WO2018096851A1 - 電極材料及びその製造方法 - Google Patents
電極材料及びその製造方法 Download PDFInfo
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- WO2018096851A1 WO2018096851A1 PCT/JP2017/037836 JP2017037836W WO2018096851A1 WO 2018096851 A1 WO2018096851 A1 WO 2018096851A1 JP 2017037836 W JP2017037836 W JP 2017037836W WO 2018096851 A1 WO2018096851 A1 WO 2018096851A1
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- oxide
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/88—Processes of manufacture
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/90—Selection of catalytic material
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/90—Selection of catalytic material
- H01M4/9075—Catalytic material supported on carriers, e.g. powder carriers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/90—Selection of catalytic material
- H01M4/92—Metals of platinum group
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/90—Selection of catalytic material
- H01M4/92—Metals of platinum group
- H01M4/921—Alloys or mixtures with metallic elements
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/90—Selection of catalytic material
- H01M4/92—Metals of platinum group
- H01M4/925—Metals of platinum group supported on carriers, e.g. powder carriers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/10—Fuel cells with solid electrolytes
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/10—Fuel cells with solid electrolytes
- H01M2008/1095—Fuel cells with polymeric electrolytes
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Definitions
- the present invention relates to an electrode material and a manufacturing method thereof.
- a fuel cell is a device that generates electric power by electrochemically reacting a fuel such as hydrogen or alcohol with oxygen, and depending on the electrolyte, operating temperature, etc., polymer electrolyte (PEFC), phosphoric acid (PAFC), It is divided into molten carbonate form (MCFC) and solid oxide form (SOFC).
- PEFC polymer electrolyte
- PAFC phosphoric acid
- MCFC molten carbonate form
- SOFC solid oxide form
- a polymer electrolyte fuel cell is a fuel cell that uses an ion conductive polymer membrane (ion exchange membrane) as an electrolyte, but is used for stationary power sources and fuel cell vehicle applications, There is a need to maintain desired power generation performance over a long period of time.
- a carbon having a high conductivity also referred to as electric conductivity
- a material in which fine platinum is supported thereon has a high electrochemical characteristic, and thus is generally used as an electrode material.
- Patent Document 1 a carbon having a high conductivity (also referred to as electric conductivity) as a carrier and a material in which fine platinum is supported thereon has a high electrochemical characteristic, and thus is generally used as an electrode material.
- Patent Document 1 a carbon having a high conductivity (also referred to as electric conductivity) as a carrier and a material in which fine platinum is supported thereon has a high electrochemical characteristic, and thus is generally used as an electrode material.
- JP 2012-17490 A International Publication No. 2011/066451 JP 2004-363056 A
- a material in which platinum is supported on a carbon support (hereinafter also referred to as “Pt / C”) is generally used as the electrode material (see Patent Document 1).
- Pt / C a material in which platinum is supported on a carbon support
- the carbon carrier oxidation reaction (C + 2H 2 O ⁇ CO 2 + 4H + + 4e ⁇ ) may proceed.
- the potential of the electrode exceeds 0.9 V
- the oxidation reaction of the carbon support carrying platinum is likely to proceed. In this case, aggregation or loss of the supported platinum occurs, and the effective electrode area is reduced, so that the battery performance is improved. It will be significantly reduced (see Patent Documents 2 and 3).
- an electrode that can withstand large load fluctuations caused by starting and stopping, etc. is required, but the actual situation is that a separate control device is installed so that the potential of the electrode falls below 0.9V. It is.
- the electrode material is required to have resistance to the strongly acidic environment.
- Patent Document 2 discloses an electrode catalyst in which a noble metal and / or an alloy containing a noble metal is supported on an electrode catalyst carrier that is a metal oxide primary particle fusion, and titanium oxide is disclosed as a metal oxide. Yes.
- titanium oxide (TiO 2 ) has a problem in that the conductivity is not sufficient.
- Patent Document 2 also describes that conductivity is imparted by doping niobium into titanium oxide, but there is concern about the possibility of elution of the dopant out of the particles and the influence on the power generation characteristics of the fuel cell. There is a need to.
- titanium oxide having a magnetic phase structure represented by Ti n O 2n-1 (n ⁇ 4), particularly Ti 4 O 7 is not included in carbon as an oxide that does not contain a metal element dopant and exhibits conductivity. It is known to have comparable high conductivity.
- Ti 4 O 7 is synthesized by reducing (deoxygenating) the raw material titanium oxide (TiO 2 ) at a high temperature of 900 ° C. or higher, it has been obtained as a Ti 4 O 7 single phase so far. Since the particles proceeded by heat treatment at a high temperature, the specific surface area was as low as about 1 m 2 / g.
- the present invention provides an electrode material that is excellent in resistance to a high potential and strongly acidic environment, has high conductivity, and has high electrochemical characteristics, and a fuel cell using the same.
- Another object of the present invention is to provide a production method for easily and easily obtaining such an electrode material.
- titanium suboxide especially Ti 4 O 7 as a carrier that can replace carbon as an electrode material
- titanium oxide described in the present specification means titanium oxide (also referred to as titanium dioxide) distributed in the normal market, and specifically, in qualitative tests such as X-ray diffraction measurement. This refers to what is called “TiO 2 ”.
- the present invention provides an electrode material having a structure in which a noble metal and / or an oxide thereof is supported on a titanium suboxide support having a crystal phase of Ti 4 O 7 single phase and a specific surface area of 10 m 2 / g or more. It is.
- the noble metal is at least one metal selected from the group consisting of platinum, ruthenium, iridium, rhodium and palladium, and preferably has an average primary particle diameter of 1 to 20 nm, and the noble metal is platinum. It is more preferable.
- the electrode material is preferably an electrode material for a polymer electrolyte fuel cell.
- the present invention is also a fuel cell comprising an electrode composed of the above electrode material.
- the present invention further provides a method for producing the above electrode material, which obtains a titanium suboxide support having a crystal phase of Ti 4 O 7 single phase and a specific surface area of 10 m 2 / g or more.
- Step (1) and Step (2) for supporting the noble metal and / or oxide thereof using a mixed solution containing the titanium suboxide support obtained in step (1) and the noble metal and / or water-soluble compound thereof. It is also a manufacturing method of the electrode material containing.
- the step (1) is preferably a step of firing a dry mixture containing a rutile-type titanium oxide having a specific surface area of 20 m 2 / g or more and titanium metal and / or titanium hydride in a hydrogen atmosphere.
- the electrode material of the present invention is excellent in resistance to a high potential and strong acid environment, and has high conductivity equal to or higher than that of a material in which platinum is supported on a conventionally used carbon support, and has high electrochemical characteristics. It is what has. Therefore, it is useful as an electrode material for fuel cells such as solid polymer fuel cells, and display devices such as solar cells, transistors, and liquid crystals. Especially, it is extremely useful for a polymer electrolyte fuel cell. Since the manufacturing method of the present invention can provide such an electrode material easily and simply, it can be said that it is an industrially extremely advantageous technique.
- FIG. 2 is a powder X-ray diffraction pattern of the powder obtained in Example 1.
- FIG. 2 is a transmission electron microscope (abbreviated as TEM) photograph of the powder obtained in Example 1.
- FIG. 3 is a powder X-ray diffraction pattern of the powder obtained in Example 2.
- 3 is a TEM photograph of powder obtained in Example 2.
- 2 is a powder X-ray diffraction pattern of the powder obtained in Comparative Example 1.
- 4 is a TEM photograph of powder obtained in Comparative Example 1.
- 4 is a powder X-ray diffraction pattern of the powder obtained in Comparative Example 2.
- 4 is a TEM photograph of powder obtained in Comparative Example 2.
