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WO2019142696A1 - Catalyseur de réduction d'oxygène - Google Patents

Catalyseur de réduction d'oxygène Download PDF

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Publication number
WO2019142696A1
WO2019142696A1 PCT/JP2019/000194 JP2019000194W WO2019142696A1 WO 2019142696 A1 WO2019142696 A1 WO 2019142696A1 JP 2019000194 W JP2019000194 W JP 2019000194W WO 2019142696 A1 WO2019142696 A1 WO 2019142696A1
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Prior art keywords
oxygen reduction
reduction catalyst
cobalt
content
diffraction
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English (en)
Japanese (ja)
Inventor
建燦 李
海林 汪
竜一 光本
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Resonac Holdings Corp
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Showa Denko KK
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
    • B01J27/02—Sulfur, selenium or tellurium; Compounds thereof
    • B01J27/04—Sulfides
    • B01J27/043—Sulfides with iron group metals or platinum group metals
    • 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
    • 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
    • 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

Definitions

  • the present invention relates to a cobalt compound oxygen reduction catalyst containing a sulfur atom.
  • Cobalt compounds such as tricobalt tetraoxide (Co 3 O 4 ) and the like have catalytic properties and are used as catalysts for various applications.
  • Patent Document 1 discloses a composite carrier in which dissolution under strong acid is suppressed by supporting a transition metal oxide on a rare earth sulfate as a carrier used for a fuel cell catalyst, and cobalt oxide particles are disclosed. Although it is described that it may contain, the use of cobalt compounds as a catalyst has not been studied.
  • Patent Document 2 discloses a bifunctional air electrode for a secondary air battery including a bifunctional catalyst capable of reducing oxygen and generating oxygen, and using Co 3 O 4 or the like as an oxygen reduction catalyst It is stated that it may contain CoO.
  • the present invention has the following configuration.
  • the oxygen reduction catalyst according to item 1 or 2 wherein the crystal structure of cobalt monoxide (CoO) is further confirmed in X-ray diffraction measurement.
  • a fuel cell electrode catalyst comprising the oxygen reduction catalyst according to any one of the above 1 to 4.
  • a membrane electrode assembly comprising a cathode, an anode, and a polymer electrolyte membrane disposed between the cathode and the anode, wherein the cathode is the electrode for a fuel cell according to the above item 6.
  • Membrane electrode assembly [8] A fuel cell comprising the membrane electrode assembly according to the above item 7.
  • the oxygen reduction catalyst which is a cobalt compound of the present invention has a high oxygen reduction ability by containing a sulfur atom.
  • a fuel cell catalyst of a cathode electrode when it is used as a fuel cell catalyst of a cathode electrode, a fuel cell having high power generation characteristics can be obtained.
  • FIG. Among the diffraction peaks, the peaks of the strongest diffraction intensity among the peaks corresponding to tricobalt tetraoxide (Co 3 O 4 ) and cobalt monoxide (CoO) are indicated by ⁇ and ⁇ , respectively.
  • FIG. 7 is an X-ray diffraction spectrum of the oxygen reduction catalyst (3) produced in Example 3.
  • FIG. Among the diffraction peaks the peaks of the strongest diffraction intensity among the peaks corresponding to tricobalt tetraoxide (Co 3 O 4 ) and cobalt monoxide (CoO) are indicated by ⁇ and ⁇ , respectively.
  • 7 is an X-ray diffraction spectrum of the oxygen reduction catalyst (4) produced in Example 4.
  • the peaks of the strongest diffraction intensity among the peaks corresponding to tricobalt tetraoxide (Co 3 O 4 ) and cobalt monoxide (CoO) are indicated by ⁇ and ⁇ , respectively.
  • FIG. 1 It is a X-ray-diffraction spectrum of the oxygen reduction catalyst (c1) produced by the comparative example 1.
  • FIG. 1 It is a X-ray-diffraction spectrum of the oxygen reduction catalyst (c2) produced by the comparative example 2.
  • the peaks of the strongest diffraction intensity among the peaks respectively corresponding to cobalt monoxide (CoO), Co 9 S 8 and cobalt monosulfide (CoS) are shown by ⁇ , ⁇ and ⁇ , respectively.
