JP2010275592A - Electrode for electrolysis, method of manufacturing the same and active oxygen species generator using electrode for electrolysis - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode for electrolysis capable of stably generating active oxygen species for a long time and an active oxygen species generator using the electrode for electrolysis. <P>SOLUTION: The electrode 1 for electrolysis for generating the active oxygen species such as ozone, OH radical or the like by the electrolysis of water includes an electrode base body 2 comprising Ti or the like, a conductive layer 3 formed on the electrode base body 2 and comprising Pt or the like and an insulating body layer 4 covering the conductive layer 3 and comprising Ta<SB>2</SB>O<SB>5</SB>(tantalum) or the like and at least one side surface of the conductive body layer 3 is exposed from the insulating layer 4. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electrode for electrolysis that electrolyzes water to generate active oxygen species such as ozone and OH radicals, a method for producing the same, and an active oxygen species generator using the electrode for electrolysis.

  As this type of electrolysis electrode, a substrate formed of a porous body or a net (hereinafter referred to as an electrode base) is proposed in which an electrode catalyst made of platinum (Pt) or an alloy containing platinum is provided on an electrode base. (For example, refer to Patent Document 1).

JP 2002-80986 A

  However, this electrode for electrolysis has a problem that the surface area of the electrode changes with the consumption of the electrode catalyst accompanying electrolysis, and the generation of active oxygen species such as ozone and OH radicals becomes unstable. That is, when the electrode catalyst is consumed and thinned, the surface area of the electrode is reduced, and the current density flowing through the electrode for electrolysis is increased, so that there is a disadvantage that active oxygen species such as ozone are generated more than necessary. In addition, the electrode catalyst using expensive platinum or the like must be thickened, which causes a problem in terms of cost.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an electrode for electrolysis capable of stably generating active oxygen species for a long time, a method for producing the same, and an active oxygen species generating apparatus using the electrode for electrolysis.

  A first invention is an electrode for electrolysis that generates active oxygen species such as ozone and OH radicals by electrolyzing water, and covers a substrate, a conductor layer provided on the substrate, and the conductor layer And an insulator layer formed so that a part of the conductor layer is exposed.

A second invention is an electrode for electrolysis that generates active oxygen species such as ozone and OH radicals by electrolyzing water, a substrate made of Ti, a conductor layer made of Pt provided on the substrate, And an insulator layer made of Ta ₂ O ₅ so as to cover the conductor layer and to expose a part of the conductor layer.

3rd invention is the manufacturing method of the electrode for electrolysis which electrolyzes water and produces | generates active oxygen species, such as ozone and OH radical,
After the conductor layer is formed on the substrate, the conductor layer is covered with the insulator layer, and the insulator layer is formed so that a part of the conductor layer is exposed.

  The invention relating to the fourth method for producing an electrode for electrolysis is characterized in that, in the third invention, the insulator layer is cut, polished or cut in order to expose a part of the conductor layer. .

  An invention relating to a fifth active oxygen species generating device includes an anode comprising the electrode for electrolysis described in the first or second invention, a cathode, a water tank in which these anode and cathode are inserted, and the anode and cathode. It is characterized by comprising a power supply for passing a constant direct current between them.

  In the electrode for electrolysis of the present invention, the conductor layer and the insulator layer are consumed from the end, so that the exposed area of the conductor layer is kept almost constant and the active oxygen species can be stably generated for a long time. Can do. Further, since the conductor layer may be a thin film, the amount of noble metal such as platinum used is small.

  Further, in the method for producing an electrode for electrolysis according to the present invention, at least a part of the conductor layer can be exposed from the insulator layer, and the electrode for electrolysis can be produced easily and inexpensively.

  Furthermore, since the active oxygen species generating apparatus of the present invention uses the above-described electrolysis electrode as an anode, the active oxygen species can be stably supplied, and the purification and sterilization of dirty air can be stably performed. It can be carried out.