- 4 is a powder X-ray diffraction pattern of the powder obtained in Comparative Example 3.
- 4 is a TEM photograph of powder obtained in Comparative Example 3.
- 4 is a powder X-ray diffraction pattern of the powder obtained in Comparative Example 4.
- 4 is a TEM photograph of powder obtained in Comparative Example 4.
- 6 is a powder X-ray diffraction pattern of the powder obtained in Comparative Example 5.
- 6 is a TEM photograph of powder obtained in Comparative Example 5. It is XRD data analysis explanatory drawing for determining a crystal phase.
- Electrode Material of the present invention has a structure in which a noble metal and / or an oxide thereof is supported on a titanium suboxide support.
- the titanium suboxide support has a crystal phase of Ti 4 O 7 single phase.
- crystalline phase is a Ti 4 O 7 single phase
- the electrode material, a noble metal and / or X-ray diffraction (XRD) measurement pattern in measured in the state where the oxide is supported, Ti 4 This means an electrode material in which O 7 is present and other titanium oxides are not present.
- the other titanium oxides include anatase type, brookite type or rutile type titanium oxide, and Ti n O 2n-1 (n Represents a compound represented by 2 or an integer of 5 to 9. As shown in FIG.
- the determination is made by the following method. If there is a lot of noise in the entire XRD measurement data, use the analysis software attached to the XRD (for example, powder X-ray diffraction pattern comprehensive analysis software JADE7J attached to the Rigaku X-ray diffractometer (RINT-TTR3)). The following determination may be made after performing smoothing and background removal.
- the analysis software attached to the XRD for example, powder X-ray diffraction pattern comprehensive analysis software JADE7J attached to the Rigaku X-ray diffractometer (RINT-TTR3). The following determination may be made after performing smoothing and background removal.
- Ti 4 O 7 If there are peaks at 26.0 to 26.6 ° and 20.4 to 21.0 ° in the pattern, it is determined that Ti 4 O 7 is present. At this time, the ratio of the intensity of the maximum peak existing at 20.4 to 21.0 °, where the intensity of the maximum peak existing at 26.0 to 26.6 ° is 100, is preferably more than 10. More than 20 is more preferable.
- Ti n O 2n-1 (n represents an integer of 5 to 9) and rutile titanium oxide>
- the intensity of the maximum peak existing at 26.0 to 26.6 ° is 100, and if the intensity ratio of 27.7 ° is 15 or less, it can be distinguished from the peaks and noises of other titanium oxides. Therefore, it is determined that Ti n O 2n-1 (n represents an integer of 5 to 9) and rutile titanium oxide do not exist.
- Ti 2 O 3 When the ratio of the intensity of the maximum peak existing at 23.5 to 24.1 ° to the intensity 100 of the maximum peak existing at 26.0 to 26.6 ° in the pattern is 15 or less, other titanium oxides Since it cannot be distinguished from an object peak and noise, it is determined that Ti 2 O 3 does not exist.
- the titanium suboxide support has a specific surface area of 10 m 2 / g or more.
- the specific surface area is in this range, it can be said that it is a level that can be suitably used practically as an electrode material.
- the electrode material of the present invention is It exceeds 10 m 2 / g. Further, for example, it is also suitable for an automotive fuel cell application that requires an electrode that can withstand a large load fluctuation.
- the specific surface area is preferably 13 m 2 / g or more, more preferably 16 m 2 / g or more.
- a noble metal such as platinum
- / or an oxide thereof can be supported with a suitable primary particle size.
- the range of the specific surface area preferable as the electrode material is the same.
- the specific surface area (also referred to as SSA) means the BET specific surface area.
- the BET specific surface area refers to a specific surface area obtained by the BET method, which is one method for measuring the specific surface area.
- the specific surface area refers to the surface area per unit mass of a certain object.
- the BET method is a gas adsorption method in which gas particles such as nitrogen are adsorbed on solid particles and the specific surface area is measured from the amount adsorbed.
- a specific surface area can be calculated
- the average primary particle diameter of the titanium suboxide support is preferably 20 to 200 nm. Within this range, better electrochemical properties can be obtained. Further, the resistance at the particle interface is sufficiently reduced, and better conductivity can be obtained. More preferably, it is 30 to 150 nm.
- carrier can be calculated
- the noble metal supported on the titanium suboxide support is not particularly limited, but from the viewpoint of easily and stably performing the catalytic reaction of the electrode, from the group consisting of platinum, ruthenium, iridium, rhodium and palladium. It is preferred that it is at least one metal selected. Among these, platinum is more preferable.
- the noble metal is supported, the specific surface area of the electrode material becomes larger than the specific surface area of the titanium suboxide support.
- the noble metal and / or oxide thereof preferably has an average primary particle size of 1 to 20 nm.
- the preferred average particle diameter of the precious metal and / or oxide thereof varies depending on the design concept of the fuel cell. For example, when obtaining a high current density, 1 to 5 nm is more preferable, and when importance is attached to the durability of the electrode, 5 to 20 nm is more preferable.
- the average primary particle diameter of a noble metal is calculated
- the average primary particle diameter of the noble metal and / or oxide thereof is 30% of the average primary particle diameter of the titanium suboxide support. The following is preferable.
- the amount of the noble metal and / or oxide thereof supported is preferably 0.01 to 30 parts by weight in terms of elements of the noble metal based on 100 parts by weight of the titanium suboxide support (when two or more kinds are used, the total amount thereof) It is preferable that the loading amount of is in this range). Thereby, a noble metal and / or its oxide are disperse
- the noble metal generates an alloy depending on the manufacturing conditions described later, but it may further improve conductivity and electrochemical characteristics, so even if a part or the whole of the platinum particles is an alloy with titanium. I do not care.
- the noble metal and / or its oxide may further contain at least one metal selected from the group consisting of nickel, cobalt, iron, copper and manganese.
- the electrode material of the present invention is excellent in resistance to a high potential and strong acid environment, and has high conductivity equal to or higher than that of a material in which platinum is supported on a conventionally used carbon support, and has high electrochemical characteristics. Therefore, it can be suitably used for electrode material applications of display devices such as fuel cells, solar cells, transistors, and liquid crystals. Especially, it is suitable for the electrode material use for polymer electrolyte fuel cells (PEFC).
- PEFC polymer electrolyte fuel cells
- the embodiment in which the electrode material is an electrode material of a polymer electrolyte fuel cell is one of the preferred embodiments of the present invention, and a fuel cell including an electrode composed of the electrode material is included in the present invention. Is included.
- the electrode material of the present invention comprises a step (1) of obtaining a titanium suboxide support having a crystal phase of Ti 4 O 7 single phase and a specific surface area of 10 m 2 / g or more, and a step Using the titanium suboxide support obtained in (1) and the noble metal and / or water-soluble compound thereof, the production method comprising the step (2) of supporting the noble metal and / or oxide thereof is easily and easily obtained. be able to.
- This manufacturing method may further include one or more other steps that are employed during normal powder production, as necessary. Hereinafter, each step will be further described.
- Step (1) is a step of obtaining a titanium suboxide support having a specific surface area of 10 m 2 / g or more and a crystal phase of Ti 4 O 7 single phase.
- a titanium suboxide support having a specific surface area of 10 m 2 / g or more and a crystal phase of Ti 4 O 7 single phase.
- Ti 4 O 7 having a specific surface area in this range and having a single crystal phase for a noble metal and / or oxide supporting step (step (2))
- a high potential and strongly acidic environment is obtained.
- the specific surface area of the titanium suboxide support is preferably 13 m 2 / g or more, more preferably 16 m 2 / g or more.
- the step (1) is not particularly limited as long as it can provide the above-described titanium suboxide support.
