytic solution 18 used on the processing surface (the region other than the groove inner wall serving as the flow path of the flow path substrate 22 and the surface constituting the inner wall of the liquid flow path 10 of the electrode substrate 24) is 125 °. there were.

6) The electrode substrate 24 was masked with a polyimide tape on the surface other than the surface constituting the inner wall of the liquid flow path 10 and then subjected to plasma treatment using oxygen. Plasma treatment conditions were as follows: the substrate was set on the anode, and the oxygen flow rate was 50 sccm, the degree of vacuum was 150 mTorr, and the power density was 1.27 W / cm ² for 5 minutes. At this time, the contact angle of the processing surface (the surface constituting the inner wall of the liquid channel 10 of the electrode substrate 24) with respect to the electrolytic solution 18 used was 15 °.

  7) The flow path substrate 22 and the electrode substrate 24 were overlapped with the position of the exposed portion 16A of the electrode 16 accurately aligned. These were sandwiched between two jigs obtained by processing an acrylic plate having a thickness of 10 mm, and tightened with screws to prevent the electrolyte solution 18 from leaking from the flow path. The exposed portion 16A of the electrode 16 was disposed so that one side thereof was positioned on the boundary 20 between the gas flow channel 12 and the liquid flow channel 10 and extended to the gas flow channel 12 side by 10 μm. A cell was thus obtained.

  0.01N dilute sulfuric acid was supplied to the liquid channel 10 from the inlet 10A using a syringe pump. Even when supplied at a flow rate of 10 mL / min, dilute sulfuric acid does not leak from the liquid flow path 10 to the gas flow path 12, and a gas-liquid interface is formed in the vicinity of the boundary 20 between the liquid flow path 10 and the gas flow path 12. It was confirmed by observation with a microscope.

Then, while supplying 0.01 N diluted sulfuric acid as an electrolytic solution 18 at a flow rate of 10 μL / min using a syringe pump, a voltage was applied between the pair of electrodes 16 to perform constant current electrolysis at 200 μA. The gas 14 generated from both electrodes 16 was initially attached to the electrode 16, but it was confirmed that it quickly merged with the gas 14 in the gas flow path 12 and disappeared when contacting the gas-liquid interface. At this time, the diameter of the bubbles attached to the electrode 16 disappeared after growing to 20 to 30 μm. When the current was increased to 300 μA and an experiment was performed under the same conditions as described above, bubbles generated at the electrode 16 were sucked into the gas flow path 12 and could be separated into gas and liquid. The current density at this time was 150 mA / cm ² .

(Comparative Example 1-1)
Example 1 except that the position of the exposed portion 16A of the electrode 16 on the electrode substrate 24 is shifted parallel to the substrate surface and separated from the boundary 20 between the gas channel 12 and the liquid channel 10 by 100 μm toward the gas channel 12 side. The same experiment as in Example 1 was performed. Although 0.01 N dilute sulfuric acid was supplied to the liquid flow path 10 as the electrolytic solution 18, the dilute sulfuric acid did not reach the position of the electrode 16 and was not in contact therewith, so electrolysis could not be performed.

(Comparative Example 1-2)
The position of the exposed portion 16A of the electrode 16 on the electrode substrate 24 is shifted in parallel with the substrate surface, and the position of the electrode 16 is 115 μm away from the boundary 20 between the gas flow path 12 and the liquid flow path 10 toward the liquid flow path 10. Were the same as in Example 1-1. The entire exposed portion 16A of the electrode 16 was an electrolyte contact region, and the region was located beyond the boundary 20 by more than 100 μm.

  Then, while supplying 0.01 N dilute sulfuric acid as an electrolytic solution 18 at a flow rate of 10 μL / min using a syringe pump, a voltage was applied between the electrodes to perform constant current electrolysis at 300 μA. The gas 14 generated from both electrodes increased while remaining attached to the electrodes, and could not be separated into the gas flow path 12.

(Example 1-2)
The position of the exposed portion 16A of the electrode 16 on the electrode substrate 24 is shifted parallel to the substrate surface, and the position of the electrode 16 is separated from the boundary 20 between the gas flow channel 12 and the liquid flow channel 10 by 100 μm toward the liquid flow channel 10. Were the same as in Example 1-1. The entire exposed portion 16A of the electrode 16 is an electrolyte contact region, and the entire region is located within 100 μm from the boundary 20.

