WO2013038927A1 - 塩素発生用陽極 - Google Patents
塩素発生用陽極 Download PDFInfo
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- WO2013038927A1 WO2013038927A1 PCT/JP2012/072236 JP2012072236W WO2013038927A1 WO 2013038927 A1 WO2013038927 A1 WO 2013038927A1 JP 2012072236 W JP2012072236 W JP 2012072236W WO 2013038927 A1 WO2013038927 A1 WO 2013038927A1
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- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
- C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
- C25B11/091—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds
- C25B11/093—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds at least one noble metal or noble metal oxide and at least one non-noble metal oxide
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
- C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
- C02F1/467—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction
- C02F1/4672—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction by electrooxydation
- C02F1/4674—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction by electrooxydation with halogen or compound of halogens, e.g. chlorine, bromine
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B1/00—Electrolytic production of inorganic compounds or non-metals
- C25B1/01—Products
- C25B1/24—Halogens or compounds thereof
- C25B1/26—Chlorine; Compounds thereof
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
- C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
- C25B11/091—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds
- C25B11/097—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds comprising two or more noble metals or noble metal alloys
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
- C25C7/00—Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells
- C25C7/02—Electrodes; Connections thereof
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
- C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
- C02F1/46104—Devices therefor; Their operating or servicing
- C02F1/46109—Electrodes
- C02F2001/46133—Electrodes characterised by the material
- C02F2001/46138—Electrodes comprising a substrate and a coating
- C02F2001/46142—Catalytic coating
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
- C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
- C02F1/46104—Devices therefor; Their operating or servicing
- C02F1/46109—Electrodes
- C02F2001/46133—Electrodes characterised by the material
- C02F2001/46138—Electrodes comprising a substrate and a coating
- C02F2001/46147—Diamond coating
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/08—Seawater, e.g. for desalination
Definitions
- the present invention relates to a chlorine generating anode used when electrolytically collecting a desired metal at the cathode by electrolysis, and a chlorine generating anode used for generating chlorine from a chloride aqueous solution such as salt electrolysis, hydrochloric acid electrolysis and seawater electrolysis. More specifically, the present invention relates to a chlorine generating anode that is used for electrolytic collection, salt electrolysis, hydrochloric acid electrolysis, seawater electrolysis and the like in which an aqueous solution is used as an electrolytic solution and the main reaction at the anode is chlorine generation.
- Electrolytic collection is performed by immersing the anode and cathode in an aqueous solution containing metal ions to be collected (hereinafter referred to as electrolytic collection solution) and energizing to deposit the metal on the cathode.
- electrolytic collection solution for example, copper, zinc, nickel, cobalt, lead, platinum group metals (platinum, iridium, ruthenium, palladium, etc.), noble metals (silver, gold), other transition metal elements, rare metals or critical metals
- Electrolytic collection prepared through the process of extracting the target metal ion after crushing ore containing any one or more of the metal elements to be dissolved, dissolving the metal ion using an appropriate acid, etc.
- a method of producing a metal by electrolysis using a liquid is included. Electrolytic extraction is also used in various applications in mobile devices such as primary batteries, secondary batteries, fuel cells, mobile phones, and other electronic devices, electrical components, electronic components, plated steel sheets, plated ornaments, etc.
- the used metal or alloy is pulverized and the metal ions are dissolved, and then the metal is regenerated by electrolysis using an electrolytic collection solution containing the target metal ions. And collected.
- the electrolytic collection includes a process of recovering a metal by electrolysis using an electrolytic collection solution containing a target metal ion through a process of extracting metal ions from a plating waste solution.
- the main reaction of the anode changes depending on whether or not chloride ions are included.
- the main reaction of the anode may be chlorine generation.
- carbon electrodes such as graphite and glassy carbon, lead alloy electrodes, platinum-coated titanium electrodes, oxide-coated titanium electrodes, etc. are used.
- An oxide-coated titanium electrode in which a titanium substrate is coated with a complex oxide of titanium and titanium is often used. Whether chlorine generation is the main reaction of the anode is affected by the chloride ion concentration in the electrowinning solution, the presence or absence of complex formation between metal ions and chloride ions, their stability, and pH. .
- salt electrolysis is a method in which electrolysis is performed using a high-concentration sodium chloride aqueous solution, chlorine is produced at the anode, and hydrogen and a high-concentration sodium hydroxide solution are produced at the cathode. It is a method for producing chlorine used for sterilization on the anode by electrolysis of an aqueous hydrochloric acid solution in the fields of medicine, livestock and the like.
- the chlorine generating anode is also used in the electrolysis of acids other than hydrochloric acid when chlorine is generated at the anode.
- seawater electrolysis is a method of electrolyzing seawater to generate chlorine.
- the generated chlorine and water react to produce hypochlorous acid, so that microorganisms in seawater can be killed.
- the electrolyzed water is used as cooling water for nuclear power generation.
- the anode for chlorine generation used in the above-described electrowinning, salt electrolysis, hydrochloric acid electrolysis, seawater electrolysis and the like is an oxide-coated titanium electrode, particularly a composite of ruthenium and titanium produced by a thermal decomposition method. It is well known that an electrode in which a titanium substrate is coated with a catalyst layer containing an oxide is used.
- Such a chlorine generating anode is disclosed in, for example, Patent Documents 1 to 7.
- the energy consumed in electrowinning, salt electrolysis, hydrochloric acid electrolysis, and seawater electrolysis using a chlorine generating anode is the product of the electrolysis voltage and the amount of electricity applied.
- the product at the cathode or anode metal produced at the cathode for electrowinning, hydrogen produced at the cathode for chlorine electrolysis, chlorine produced at the sodium hydroxide and anode, chlorine produced at the anode for hydrochloric acid electrolysis and seawater electrolysis
- the electrical energy hereinafter referred to as the power consumption basic unit
- the power consumption basic unit the electrical energy required for generating the target product per unit weight becomes smaller as the electrolysis voltage is lower.
- This electrolytic voltage is a potential difference between the anode and the cathode, and the potential of the cathode is determined by the cathode reaction.
- the anodic reaction is mainly generated by chlorine
- the potential of the anode varies depending on the material used for the anode. For example, for materials with low and high catalytic activity for chlorine generation, the higher the catalytic activity, the lower the potential of the anode. Therefore, in order to reduce the basic unit of electric energy in electrowinning, salt electrolysis, hydrochloric acid electrolysis, and seawater electrolysis using a chlorine generating anode, the anode should be made of a material having high catalytic activity and the potential of the anode should be lowered. Is important and necessary.
- the chlorine generation anode has a catalyst that is opposite to chlorine generation for reactions that may occur on the anode other than chlorine generation (hereinafter referred to as side reactions).
- Low activity is required.
- a titanium electrode coated with crystalline ruthenium and titanium composite oxide is used as the anode, not only the generation of chlorine at the anode but also the electrolytic collection solution.
- the divalent cobalt ions therein are oxidized, and cobalt oxyhydroxide (CoOOH) is deposited on the anode, causing side reactions that accumulate.