It is explanatory drawing for demonstrating the manufacturing process of the electrode for electrolysis applied to description of embodiment of this invention. It is explanatory drawing for demonstrating the ozone production | generation efficiency and time-dependent change of the electrode for electrolysis applied to description of embodiment of this invention. It is explanatory drawing for demonstrating another manufacturing process of the electrode for electrolysis applied to description of embodiment of this invention. It is explanatory drawing which shows schematic structure of the air cleaner which is an application example of the active oxygen species production | generation apparatus applied to description of embodiment of this invention. It is a front view of an electric washing machine. It is right sectional drawing of the electric washing machine in the state which closed the door. It is right side sectional drawing of the electric washing machine in the state where the door was opened. It is a purification circulation channel figure showing composition of a circulation channel which circulates water, and an ozone supply channel which supplies air containing ozone.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 4. In FIG. 1, which is an explanatory diagram for explaining the manufacturing process of the electrode for electrolysis, the upper stage is a perspective view of each, and the lower stage is a cross-sectional plan view thereof. An electrode substrate 2 is used. The electrode substrate 2 is 2 cm wide × 8 cm long × 1 mm thick. If the electrode substrate 1 is thin, it is easily deformed. If the electrode substrate 1 is thick, processing becomes difficult and the cost is high. Therefore, the thickness is suitably in the range of 0.5 to 2 mm.

  The electrode substrate 2 is covered with a conductor layer 3 made of, for example, Pt (platinum). The thickness of the conductor layer 3 is 100 to 200 nm. If the film thickness is thin, the conductivity is deteriorated, and if it is thick, not only is the cost high, but if the insulator layer 4 described later is corroded first, only the conductor layer 3 remains, and the conductor layer 3 Therefore, the thickness of the conductor layer 3 is suitably in the range of 20 to 300 nm.

Furthermore, the conductor layer 3 is covered with an insulator layer 4 made of, for example, Ta ₂ O ₅ (tantalum oxide). The thickness of the insulator layer 4 is preferably 300 to 1000 nm, and may be 200 to 2000 nm. If the insulator layer 4 is thin, only the insulator layer 4 is corroded first and then only the conductor layer 3 remains, and the exposed area of the conductor layer 3 gradually increases. Further, if the insulator layer 4 is thick, only the conductor layer 3 is corroded, and the inside of the insulator layer 4 becomes a tunnel shape, and finally no active oxygen species such as ozone is emitted. The range mentioned above is good for the thickness.

The conductor layer 3 made of Pt and the insulator layer 4 made of Ta ₂ O ₅ are respectively formed by sputtering, but may be formed by sintering, and the conductor layer 3 is formed by plating. Also good.

  The electrode 1 for electrolysis thus produced is finally polished on one side surface (the right side surface in FIG. 1), so that one side surface of the conductor layer 3 is used as a generation surface for ozone or the like from the insulator layer 4 to the outside. It is supposed to be exposed. The polishing of this one side surface is the sum of the thicknesses of the conductor layer 3 and the insulator layer 4, and it is sufficient to perform the respective maximum values of 500 nm + 2000 nm = 2500 nm or more. Polishing can be performed using abrasive paper, and sand blasting may be used. Furthermore, instead of polishing, the conductor layer 3 may be exposed to the outside by notching or by cutting the electrode base 2, the conductor layer 3, and the insulator layer 4 so as to be longitudinally cut. .

  FIG. 2 shows the ozone generation efficiency characteristic (upper stage) of the electrode 1 for electrolysis thus produced and the change over time in the cross-sectional shape (lower stage). The ozone generation efficiency is 5% at the time point a at the beginning of electrolysis, but becomes 3.5% at time point b due to a change in the cross-sectional shape accompanying the generation of ozone and the like, and 2% after 20 hours (time point c) from the start of electrolysis After that, it becomes stable, and after that almost no change.

  This is because, in the electrode 1 for electrolysis of the present invention, the corrosion of the conductor layer 3 and the insulator layer 4 proceeds almost simultaneously due to the generation of active oxygen species such as ozone and OH radicals, and is exposed from the insulator layer 4. Since the surface area of the conductor layer 3 is kept substantially constant for a long time, the ozone generation efficiency becomes substantially constant, and active oxygen species can be stably generated for a long time. Moreover, since the conductor layer 3 made of Pt is a thin film, it can be manufactured at low cost.

FIG. 3 shows a manufacturing process of the electrode 1 for electrolysis according to another embodiment of the present invention, and the same reference numerals are attached to the same components as those in FIG. In this embodiment, the conductor layer 3 is coated in the laterally long direction at the upper and lower intermediate positions of the electrode substrate 2, and further the insulator layer 4 made of Ta ₂ O ₅ is coated.

Then, instead of polishing the electrode base 2, the conductor layer 3 made of Pt, and the insulator layer 4 made of Ta ₂ O ₅ , one side surface of the conductor layer 3 is cut into an L shape instead of polishing. And two electrolysis electrodes 1 can be manufactured simultaneously. The cutting may be performed by pressing using a mold or by laser processing.