  Then, while supplying 0.01 N dilute sulfuric acid as an electrolytic solution 18 at a flow rate of 10 μL / min using a syringe pump, a voltage was applied between the electrodes to perform constant current electrolysis at 300 μA. The gas 14 generated from both electrodes grew while adhering to the electrodes, and although it took longer time than Example 1-1, it could be quickly separated into the gas flow path 12.

(Example 1-3)
The position of the exposed portion 16A of the electrode 16 on the electrode substrate 24 is shifted parallel to the substrate surface, and the position of the electrode 16 is separated from the boundary 20 between the gas flow channel 12 and the liquid flow channel 10 by 50 μm toward the liquid flow channel 10. Were the same as in Example 1-1. The entire exposed portion 16A of the electrode 16 is an electrolyte contact region, and the entire region is located within 50 μm from the boundary 20.

  Then, while supplying 0.01 N dilute sulfuric acid as an electrolytic solution 18 at a flow rate of 10 μL / min using a syringe pump, a voltage was applied between the electrodes to perform constant current electrolysis at 300 μA. The gas 14 generated from both electrodes grew while adhering to the electrodes, and took longer than Example 1-1, but could be separated into the gas flow path 12 more quickly than Example 1-2. .

(Example 1-4)
Example 1-1, except that a platinum foil having a thickness of 50 μm was used instead of the platinum foil having a thickness of 10 μm, and the width of the opening 26A of the opening substrate 26 of the electrode substrate 24 was increased in accordance with the thickness of the platinum foil. Similarly, an electrolysis cell was fabricated and experimented. The exposed portion 16A of the electrode 16 was arranged so that one side thereof was located on the boundary 20 between the gas flow channel 12 and the liquid flow channel 10 and extended to the liquid flow channel 10 side by 50 μm.

Then, while supplying 0.01 N dilute sulfuric acid as the electrolytic solution 18 at a flow rate of 10 μL / min using a syringe pump, a voltage was applied between the pair of electrodes 16 to perform constant current electrolysis at 500 μA. The gas 14 generated from both electrodes 16 was initially attached to the electrode 16, but it was confirmed that the gas 14 disappeared as soon as it was sucked into the gas flow path 12 when it contacted the gas-liquid interface. At this time, the diameter of the bubbles attached to the electrode 16 was 100 to 150 μm and was sucked into the gas flow path 12. The experiment was performed under the same conditions as above with the current increased to 900 μA, but the bubbles generated at the electrode 16 were united with the gas 14 in the gas flow path, and the bubbles could be separated. The current density at this time was 90 mA / cm ² .

(Example 1-5)
Example 1-1, except that a platinum plate having a thickness of 100 μm is used instead of the platinum foil having a thickness of 10 μm, and the width of the opening 26A of the opening substrate 26 of the electrode substrate 24 is increased in accordance with the thickness of the platinum plate. Similarly, an electrolysis cell was fabricated and experimented. The exposed portion 16A of the electrode 16 was disposed so that one side thereof was positioned on the boundary 20 between the gas flow path 12 and the liquid flow path 10 and extended to the liquid flow path 10 side by 100 μm.

Then, while supplying 0.01 N dilute sulfuric acid as the electrolytic solution 18 at a flow rate of 10 μL / min using a syringe pump, a voltage was applied between the pair of electrodes 16 to perform constant current electrolysis at 500 μA. The gas 14 generated from both electrodes 16 was initially attached to the electrode 16, but it was confirmed that the gas 14 disappeared as soon as it was sucked into the gas flow path 12 when it contacted the gas-liquid interface. At this time, the diameter of the bubbles attached to the electrode 16 was 200 to 300 μm and was sucked into the gas flow path 12. The experiment was performed under the same conditions as described above with the current increased to 1.4 mA, but the bubbles generated at the electrode 16 were united with the gas 14 in the gas flow path 12 and the bubbles could be separated. The current density at this time was 70 mA / cm ² .

(Example 1-6)
The experiment was performed in the same manner as in Example 1-1 except that the flow path substrate 22 and the electrode substrate 24 were not subjected to the plasma treatment using tetrafluoromethane. The contact angle with respect to the electrolyte solution 18 used by this non-plasma-treated surface (a region other than the groove inner wall serving as the flow path of the flow path substrate 22 and the surface constituting the inner wall of the liquid flow path 10 of the electrode substrate 24) is 85 °. there were.

  Then, while supplying 0.01 N dilute sulfuric acid as the electrolytic solution 18 at a flow rate of 10 μL / min using a syringe pump, a voltage was applied between the pair of electrodes 16 to perform constant current electrolysis at 500 μA. The gas 14 generated from both electrodes 16 was initially attached to the electrode 16, but it was confirmed that the gas 14 disappeared as soon as it was sucked into the gas flow path 12 when it contacted the gas-liquid interface. However, the gas-liquid interface was unstable, and after a while, the electrolyte solution 18 entered the gas flow path 12 and the bubbles could not be separated.