- the chlorine generating anode used for electrowinning, salt electrolysis, hydrochloric acid electrolysis, and seawater electrolysis is 1) high in catalytic activity for chlorine generation, and 2) a secondary that causes precipitation of metal oxides on the anode.
- the anode potential is low, in other words, the overvoltage with respect to the anode reaction is small, and even if the electrolysis is continued, the anode potential does not increase due to the side reaction. 5) Therefore, the electrolysis voltage is low and the electrolysis is low.
- Patent Document 1 a catalyst layer containing amorphous iridium oxide or amorphous ruthenium oxide as an anode for cobalt electrowinning using a chloride electrolyte.
- An electrode formed on a conductive substrate is disclosed, and compared with a conventional anode, that is, a titanium electrode coated with a crystalline oxide of ruthenium and titanium, the anode potential is reduced, and oxyhydration at the anode is performed. It was clarified that side reactions such as the formation of cobalt can be suppressed.
- Patent Document 1 an anode for cobalt electrowinning in which a catalyst layer containing amorphous iridium oxide or amorphous ruthenium oxide is formed on a conductive substrate.
- the anode formed with a catalyst layer made of an amorphous ruthenium and titanium composite oxide was coated with a crystalline ruthenium and titanium composite oxide. It was clarified that the anode potential and the electrolysis voltage can be reduced as compared with the titanium electrode, and the precipitation of cobalt oxyhydroxide generated as a side reaction of the anode can be suppressed.
- salt electrolysis, hydrochloric acid electrolysis, and seawater electrolysis required further reduction in anode potential and further reduction in electrolysis voltage by further increasing the catalytic activity against chlorine generation. .
- the present invention has been made in view of the above circumstances, and the object of the present invention is to provide a carbon electrode, a lead electrode in electrowinning, salt electrolysis, hydrochloric acid electrolysis, and seawater electrolysis in which the main reaction at the anode is chlorine generation.
- the potential of the anode for chlorine generation is lower, which can reduce the electrolysis voltage and the power consumption, and It is to provide an anode for chlorine generation that can be used as an anode for sampling, salt electrolysis, hydrochloric acid electrolysis, seawater electrolysis and the like.
- the present inventor has solved the above problems by using an anode in which a catalyst layer containing amorphous ruthenium oxide and amorphous tantalum oxide is formed on a conductive substrate.
- the present inventors have found that the present invention can be accomplished and have completed the present invention.
- the anode for chlorine generation according to claim 1 of the present invention is an anode for chlorine generation in which generation of chlorine from an aqueous solution is a main reaction of the anode, and includes amorphous ruthenium oxide and amorphous tantalum oxide.
- the catalyst layer is formed on a conductive substrate.
- valve metals such as titanium, tantalum, zirconium, niobium, tungsten and molybdenum, and valve metals such as titanium-tantalum, titanium-niobium, titanium-palladium and titanium-tantalum-niobium are mainly used. Alloy, an alloy of valve metal and platinum group metal and / or transition metal, or conductive diamond (for example, boron-doped diamond) is preferable, but is not limited thereto.
- the shape may be various shapes such as a plate, a net, a rod, a sheet, a tube, a line, a porous plate, a porous, a three-dimensional porous body in which true spherical metal particles are combined. Can do.
- a metal other than the valve metal such as iron or nickel or a conductive ceramic surface coated with the above valve metal, alloy, conductive diamond or the like may be used.
- Claim 2 is an anode for chlorine generation of Claim 1, Comprising: It has the structure used for any one among electrowinning, salt electrolysis, hydrochloric acid electrolysis, and seawater electrolysis. .
- It has the structure used for any one among electrowinning, salt electrolysis, hydrochloric acid electrolysis, and seawater electrolysis.
- (1) Compared with carbon electrode, lead electrode, lead alloy electrode, metal-coated titanium electrode, metal oxide-coated titanium electrode in electrowinning, salt electrolysis, hydrochloric acid electrolysis, and seawater electrolysis, where the main reaction at the anode is chlorine generation
- the potential of the anode with respect to the generation of chlorine is low, which has the effect of reducing the electrolysis voltage and reducing the basic unit of electric energy.
- the invention according to claim 3 is the chlorine generating anode according to claim 1 or 2, wherein the catalyst layer is made of a mixture of amorphous ruthenium oxide and amorphous tantalum oxide.
- the catalyst layer is made of a mixture of amorphous ruthenium oxide and amorphous tantalum oxide.
- Patent Document 7 and Non-Patent Document 1 disclose that durability is lowered in an electrode having a coating layer containing ruthenium oxide and tantalum oxide obtained by thermal decomposition at 450 ° C. or higher. Such a result is a problem that occurs when oxygen is generated on the electrode in the catalyst layer containing crystalline ruthenium oxide obtained by performing thermal decomposition at a temperature of at least 350 ° C. or higher.
- the inventor of the present application has high durability as an anode for generating chlorine, in which an anode in which a catalyst layer in a state in which ruthenium oxide is amorphous in a mixture of amorphous tantalum oxide is formed is used. I found out.
- a precursor solution containing ruthenium and tantalum is applied on the conductive substrate, and then a predetermined temperature is applied.
- Various physical vapor deposition methods such as sputtering and CVD, chemical vapor deposition, and the like can be used in addition to the thermal decomposition method in which the heat treatment is performed. Further, among the methods for producing the chlorine generating anode of the present invention, a production method by a thermal decomposition method will be described in particular.
- ruthenium and tantalum such as inorganic compounds, organic compounds, ions, and complexes
- a precursor solution containing various forms of ruthenium and tantalum such as inorganic compounds, organic compounds, ions, and complexes
- the titanium substrate A catalyst layer containing amorphous ruthenium oxide and amorphous tantalum oxide is formed thereon.
- the molar ratio of ruthenium to tantalum in the butanol solution is 10:90.
- a catalyst layer containing a mixture of amorphous ruthenium oxide and amorphous tantalum oxide is formed. Further, when the precursor solution is applied and then thermally decomposed at 260 ° C., a catalyst layer made of a mixture of amorphous ruthenium oxide and amorphous tantalum oxide is formed.
- the molar ratio of ruthenium and tantalum contained in the precursor solution applied to the titanium substrate If the precursor solution contains a metal component other than ruthenium and tantalum, the catalyst layer also depends on the type of the metal component and the molar ratio in all metal components contained in the precursor solution. Whether it contains amorphous ruthenium oxide and amorphous tantalum oxide varies.
- the range of the thermal decomposition temperature at which a catalyst layer containing ruthenium and amorphous tantalum oxide is obtained tends to be widened.
- the conditions for forming a catalyst layer containing amorphous ruthenium oxide and amorphous tantalum oxide include the preparation method and materials of the precursor solution, for example, the precursor It also varies depending on the ruthenium and tantalum raw materials used in the preparation of the solution, the type of solvent, and the type and concentration of additives added to promote thermal decomposition.