- the step (1) is a step of firing a raw material mixture containing titanium oxide and / or titanium hydroxide in a reducing atmosphere. preferable.
- titanium oxide or titanium hydroxide is used, impurities contained in the production of the electrode material are reduced, and these are easily available, and are excellent in terms of stable supply.
- a rutile-type titanium oxide having a specific surface area of 20 m 2 / g or more is used, whereby a titanium suboxide support having a large specific surface area and a crystal phase of Ti 4 O 7 single phase is more preferable. Obtained efficiently. More preferably, rutile type titanium oxide having a specific surface area of 50 m 2 / g or more is used.
- a reducing aid may be added to the raw material mixture.
- reducing aids include metal titanium, titanium hydride, sodium borohydride, and the like, among which metal titanium and titanium hydride are preferable. Titanium metal and titanium hydride may be used in combination.
- a titanium suboxide support whose crystal phase is a Ti 4 O 7 single phase can be obtained more efficiently.
- the content of metal titanium is preferably 5 to 50 parts by weight with respect to 100 parts by weight of titanium oxide and / or titanium hydroxide (the total amount when two or more are used). More preferably, it is 10 to 40 parts by weight.
- the raw material mixture may also contain other optional components as long as the effects of the present invention are not impaired.
- Other optional components include, for example, compounds containing elements belonging to Groups 1 to 15 of the periodic table. Among them, for example, at least one selected from the group consisting of nickel, cobalt, iron, copper and manganese Compounds containing metals are preferred. Specifically, it is preferable that these elements contain oxides, hydroxides, chlorides, carbonates, sulfates, nitrates, nitrites and the like.
- the said raw material mixture can be obtained by mixing the component mentioned above with a normal mixing method, it is suitable to employ
- the raw material mixture is subjected to firing in a reducing atmosphere. At that time, the raw material mixture may be fired as it is, or when the raw material mixture contains a solvent, it may be fired after removing the solvent. .
- the reducing atmosphere is not particularly limited, and examples thereof include a hydrogen (H 2 ) atmosphere, a carbon monoxide (CO) atmosphere, an ammonia (NH 3 ) atmosphere, and a mixed gas atmosphere of hydrogen and an inert gas.
- a hydrogen atmosphere since the said titanium suboxide support
- the hydrogen atmosphere at this time may contain carbon monoxide and ammonia. Therefore, particularly preferably as the step (1), a dry mixture containing rutile type titanium oxide (preferably, rutile type titanium oxide having a specific surface area in a predetermined range as described above) and metal titanium is fired in a hydrogen atmosphere. It is a process.
- Firing may be performed only once, or may be performed twice or more. Even in the case of performing it twice or more, it is preferable to carry out any step under a reducing atmosphere (preferably a hydrogen atmosphere).
- a reducing atmosphere preferably a hydrogen atmosphere.
- the firing temperature depends on the conditions of the reducing atmosphere, such as the hydrogen concentration, but is preferably 500 ° C. to 1100 ° C., for example. Thereby, it becomes possible to make a high specific surface area and high electroconductivity more compatible in the electrode material obtained.
- the lower limit of the firing temperature is more preferably 600 ° C or higher, still more preferably 650 ° C or higher, and the upper limit is more preferably 1050 ° C or lower, still more preferably 900 ° C or lower, particularly preferably 850 ° C or lower.
- the firing temperature means the highest temperature reached in the firing step.
- the firing time that is, the holding time at the firing temperature is also preferably 5 minutes to 100 hours, for example, depending on the conditions of the reducing atmosphere such as the concentration of hydrogen.
- the firing time is within this range, the reaction proceeds more sufficiently and the productivity is excellent. More preferably, it is 30 minutes to 24 hours, still more preferably 60 minutes to 10 hours, and particularly preferably 2 to 10 hours.
- finish of baking you may carry out by mixing or substituting gas (for example, nitrogen gas) other than hydrogen.
- Step (2) uses a mixed solution containing the titanium suboxide support obtained in step (1) and a noble metal and / or a water-soluble compound thereof (hereinafter also collectively referred to as a noble metal compound), and uses the mixed solution. This is a step of supporting an oxide. After the step (1), before the step (2), one or more other steps such as pulverization, washing with water, and classification may be included as necessary. Other steps are not particularly limited.
- the mixed solution includes the titanium suboxide support obtained in the step (1) and the noble metal compound.
- the mixed solution includes, for example, a slurry containing the titanium suboxide support obtained in the step (1), and a noble metal. It is preferably obtained by mixing with a solution of the compound. By using this mixed solution, the noble metal and / or oxide thereof can be supported in a higher dispersion.
- each content component of a liquid mixture can each be used 1 type or 2 types or more.
- the method for obtaining the mixed solution that is, the method for mixing the components is not particularly limited.
- a method of adding a solution of a noble metal compound and stirring and mixing the slurry containing a titanium suboxide support in a container Is mentioned.
- the temperature at the time of addition is preferably 40 ° C. or less, and it is preferable to heat the mixture to a predetermined temperature while stirring and mixing.
- Mixing may be carried out using a stirrer with a stirrer, or using a stirrer equipped with a propeller type or cocoon type stirring blade.
- the slurry further contains a solvent.
- a solvent for example, water, an acidic solvent, an organic solvent, and these mixtures are mentioned.
- the organic solvent include alcohol, acetone, dimethyl sulfoxide, dimethylformamide, tetrahydrofuran, dioxane, etc.
- examples of the alcohol include monovalent water-soluble alcohols such as methanol, ethanol, propanol; ethylene glycol, glycerin, and the like. Dihydric or higher water-soluble alcohols; and the like.
- the solvent is preferably water, and more preferably ion-exchanged water.
- the content of the solvent is not particularly limited. For example, 100 to 100000 weights per 100 parts by weight of the solid content of the titanium suboxide support obtained in step (1) (the total solid content when two or more types are used). Part. Thereby, an electrode material can be obtained more simply. More preferred is 500 to 50000 parts by weight, and still more preferred is 1000 to 30000 parts by weight.
- the slurry may also contain additives such as acids, alkalis, chelate compounds, organic dispersants, and polymer dispersants. Inclusion of these additives is expected to improve the dispersibility of the titanium suboxide support contained in the slurry.
- the noble metal compound solution is not particularly limited as long as it is a solution containing a noble metal compound (that is, a noble metal and / or a water-soluble compound thereof).
- a noble metal compound that is, a noble metal and / or a water-soluble compound thereof.
- inorganic salts such as sulfates, nitrates, chlorides, and phosphates of noble metals.
- examples thereof include solutions of salts; organic acid salts such as acetates and oxalates of noble metals; and dispersion solutions of nano-sized noble metals.
- a solution such as a chloride solution, a nitrate solution, a dinitrodiammine nitric acid solution, and a bis (acetylacetonato) platinum (II) solution is preferable.
- the noble metal is as described above, and platinum is particularly preferable. Therefore, the chloroplatinic acid aqueous solution and the dinitrodiammine platinum nitric acid aqueous solution are particularly preferable as the noble metal solution, and the chloroplatinic acid aqueous solution is most preferable from the viewpoint of reactivity.
- the amount of the noble metal solution used is not particularly limited, but is preferably 0.01 to 50 parts by weight with respect to 100 parts by weight of the total solid content of the titanium suboxide support in terms of elements of the noble metal. Thereby, a noble metal and / or its oxide can be disperse
- reduction treatment, surface treatment and / or neutralization treatment may be performed on the mixed solution as necessary.
- a reduction process it is preferable to reduce a noble metal compound moderately by adding a reducing agent to a liquid mixture.
- a surfactant it is preferable to add a surfactant to the mixed solution, whereby the surface of the titanium suboxide support or the noble metal compound can be brought into an optimum state.