(Example 1-7)
The experiment was performed in the same manner as in Example 1-1 except that the electrode substrate 24 was not subjected to the plasma treatment using oxygen. The contact angle of the plasma-treated non-treated surface (the surface constituting the inner wall of the liquid channel 10 of the electrode substrate 24) with respect to the electrolytic solution 18 used was 65 °.

  Then, while supplying 0.01 N dilute sulfuric acid as the electrolytic solution 18 at a flow rate of 10 μL / min using a syringe pump, a voltage was applied between the pair of electrodes 16 to perform constant current electrolysis at 500 μA. The gas 14 generated from both electrodes 16 was initially attached to the electrode 16, but it was confirmed that the gas 14 disappeared as soon as it was sucked into the gas flow path 12 when it contacted the gas-liquid interface. However, after a while, the generated gas 14 adhered to the bottom surface of the liquid channel 10 (the surface constituting the liquid channel 10 of the electrode substrate 24), and the bubbles could not be separated.

(Comparative Example 1-3)
Example 1-1, except that a platinum plate having a thickness of 200 μm was used instead of the platinum foil having a thickness of 10 μm, and the width of the opening 26A of the opening substrate 26 of the electrode substrate 24 was increased to match the thickness of the platinum plate. Similarly, an electrolysis cell was fabricated and experimented. The exposed portion 16A of the electrode 16 was disposed so that one side thereof was positioned on the boundary 20 between the gas flow path 12 and the liquid flow path 10 and extended to the liquid flow path 10 side by 200 μm. For this reason, the entire exposed portion 16A of the electrode 16 is an electrolyte contact region, and a region located beyond 100 μm from the boundary 20 exists in the region.

  Then, while supplying 0.01 N dilute sulfuric acid as the electrolytic solution 18 at a flow rate of 10 μL / min using a syringe pump, a voltage was applied between the pair of electrodes 16 to perform constant current electrolysis at 500 μA. The gas 14 generated from both electrodes 16 grew while adhering to the electrode 16, came into contact with the upper surface of the electrode 16 (inner wall of the liquid flow channel 10), and could not be separated into the gas flow channel 12.

(Example 2-1)
The electrolysis cell shown in FIGS. 7 and 8 was produced as follows. In addition, FIG. 7 is a top view which shows the electrolysis cell produced in Example 2-1. 8 is a cross-sectional view taken along the line 2-2 of FIG.

  1) An acrylic plate (30 mm × 70 mm, 2 mmt) as the flow path substrate 22 is machined, and the two liquid flow paths 12 are sandwiched between the liquid flow path 10 and the liquid flow path 10 so that the cross section is rectangular. A groove was formed. The dimensions of the liquid channel 10 were a width of 1.0 mm, a depth of 10 μm, and a length applied to the electrode 16 of 20 mm. The dimensions of the gas channel 12 were a width of 1.0 mm, a depth of 500 μm, and a length applied to the electrode 16 of 20 mm. In this way, a flow path substrate 22 in which the gas flow path 12 was deeper than the liquid flow path was obtained.

  2) An acrylic plate (30 mm × 70 mm, 1 mmt) as the opening substrate 26 of the electrode substrate 24 is machined, and the convex portion 28A processed into the polycarbonate plate as the opening substrate 26 and the polycarbonate plate as the convex substrate 28 is accommodated. A shaped opening 26A was formed. The dimensions of the opening 26A were 1.02 mm in width and 20 mm in length.

  3) An acrylic plate (30 mm × 70 mm, 2 mmt) as the convex substrate 28 of the electrode substrate 24 was machined to form a convex portion 28A having a width of 1 mm, a length of 20 mm, and a height of 1 mm.

4) A platinum foil having a thickness of 10 μm is processed, and the end portion is bent to form an electrode 16 having an L-shaped cross section, which is sandwiched between the opening substrate 26 and the convex substrate 28, and within the opening 26A of the opening substrate 26 The overlapping gap was filled with an adhesive and bonded so that the end face of the electrode 16 having an L-shaped cross section and the upper surface of the convex portion 28A were exposed on the periphery. After the adhesive was cured, the surface was polished and the unevenness was processed to 10 μm or less. In this way, an electrode substrate 24 having a pair of electrodes 16 was produced.
5) The flow path substrate 22 and the electrode substrate 24 were subjected to plasma treatment using oxygen. Plasma treatment conditions were as follows: a polycarbonate plate was set on the anode, and the oxygen flow rate was 50 sccm, the degree of vacuum was 150 mTorr, and the power density was 1.27 W / cm ² for 5 minutes. At this time, the contact angle with respect to the electrolytic solution 18 used by the processing surface (the inner wall of the groove serving as the flow path of the flow path substrate 22 and the entire surface constituting each flow path of the electrode substrate 24) was 15 °.