- the conditions for forming the catalyst layer containing amorphous ruthenium oxide and amorphous tantalum oxide by the thermal decomposition method are the butanol solvent in the thermal decomposition method described above. Is not limited to the molar ratio of ruthenium and tantalum and the range of the thermal decomposition temperature associated therewith, the above-mentioned conditions are merely examples, and the method for producing a chlorine-generating anode of the present invention is described above. In all methods other than those described above, any method can be used as long as a catalyst layer containing amorphous ruthenium oxide and amorphous tantalum oxide can be formed on the conductive substrate.
- such a method naturally includes a method involving heat treatment in the process of preparing the precursor solution as disclosed in Patent Document 8.
- a diffraction peak corresponding to ruthenium oxide or tantalum oxide is not observed by a commonly used X-ray diffraction method, Or you can know by being broad.
- a fourth aspect of the present invention is the chlorine generating anode according to any one of the first to third aspects, wherein the catalyst layer has a ruthenium to tantalum molar ratio of 90:10 to 10:90. It has a certain configuration. With this configuration, in addition to the action obtained in any one of claims 1 to 3, (1) The catalyst layer has a high electronic conductivity, and has a function of maintaining a high catalytic activity for chlorine generation and a suppressing effect on side reactions for a long time.
- the ruthenium molar ratio is larger than 90 mol%, the ratio of tantalum oxide is small, and it is difficult to obtain an effect of stabilizing ruthenium oxide in the catalyst layer, which is not preferable.
- the ruthenium molar ratio is smaller than 10 mol%, the electronic conductivity of the catalyst layer is lowered, and the resistance of the electrode itself is increased, which may cause a voltage increase, which is not preferable.
- a fifth aspect of the present invention is the chlorine generating anode according to any one of the first to fourth aspects, wherein an intermediate layer is formed between the catalyst layer and the conductive substrate. It has a configuration. With this configuration, in addition to the action obtained in any one of claims 1 to 4, (1) By forming an intermediate layer between the catalyst layer and the conductive substrate and simultaneously covering the surface of the conductive substrate, even if the electrolyte solution penetrates into the catalyst layer, the electrolyte solution is conductive substrate Therefore, the conductive substrate is not corroded by the acidic electrolyte, and the corrosion product prevents the current from flowing smoothly between the conductive substrate and the catalyst layer. Have.
- the catalyst layer containing amorphous ruthenium oxide and amorphous tantalum oxide Compared to the catalyst layer, oxygen generation does not occur preferentially in the intermediate layer even when the electrolyte solution penetrates into the catalyst layer and reaches the intermediate layer. It has a higher durability than that, and thus has an effect of protecting the conductive substrate. At the same time, by coating such a more durable oxide or composite oxide on the conductive substrate, it is possible to suppress the corrosion of the conductive substrate due to the electrolyte as compared with the case where there is no intermediate layer. Has an effect.
- the intermediate layer is low in catalytic activity for chlorine generation compared to the catalyst layer, but sufficiently covers the conductive substrate and has an action of suppressing corrosion of the conductive substrate.
- examples include alloys, carbon-based materials such as boron-doped diamond (conductive diamond), metal compounds such as oxides and sulfides, and composite compounds such as metal composite oxides.
- a thin film of tantalum, niobium, or the like is preferable for a metal
- an alloy of tantalum, niobium, tungsten, molybdenum, titanium, platinum, or the like is preferable for an alloy.
- an intermediate layer using a carbon-based material such as boron-doped diamond (conductive diamond) has a similar action.
- the intermediate layer made of the above metal, alloy, or carbon-based material is formed by various methods such as a thermal decomposition method, a sputtering method, a CVD method, various physical vapor deposition methods, a chemical vapor deposition method, a hot dipping method, and an electroplating method. be able to.
- a thermal decomposition method a sputtering method, a CVD method, various physical vapor deposition methods, a chemical vapor deposition method, a hot dipping method, and an electroplating method.
- a metal compound such as an oxide or sulfide, or a metal composite oxide
- an intermediate layer made of an oxide containing crystalline ruthenium oxide is suitable.
- the catalyst layer is produced by a thermal decomposition method, it is advantageous in terms of simplifying the anode production process to form an intermediate layer made of an oxide or a composite oxide by the same thermal decomposition method.
- a sixth aspect of the present invention is the chlorine generating anode according to the fifth aspect, wherein the intermediate layer is made of tantalum, niobium, tungsten, molybdenum, titanium, platinum, or an alloy of any of these metals. It has the composition which becomes. With this configuration, in addition to the action obtained in claim 5, (1) By using the above-mentioned metal or alloy for the intermediate layer, it has an effect that the corrosion of the conductive substrate can be effectively suppressed. (2)
- the intermediate layer can be formed by various methods such as a thermal decomposition method, a sputtering method, a CVD method and various physical vapor deposition methods, chemical vapor deposition methods, hot dipping methods, and electroplating methods, and is excellent in mass productivity.
- a seventh aspect of the present invention is the chlorine generating anode according to the fifth aspect, wherein the intermediate layer includes a composite oxide of crystalline ruthenium and titanium.
- the intermediate layer containing a crystalline ruthenium-titanium composite oxide is formed by applying a precursor solution containing ruthenium and titanium on a conductive substrate and then heat-treating at a predetermined temperature, as well as sputtering. It can be produced by various physical vapor deposition methods such as the CVD method and chemical vapor deposition method.
- a precursor solution containing ruthenium and titanium on a conductive substrate and then heat-treating at a predetermined temperature, as well as sputtering.
- It can be produced by various physical vapor deposition methods such as the CVD method and chemical vapor deposition method.
- an intermediate layer made of a composite oxide of crystalline ruthenium and titanium obtained by thermally decomposing a precursor solution containing ruthenium and titanium at a temperature of 450 ° C. to 550 ° C. is suitable. .
- An eighth aspect of the invention is the chlorine generating anode according to the fifth aspect, wherein the intermediate layer includes a crystalline ruthenium oxide and an amorphous tantalum oxide.
- the intermediate layer containing crystalline ruthenium oxide and amorphous tantalum oxide is applied by a thermal decomposition method in which a precursor solution containing ruthenium and tantalum is applied on a conductive substrate and then heat-treated at a predetermined temperature. It can be produced by various physical vapor deposition methods such as sputtering and CVD, and chemical vapor deposition.
- thermal decomposition an intermediate layer made of crystalline ruthenium oxide and amorphous tantalum oxide obtained by thermally decomposing a precursor solution containing ruthenium and tantalum at a temperature of 400 ° C. to 550 ° C. is suitable. It is.
- a ninth aspect of the present invention is the chlorine generating anode according to the fifth aspect, wherein the intermediate layer is a conductive diamond.
- the intermediate layer is made of conductive diamond, the corrosion resistance to the acidic aqueous solution is very high, and therefore has an effect that corrosion of the conductive substrate can be particularly effectively suppressed.
- the potential of chlorine generation at the anode can be made lower than in the past, so in electrowinning, salt electrolysis, hydrochloric acid electrolysis, seawater electrolysis, etc. It is possible to reduce the electrolysis voltage with respect to an aqueous solution having a wide pH range, thereby having the effect of greatly reducing the electric power consumption rate.