  • FIG. Among the diffraction peaks, the peaks of the strongest diffraction intensities among the peaks respectively corresponding to Co 9 S 8 , cobalt monosulfide (CoS) and tricobalt tetrasulfide (Co 3 S 4 ) are shown by ⁇ , ⁇ and ⁇ , respectively. .
  • FIG. 10 is an X-ray diffraction spectrum of the oxygen reduction catalyst (c4) prepared in Comparative Example 4.
  • FIG. Among the diffraction peaks the peaks of the strongest diffraction intensities among the peaks respectively corresponding to Co 9 S 8 , cobalt monosulfide (CoS) and tricobalt tetrasulfide (Co 3 S 4 ) are shown by ⁇ , ⁇ and ⁇ , respectively. .
  • It is an X-ray diffraction spectrum of the oxygen reduction catalyst (c5) prepared in Comparative Example 5.
  • the peak of the strongest diffraction intensity among peaks corresponding to tricobalt tetraoxide (Co 3 O 4 ) is indicated by ⁇ .
  • the oxygen reduction catalyst of the present invention is characterized in that the crystal structure of tricobalt tetraoxide (Co 3 O 4 ) is confirmed in X-ray diffraction measurement, and the sulfur atom content is 1.0 to 15.0 mass%. Cobalt compounds.
  • the oxygen reduction catalyst of the present invention can be said to be an oxygen reduction catalyst consisting of a specific cobalt compound. However, this does not strictly exclude the presence of the impurities in the oxygen reduction catalyst of the present invention, and unavoidable impurities resulting from the raw material and / or the production process and the like, and other impurities in the range not deteriorating the characteristics of the catalyst. Is included in the oxygen reduction catalyst of the present invention.
  • the oxygen reduction catalyst of the present invention contains cobalt oxide as a main component, but may contain other transition metal element oxygen-containing compounds.
  • the transition metal element include Group 4 elements, Group 5 elements, Group 6 elements, and iron group elements in the periodic table.
  • the iron group elements include elemental species of iron, cobalt and nickel.
  • the oxygen reduction catalyst of the present invention is confirmed to have a crystal structure of tricobalt tetraoxide (Co 3 O 4 ) in X-ray diffraction (XRD) measurement.
  • XRD X-ray diffraction
  • a peak of the strongest diffraction intensity appears at a position where the diffraction angle 2 ⁇ is 36.9 ° in the XRD spectrum as in the reference code 98-002-4210.
  • the oxygen reduction catalyst of the present invention has high acid resistance under strong acidity by having a crystal structure of tricobalt tetraoxide (Co 3 O 4 ).
  • the oxygen reduction catalyst of the present invention has a sulfur atom content of 1.0 to 15.0% by mass.
  • the lower limit of the sulfur atom content is preferably 1.5% by mass, more preferably 1.6% by mass.
  • the upper limit of the sulfur atom content is preferably 12.0% by mass, more preferably 10.0% by mass.
  • the sulfur atom content can be quantified by inductively coupled plasma mass spectrometry or infrared absorption method for gasified components. For example, it can be determined using a carbon / sulfur analyzer EMIA-920V (manufactured by Horiba, Ltd.) using an infrared absorption method.
  • tricobalt tetraoxide content is included in the oxygen reduction catalyst of the present invention.
  • the tricobalt tetraoxide content is a value determined from the ratio of peak intensities in an XRD spectrum obtained by X-ray diffraction (XRD), as described later. That is, it is% calculated from the peak ratio.
  • the tricobalt tetraoxide content is preferably 20.0 to 95.0%, more preferably 20.0 to 90.0%, still more preferably 20.0 to 85.0%.
  • Crystal structure of cobalt monoxide (CoO) In the oxygen reduction catalyst of the present invention, preferably, the crystal structure of cobalt monoxide (CoO) is confirmed in X-ray diffraction measurement. In the crystal structure of cobalt monoxide (CoO), a peak of the strongest diffraction intensity appears at a position at a diffraction angle 2 ⁇ of 42.4 ° in the XRD spectrum as in the reference code 98-017-4027.