  6) The flow path substrate 22 and the electrode substrate 24 were overlapped with the position of the exposed portion 16A of the electrode 16 accurately aligned. These were sandwiched between two jigs obtained by processing an acrylic plate having a thickness of 10 mm, and tightened with screws to prevent the electrolyte solution 18 from leaking from the flow path. The exposed portion 16A of the electrode 16 was disposed so that one side thereof was positioned on the boundary 20 between the gas flow channel 12 and the liquid flow channel 10 and extended to the gas flow channel 12 side by 10 μm. A cell was thus obtained.

  0.01N dilute sulfuric acid was supplied to the liquid channel 10 from the inlet 10A using a syringe pump. Even when supplied at a flow rate of 10 mL / min, dilute sulfuric acid does not leak from the liquid flow path 10 to the gas flow path 12, and a gas-liquid interface is formed in the vicinity of the boundary 20 between the liquid flow path 10 and the gas flow path 12. It was confirmed by observation with a microscope.

Then, while supplying 0.01 N diluted sulfuric acid as an electrolytic solution 18 at a flow rate of 10 μL / min using a syringe pump, a voltage was applied between the pair of electrodes 16 to perform constant current electrolysis at 200 μA. The gas 14 generated from both electrodes 16 was initially attached to the electrode 16, but it was confirmed that it quickly merged with the gas 14 in the gas flow path 12 and disappeared when contacting the gas-liquid interface. At this time, the diameter of the bubbles attached to the electrode 16 disappeared after growing to 20 to 30 μm. When the current was increased to 300 μA and an experiment was performed under the same conditions as described above, bubbles generated at the electrode 16 were sucked into the gas flow path 12 and could be separated into gas and liquid. The current density at this time was 150 mA / cm ² .

(Example 2-2)
An electrolytic cell was produced and experimented in the same manner as in Example 2-1, except that the depth of the liquid channel 10 was changed to 50 μm.

Then, 0.01 N dilute sulfuric acid was supplied to the flow path as an electrolytic solution 18 using a syringe pump, and voltage was applied between the electrodes 16 to perform constant current electrolysis at 200 μA. It was confirmed that the gas 14 generated from both electrodes 16 quickly merged with the gas 14 in the gas flow path 12 and disappeared. When the current was increased to 500 μA and an experiment was performed under the same conditions as described above, bubbles generated at the electrode 16 were sucked into the gas flow path 12 and could be separated into gas and liquid. The current density at this time was 250 mA / cm ² .

(Example 2-3)
An electrolysis cell was produced and tested in the same manner as in Example 2-1, except that the depth of the liquid channel 10 was set to 100 μm.

  Then, 0.01 N dilute sulfuric acid was supplied to the flow path as an electrolytic solution 18 using a syringe pump, and voltage was applied between the electrodes 16 to perform constant current electrolysis at 200 μA. It was confirmed that the gas generated from both electrodes 16 quickly merged with the gas 14 in the gas flow path 12 and disappeared. However, after a while, it was confirmed that the gas 14 generated from both electrodes 16 partially merged with the gas 14 in the gas flow path 12 and disappeared, but most of the gas 14 was united and enlarged on the liquid flow path. It was not pulled out into the flow path 12.

(Example 2-4)
Example 2-1 except that a platinum foil having a thickness of 50 μm was used instead of the platinum foil having a thickness of 10 μm, and the width of the opening 26A of the opening substrate 26 of the electrode substrate 24 was increased according to the thickness of the platinum foil. Similarly, an electrolysis cell was fabricated and experimented. The exposed portion 16A of the electrode 16 was arranged so that one side thereof was located on the boundary 20 between the gas flow channel 12 and the liquid flow channel 10 and extended to the liquid flow channel 10 side by 50 μm.