- the potential of chlorine generation at the anode can be lowered as compared with the conventional case, it is possible to suppress various side reactions that may occur on the anode.
- the cost of the anode in long-term electrolysis can be reduced.
- the cost of the catalyst layer is reduced by using ruthenium oxide and the thermal decomposition temperature is low as compared with the conventional titanium electrode on which the catalyst layer containing iridium oxide is formed. The cost in the layer forming process is also reduced.
- the present invention is an electrowinning of metals other than nickel and cobalt. It can also be used as an anode for generating chlorine.
- Example 1 A commercially available titanium plate (length 5 cm, width 1 cm, thickness 1 mm) was immersed in a 10% oxalic acid solution at 90 ° C. for 60 minutes for etching treatment, washed with water, and dried. Next, in a butanol (n-C 4 H 9 OH) solution containing 6 vol% concentrated hydrochloric acid, the molar ratio of ruthenium and tantalum is 90:10, and the total of ruthenium and tantalum is 50 g / L in terms of metal.
- a butanol (n-C 4 H 9 OH) solution containing 6 vol% concentrated hydrochloric acid
- This coating solution was applied to the dried titanium plate, dried at 120 ° C. for 10 minutes, and then thermally decomposed in an electric furnace maintained at 260 ° C. for 20 minutes. This application, drying, and thermal decomposition were repeated a total of 5 times to produce a chlorine generating anode of Example 1 in which a catalyst layer was formed on a titanium plate as a conductive substrate.
- Comparative Example 1 The chlorine generating anode of Comparative Example 1 was prepared in the same manner as in Example 1 except that the thermal decomposition temperature when forming the catalyst layer was changed from 260 ° C to 500 ° C.
- the thermal decomposition temperature when forming the catalyst layer was changed from 260 ° C to 500 ° C.
- a diffraction peak corresponding to RuO 2 was found in the X-ray diffraction image, but a diffraction peak corresponding to Ta 2 O 5 was found. There wasn't.
- a Ti diffraction peak was observed, which was attributed to the titanium plate. That is, on the chlorine generating anode of Comparative Example 1, a catalyst layer made of crystalline ruthenium oxide and amorphous tantalum oxide was formed.
- a nickel electrolysis solution was prepared by dissolving 0.85 mol / L NiCl 2 in distilled water and then adding hydrochloric acid to a pH of 1.0. This nickel electrolysis liquid was put into a 200 mL beaker, and a nickel plate (2 cm ⁇ 2 cm) was immersed in this as a cathode.
- the chlorine generating anode of any of the above-mentioned Example 1 and Comparative Example 1 is embedded in a polytetrafluoroethylene holder and the electrode area in contact with the nickel electrolyzed liquid is regulated to 1 cm 2 , the same
- the electrolytic collection solution was placed opposite to the cathode with a predetermined distance between the electrodes.
- the voltage was measured.
- the nickel electrowinning liquid was electrolyzed at 60 ° C. while stirring at 600 rpm using a stirrer.
- Table 1 shows the electrolytic voltage when nickel was electrowinned using the chlorine generating anode of Example 1 or Comparative Example 1 described above.
- Comparative Example 2 A commercially available titanium plate (length 5 cm, width 1 cm, thickness 1 mm) was immersed in a 10% oxalic acid solution at 90 ° C. for 60 minutes for etching treatment, washed with water, and dried. Next, ruthenium trichloride trihydrate is added to a butanol (n-C 4 H 9 OH) solution so that the molar ratio of ruthenium to titanium is 30:70 and the total of ruthenium and titanium is 70 g / L in terms of metal. objects added with the coating solution (RuCl 3 ⁇ 3H 2 O) and titanium -n- butoxide (Ti (C 4 H 9 O ) 4) were prepared.
- This coating solution was applied to the dried titanium plate, dried at 120 ° C. for 10 minutes, and then thermally decomposed in an electric furnace maintained at 500 ° C. for 20 minutes. This coating, drying, and thermal decomposition were repeated 5 times in total to produce a chlorine generating anode in which a catalyst layer was formed on a titanium plate as a conductive substrate.
- an X-ray diffraction image shows a diffractive peak corresponding to a solid solution of RuO 2 and TiO 2 (complex oxide of ruthenium and titanium). It was. A Ti diffraction peak was observed, which was attributed to the titanium plate. That is, in the chlorine generating anode of Comparative Example 2, a catalyst layer made of a crystalline ruthenium and titanium composite oxide was formed on a titanium plate.
- Comparative Example 3 The chlorine generating anode of Comparative Example 3 was produced in the same manner as Comparative Example 2 except that the thermal decomposition temperature when forming the catalyst layer was changed from 500 ° C to 260 ° C.
- a diffraction peak corresponding to the composite oxide of ruthenium and titanium as in Comparative Example 2 was not observed in the X-ray diffraction image.
- a Ti diffraction peak was observed, which was attributed to the titanium plate. That is, a catalyst layer made of a composite oxide of amorphous ruthenium and titanium containing amorphous ruthenium oxide was formed on the chlorine generating anode of Comparative Example 3.
- a nickel electrolysis solution was prepared by dissolving 0.85 mol / L NiCl 2 in distilled water and then adding hydrochloric acid to a pH of 1.0.
- This nickel electrolysis liquid was put into a 200 mL beaker, and a nickel plate (2 cm ⁇ 2 cm) was immersed in this as a cathode.
- the chlorine generation anode of any of the above-mentioned Example 1, Comparative Example 2, and Comparative Example 3 is embedded in a polytetrafluoroethylene holder, and the electrode area in contact with the nickel electrowinning liquid is regulated to 1 cm 2
- the nickel electrowinning solution was placed opposite to the cathode at a predetermined distance.
- the terminal-to-terminal voltage (electrolytic voltage) between the anode and cathode was measured.
- the nickel electrowinning liquid was electrolyzed at 60 ° C. while stirring at 600 rpm using a stirrer.
- Table 2 and Table 3 show the electrolysis voltages when nickel was electrowinned using the chlorine generating anodes of Example 1, Comparative Example 2, and Comparative Example 3 described above.
- the chlorine generating anode (Example 1) having a catalyst layer made of amorphous ruthenium oxide and amorphous tantalum oxide according to the present invention is a catalyst containing crystalline ruthenium oxide that has already been put into practical use.
- the electrolysis voltage is significantly lower than that of the chlorine generating anode (Comparative Example 3) in which the layer is formed, and the solid solution of amorphous ruthenium oxide and amorphous titanium oxide that the present inventor has already disclosed in Patent Document 1
- the electrolytic voltage could be further reduced as compared with the chlorine generating anode (Comparative Example 2) in which a catalyst layer made of (amorphous ruthenium and titanium composite oxide) was formed.
- Example 2 A commercially available titanium plate (length 5 cm, width 1 cm, thickness 1 mm) was immersed in a 10% oxalic acid solution at 90 ° C. for 60 minutes for etching treatment, washed with water, and dried. Next, in a butanol (n-C 4 H 9 OH) solution containing 6 vol% concentrated hydrochloric acid, the molar ratio of ruthenium and tantalum is 30:70, and the total of ruthenium and tantalum is 50 g / L in terms of metal.