  • the content of cobalt monoxide (CoO) crystals in the crystals of a cobalt compound confirmed in X-ray diffraction (XRD) measurement (hereinafter sometimes referred to as "cobalt monoxide content") As 80.0% or less is preferable.
  • the cobalt monoxide content is a value determined from the ratio of peak intensities in an XRD spectrum obtained by X-ray diffraction (XRD).
  • the cobalt monoxide content is preferably 5.0 to 80.0%, more preferably 10.0 to 80.0%, and still more preferably 15.0 to 80.0%.
  • the oxygen reduction catalyst of the present invention is at least tricobalt tetraoxide (Co 3 O 4 ) because the natural potential is higher when the sulfur atom is doped when the content of tricobalt tetraoxide is higher in the examples described later. It is considered that the crystal structure of is doped with sulfur atoms.
  • the oxygen reduction catalyst of the present invention may be confirmed to have a crystal structure of cobalt sulfate (II) (CoSO 4 ) in X-ray diffraction (XRD) measurement.
  • II cobalt sulfate
  • XRD X-ray diffraction
  • the oxygen reduction catalyst may include cobalt (II) sulfate (CoSO 4 ).
  • Cobalt (II) sulfate (CoSO 4 ) is water soluble and is basically removed from the resulting oxygen reduction catalyst by water washing after calcination in the manufacturing process. If the oxygen reduction catalyst of cobalt (II) sulfate as contained (CoSO 4), when used as an electrode catalyst for a fuel cell, cobalt sulfate from the fuel cell electrode catalyst in operation (II) (CoSO 4) However, the composition of the oxygen reduction catalyst of the present invention is maintained, and there is no particular influence on the catalyst characteristics and the operation performance.
  • the oxygen reduction catalyst of the present invention may be Co 9 S 8 , cobalt monosulfide (CoS) and tricobalt tetrasulfide (Co 3 S) depending on the conditions of the production method described later.
  • the crystal structure of 4 may be included.
  • the peak of the strongest diffraction intensity appears at a position where the diffraction angle 2 ⁇ is 52.1 ° in the XRD spectrum as in the reference code 98-003-1753.
  • the above-described oxygen reduction catalyst of the present invention is not particularly limited in use, but can be suitably used particularly as an electrode catalyst for a fuel cell.
  • One of the preferred embodiments of the present invention is a fuel cell electrode having a catalyst layer containing the above-described oxygen reduction catalyst of the present invention.
  • the fuel cell electrode includes a fuel cell electrode catalyst comprising the oxygen reduction catalyst of the present invention.
  • the catalyst layer constituting the fuel cell electrode includes an anode catalyst layer and a cathode catalyst layer, but the oxygen reduction catalyst of the present invention can be used for any of them. Since the oxygen reduction catalyst of the present invention has high oxygen reduction ability, it is preferably used in the cathode catalyst layer.
  • the catalyst layer preferably further comprises a polyelectrolyte.
  • the polymer electrolyte is not particularly limited as long as it is generally used in a fuel cell catalyst layer.
  • a perfluorocarbon polymer having a sulfo group for example, Nafion (NAFION (registered trademark)
  • NAFION registered trademark
  • hydrocarbon-based polymer compound having a sulfo group a polymer compound doped with an inorganic acid such as phosphoric acid
  • the organic / inorganic hybrid polymer partially substituted with a proton conductive functional group, a proton conductor obtained by impregnating a polymer matrix with a phosphoric acid solution or a sulfuric acid solution, etc.
  • the catalyst layer may further include electron conductive particles made of carbon, conductive polymer, conductive ceramics, metal or conductive inorganic oxide such as tungsten oxide or iridium oxide, as necessary. Good.
  • the fuel cell electrode may further have a porous support layer in addition to the catalyst layer.
  • the porous support layer is a layer that diffuses a gas (hereinafter also referred to as a "gas diffusion layer").
  • gas diffusion layer Any gas diffusion layer may be used as long as it has electron conductivity, high gas diffusivity, and high corrosion resistance, but generally it is a carbon-based porous material such as carbon paper or carbon cloth. Materials are used.
  • the membrane electrode assembly of the present invention is a membrane electrode assembly having a cathode, an anode, and a polymer electrolyte membrane disposed between the cathode and the anode, and at least one of the cathode and the anode.