Then, 0.01 N dilute sulfuric acid was supplied as an electrolytic solution 18 to the flow path using a syringe pump, and voltage was applied between the electrodes to conduct constant current electrolysis at 200 μA. It was confirmed that the gas 14 generated from both electrodes quickly merged with the gas 14 in the gas flow path 12 and disappeared. When the current was increased to 100 μA and an experiment was performed under the same conditions as described above, bubbles generated at the electrodes were sucked into the gas flow path 12 and could be separated into gas and liquid. The current density at this time was 10 mA / cm ² .

(Example 2-5)
The experiment was performed in the same manner as in Example 2-1, except that the plasma treatment using oxygen was not performed on the flow path substrate 22 and the electrode substrate 24. The contact angle with respect to the electrolyte solution 18 used by this plasma-treated non-treated surface (the region of the groove constituting the flow path of the flow path substrate 22 and the area constituting the inner wall of the liquid flow path 10 of the electrode substrate 24) was 85 °. It was.

  Then, while supplying 0.01 N diluted sulfuric acid as the electrolytic solution 18 at a flow rate of 10 μL / min using a syringe pump, voltage was applied between the pair of electrodes 16 to perform constant current electrolysis at 100 μA. The gas 14 generated from both electrodes 16 was initially attached to the electrode 16, but it was confirmed that the gas 14 disappeared as soon as it was sucked into the gas flow path 12 when it contacted the gas-liquid interface. However, the gas-liquid interface was unstable, and after a while, the electrolyte solution 18 entered the gas flow path 12 and the bubbles could not be separated.

(Example 2-6)
The experiment was performed in the same manner as in Example 2-1, except that the flow path substrate 22 and the electrode substrate 24 were not subjected to the plasma treatment using oxygen, but instead were subjected to the plasma treatment using tetrafluoromethane. As for the plasma treatment conditions, each substrate was set on the anode, and the treatment was performed for 90 seconds at a tetrafluoromethane flow rate of 50 sccm, a degree of vacuum of 150 mTorr, a power density of 1.27 W / cm ² . The contact angle with respect to the electrolyte solution 18 used of this plasma treatment surface (the region of the groove constituting the flow path of the flow path substrate 22 and the area constituting the inner wall of the liquid flow path 10 of the electrode substrate 24) was 95 °.

  Then, while supplying 0.01 N diluted sulfuric acid as the electrolytic solution 18 at a flow rate of 1 μL / min using a syringe pump, a voltage was applied between the pair of electrodes 16 to perform constant current electrolysis at 100 μA. The gas 14 generated from both electrodes 16 was initially attached to the electrode 16, but it was confirmed that the gas 14 disappeared as soon as it was sucked into the gas flow path 12 when it contacted the gas-liquid interface. However, the gas-liquid interface was unstable, and after a while, the electrolyte solution 18 entered the gas flow path 12 and the bubbles could not be separated.

  Further, when 0.01 N dilute sulfuric acid was supplied as an electrolytic solution 18 at a flow rate of 10 μL / min using a syringe pump, a gas-liquid interface could not be formed, and the electrolytic solution 18 entered the gas flow path 12. I have.

(Example 3-1)
The electrolysis cell shown in FIGS. 9 and 10 was produced as follows. In addition, FIG. 9 is a top view which shows the electrolysis cell produced in Example 3-1. 10 is a cross-sectional view taken along line 3-3 of FIG.

  1) Two gas flow paths sandwiching the liquid flow path 10 and the liquid flow path 10 so that a polycarbonate plate (30 mm × 70 mm, thickness 2 mm) as the flow path substrate 22 is machined to have a rectangular cross section. A groove to be 12 was formed. The liquid channel 10 had a width of 1.4 mm, a depth of 500 μm, and a length applied to the electrode 16 of 30 mm. The dimensions of the gas channel 12 were a width of 1.0 mm, a depth of 100 μm, and a length applied to the electrode 16 of 30 mm. In this way, a flow path substrate 22 in which the gas flow path 12 was shallower than the liquid flow path 10 was obtained.

  2) A polycarbonate plate (30 mm × 70 mm, thickness 2 mm) as the electrode substrate 24 was also machined to form a groove 24A in which the electrode 16 made of platinum wire was accommodated. The dimensions of the groove 24A were a width of 100 μm, a depth of 100 μm, and a length applied to the electrode 16 of 30 mm. Further, the groove 24A in which the electrode 16 made of platinum wire is accommodated was formed so that the boundary 20 between the liquid flow path 10 and the gas flow path 12 prepared in the above 1) was at the center. An electrode 16 made of platinum wire having a diameter of 100 μm was used, and the electrode 16 was accommodated in the groove, and exposed from the through-holes opened at both ends of the groove 24A to be the terminal 30, which was connected to the power source. In this way, an electrode substrate 24 was obtained.