- a butanol (n-C 4 H 9 OH) solution containing 6 vol% concentrated hydrochloric acid
- This coating solution was applied to the dried titanium plate, dried at 120 ° C. for 10 minutes, and then thermally decomposed in an electric furnace maintained at 280 ° C. for 20 minutes. This coating, drying, and thermal decomposition were repeated 5 times in total to produce a chlorine generating anode in which a catalyst layer was formed on a titanium plate as a conductive substrate.
- a cobalt electrowinning solution was prepared by dissolving 0.90 mol / L CoCl 2 in distilled water and then adding hydrochloric acid to a pH of 1.6.
- This cobalt electrolysis solution was put into a 200 mL beaker, and immersed in this as a platinum plate (2 cm ⁇ 2 cm) as a cathode.
- the chlorine generating anode of Example 2 was embedded in a holder made of polytetrafluoroethylene, and immersed in the cobalt electrowinning liquid in a state where the electrode area in contact with the cobalt electrowinning liquid was regulated to 1 cm 2 .
- Comparative Example 4 The chlorine generating anode of Comparative Example 4 was produced by the same method as Comparative Example 2 except that the thermal decomposition temperature at the time of forming the catalyst layer was changed from 500 ° C to 360 ° C.
- an X-ray diffraction image showed a weak and broad diffraction line corresponding to a complex oxide of ruthenium and titanium. That is, the catalyst layer of the chlorine generating anode in Comparative Example 4 contained amorphous ruthenium and titanium composite oxide.
- a cyclic voltammogram was measured under the same conditions as in Example 2 using the chlorine generating anode of Comparative Example 4 instead of the chlorine generating anode of Example 2.
- Example 2 The cyclic voltammograms obtained in Example 2 and Comparative Example 4 are shown together in FIG. From FIG. 1, a reduction current with a peak was observed in Comparative Example 4, whereas in Example 2, the oxidation current was finally larger than that in Comparative Example 4, but a reduction with a peak as in Comparative Example 4 was observed. No current was seen. In Comparative Example 4, there is a reduction current peak, which is a reduction of cobalt oxyhydroxide adhering to the chlorine generating anode.
- the oxidation current of Example 2 is larger than that of Comparative Example 4 in that the oxidation start of cobalt oxyhydroxide is slower than that of Comparative Example 4 at the chlorine generating anode of Example 2 and does not occur at a low potential. This is because the chlorine generation anode of Example 2 has higher catalytic activity for chlorine generation, and therefore the chlorine generation current is increased.
- the production of cobalt oxyhydroxide was suppressed, no reduction current with a peak due to the reduction of cobalt oxyhydroxide as in Comparative Example 4 was observed.
- the chlorine generation anode (Example 2) in which the catalyst layer made of amorphous ruthenium oxide and amorphous tantalum oxide according to the present invention is formed is an amorphous material already disclosed in Patent Document 1 by the present inventor.
- the electrowinning of cobalt rather than the anode for chlorine generation (Comparative Example 4) in which a catalyst layer containing a solid solution of porous ruthenium oxide and amorphous titanium oxide (amorphous ruthenium and titanium composite oxide) is formed. It has been found that the potential for chlorine generation can be lowered, and at the same time, the production of cobalt oxyhydroxide on the chlorine generating anode can be further suppressed.
- Example 3 [Hydrochloric acid electrolysis] (Example 3) Using the chlorine generating anode of Example 2, the cobalt electrowinning solution in Example 2 was a hydrochloric acid electrolyte in which only hydrochloric acid was added to distilled water and the pH was adjusted to 1.6, and the scanning speed was 50 mV / s. The cyclic voltammogram was measured under the same conditions except for the change.
- Comparative Example 5 Using the chlorine generation anode of Comparative Example 4, the cobalt electrolyzed solution in Comparative Example 4 was a hydrochloric acid electrolyte in which only hydrochloric acid was added to distilled water to adjust the pH to 1.6, and the scanning speed was 50 mV / s. The cyclic voltammogram was measured under the same conditions except for the change.
- Example 3 The cyclic voltammograms obtained in Example 3 and Comparative Example 5 are shown together in FIG. From FIG. 2, the chlorine generation anode of Example 3 has a chlorine generation current that is about four times larger at the same potential than that of Comparative Example 5, and the chlorine generation anode of Example 3 is more than that of Comparative Example 5. It was found that the overvoltage for chlorine generation was smaller and the catalytic activity was higher. That is, the chlorine generating anode (Example 3) in which the catalyst layer made of amorphous ruthenium oxide and amorphous tantalum oxide according to the present invention is formed is an amorphous material already disclosed in Patent Document 1 by the present inventor.
- Chlorine generation in hydrochloric acid electrolysis than the anode for chlorine generation (Comparative Example 5) in which a catalyst layer containing a solid solution of porous ruthenium oxide and amorphous titanium oxide (amorphous ruthenium and titanium composite oxide) is formed It was found that the potential of can be lowered.
- Example 4 A commercially available titanium plate (length 5 cm, width 1 cm, thickness 1 mm) was immersed in a 10% oxalic acid solution at 90 ° C. for 60 minutes for etching treatment, washed with water, and dried. Next, in a butanol (n-C 4 H 9 OH) solution containing 6 vol% concentrated hydrochloric acid, the molar ratio of ruthenium and tantalum is 80:20, and the total of ruthenium and tantalum is 70 g / L in terms of metal.
- a butanol (n-C 4 H 9 OH) solution containing 6 vol% concentrated hydrochloric acid
- This coating solution was applied to the dried titanium plate, dried at 120 ° C. for 10 minutes, and then thermally decomposed in an electric furnace maintained at 300 ° C. for 20 minutes. This coating, drying, and thermal decomposition were repeated 5 times in total to produce a chlorine generating anode in which a catalyst layer was formed on a titanium plate as a conductive substrate.
- Comparative Example 6 The chlorine generating anode of Comparative Example 6 was produced in the same manner as in Example 4 except that the thermal decomposition temperature when forming the catalyst layer was changed from 300 ° C to 500 ° C.
- the thermal decomposition temperature when forming the catalyst layer was changed from 300 ° C to 500 ° C.
- a diffraction peak corresponding to RuO 2 was observed in the X-ray diffraction image, but a diffraction peak corresponding to Ta 2 O 5 was observed. I could't.
- a Ti diffraction peak was observed, which was attributed to the titanium plate. That is, a catalyst layer made of crystalline ruthenium oxide and amorphous tantalum oxide was formed on the chlorine generating anode of Comparative Example 6.
- a saturated potassium chloride solution is filled in a container different from the NaCl aqueous solution, and a commercially available silver-silver chloride reference electrode is immersed therein, and the NaCl aqueous solution and the saturated potassium chloride solution are connected using a salt bridge and a Lugin tube.