- a neutralization process it is preferable to carry out by adding a basic solution to a liquid mixture.
- the reducing agent is not particularly limited.
- the addition amount is not particularly limited, but is preferably 0.1 to 1 times the molar equivalent of the noble metal contained in the mixed solution.
- an anionic surfactant an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant, or the like can be used. These are not particularly limited.
- examples of the anionic surfactant include carboxylate type anionic surfactants such as soap, sulfonate type such as sodium lauryl sulfate, and sulfate esters such as lauryl sulfate sodium salt. Salt.
- examples of cationic surfactants include quaternary ammonium salt types such as polydimethyldiallylammonium chloride and amine salt types such as dihydroxyethyl stearylamine.
- amphoteric surfactants include amino acid types such as methyl laurylaminopropionate and betaine types such as lauryl dimethyl betaine.
- nonionic surfactant include polyethylene glycol types such as polyethylene glycol nonylphenyl ether, polyvinyl alcohol, and polyvinyl pyrrolidone.
- the addition amount is not particularly limited, but is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 5.0 parts by weight with respect to 100 parts by weight of the total amount of the titanium suboxide support. Part.
- the basic solution but is not particularly limited, aqueous NaOH, NH 3 aq, sodium carbonate aqueous solution and the like, preferably aqueous NaOH.
- the neutralization temperature in the neutralization step is preferably 60 ° C to 100 ° C, more preferably 70 ° C to 100 ° C.
- step (2) water and by-products (both by-products, as described above, which may be subjected to reduction treatment, surface treatment and / or neutralization treatment as necessary). Is preferably removed.
- the removing means is not particularly limited, but it is preferable to remove moisture and by-products by, for example, filtration, washing with water, drying, evaporation under heating, and the like.
- the by-product is preferably removed by washing with water. If a by-product remains in the electrode material, it may elute into the system during operation of the polymer electrolyte fuel cell, which may cause deterioration of power generation characteristics or damage to the system.
- the washing method is not particularly limited as long as it is a method capable of removing a water-soluble substance not supported on the titanium suboxide support out of the system, and includes washing with filtration and decantation. At this time, it is preferable to remove by-products by washing with water until the electric conductivity of the washing water becomes 10 ⁇ S / cm or less. More preferably, washing with water is performed until the conductivity becomes 3 ⁇ S / cm or less.
- the powder is fired after removing water and by-products from the mixed solution.
- a noble metal with low crystallinity and its oxide which are less likely to exhibit electrochemical characteristics, can have a crystallinity suitable for the expression of electrochemical characteristics.
- the degree of crystallinity should just be a grade which can confirm the peak originating in a noble metal or its oxide in XRD.
- the firing temperature is not particularly limited, but is preferably 500 to 900 ° C., for example.
- the firing time is not particularly limited, but for example, it is preferably 30 minutes to 24 hours.
- the noble metal or its oxide and the titanium suboxide support can be brought into a bonded state suitable for the expression of electrochemical characteristics.
- a suitable bonding state can be confirmed by the fact that, in XRD, the peak derived from the noble metal or its oxide is shifted to the high angle side or the low angle side as compared with the case where it is not fired in a reducing atmosphere. Preferably, it is shifted to the high angle side.
- the step (2) is particularly preferably a step of firing the powder obtained by reducing and then filtering and drying the mixed solution containing the titanium suboxide support and the noble metal compound obtained in the step (1).
- the fuel cell The electrode material of the present invention and the electrode material obtained by the production method of the present invention can be suitably used for electrode materials for fuel cells. Especially, it is suitable for the electrode material use for a polymer electrolyte fuel cell (PEFC). In particular, it is useful as an alternative material for a material in which platinum is supported on a carbon carrier that has been generally used. Such an electrode material is suitable for both a positive electrode (also referred to as an air electrode) and a negative electrode (also referred to as a fuel electrode), and is suitable for both a cathode (anode) and an anode (cathode).
- a polymer electrolyte fuel cell using the electrode material of the present invention or the electrode material obtained by the production method of the present invention is one of the preferred embodiments of the present invention.
- Example 1 Rutile type titanium oxide (made by Sakai Chemical Industry Co., Ltd., trade name “STR-100N”, specific surface area 100 m 2 / g) 2.0 g and titanium metal (made by Wako Pure Chemical Industries, trade name “Titanium, Powder”) After 3 g of dry mixing, the temperature was raised to 700 ° C. over 70 minutes in a hydrogen atmosphere, held at 700 ° C. for 6 hours, cooled to room temperature, and the titanium oxide whose crystal phase was represented by Ti 4 O 7 A carrier was obtained. 0.7 g of the obtained titanium suboxide support and 114 g of ion-exchanged water were weighed and mixed in a beaker to obtain a titanium suboxide support slurry.
- STR-100N specific surface area 100 m 2 / g
- titanium metal made by Wako Pure Chemical Industries, trade name “Titanium, Powder”
- Example 2 A titanium suboxide support slurry was obtained in the same manner as in Example 1.
- 0.9 g of an aqueous chloroplatinic acid solution (15.343% as platinum, manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) was diluted with 5.3 g of ion-exchanged water, and then hydrazine chloride (manufactured by Tokyo Chemical Industry Co., Ltd., trade name “ Hydrazine Dihydrochloride ”) 0.037 g was added, and a mixture obtained by stirring and mixing was prepared (this is referred to as“ mixed aqueous solution ”).
- aqueous chloroplatinic acid solution 15.343% as platinum, manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.
- hydrazine chloride manufactured by Tokyo Chemical Industry Co., Ltd., trade name “ Hydrazine Dihydrochloride ”
- Comparative Example 1 20.00 g of anatase type titanium oxide sol (manufactured by Sakai Chemical Industry Co., Ltd., trade name “CSB”, specific surface area 280 m 2 / g) is stirred while being heated to a liquid temperature of 80 ° C. Obtained. After dry-mixing 5.0 g of the obtained powder A and 0.75 g of metal titanium (trade name “titanium, powder” manufactured by Wako Pure Chemical Industries, Ltd.), the temperature was raised to 900 ° C. over 270 minutes in a hydrogen atmosphere. After maintaining at 900 ° C. for 10 hours, the mixture was cooled to room temperature to obtain a titanium suboxide support whose crystal phase was represented by Ti 4 O 7 .
- CSB specific surface area 280 m 2 / g
- titanium suboxide support slurry 0.9 g of the obtained titanium suboxide support and 40 g of ethanol were weighed and mixed in a beaker to obtain a titanium suboxide support slurry. While stirring the titanium suboxide support slurry, 0.14 g of bis (acetylacetonato) platinum (II) (manufactured by NE Chemcat, 49.5% as platinum) was added, and then the mixture was heated and held at a liquid temperature of 60 ° C. While stirring, all the liquid was evaporated to obtain powder 3.
- II bis (acetylacetonato) platinum
- Comparative Example 2 1.8 g of the titanium suboxide support obtained in Comparative Example 1, 0.2 g of anatase type titanium oxide (manufactured by Sakai Chemical Industry Co., Ltd., trade name “SSP-25”, specific surface area 270 m 2 / g), and 114 g of ion-exchanged water was weighed into a beaker and mixed with stirring to obtain a slurry containing a titanium suboxide support and titanium oxide. A powder 4 was obtained in the same manner as in Example 2, except that the slurry containing the titanium suboxide support and titanium oxide was used.
- Comparative Example 4 Rutile type titanium oxide (made by Sakai Chemical Industry Co., Ltd., trade name “STR-100N”, specific surface area 100 m 2 / g) 2.0 g and titanium metal (made by Wako Pure Chemical Industries, trade name “Titanium, Powder”) After 6 g of dry mixing, the temperature was raised to 700 ° C. over 70 minutes in a hydrogen atmosphere, held at 700 ° C. for 1 hour, and then cooled to room temperature to be a mixed phase of Ti 4 O 7 and Ti 2 O 3 A titanium suboxide support was obtained. A powder 6 was obtained in the same manner as in Example 2 except that this titanium suboxide support was used.