3) The flow path substrate 22 and the electrode substrate 24 were subjected to plasma treatment using tetrafluoromethane. Plasma treatment conditions were as follows: the substrate was set on the cathode, and a tetrafluoromethane flow rate of 50 sccm, a vacuum degree of 150 mTorr, a power density of 1.78 W / cm ² , and a treatment for 30 seconds. At this time, the contact angle with respect to the electrolytic solution 18 used by the processing surface (the inner wall of the groove serving as the flow path of the flow path substrate 22 and the entire surface constituting each flow path of the electrode substrate 24) was 125 °.

  4) The flow path substrate 22 and the electrode substrate 24 were overlapped with the position of the exposed portion 16A of the electrode 16 accurately aligned. These were sandwiched between two jigs obtained by processing an acrylic plate having a thickness of 10 mm, and tightened with screws to prevent the electrolyte solution 18 from leaking from the flow path. The exposed portion 16 </ b> A of the electrode 16 is arranged so that the center thereof is located on the boundary 20 between the gas flow path 12 and the liquid flow path 10. A cell was thus obtained.

  0.01N dilute sulfuric acid was supplied to the liquid channel 10 from the inlet 10A using a syringe pump. Even when supplied at a flow rate of 10 mL / min, dilute sulfuric acid does not leak from the liquid flow path 10 to the gas flow path 12, and a gas-liquid interface is formed in the vicinity of the boundary 20 between the liquid flow path 10 and the gas flow path 12. It was confirmed by observation with a microscope.

  Then, while supplying 0.01 N dilute sulfuric acid as the electrolytic solution 18 at a flow rate of 10 μL / min using a syringe pump, a voltage was applied between the pair of electrodes 16 to perform constant current electrolysis at 500 μA. The gas 14 generated from both electrodes 16 was initially attached to the electrode 16, but it was confirmed that it quickly merged with the gas 14 in the gas flow path 12 and disappeared when contacting the gas-liquid interface. At this time, the diameter of the bubbles attached to the electrode 16 disappeared after growing to 20 to 30 μm. When the current was increased to 2.0 mA and an experiment was performed under the same conditions as described above, bubbles generated in the electrode 16 were sucked into the gas flow path 12 and could be separated into gas and liquid. However, when the current was increased to 3.0 mA and an experiment was performed under the same conditions as described above, bubbles generated in the electrodes adhered to the liquid flow channel and became larger, eventually flowing through the liquid flow channel. No. 12 can be absorbed.

(Example 3-2)
The experiment was performed in the same manner as in Example 3-1, except that the polycarbonate plate as the flow path substrate 22 and the electrode substrate 24 was changed to an acrylic plate. It should be noted that the plasma processing surface using tetrafluoromethane with respect to the acrylic plate (the surface constituting the flow path of the flow path substrate 22 and the surface constituting each flow path inner wall of the electrode substrate 24) to the electrolytic solution 18 used. The angle was 110 °.

  Then, while supplying 0.01 N dilute sulfuric acid as the electrolytic solution 18 at a flow rate of 10 μL / min using a syringe pump, a voltage was applied between the electrodes to perform constant current electrolysis at 500 μA. It was confirmed that the gas 14 generated from both electrodes was initially attached to the electrode, but disappeared as soon as it was drawn into the gas flow path 12 when it contacted the gas-liquid interface. At this time, the diameter of the bubbles adhering to the electrode grew to an average of 200 to 300 μm, and then merged with the gas 14 in the gas flow channel 12 to separate the bubbles.

(Comparative Example 3-1)
The position of the electrode 16 made of a wire on the electrode substrate 24 is shifted parallel to the substrate surface, and the center of the electrode 16 is separated from the boundary 20 between the gas flow channel 12 and the liquid flow channel 10 by 150 μm to the gas flow channel 12 side. The experiment was performed in the same manner as in Example 3-1. Although 0.01 N dilute sulfuric acid was supplied to the liquid flow path 10 as the electrolytic solution 18, the dilute sulfuric acid did not reach the position of the electrode 16 and was not in contact therewith, so electrolysis could not be performed.

(Comparative Example 3-2)
The position of the electrode 16 made of a wire on the electrode substrate 24 is shifted parallel to the substrate surface, and the center of the electrode 16 is separated from the boundary 20 between the gas flow channel 12 and the liquid flow channel 10 by 150 μm to the liquid flow channel 10 side. The experiment was performed in the same manner as in Example 3-1. The entire exposed portion 16A of the electrode 16 was an electrolyte contact region, and the region was located beyond the boundary 20 by more than 100 μm.