- a three-electrode electrochemical cell was obtained. Using this electrochemical cell, between the chlorine evolution for the anode and cathode, the electrolysis by flowing either electrolysis current density 50 mA / cm 2 or 100 mA / cm 2 in electrode area basis chlorine generating anode While performing, the potential of the chlorine generating anode with respect to the reference electrode was measured.
- the NaCl aqueous solution was electrolyzed at 30 ° C. with stirring at 800 rpm using a stirring bar.
- Table 4 shows the anode potential when electrolysis was performed using the chlorine generating anode of Example 4 or Comparative Example 6 described above.
- the main reaction at the anode is chlorine generation in electrowinning, salt electrolysis, hydrochloric acid electrolysis, seawater electrolysis, compared with carbon electrode, lead electrode, lead alloy electrode, metal-coated titanium electrode, metal oxide-coated titanium electrode.
- the potential of the anode for chlorine generation is low, which can reduce the electrolysis voltage and the power consumption, and can be used as an anode for electrowinning, salt electrolysis, hydrochloric acid electrolysis, seawater electrolysis, etc.
- a certain chlorine generating anode can be provided.
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Abstract
Description
上記のような電解採取、食塩電解、塩酸電解、海水電解などに用いられる塩素発生用陽極としては、すでに述べたように酸化物被覆チタン電極、特に熱分解法で製造されたルテニウムとチタンの複合酸化物を含む触媒層でチタン基体を被覆した電極が用いられていることは周知である。このような塩素発生用陽極については、例えば、特許文献1~特許文献7に開示されている。
本発明の請求項1に記載の塩素発生用陽極は、水溶液からの塩素発生を陽極の主反応とする塩素発生用陽極であって、非晶質の酸化ルテニウムと非晶質の酸化タンタルを含む触媒層を導電性基体上に形成した構成を有している。
この構成により、
(1)非晶質の酸化ルテニウムと非晶質の酸化タンタルを含む触媒層は、幅広いpHの水溶液中における陽極反応としての塩素発生に対して選択的に高い触媒活性を示し、塩素発生に対する陽極の電位が著しく低くなるという作用を有する。
(2)非晶質のルテニウムとチタンの複合酸化物で被覆したチタン電極や、結晶質のルテニウムとチタンの複合酸化物で被覆したチタン電極よりも塩素発生に対する触媒活性が高く、電解採取、食塩電解、酸電解、海水電解といった電解の種類によらず、他の塩素発生用陽極を用いる場合に比べて、電解電圧を低減することができるという作用を有する。
(3)非晶質の酸化ルテニウムまたは非晶質の酸化イリジウムを含む触媒層を形成した陽極、特に非晶質のルテニウムとチタンの複合酸化物からなる触媒層を形成した陽極と比べても、さらに陽極の電位を低下させることが可能で、電解電圧を低減できるという、極めて特異な作用を有する。
(4)塩素発生に対する陽極の電位が低くなり、塩素発生が他の副反応に対して優先されることによって、オキシ水酸化コバルト、オキシ水酸化マンガン、二酸化鉛などの陽極での析出及び蓄積といった、陽極での副反応が抑制されるという作用を有する。
(5)ルテニウムはイリジウムに比べて1/3以下の価格であることから、非晶質の酸化イリジウムと非晶質の酸化タンタルを含む触媒層での塩素発生に対する触媒活性以上の高い触媒活性を、非晶質の酸化ルテニウムと非晶質の酸化タンタルを含むより安価な触媒層で達成することができるという作用を有する。
この構成により、請求項1で得られる作用に加え、
(1)陽極での主反応が塩素発生である電解採取、食塩電解、塩酸電解、海水電解において、炭素電極、鉛電極、鉛合金電極、金属被覆チタン電極、金属酸化物被覆チタン電極に比べて、塩素発生に対する陽極の電位が低く、それによって電解電圧の低減と、電力量原単位を削減することができるという作用を有する。
この構成により、請求項1又は2で得られる作用に加え、
(1)触媒層が、非晶質の酸化ルテニウムと非晶質の酸化タンタルとの混合物からなることによって、塩素発生用陽極に応用可能な耐久性が得られるという作用を有する。
この構成により、請求項1乃至3の内いずれか1項で得られる作用に加え、
(1)触媒層の高い電子導電性を維持し、かつ塩素発生に対する高い触媒活性と副反応に対する抑制効果を長時間保つことができるという作用を有する。
ここで、ルテニウムのモル比が90モル%よりも大きくなると、酸化タンタルの割合が少ないため酸化ルテニウムを触媒層中で安定化する効果が得られにくくなり、好ましくない。また、ルテニウムのモル比が10モル%よりも小さくなると、触媒層の電子導電性が低下するため電極自体の抵抗が大きくなり、これによる電圧上昇を引き起こす可能性があるため、好ましくない。
この構成により、請求項1乃至4の内いずれか1項で得られる作用に加え、
(1)触媒層と導電性基体の間に中間層が形成され、同時に導電性基体の表面を被覆していることによって、触媒層中に電解液が浸透しても、電解液が導電性基体に到達することを防止し、したがって導電性基体が酸性の電解液によって腐食することがなく、腐食生成物によって導電性基体と触媒層の間で電流が円滑に流れなくなることを抑制するという作用を有する。
(2)本発明の電解採取用陽極の触媒層とは異なる酸化物や複合酸化物からなる中間層を形成した場合は、非晶質の酸化ルテニウムと非晶質の酸化タンタルを含む触媒層に比べて酸素発生に対する触媒活性が低いため、触媒層中を電解液が浸透して中間層に至った場合でも、中間層では酸素発生が触媒層に比べて優先的に起こらないことから、触媒層よりも耐久性が高く、よって導電性基体を保護するという作用を有する。同時に、このようなより耐久性の高い酸化物または複合酸化物が導電性基体を被覆することで、中間層がない場合に比べて、電解液による導電性基体の腐食を抑制することができるという作用を有する。
この構成により、請求項5で得られる作用に加え、
(1)上記の金属または合金を中間層に用いることで、導電性基体の腐食を効果的に抑制することができるという作用を有する。
(2)熱分解法、スパッタリング法やCVD法など各種の物理蒸着法や化学蒸着法、溶融めっき法、電気めっき法などの様々な方法により中間層を形成することができ、量産性に優れる。
この構成により、請求項5で得られる作用に加え、