  FIG. 4 shows a schematic configuration of an air cleaner 11 to which the active oxygen species generating apparatus 10 using the above-described electrolysis electrode 1 is applied. In FIG. 4, 12 is an anode from the above-described electrolysis electrode 1, 13 is a cathode (electrode with Pt on a Ti substrate), 14 is a DC power source (in normal operation, a constant DC power source of 100 to 500 mA). 15 is a water tank in which the anode 12 and the cathode 13 are inserted, 16 is an air filter, 17 is a pump, 18 is electrolyzed water in the water tank 15 above the air filter 16 by the pump 17. It is a water conduit that guides and drops the air filter 16.

  When a direct current flows between the anode 12 and the cathode 13 from the DC power source 14 of the active oxygen species generator 10, electrolyzed water containing active oxygen species such as ozone and OH radicals is generated in the water tank 15. Since this electrolyzed water is dropped by the pump 17 through the water conduit 18 to the air filter 16, the indoor air circulated and supplied to the air filter 16 by the blower fan (not shown) passes through the air filter 16. Purified and sterilized. Since the electrolysis electrode 1 is used for the anode 12 of the active oxygen species generating apparatus 10, the active oxygen species can be stably generated, and the air cleaning function and the sterilization function can be stably exhibited over a long period of time. .

  Next, based on FIG. 5 thru | or FIG. 8, the electric washing machine using the ozone generation unit 33 using the electrode 1 for electrolysis is demonstrated. The electric washing machine 20 includes a housing 21 having a substantially rectangular shape in a front view that constitutes an outer shell thereof. A later-described washing tub is disposed inside the housing 21, and a later-described water storage tub is disposed below the inside of the housing 21.

  A housing opening 21 </ b> A formed at the upper front of the housing 21 is provided with a door 22 that can be opened and closed. An operation / display section 23 in which a plurality of operation keys and a display are arranged is arranged on the upper front portion of the housing 21.

  5 and 6, the electric washing machine 20 is provided with a washing tub 30 (accommodating chamber). The washing tub 30 is disposed in the outer tub 31 and the outer tub 31, and stores laundry. And a cylindrical drum 34 (inner tank). A DD motor 32 is attached to the back surface of the outer tub 31, and the drum 34 can be rotated in the outer tub 31 by the DD motor 32. The outer tub 31 is attached to the bottom of the housing 21 by a plurality of dampers, and is supported in the housing 21 so as to be swingable.

  A water inlet unit 35 is provided on the upper left side of the outer tub 31. The water inlet unit 35 is a unit through which water passes when the water for rinsing is supplied into the ozone generation unit 33 and the outer tub 31. In this unit 35, a detergent container 37 (see FIG. 8) is provided, and the supplied water flows through the detergent container 37, and accordingly, the detergent is supplied with water or not supplied. It can be selected.

  This electric washing machine 20 can use bath water for easy washing. For this purpose, a bath water pump 36 (see FIG. 8) is provided as means for pumping bath water so as to be adjacent to the right side of the water inlet unit 25.

  Further, the washing tub 20 can be dried in addition to washing and rinsing. Therefore, a drying air passage 38 (see FIG. 8) as an outflow passage is connected to the right rear side of the outer tub 31. The drying air path 38 sucks out and discharges moist air from the outlet of the outer tub 31, and dehumidifies the air while guiding the air upward. A blower unit 40 is connected to the upper part of the drying air path 38 via a connection hose 39. The blower unit 40 equipped with a heater for heating the air to be fed again passes the dehumidified air (dry air) guided by the dry air passage 38 through the connection hose 41 and the dry air inlet (not shown). This is for flowing into the outer tub 31.

  Here, the drying air path 38, the connection hose 39, the blower unit 40, and the connection hose 41 function as a circulation channel, and this circulation channel is connected to the drying air inlet (inlet of the outer tub 31) and the outlet. Yes.

  The electric washing machine 20 is provided with an ozone generation unit 33 (see FIG. 8) in the vicinity of the blower unit 40. The ozone generation unit 33 functions as water purification means using the electrolysis electrode 1.