  Then, while supplying 0.01 N dilute sulfuric acid as the electrolytic solution 18 at a flow rate of 10 μL / min using a syringe pump, a voltage was applied between the electrodes to perform constant current electrolysis at 500 μA. Bubbles generated at the electrode 16 adhered to the liquid flow path 10 or flowed through the liquid flow path 10 and were not sucked into the gas flow path 12 and could not be separated into gas and liquid.

(Example 3-3)
An electrolysis cell was produced in the same manner as in Example 3-2 except that the plasma treatment using tetrafluoromethane was not performed. Electrolyte used on the non-processed surfaces (surfaces constituting the flow path of the flow path substrate 22 and the flow path of the electrode substrate 24) of the flow path substrate 22 (acrylic plate) and the electrode substrate 24 (acrylic plate) The contact angle with respect to 18 was 65 °.

  Then, while supplying 0.01 N dilute sulfuric acid as the electrolytic solution 18 at a flow rate of 10 μL / min using a syringe pump, a voltage was applied between the electrodes to perform constant current electrolysis at 500 μA. It was confirmed that the gas 14 generated from both electrodes was initially attached to the electrode, but disappeared as soon as it was drawn into the gas flow path 12 when it contacted the gas-liquid interface. However, after a while, the generated gas 14 flowed through the liquid channel 10 and could not be gas-liquid separated.

Example 4
The electrolysis cell shown in FIGS. 11 and 12 was produced as follows. In addition, FIG. 11 is a top view which shows the electrolysis cell produced in Example 4. FIG. 12 is a cross-sectional view taken along line 4-4 of FIG.

  A polycarbonate plate (30 mm × 70 mm, thickness 2 mm) as the flow path substrate 22 is machined, and the two gas flow paths 12 are sandwiched between the liquid flow path 10 and the liquid flow path 10 so that the cross section is rectangular. A groove was formed. The dimensions of the liquid channel 10 were a width of 200 μm, a depth of 500 μm, and a length applied to the electrode 16 of 20 mm. The dimensions of the gas channel 12 were a width of 1.0 mm, a depth of 100 μm, and a length applied to the electrode 16 of 20 mm. In this way, a flow path substrate 22 in which the gas flow path 12 was shallower than the liquid flow path 10 was obtained.

  2) A polycarbonate plate (30 mm × 70 mm, thickness 2 mm) as the electrode substrate 24 was also machined to form a recess 24B in which the electrode 16 made of a platinum plate having a thickness of 100 μm was accommodated. The dimensions of the recess 24B were 10 mm in width, 20 mm in length, and 100 μm in depth. Two recesses 24B for accommodating the electrodes 16 made of a platinum plate are formed. The end face (exposed portion 16A) of the electrode 16 and the side wall of the recess 24B have a gap 24C of 10 μm, and the end face (exposed portion 16A) of the electrode 16 is on the boundary 20 between the liquid flow path 10 and the gas flow path 12. It was stored in the depression 24B so as to be positioned.

3) The flow path substrate 22 was subjected to a plasma treatment using tetrafluoromethane. Plasma treatment conditions were as follows: the substrate was set on the cathode, and a tetrafluoromethane flow rate of 50 sccm, a vacuum degree of 150 mTorr, a power density of 1.78 W / cm ² , and a treatment for 30 seconds. At this time, the contact angle with respect to the electrolytic solution 18 used by the processing surface (the groove inner wall serving as the flow path of the flow path substrate 22) was 125 °.

4) A fluorine resin coating agent (heat-resistant TFE coat manufactured by Fine Chemical Japan Co., Ltd.) was spray-coated on the electrode surface made of a platinum plate before being stored in the recess 24B of the electrode substrate 24, and heat-cured (175 ° C., 1 hour). The contact angle of the treated surface (surface of the electrode 16) with respect to the electrolytic solution 18 used was 119 °. However, the end surface (exposed portion 16A) of the electrode 16 in contact with the electrolytic solution 18 was polished with a sandpaper, and the fluororesin coat was scraped to expose the electrode 16.

  5) The flow path substrate 22 and the electrode substrate 24 were overlapped with the position of the exposed portion 16A of the electrode 16 accurately aligned. These were sandwiched between two jigs obtained by processing an acrylic plate having a thickness of 10 mm, and tightened with screws to prevent the electrolyte solution 18 from leaking from the flow path. The end face (exposed portion 16 </ b> A) of the electrode 16 was disposed so as to be located on the boundary 20 between the gas flow path 12 and the liquid flow path 10. A cell was thus obtained.