(1)触媒層中の酸化ルテニウムと中間層中の複合酸化物が同じ結晶系に属し、原子間距離が近いことから、中間層上に形成される触媒層との間の密着性がよく、よって耐久性が特に向上するという作用を有する。
この構成により、請求項5で得られる作用に加え、
(1)触媒層中の酸化ルテニウムと中間層中の酸化ルテニウムが同じ結晶系に属し、原子間距離が近いことから、中間層上に形成される触媒層との間の密着性がよく、よって耐久性が特に向上するという作用を有する。
この構成により、請求項5で得られる作用に加え、
(1)中間層が導電性ダイヤモンドであることにより、酸性水溶液に対する耐食性が非常に高いため、導電性基体の腐食を特に効果的に抑制できるという作用を有する。
1)水溶液からの塩素発生を主反応とする塩素発生用陽極において、従来に比べて、陽極における塩素発生の電位を低くすることができることから、電解採取、食塩電解、塩酸電解、海水電解などにおいて、幅広いpHの水溶液に対して、電解電圧を低減することが可能となり、これによって電力量原単位を大幅に削減できるという効果を有する。
2)また、従来に比べて、陽極における塩素発生の電位を低くすることができることから、陽極上で生じる可能性がある様々な副反応を抑制することが可能となり、例えば、コバルトの電解採取の副反応である陽極でのオキシ水酸化コバルトの電着及び蓄積が抑制されることで、長期間の電解において電解電圧の上昇を抑制することができるという効果を有する。
3)上記の効果とともに、副反応によって陽極上に析出及び蓄積する酸化物やその他の化合物を取り除く作業が必要なくなる、またはその作業が軽減されることから、このような作業による陽極のダメージが抑制され、したがって陽極の寿命が長くなるという効果を有する。
4)上記の効果とともに、副反応によって陽極上に析出及び蓄積した酸化物やその他の化合物を取り除く作業が不要、または少なくなることから、陽極のメンテナンス及び交換が抑制または軽減されるという効果を有する。また、除去作業が不要となる或いは少なくなることによって、電解を休止する必要性が抑えられるため、連続的かつより安定した電解が可能になるという効果を有する。
5)上記の効果とともに、陽極上への析出物が抑制されることにより、析出物によって陽極の有効表面積が制限されることや陽極での電解可能な面積が不均一となることを防ぐことができ、例えば、陰極上に金属が不均一に生成して電解採取で得られる金属の品質低下が発生することを抑制することができるという効果を有する。
6)また、上記のような理由で陰極上で不均一に成長した金属が、陽極に達してショートし、電解採取ができなくなることを防止することができるという効果を有する。また、陰極上で金属が不均一にかつデンドライト成長することが抑制されるため、陽極と陰極の極間距離を短くすることができ、電解液のオーム損による電解電圧の増加を抑制できるという効果を有する。
7)また、上記のように、副反応で生じる陽極上への析出物による様々な問題が解消されることによって、安定で連続的な電解が可能になり、保守及び管理作業を低減することができるとともに、電解採取で得られる金属の製品管理が容易になるという効果を有する。また、長期間の電解における陽極のコストを低減できるという効果を有する。
8)また、本発明によれば、従来の酸化イリジウムを含む触媒層を形成したチタン電極に比べて、酸化ルテニウムを用いることにより触媒層のコストが削減され、また熱分解温度が低いことから触媒層の形成工程におけるコストも削減されるという効果を有する。
(実施例1)
市販のチタン板(長さ5cm、幅1cm、厚さ1mm)を10%のシュウ酸溶液中に90℃で60分間浸漬してエッチング処理を行った後、水洗し、乾燥した。次に、6vol%の濃塩酸を含むブタノール(n-C4H9OH)溶液に、ルテニウムとタンタルのモル比が90:10で、ルテニウムとタンタルの合計が金属換算で50g/Lとなるように三塩化ルテニウム三水和物(RuCl3・3H2O)と五塩化タンタル(TaCl5)を添加した塗布液を調製した。この塗布液を上記乾燥後のチタン板に塗布し、120℃で10分間乾燥し、次いで260℃に保持した電気炉内で20分間、熱分解した。この塗布、乾燥、熱分解を計5回繰り返し行い、導電性基体であるチタン板上に触媒層を形成した実施例1の塩素発生用陽極を作製した。
比較例1の塩素発生用陽極は、触媒層を形成する際の熱分解温度を260℃から500℃に変えた以外は実施例1と同じ方法で作製した。比較例1の塩素発生用陽極をX線回折法により構造解析したところ、X線回折像にはRuO2に相当する回折ピークは見られたが、Ta2O5に相当する回折ピークは見られなかった。なお、Tiの回折ピークが見られたが、これはチタン板によるものであった。すなわち、比較例1の塩素発生用陽極には、結晶質の酸化ルテニウムと非晶質の酸化タンタルからなる触媒層が形成されていた。
市販のチタン板(長さ5cm、幅1cm、厚さ1mm)を10%のシュウ酸溶液中に90℃で60分間浸漬してエッチング処理を行った後、水洗し、乾燥した。次に、ブタノール(n-C4H9OH)溶液に、ルテニウムとチタンのモル比が30:70で、ルテニウムとチタンの合計が金属換算で70g/Lとなるように三塩化ルテニウム三水和物(RuCl3・3H2O)とチタニウム‐n‐ブトキシド(Ti(C4H9O)4)を添加した塗布液を調製した。この塗布液を上記乾燥後のチタン板に塗布し、120℃で10分間乾燥し、次いで500℃に保持した電気炉内で20分間熱分解した。この塗布、乾燥、熱分解を計5回繰り返し行い、導電性基体であるチタン板上に触媒層を形成した塩素発生用陽極を作製した。
比較例3の塩素発生用陽極は、触媒層を形成する際の熱分解温度を500℃から260℃に変えた以外は比較例2と同じ方法で作製した。比較例3の塩素発生用陽極をX線回折法により構造解析したところ、X線回折像には比較例2のようなルテニウムとチタンの複合酸化物に相当する回折ピークは見られなかった。なお、Tiの回折ピークが見られたが、これはチタン板によるものであった。すなわち、比較例3の塩素発生用陽極には、非晶質の酸化ルテニウムを含む非晶質のルテニウムとチタンの複合酸化物からなる触媒層が形成されていた。
(実施例2)
市販のチタン板(長さ5cm、幅1cm、厚さ1mm)を10%のシュウ酸溶液中に90℃で60分間浸漬してエッチング処理を行った後、水洗し、乾燥した。次に、6vol%の濃塩酸を含むブタノール(n-C4H9OH)溶液に、ルテニウムとタンタルのモル比が30:70で、ルテニウムとタンタルの合計が金属換算で50g/Lとなるように三塩化ルテニウム三水和物(RuCl3・3H2O)と五塩化タンタル(TaCl5)を添加した塗布液を調製した。この塗布液を上記乾燥後のチタン板に塗布し、120℃で10分間乾燥し、次いで280℃に保持した電気炉内で20分間熱分解した。この塗布、乾燥、熱分解を計5回繰り返し行い、導電性基体であるチタン板上に触媒層を形成した塩素発生用陽極を作製した。
比較例4の塩素発生用陽極は、触媒層を形成する際の熱分解温度を500℃から360℃に変えた以外は比較例2と同じ方法で作製した。比較例4の塩素発生用陽極をX線回折法により構造解析したところ、X線回折像にはルテニウムとチタンの複合酸化物に相当する弱くブロードな回折線が見られた。すなわち、比較例4の塩素発生用陽極の触媒層には非晶質のルテニウムとチタンの複合酸化物が含まれていた。次に、実施例2の塩素発生用陽極の代わりに比較例4の塩素発生用陽極を用いて、実施例2と同じ条件でサイクリックボルタモグラムを測定した。
(実施例3)
実施例2の塩素発生用陽極を用いて、実施例2におけるコバルト電解採取液を、蒸留水に塩酸のみを加えてpHを1.6に調整した塩酸電解液とし、走査速度を50mV/sに変えた以外の条件は同じとしてサイクリックボルタモグラムを測定した。
比較例4の塩素発生用陽極を用いて、比較例4におけるコバルト電解採取液を、蒸留水に塩酸のみを加えてpHを1.6に調整した塩酸電解液とし、走査速度を50mV/sに変えた以外の条件は同じとしてサイクリックボルタモグラムを測定した。
(実施例4)