  • One of the electrodes is the fuel cell electrode of the present invention described above.
  • a conventionally known fuel cell electrode for example, a fuel cell electrode containing a platinum-based catalyst such as platinum-supported carbon.
  • a platinum-based catalyst such as platinum-supported carbon.
  • the membrane electrode assembly of the present invention when the fuel cell electrode of the present invention has a gas diffusion layer, in the membrane electrode assembly of the present invention, this gas diffusion layer is disposed on the opposite side of the catalyst layer as viewed from the polymer electrolyte membrane.
  • the polymer electrolyte membrane for example, an electrolyte membrane or a hydrocarbon-based electrolyte membrane using a perfluorosulfonic acid type is generally used, but a membrane or a porous membrane in which a polymer microporous membrane is impregnated with a liquid electrolyte A membrane filled with a polymer electrolyte may be used.
  • the membrane / electrode assembly of the present invention can be appropriately formed using a conventionally known method.
  • the fuel cell of the present invention comprises the above-mentioned membrane electrode assembly.
  • the fuel cell of the present invention further includes two current collectors in a state in which the membrane electrode assembly is sandwiched.
  • the current collector can be a conventionally known one generally employed for fuel cells.
  • the method for producing the oxygen reduction catalyst of the present invention is not particularly limited as long as the oxygen reduction catalyst within the range of the above constitution can be obtained.
  • a method of firing a compound containing a cobalt atom and a sulfur atom as a raw material in an atmosphere containing oxygen gas (Production Method 1) or a method of mixing a cobalt compound and a sulfur source and firing under an atmosphere containing oxygen gas Production method 2) can be mentioned.
  • the manufacturing method 1 will be described in detail.
  • a compound containing a cobalt atom and a sulfur atom is used as a raw material for firing in an oxygen gas-containing atmosphere.
  • the compound containing a cobalt atom and a sulfur atom is not particularly limited, but as an inorganic compound, cobalt monosulfide (CoS), cobalt disulfide (CoS 2 ), tricobalt tetrasulfide (Co 3 S 4 ), Co it can be mentioned cobalt sulfides such as 9 S 8. These cobalt sulfides may be used alone or in combination of two or more.
  • cobalt monosulfide (CoS) or tricobalt tetrasulfide (Co 3 S 4 ) because oxygen atoms are easily contained.
  • the oxygen gas-containing atmosphere is more preferably a nitrogen gas and / or a mixed gas atmosphere of argon gas and oxygen gas.
  • the oxygen gas content of the oxygen gas-containing atmosphere is preferably 0.1 to 10.0% by volume, and more preferably 0.1 to 5.0% by volume.
  • the firing temperature is preferably in the range of 450 ° C. to 850 ° C., and more preferably 500 ° C. to 800 ° C. When fired at around 600 to 700 ° C., tricobalt tetraoxide (Co 3 O 4 ) is easily generated.
  • the firing time is preferably 1 to 15 hours, and preferably 1 to 12 hours. If the firing time is longer than the above range under a stream of oxygen gas-containing atmosphere, sulfur atoms will flow out of the system, and the sulfur atom content will tend to be smaller than the above-described range of the configuration.
  • the firing time and temperature are adjusted to one another.
  • the fired product obtained after firing may contain cobalt (II) sulfate.
  • Cobalt (II) sulfate is water-soluble, and it is preferable to carry out a water washing treatment for washing the calcined product obtained by the calcination treatment with water.
  • a water washing treatment for washing with water, for example, a method in which the baked product is placed in pure water at room temperature and stirred using a magnetic stirrer is mentioned.
  • the conditions for the stirring treatment include stirring at a rotational speed of 100 to 300 rpm for 5 to 20 hours. It is preferable to filter and dry the stirred baked product at 70 to 120 ° C. for 30 minutes to 5 hours.
  • the oxygen reduction catalyst of the present invention can be obtained.
  • Example 1 (1) Preparation of oxygen reduction catalyst 0.5 g of cobalt monosulfide (CoS) (manufactured by Wako Pure Chemical Industries, Ltd.) was weighed, placed in a quartz inner case, and nitrogen gas (gas flow rate) using a rotary calciner (manufactured by Motoyama) In a mixed gas atmosphere of 95 mL / min) and oxygen gas (gas flow rate 5 mL / min), the temperature was raised to 600 ° C. at a heating rate of 10 ° C./min, and calcination was performed at 600 ° C. for 12 hours.