  In the electric washing machine 20, a water storage tank 42 provided below the washing tub 30 stores water drained from the outer tub 31 and bath water pumped up by the bath water pump 36. In the vicinity of the water storage tank 42, a circulation pump 43 for pumping out water from the water storage tank 42 is provided. In addition, a number of hoses are arranged to move water between the outer tub 31, the water inlet unit 35, the drying air path 38, the water storage tank 42, etc., and the ozone generating unit 33 is shown in FIG. As described above, the water supplied from the water inlet unit 35 temporarily accumulates, and during that time, a direct current flows between the DC power source 14 and the anode 12 and the cathode 13, thereby generating electrolyzed water in which ozone is dissolved. This electrolyzed water is supplied into the outer tub 31 when it is easy to wash.

  FIG. 8 is a purification circulation channel diagram showing a configuration of a circulation channel for circulating water and an ozone supply channel for supplying air containing ozone in the electric washing machine 20 described in FIGS. 5 to 7. Referring to FIG. 8, tap water supplied from faucet 44 is supplied into laundry tub 30 through water inlet unit 35 and connection hose 46 by opening / closing control of water supply valve 45. At this time, by switching the water supply valve 45, the tap water flows through the first flow path 47 in the detergent container 37 in the water inlet unit 35 or passes through the second flow path 48 and flows in the water inlet unit 35. It can be selected whether to flow through the softener container 49 or to the ozone generation unit 33.

  The water in the washing tub 30 (outer tub 31) can be discharged by controlling the opening and closing of the drain valve 51 provided in the drain port pipe 50. A filter unit 53 is connected to the drain valve 51 via an intermediate hose 52. The filter unit 53 is for capturing lint and foreign matter contained in the water discharged from the outer tub 31. The water that has entered the filter unit 53 passes through the drain pipe 54 and the valve 58 and is discharged from the drain hose 55 to the outside of the housing 21. Outside the housing 21, for example, it passes through an external drain hose 56 and is discharged to a drain trap 57.

  The above is the flow of water when not performing the water-saving function when washing and rinsing with tap water.

  In the embodiment described above, Ti (titanium) is used for the electrode base 2 of the electrode 1 for electrolysis because Ti is excellent in corrosion resistance and workability and is inexpensive. In addition to Ti, the electrode substrate 2 may be made of Zr (zirconium), stainless steel, an alloy containing Ti, or the like.

Similarly, Pt (platinum) was used for the conductor layer 3 because Pt is excellent in corrosion resistance and conductivity. For the conductor layer 2, an alloy containing Rh (rhodium), Ru (ruthenium), Pd (palladium), Ir (iridium), Os (oscium) in addition to Pt can be used. Further, Ta ₂ O ₅ (tantalum oxide) is used for the insulator layer 4 because it is excellent in corrosion resistance and insulation. The insulator layer 4 can use the same valve metal (Ti, Zr, Cr (chromium), Al (aluminum), W (tungsten)) oxide as the Ta (tantalum), or an oxide of an alloy containing the valve metal. It is.

  Although the embodiments of the present invention have been described above, various alternatives, modifications, and variations can be made by those skilled in the art based on the above description, and the present invention is not limited to the various embodiments described above without departing from the spirit of the present invention. It encompasses alternatives, modifications or variations.

DESCRIPTION OF SYMBOLS 1 Electrode for electrolysis 2 Electrode base 3 Conductor layer 4 Insulator layer 10 Active oxygen species generator

Claims (5)

  In an electrode for electrolysis that generates active oxygen species such as ozone and OH radicals by electrolyzing water, a substrate, a conductor layer provided on the substrate, and the conductor layer are coated and coated on the conductor layer. An electrode for electrolysis comprising an insulator layer partially exposed. In an electrode for electrolysis that generates active oxygen species such as ozone and OH radicals by electrolyzing water, a substrate made of Ti, a conductor layer made of Pt provided on the substrate, and the conductor layer are covered. And an insulator layer made of Ta ₂ O ₅ formed so that a part of the conductor layer is exposed. In a method for producing an electrode for electrolysis that generates active oxygen species such as ozone and OH radicals by electrolyzing water,
A method for producing an electrode for electrolysis comprising: forming a conductor layer on a substrate; and covering the conductor layer with an insulator layer and forming the insulator layer so that a part of the conductor layer is exposed. Method.   4. The method for producing an electrode for electrolysis according to claim 3, wherein the insulating layer is cut, polished or cut to expose a part of the conductor layer.   An anode comprising the electrode for electrolysis according to claim 1 or 2, a cathode, a water tank in which the anode and the cathode are inserted, and a power source for supplying a constant direct current between the anode and the cathode. An active oxygen species generator characterized by the above.

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