- Comparative Example 5 1.0 g of the titanium suboxide support obtained in Example 1, 0.5 g of anatase type titanium oxide (manufactured by Sakai Chemical Industry Co., Ltd., trade name “SSP-25”, specific surface area 270 m 2 / g), and 114 g of ion-exchanged water was weighed into a beaker and mixed with stirring to obtain a slurry containing a titanium suboxide support and titanium oxide. A powder 7 was obtained in the same manner as in Example 1 except that the slurry containing the titanium suboxide support and titanium oxide was used.
- Electrochemical effective surface area (1) Production of working electrode A 5% by weight perfluorosulfonic acid resin solution (manufactured by Aldrich), isopropyl alcohol (manufactured by Wako Pure Chemical Industries, Ltd.) and ion-exchanged water are added to a sample to be measured and dispersed by ultrasonic waves. A paste was prepared. The paste was applied to a rotating glassy carbon disk electrode and thoroughly dried. The rotating electrode after drying was used as a working electrode. (2) Cyclic voltammetry measurement Rotating electrode device (Hokuto Denko, trade name “HR-301”) is connected to Automatic Polarization System (Hokuto Denko, trade name “HZ-5000”), and the measurement sample obtained above is connected to the working electrode.
- ECSA Electrochemical effective surface area
- a platinum electrode and a reversible hydrogen electrode (RHE) electrode were used for the counter electrode and the reference electrode, respectively.
- RHE reversible hydrogen electrode
- cyclic voltammetry was performed at 25 ° C. with an electrolytic solution saturated with argon gas (0.1 mol / l perchloric acid aqueous solution) from 1.2 V to 0.05 V at a sweep rate of 50 mV / sec.
- X-ray diffraction pattern Under the following conditions, a powder X-ray diffraction pattern was measured using an X-ray diffractometer (trade name “RINT-TTR3” manufactured by Rigaku Corporation). The results are shown in FIGS. 1-1 to 7-1.
- Average primary particle diameter of supported platinum First, in a transmission electron micrograph (also referred to as a TEM image or TEM photograph), the major axis and minor axis of the platinum particle are measured with a ruler, and the average of the major axis and minor axis is measured. The primary particle size was determined by dividing the value by the imaging magnification. Furthermore, 80 platinum particles in the TEM image were randomly extracted, and the primary particle size of all particles was measured by the above method. The maximum primary particle size among the measured values was the maximum, and the minimum value among the measured values was the minimum. The average primary particle size was determined by averaging the measured values as the primary particle size.
- the TEM image photographing magnification may be any magnification, but a preferable range is 20,000 times to 500,000 times.
- the volume of platinum supported was calculated from the amount of platinum supported, and the volume per platinum particle was determined from the average primary particle diameter of platinum. By dividing the volume of platinum carried by the volume of one platinum particle, the number of platinum particles was determined and used as an indicator of platinum dispersibility. Specifically, it was calculated by the following formula (ii). The calculation was performed assuming that the platinum density was 21.45 (g / cm 3 ), the circumferential ratio was 3.14, and platinum was a true sphere. The results are shown in Table 1.
- the powders obtained in Comparative Example 2 and Comparative Example 5 not only have peaks at 26.0 to 26.6 ° and 20.4 to 21.0 °, but also 25.0 to 25. There is also a peak at .6 ° (from FIG. 8, this is a peak derived from anatase-type titanium oxide) (see black circles in FIGS. 4-1 and 7-1). Therefore, the crystal phase was judged to be a mixed phase of Ti 4 O 7 and anatase type titanium oxide.
- the powder obtained in Comparative Example 3 has not only peaks at 26.0 to 26.6 ° and 20.4 to 21.0 °, but also peaks at 27.7 ° (from FIG. There is a peak derived from Ti n O 2n-1 (n represents an integer of 5 to 9) (see black circles in FIG. 5-1). Therefore, the crystal phase was judged to be a mixed phase of Ti 4 O 7 and Ti n O 2n-1 (n represents an integer of 5 to 9).
- the powder obtained in Comparative Example 4 not only has peaks at 26.0 to 26.6 ° and 20.4 to 21.0 °, but also peaks at 26.7 to 28.7 ° (see FIG. 8 is a peak derived from Ti 2 O 3 ) (see black circles in FIG. 6-1). Therefore, it was judged that the crystal phase was a mixed phase of Ti 4 O 7 and Ti 2 O 3 .
- the powders obtained in Examples 1 and 2 have a structure in which the crystal phase of the support is a Ti 4 O 7 single phase and platinum is supported.
- the powder obtained in Comparative Examples 2 and 5 the crystal phase of the carrier is Ti 4 O 7 instead of the single-phase, have become mixed phase of Ti 4 O 7 and anatase type titanium oxide.
- the powder obtained in Comparative Example 3 is a mixed phase of Ti 4 O 7 and Ti n O 2n-1 (n represents an integer of 5 to 9).
- Ti 4 O 7 and Ti 2 O 3 are mixed. Under this difference, when ECSA, which is an indicator of electrochemical characteristics, is compared, the powders obtained in Examples 1 and 2 have significantly higher ECSA than the powders obtained in Comparative Examples 2 to 4 (Table 1).
- the powder obtained in Comparative Example 1 is a titanium suboxide support whose crystal phase is Ti 4 O 7 single phase, similar to the powder obtained in Examples 1 and 2, but the powder obtained in Examples 1 and 2 is Compared to Comparative Example 1, the specific surface area of the carrier is large, and thus the platinum particles are fine, which is different from the powder obtained in Comparative Example 1. Furthermore, in addition to the observation result of the TEM image, since the number of calculated platinum particles is large, the platinum particles included in the powders of Examples 1 and 2 are more highly dispersed than the platinum particles included in the powder of Comparative Example 1. It is also estimated that the state. Under these differences, when ECSA, which is an indicator of electrochemical characteristics, is compared, the powders obtained in Examples 1 and 2 have significantly higher ECSA than the powder obtained in Comparative Example 1 (Table 1).
- ECSA electrochemical characteristics equivalent to the material in which platinum having a particle diameter of about 4 nm is supported on a conventionally used carbon support are shown. It can be said that the powders obtained in Examples 1 and 2 have high electrochemical characteristics equivalent to or higher than those of a material in which platinum is supported on a carbon support.
- the electrode material of the present invention is highly conductive and can realize high electrochemical characteristics, and such an electrode material can be easily and easily manufactured by the manufacturing method of the present invention.
- the electrode material of the present invention is also extremely resistant to a high potential and a strong acidic environment, compared to a material in which platinum is supported on a carbon carrier that is generally used conventionally.
- the electrode material of the present invention can be expected to maintain its performance even under high temperature and high humidity.