  Since a 10 μm gap 24C was provided between the end face (exposed portion 16A) of the electrode 16 made of polished and conductive platinum plate and the side wall of the depression 24B, the electrolytic solution 18 also flowed into the gap 24C. The end face (exposed portion 16A) of the electrode 16 is in contact with the electrolytic solution 18, and electrolysis can occur.

    0.01N dilute sulfuric acid was supplied to the liquid channel 10 from the inlet 10A using a syringe pump. Even when supplied at a flow rate of 180 mL / min, dilute sulfuric acid does not leak from the liquid flow path 10 to the gas flow path 12, and a gas-liquid interface is formed in the vicinity of the boundary 20 between the liquid flow path 10 and the gas flow path 12. It was confirmed by observation with a microscope.

  Then, while supplying 0.01 N dilute sulfuric acid as the electrolytic solution 18 at a flow rate of 10 μL / min using a syringe pump, a voltage was applied between the pair of electrodes 16 to perform constant current electrolysis at 500 μA. The gas 14 generated from both electrodes 16 was initially attached to the electrode 16, but it was confirmed that it quickly merged with the gas 14 in the gas flow path 12 and disappeared when contacting the gas-liquid interface. At this time, the diameter of the bubbles attached to the electrode 16 disappeared after growing to 20 to 30 μm. When the current was increased to 5.0 mA and an experiment was performed under the same conditions as described above, bubbles generated at the electrode 16 were sucked into the gas flow path 12 and could be separated into gas and liquid.

  In each of the above examples, water was electrolyzed and decomposed into oxygen and hydrogen, and each could be recovered. In the present embodiment, an example is shown in which sulfuric acid is used as a substance for causing an electrolysis reaction of water, but it is not limited to sulfuric acid, and other substances may be used.

It is a top view which shows the electrolysis cell which concerns on embodiment. It is sectional drawing which shows the electrolysis cell which concerns on embodiment. It is a partial expanded sectional view which shows the electrode position in the electrolysis cell which concerns on embodiment. It is sectional drawing which shows the electrolysis cell which concerns on other embodiment. It is a top view which shows the electrolysis cell produced in Example 1-1. It is 1-1 sectional drawing of FIG. It is a top view which shows the electrolysis cell produced in Example 2-1. It is 2-2 sectional drawing of FIG. It is a top view which shows the electrolysis cell produced in Example 3-1. It is 3-3 sectional drawing of FIG. 6 is a plan view showing an electrolysis cell produced in Example 4. FIG. It is 4-4 sectional drawing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Liquid flow path 10A Inlet 10B Discharge port 12 Gas flow path 12A Gas discharge flow path 12B Discharge port 14 Gas 16 Electrode 16A Exposed portion 18 Electrolyte 20 Liquid flow path and gas flow path boundary 22 Flow path substrate 24 Electrode substrate 24A Groove 24B Dimple 24C Gap 26 Open substrate 26A Open 28 Convex substrate 28A Convex portion 30 Terminal

Claims (6)

A liquid flow path through which the electrolyte flows,
A gas flow path disposed in contact with a width direction end of the liquid flow path, wherein an electrolyte and a gas-liquid interface flowing in the liquid flow path in the vicinity of a boundary surface with the liquid flow path A gas flow path for forming;
A pair of electrodes arranged to constitute at least a part of an inner wall of the liquid flow path and / or the gas flow path, and for causing electrolysis of the electrolytic solution, at least a part of which is the electrolyte and A pair of electrodes that are in contact with each other and the entire contact area with the electrolytic solution is located within 100 μm from the boundary surface of the liquid channel and the gas channel;
An electrolysis cell comprising: The gas channel and the liquid channel have a rectangular cross section, the gas channel is thinner than the liquid channel, and the contact angle of the gas channel inner wall with the electrolyte is 90 ° or more. The electrolysis cell according to claim 1. The gas channel and the liquid channel have a rectangular cross section, the gas channel is thicker than the liquid channel, and the contact angle of the inner wall of the liquid channel with respect to the electrolyte is 90 ° or less. The electrolysis cell according to claim 1.   The electrolysis cell according to claim 1, wherein the pair of electrodes has a width of 100 μm or less.   The electrolysis cell according to claim 1, wherein the electrolysis reaction is a reaction in which water is decomposed into oxygen and hydrogen.   An electrolysis method using the electrolysis cell according to any one of claims 1 to 5, wherein the electrolytic solution is electrolyzed by the pair of electrodes.

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