市販のチタン板(長さ5cm、幅1cm、厚さ1mm)を10%のシュウ酸溶液中に90℃で60分間浸漬してエッチング処理を行った後、水洗し、乾燥した。次に、6vol%の濃塩酸を含むブタノール(n-C4H9OH)溶液に、ルテニウムとタンタルのモル比が80:20で、ルテニウムとタンタルの合計が金属換算で70g/Lとなるように三塩化ルテニウム三水和物(RuCl3・3H2O)と五塩化タンタル(TaCl5)を添加した塗布液を調製した。この塗布液を上記乾燥後のチタン板に塗布し、120℃で10分間乾燥し、次いで300℃に保持した電気炉内で20分間熱分解した。この塗布、乾燥、熱分解を計5回繰り返し行い、導電性基体であるチタン板上に触媒層を形成した塩素発生用陽極を作製した。
比較例6の塩素発生用陽極は、触媒層を形成する際の熱分解温度を300℃から500℃に変えた以外は実施例4と同じ方法で作製した。比較例6の塩素発生用陽極をX線回折法により構造解析したところ、X線回折像にはRuO2に相当するするどい回折ピークは見られたが、Ta2O5に相当する回折ピークは見られなかった。なお、Tiの回折ピークが見られたが、これはチタン板によるものであった。すなわち、比較例6の塩素発生用陽極には、結晶質の酸化ルテニウムと非晶質の酸化タンタルからなる触媒層が形成されていた。
Claims (9)
- 水溶液からの塩素発生を陽極の主反応とする塩素発生用陽極であって、非晶質の酸化ルテニウムと非晶質の酸化タンタルを含む触媒層を導電性基体上に形成したものであることを特徴とする塩素発生用陽極。
- 電解採取、食塩電解、酸電解、海水電解のうち、いずれか1つに用いられることを特徴とする請求項1に記載の塩素発生用陽極。
- 前記触媒層が非晶質の酸化ルテニウムと非晶質の酸化タンタルとの混合物からなることを特徴とする請求項1または2に記載の塩素発生用陽極。
- 前記触媒層におけるルテニウムとタンタルのモル比が90:10~10:90であることを特徴とする請求項1~3のいずれかに記載の塩素発生用陽極。
- 前記触媒層と前記導電性基体の間に、中間層が形成されていることを特徴とする請求項1~4のいずれかに記載の塩素発生用陽極。
- 前記中間層が、タンタル、ニオブ、タングステン、モリブデン、チタン、白金、またはこれらのいずれかの金属の合金からなることを特徴とする請求項5に記載の塩素発生用陽極。
- 前記中間層が、結晶質のルテニウムとチタンの複合酸化物を含むことを特徴とする請求項5に記載の塩素発生用陽極。
- 前記中間層が、結晶質の酸化ルテニウムと非晶質の酸化タンタルを含むことを特徴とする請求項5に記載の塩素発生用陽極。
- 前記中間層が、導電性ダイヤモンドであることを特徴とする請求項5に記載の塩素発生用陽極。
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US14/344,757 US20140231249A1 (en) | 2011-09-13 | 2012-08-31 | Chlorine evolution anode |
RU2014114537/02A RU2561565C1 (ru) | 2011-09-13 | 2012-08-31 | Анод для выделения хлора |
CN201280044502.3A CN103797160B (zh) | 2011-09-13 | 2012-08-31 | 析氯用阳极 |
KR1020147009682A KR101577668B1 (ko) | 2011-09-13 | 2012-08-31 | 염소 발생용 양극 |
EP12831872.2A EP2757179B1 (en) | 2011-09-13 | 2012-08-31 | Chlorine-generating positive electrode |
US15/048,019 US20160168733A1 (en) | 2011-09-13 | 2016-02-19 | Chlorine evolution anode |
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WO2013151704A1 (en) * | 2012-04-02 | 2013-10-10 | The Board Of Trustees Of The Leland Stanford Junior University | Water sterilization devices and uses thereof |
WO2015122330A1 (ja) * | 2014-02-12 | 2015-08-20 | 学校法人同志社 | イオンセンサ用触媒およびこれを用いたイオンセンサならびに定量法 |
TWI679256B (zh) * | 2014-07-28 | 2019-12-11 | 義商第諾拉工業公司 | 閥金屬表面之塗料及其製法 |
KR101769526B1 (ko) | 2015-03-23 | 2017-08-21 | 서울대학교산학협력단 | 금속 산화물 전극을 이용한 축전식 탈염장치 |
CN105208202B (zh) * | 2015-08-27 | 2017-08-01 | 广东欧珀移动通信有限公司 | 一种联系人管理方法及移动终端 |
RU2657747C2 (ru) * | 2016-04-20 | 2018-06-15 | Общество с ограниченной ответственностью "БИНАКОР-ХТ" (ООО "БИНАКОР-ХТ") | Анод электролизера для получения порошков сплавов металлов |
US20180266761A1 (en) * | 2017-03-20 | 2018-09-20 | Larry Baxter | Self-Cleaning Desublimating Heat Exchanger for Gas/Vapor Separation |
CN107419292B (zh) * | 2017-04-10 | 2019-12-13 | 广东卓信环境科技股份有限公司 | 一种透气析氯电极的制备方法 |
CN108048862B (zh) * | 2017-11-16 | 2020-04-28 | 江苏安凯特科技股份有限公司 | 一种析氯用阳极及其制备方法 |
CN108048865B (zh) * | 2017-11-17 | 2020-04-28 | 江苏安凯特科技股份有限公司 | 一种电极及其制备方法和应用 |
IT201800006544A1 (it) * | 2018-06-21 | 2019-12-21 | Anodo per evoluzione elettrolitica di cloro | |
CN110387558B (zh) * | 2019-07-26 | 2020-11-24 | 浙江工业大学 | 一种钌钽析氯电极及其制备方法和测试方法 |
CN110438527A (zh) * | 2019-08-05 | 2019-11-12 | 上海氯碱化工股份有限公司 | 过渡金属掺杂的含钌涂层阳极的制备方法 |
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CN112897650B (zh) * | 2021-04-25 | 2022-09-06 | 清华大学 | 一种废水处理装置、其制备方法及处理废水的方法 |
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CN103797160B (zh) | 2016-03-16 |
EP2757179A4 (en) | 2015-05-20 |
KR101577668B1 (ko) | 2015-12-15 |
EP2757179A1 (en) | 2014-07-23 |
US20140231249A1 (en) | 2014-08-21 |
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