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Abstract
Description
本発明の電極材料は、亜酸化チタン担体に、貴金属及び/又はその酸化物が担持された構造を有する。
本明細書中、「結晶相がTi4O7単相である」電極材料とは、貴金属及び/又はその酸化物が担持された状態で測定したX線回折(XRD)測定パターン中、Ti4O7が存在し、その他のチタン酸化物が存在しない電極材料を意味し、その他のチタン酸化物とは、アナタース型、ブルッカイト型又はルチル型の酸化チタン、及び、TinO2n-1(nは、2又は5~9の整数を表す)で表される化合物をいう。図8で示されるように、一般にチタン酸化物は、その構造によってX線回折測定パターン上のピーク位置が異なるため、これを利用することで、Ti4O7が存在し、その他のチタン酸化物が存在しない(すなわち結晶相がTi4O7単相である)ことを判定できる。本発明では、以下の方法によって判定する。
なお、XRD測定データ全体にノイズが多い場合は、XRDに付属の解析ソフト(例えば、リガク社製X線回折装置(RINT-TTR3)付属の粉末X線回折パターン総合解析ソフトウェアJADE7J)等を用いて、スムージング、バックグランド除去を実施してから以下の判定を行ってもよい。
パターン中、26.0~26.6°と、20.4~21.0°とにピークが存在すれば、Ti4O7が存在すると判定する。このとき、26.0~26.6°に存在する最大ピークの強度を100としたときの20.4~21.0°に存在する最大ピークの強度の比は、10を超えることが好ましく、20を超えることがより好ましい。
パターン中、26.0~26.6°に存在する最大ピークの強度を100に対し、27.7°の強度の比が15以下であると、他のチタン酸化物のピーク及びノイズと区別がつかないため、TinO2n-1(nは5~9の整数を表す)、及び、ルチル型酸化チタンが存在しないと判定する。
パターン中、26.0~26.6°に存在する最大ピークの強度100に対し、25.0~25.6°に存在する最大ピークの強度の比が15以下であると、他のチタン酸化物のピーク及びノイズと区別がつかないため、アナタース型及びブルッカイト型酸化チタンが存在しないと判定する。
パターン中、26.0~26.6°に存在する最大ピークの強度100に対し、23.5~24.1°に存在する最大ピークの強度の比が15以下であると、他のチタン酸化物のピーク及びノイズと区別がつかないため、Ti2O3が存在しないと判定する。
BET比表面積とは、比表面積の測定方法の一つであるBET法により得られた比表面積のことをいう。比表面積とは、ある物体の単位質量あたりの表面積のことをいう。
BET法は、窒素等の気体粒子を固体粒子に吸着させ、吸着した量から比表面積を測定する気体吸着法である。本明細書では、後述の実施例に記載した方法により比表面積を求めることができる。
なお、亜酸化チタン担体の平均一次粒子径は、後述の貴金属(白金等)及び/又はその酸化物の平均一次粒子径と同様の方法で求めることができる。
なお、貴金属の平均一次粒子径は、後述の実施例に記載した方法にて求められる。
本発明の電極材料は、結晶相がTi4O7単相であって、比表面積が10m2/g以上である亜酸化チタン担体を得る工程(1)と、工程(1)で得た亜酸化チタン担体と貴金属及び/又はその水溶性化合物とを用いて、貴金属及び/又はその酸化物を担持する工程(2)とを含む製造方法により、容易かつ簡便に得ることができる。この製造方法は、必要に応じて、通常の粉体製造時に採用される1又は2以上のその他の工程を更に含んでもよい。
以下、各工程について更に説明する。
工程(1)は、比表面積が10m2/g以上であり、結晶相がTi4O7単相である亜酸化チタン担体を得る工程である。比表面積がこの範囲にあり、かつ結晶相が単相であるTi4O7を、貴金属及び/又はその酸化物の担持工程(工程(2))に供することで、高電位かつ強酸性環境への耐性に優れるうえ、高導電性で、かつ高い電気化学特性を有する電極材料を与えることができる。亜酸化チタン担体の比表面積は、好ましくは13m2/g以上、より好ましくは16m2/g以上である。
金属チタンを更に含む原料混合物を焼成に供することで、結晶相がTi4O7単相である亜酸化チタン担体がより効率的に得られる。金属チタンの含有割合は、酸化チタン及び/又は水酸化チタン(2種以上用いる場合はその合計量)100重量部に対し、5~50重量部とすることが好適である。より好ましくは10~40重量部である。
なお、各原料はそれぞれ1種又は2種以上使用することができる。
本明細書中、焼成温度とは、焼成工程での最高到達温度を意味する。
工程(2)は、工程(1)で得た亜酸化チタン担体と、貴金属及び/又はその水溶性化合物(以下、貴金属化合物とも総称する)とを含む混合液を用いて、貴金属及び/又はその酸化物を担持する工程である。上記工程(1)の後、工程(2)の前に、必要に応じて粉砕、水洗、分級等の1又は2以上のその他の工程を含んでもよい。その他の工程は特に限定されない。
なお、混合液の各含有成分はそれぞれ1種又は2種以上使用することができる。
溶媒としては特に限定されず、例えば、水、酸性溶媒、有機溶媒及びこれらの混合物が挙げられる。有機溶媒としては、例えば、アルコール、アセトン、ジメチルスルホキシド、ジメチルホルムアミド、テトラヒドロフラン、ジオキサン等が挙げられ、中でもアルコールとしては、メタノール、エタノール、プロパノール等の1価の水溶性アルコール;エチレングリコール、グリセリン等の2価以上の水溶性アルコール;等が挙げられる。溶媒として好ましくは水であり、より好ましくはイオン交換水である。
ここで、副生成物は水洗により取り除くことが好ましい。電極材料中に副生成物が残存すると、固体高分子形燃料電池の運転中に系内に溶出するなどし、発電特性の悪化やシステムの損傷を引き起こすおそれがある。水洗の方法としては、亜酸化チタン担体に担持されていない水溶性物質を系外に除去できる方法であれば特に限定されず、ろ過水洗やデカンテーション等が挙げられる。このとき、水洗水の電導度が10μS/cm以下になるまで水洗することで副生成物を取り除くことが好ましい。より好ましくは電導度が3μS/cm以下になるまで水洗することである。
本発明の電極材料及び本発明の製造方法で得られる電極材料は、燃料電池用の電極材料用途に好適に用いることができる。中でも、固体高分子形燃料電池(PEFC)用の電極材料用途に特に好適である。特に、従来一般に使用されているカーボン担体上に白金を担持した材料の代替材料として有用である。このような電極材料は、正極(空気極とも称す)、負極(燃料極とも称す)のいずれにも好適であり、また、カソード(陽極)、アノード(陰極)のいずれにも好適である。本発明の電極材料、又は、本発明の製造方法で得られる電極材料を用いた固体高分子形燃料電池は、本発明の好適な実施形態の1つである。
ルチル型酸化チタン(堺化学工業社製、商品名「STR-100N」、比表面積100m2/g)2.0gと金属チタン(和光純薬工業社製、商品名「チタン,粉末」)0.3gを乾式混合した後、水素雰囲気下、700℃まで70分かけて昇温し、700℃で6時間保持した後、室温まで冷却して結晶相がTi4O7で表される亜酸化チタン担体を得た。得られた亜酸化チタン担体0.7gと、イオン交換水114gをビーカーに計量して撹拌混合し、亜酸化チタン担体スラリーを得た。
別のビーカーにて塩化白金酸水溶液(白金として15.343%、田中貴金属工業社製)0.57gをイオン交換水3.4gで希釈した後、塩化ヒドラジン(東京化成工業社製、商品名「Hydrazine Dihydrochloride」)0.024gを添加し、撹拌混合したものを準備した(これを「混合水溶液」と称す)。
亜酸化チタン担体スラリーを攪拌しながら、別のビーカーにて準備した上記の混合水溶液4.0gを添加し、その後、液温70℃に加熱保持しながら撹拌混合した。更に、0.1Nの水酸化ナトリウム水溶液10.0gを添加し撹拌混合して、液温70℃に1時間加熱保持した後、常法に従い、濾過、水洗、乾燥して水分を全て蒸発させて、粉末0.7gを得た。得られた粉末0.5gを水素雰囲気下、550℃まで昇温し、550℃で1時間保持した後、室温まで冷却して粉末1を得た。粉末1の粉末X線回折パターンから、亜酸化チタン担体とPt以外にチタンと白金の合金であるPt3Tiが確認された。
実施例1と同様にして亜酸化チタン担体スラリーを得た。
別のビーカーにて塩化白金酸水溶液(白金として15.343%、田中貴金属工業社製)0.9gをイオン交換水5.3gで希釈した後、塩化ヒドラジン(東京化成工業社製、商品名「Hydrazine Dihydrochloride」)0.037gを添加し、撹拌混合したものを準備した(これを「混合水溶液」と称す)。
亜酸化チタン担体スラリーを攪拌しながら、別のビーカーにて準備した上記の混合水溶液6.2gを添加し、その後、液温70℃に加熱保持しながら撹拌混合した。更に、0.1Nの水酸化ナトリウム水溶液16.0gを添加し撹拌混合して、液温70℃に1時間加熱保持した後、常法に従い、濾過、水洗、乾燥して水分を全て蒸発させて、粉末0.7gを得た。
得られた粉末0.5gを水素雰囲気下、550℃まで昇温し、550℃で1時間保持した後、室温まで冷却して粉末2を得た。粉末2の粉末X線回折パターンから、亜酸化チタン担体とPt以外にチタンと白金の合金であるPt3Tiが確認された。
アナタース型酸化チタンゾル(堺化学工業社製、商品名「CSB」、比表面積280m2/g)20.00gを液温80℃に加熱保持しながら攪拌し、液分を全て蒸発させ、粉末Aを得た。得られた粉末Aを5.0gと金属チタン(和光純薬工業社製、商品名「チタン,粉末」)0.75gを乾式混合した後、水素雰囲気下、900℃まで270分かけて昇温し、900℃で10時間保持した後、室温まで冷却して結晶相がTi4O7で表される亜酸化チタン担体を得た。得られた亜酸化チタン担体0.9gと、エタノール40gをビーカーに計量して撹拌混合し、亜酸化チタン担体スラリーを得た。
亜酸化チタン担体スラリーを攪拌しながら、ビス(アセチルアセトナト)白金(II)(エヌイーケムキャット社製、白金として49.5%)0.14gを添加し、その後、液温60℃に加熱保持しながら撹拌し、液分を全て蒸発させ、粉末3を得た。
比較例1で得た亜酸化チタン担体1.8gと、アナタース型酸化チタン(堺化学工業社製、商品名「SSP-25」、比表面積270m2/g)0.2gと、イオン交換水114gをビーカーに計量して撹拌混合し、亜酸化チタン担体と酸化チタンを含むスラリーを得た。この亜酸化チタン担体と酸化チタンを含むスラリーを用いたこと以外は実施例2と同様にして、粉末4を得た。
ルチル型酸化チタン(堺化学工業社製、商品名「STR-100N」、比表面積100m2/g)2.0gと金属チタン(和光純薬工業社製、商品名「チタン,粉末」)0.3gを乾式混合した後、水素雰囲気下、700℃まで70分かけて昇温し、700℃で1時間保持した後、室温まで冷却してTi4O7とTinO2n-1(nは5~9の整数を表す)との混相である亜酸化チタン担体を得た。この亜酸化チタン担体を用いたこと以外は実施例2と同様にして、粉末5を得た。
ルチル型酸化チタン(堺化学工業社製、商品名「STR-100N」、比表面積100m2/g)2.0gと金属チタン(和光純薬工業社製、商品名「チタン,粉末」)0.6gを乾式混合した後、水素雰囲気下、700℃まで70分かけて昇温し、700℃で1時間保持した後、室温まで冷却してTi4O7とTi2O3との混相である亜酸化チタン担体を得た。この亜酸化チタン担体を用いたこと以外は実施例2と同様にして、粉末6を得た。
実施例1で得た亜酸化チタン担体1.0gと、アナタース型酸化チタン(堺化学工業社製、商品名「SSP-25」、比表面積270m2/g)0.5gと、イオン交換水114gをビーカーに計量して撹拌混合し、亜酸化チタン担体と酸化チタンを含むスラリーを得た。この亜酸化チタン担体と酸化チタンを含むスラリーを用いたこと以外は実施例1と同様にして、粉末7を得た。
以下の手順により得られた各粉末の物性等を評価した。結果を表1及び各図面に示す。
(1)作用極の作製
測定対象のサンプルに、5重量%パーフルオロスルホン酸樹脂溶液(アルドリッチ社製)、イソプロピルアルコール(和光純薬工業社製)及びイオン交換水を加え、超音波により分散させてペーストを調製した。ペーストを回転グラッシーカーボンディスク電極に塗布し、充分に乾燥した。乾燥後の回転電極を作用極とした。
(2)サイクリックボルタンメトリー測定
Automatic Polarization System(北斗電工社製、商品名「HZ-5000」)に、回転電極装置(北斗電工社製、商品名「HR-301」)を接続し、作用極に、上記で得た測定サンプル付き電極を用い、対極と参照極には、それぞれ白金電極と可逆水素電極(RHE)電極を用いた。
測定サンプル付き電極のクリーニングのため、25℃で、電解液(0.1mol/lの過塩素酸水溶液)にアルゴンガスをバブリングしながら1.2Vから0.05Vまでサイクリックボルタンメトリーに供した。その後、25℃で、アルゴンガスを飽和させた電解液(0.1mol/l過塩素酸水溶液)で1.2Vから0.05Vまで掃引速度50mV/secでサイクリックボルタンメトリーを行った。
その後、掃引時に得られる水素吸着波の面積(水素吸着時の電荷量:QH(μC))から、下記数式(i)を用いて電気化学的有効比表面積を算出し、電気化学特性の指標とした。なお、数式(i)中、「210(μCcm2)」は、白金(Pt)の単位活性面積あたりの吸着電化量である。
下記条件の下、X線回折装置(リガク社製、商品名「RINT-TTR3」)を用いて、粉末X線回折パターンを測定した。結果を図1-1~7-1に示す。
X線源:Cu-Kα線
測定範囲:2θ=10~70°
スキャンスピード:5°/min
電圧:50kV
電流:300mA
電解放出形透過電子顕微鏡JEM-2100F(日本電子社製)を用いて、観察を実施した。結果を図1-2~7-2に示す。
走査型蛍光X線分析装置ZSX PrimusII(リガク社製)を用いて、試料中の白金含有量を測定し、白金担持量を算出した。
まず、透過型電子顕微鏡写真(TEM像又はTEM写真とも称す)において、白金粒子の長径と短径を定規等で計測し、その長径と短径の平均値を撮影倍率で除することにより、一次粒子径を求めた。更に、TEM像中の白金粒子を80個無作為に抽出し、上記の方法により全ての粒子の一次粒子径を計測し、計測値中最大値を最大一次粒子径、計測値中最小値を最小一次粒子径とし、計測値を平均することにより、平均一次粒子径を求めた。なお、TEM像の撮影倍率は任意の倍率でよいが、好ましい範囲は20,000倍から500,000倍である。
上記白金担持量から担持した白金の体積を算出し、白金の平均一次粒子径から白金粒子1個あたりの体積を求めた。担持した白金の体積を白金粒子1個の体積で割ることで、白金粒子の個数を求め、白金分散性の指標とした。具体的には以下の数式(ii)により算出した。なお、白金密度は21.45(g/cm3)、円周率は3.14とし、白金は真球であるとして計算した。結果を表1に示す。
JIS Z8830(2013年)の規定に準じ、試料を窒素雰囲気中、200℃で60分間熱処理した後、比表面積測定装置(マウンテック社製、商品名「Macsorb HM-1220」)を用いて、比表面積(BET-SSA)を測定した。各々の担体の比表面積を表1に示す。
実施例1、2で得た粉末は、担体の結晶相がTi4O7単相になっており、更に白金が担持した構造を有する。これに対し、比較例2、5で得た粉末は、担体の結晶相がTi4O7単相ではなく、Ti4O7とアナタース型酸化チタンとの混相になっている。同様に、比較例3で得た粉末では、Ti4O7とTinO2n-1(nは5~9の整数を表す)との混相になっており、比較例4で得た粉末では、Ti4O7とTi2O3との混相になっている。この相違の下、電気化学特性の指標となるECSAを対比すると、実施例1、2で得た粉末は、比較例2~4で得た粉末に対し、ECSAが著しく高い(表1)。
Claims (7)
- 結晶相がTi4O7単相であって、比表面積が10m2/g以上である亜酸化チタン担体に、貴金属及び/又はその酸化物が担持された構造を有する
ことを特徴とする電極材料。 - 前記貴金属は、白金、ルテニウム、イリジウム、ロジウム及びパラジウムからなる群より選択される少なくとも1種の金属であって、平均一次粒子径が1~20nmである
ことを特徴とする請求項1に記載の電極材料。 - 前記貴金属は、白金である
ことを特徴とする請求項1又は2のいずれかに記載の電極材料。 - 固体高分子形燃料電池の電極材料である
ことを特徴とする請求項1~3のいずれかに記載の電極材料。 - 請求項1~4のいずれかに記載の電極材料から構成された電極を備える
ことを特徴とする燃料電池。 - 請求項1~4のいずれかに記載の電極材料を製造する方法であって、
該製造方法は、
結晶相がTi4O7単相であって、比表面積が10m2/g以上である亜酸化チタン担体を得る工程(1)と、
工程(1)で得た亜酸化チタン担体と貴金属及び/又はその水溶性化合物とを含む混合液を用いて、貴金属及び/又はその酸化物を担持する工程(2)とを含む
ことを特徴とする電極材料の製造方法。 - 前記工程(1)は、比表面積が20m2/g以上であるルチル型酸化チタンと金属チタン及び/又は水素化チタンとを含む乾式混合物を、水素雰囲気下で焼成する工程である
ことを特徴とする請求項6に記載の製造方法。
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Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN110649294A (zh) * | 2019-09-25 | 2020-01-03 | 新源动力股份有限公司 | 表征燃料电池用Pt/C催化剂表面聚合物电解质覆盖度的方法 |
WO2020175114A1 (ja) * | 2019-02-26 | 2020-09-03 | 堺化学工業株式会社 | 電極材料及びそれを用いた電極 |
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JPWO2022210700A1 (ja) * | 2021-03-31 | 2022-10-06 |
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KR102277962B1 (ko) * | 2019-11-07 | 2021-07-15 | 현대모비스 주식회사 | 연료전지용 촉매 및 이의 제조방법 |
JP7131535B2 (ja) * | 2019-12-02 | 2022-09-06 | トヨタ自動車株式会社 | 燃料電池用触媒層 |
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CN114797860B (zh) * | 2022-03-14 | 2023-06-09 | 重庆大学 | 一种表面负载过渡金属的Ti4O7及其制备方法和应用 |
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Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH04502980A (ja) * | 1988-11-17 | 1992-05-28 | フィジカル サイエンシーズ インコーポレーテッド | 電気触媒、その製造方法、それから製造される電極及びそれらの使用方法 |
JP2010272248A (ja) * | 2009-05-19 | 2010-12-02 | Univ Of Yamanashi | 固体高分子形燃料電池用高電位安定担体および電極触媒 |
WO2013141063A1 (ja) * | 2012-03-23 | 2013-09-26 | 株式会社クラレ | 触媒およびこれを備える燃料電池 |
JP2017016853A (ja) * | 2015-06-30 | 2017-01-19 | 堺化学工業株式会社 | 電極用担体材料及びその製造方法 |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU6677700A (en) * | 1999-08-23 | 2001-03-19 | Ballard Power Systems Inc. | Supported catalysts for the anode of a voltage reversal tolerant fuel cell |
JP2004363056A (ja) | 2003-06-06 | 2004-12-24 | Nissan Motor Co Ltd | 固体高分子型燃料電池用触媒担持電極とその製造方法 |
JP4502980B2 (ja) * | 2006-07-19 | 2010-07-14 | 本田技研工業株式会社 | 内燃機関の可変動弁装置 |
US9005569B2 (en) * | 2009-11-26 | 2015-04-14 | The University Of Tokyo | Microstructure and manufacturing method therefor |
EP2506350B1 (en) | 2009-11-27 | 2017-03-29 | University of Yamanashi | Oxide-based stable high-potential carrier for solid polymer fuel cell |
JP2012017490A (ja) | 2010-07-06 | 2012-01-26 | Sumitomo Chemical Co Ltd | 電極触媒 |
CN102208658B (zh) * | 2011-04-18 | 2013-05-22 | 北京工业大学 | 一种纳米Ti4O7颗粒的制备方法 |
CN102642867B (zh) * | 2012-04-24 | 2014-01-01 | 四川大学 | 一种纳米Ti4O7粉末的制备方法 |
CN104925857A (zh) * | 2015-06-09 | 2015-09-23 | 四川大学 | 亚氧化钛粉体的旋转式动态连续制备方法 |
CN105457629A (zh) * | 2015-12-11 | 2016-04-06 | 上海源由纳米科技有限公司 | 一种负载型纳米贵金属催化剂及其制备方法和应用 |
-
2017
- 2017-10-19 CN CN201780068526.5A patent/CN109952675B/zh active Active
- 2017-10-19 WO PCT/JP2017/037836 patent/WO2018096851A1/ja active Application Filing
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- 2017-10-19 GB GB1904753.9A patent/GB2570590B/en active Active
- 2017-10-24 TW TW106136439A patent/TWI744400B/zh active
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH04502980A (ja) * | 1988-11-17 | 1992-05-28 | フィジカル サイエンシーズ インコーポレーテッド | 電気触媒、その製造方法、それから製造される電極及びそれらの使用方法 |
JP2010272248A (ja) * | 2009-05-19 | 2010-12-02 | Univ Of Yamanashi | 固体高分子形燃料電池用高電位安定担体および電極触媒 |
WO2013141063A1 (ja) * | 2012-03-23 | 2013-09-26 | 株式会社クラレ | 触媒およびこれを備える燃料電池 |
JP2017016853A (ja) * | 2015-06-30 | 2017-01-19 | 堺化学工業株式会社 | 電極用担体材料及びその製造方法 |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2020175114A1 (ja) * | 2019-02-26 | 2020-09-03 | 堺化学工業株式会社 | 電極材料及びそれを用いた電極 |
WO2021020300A1 (ja) * | 2019-08-01 | 2021-02-04 | 三井金属鉱業株式会社 | 燃料電池用触媒層、その製造方法、及びそれを備えた燃料電池 |
CN110649294A (zh) * | 2019-09-25 | 2020-01-03 | 新源动力股份有限公司 | 表征燃料电池用Pt/C催化剂表面聚合物电解质覆盖度的方法 |
WO2021241094A1 (ja) * | 2020-05-29 | 2021-12-02 | 堺化学工業株式会社 | 電極材料及びそれを用いた電極、水電解セル |
JP7494576B2 (ja) | 2020-05-29 | 2024-06-04 | 堺化学工業株式会社 | 電極材料及びそれを用いた電極、水電解セル |
WO2022014402A1 (ja) * | 2020-07-16 | 2022-01-20 | 堺化学工業株式会社 | エネルギー吸放出材 |
JPWO2022210700A1 (ja) * | 2021-03-31 | 2022-10-06 | ||
JP7255769B2 (ja) | 2021-03-31 | 2023-04-11 | 堺化学工業株式会社 | 導電性材料 |
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