  • CoS cobalt monosulfide
  • the fired product obtained by firing was placed in pure water, and stirred using a magnetic stirrer for 14 hours at room temperature and 200 rpm for washing with water.
  • the powder obtained by filtering the product washed with water was dried at 90 ° C. for 2 hours to obtain an oxygen reduction catalyst (1).
  • a fuel cell electrode (hereinafter referred to as "catalyst electrode") provided with a catalyst layer containing an oxygen reduction catalyst was produced as follows.
  • the mixture was sonicated and stirred to obtain a suspension.
  • 20 ⁇ L of this suspension was applied to a glassy carbon electrode (manufactured by Tokai Carbon Co., Ltd., diameter: 5.2 mm) and dried at 70 ° C.
  • the electrochemical evaluation of the oxygen reduction activity catalytic ability of the oxygen reduction catalyst (1) was performed as follows.
  • the catalyst electrode prepared in the above catalyst electrode preparation is polarized at a potential scanning rate of 5 mV / sec in an aqueous solution of sulfuric acid at 30 ° C. and 0.5 mol / dm 3 in each of an oxygen gas atmosphere and a nitrogen gas atmosphere, was measured.
  • a natural potential (open circuit potential) in a non-polarized state in an oxygen gas atmosphere was obtained.
  • a reversible hydrogen electrode in a sulfuric acid aqueous solution of the same concentration was used as a reference electrode.
  • an electrode potential at 10 ⁇ A (hereinafter simply referred to as electrode potential) is obtained from the difference between the reduction current curve in an oxygen gas atmosphere and the reduction current curve in a nitrogen gas atmosphere.
  • electrode potential an electrode potential at 10 ⁇ A
  • the oxygen reduction catalytic ability of the oxygen reduction catalyst (1) was evaluated using the electrode potential and the natural potential.
  • the natural potential obtained as an index of the oxygen reduction activity is shown in Table 1.
  • the intensity of the strongest diffraction peak (H1) among the peaks corresponding to tricobalt tetraoxide (Co 3 O 4 ) crystals and the intensity (H 2) of the strongest diffraction peaks among the peaks corresponding to cobalt monoxide (CoO) crystals The content of tricobalt tetraoxide (Co 3 O 4 ) in the produced oxygen reduction catalyst was determined according to the following formula. Similarly, the content of cobalt monoxide (CoO) was determined.
  • Example 2 (Preparation of oxygen reduction catalyst) An oxygen reduction catalyst (2) was obtained in the same manner as in Example 1 except that the baking time was changed to 6 hours. (Electrochemical measurement, XRD measurement, sulfur atom content) The electrochemical measurement, the XRD measurement and the sulfur atom content were measured and analyzed in the same manner as in Example 1, respectively. The XRD spectrum of the oxygen reduction catalyst (2) is shown in FIG. Only crystal structures of tricobalt tetraoxide (Co 3 O 4 ) and cobalt monoxide (CoO) were confirmed in the XRD spectrum.
  • tricobalt tetraoxide Co 3 O 4
  • CoO cobalt monoxide
  • the peaks of the strongest diffraction intensity among the peaks respectively corresponding to tricobalt tetraoxide (Co 3 O 4 ) and cobalt monoxide (CoO) are indicated by ⁇ and ⁇ , respectively. 25.
  • the above-mentioned confirmed respective diffraction peak intensities are obtained as described in Table 1, and the tricobalt tetraoxide content and the cobalt monoxide content are each 74.7%, 25. It was asked to be 3%.
  • Example 3 (Preparation of oxygen reduction catalyst) An oxygen reduction catalyst (3) was obtained in the same manner as in Example 1 except that the firing time was changed to 3 hours. (Electrochemical measurement, XRD measurement, sulfur atom content) The electrochemical measurement, the XRD measurement and the sulfur atom content were measured and analyzed in the same manner as in Example 1, respectively. The XRD spectrum of the oxygen reduction catalyst (3) is shown in FIG. Only crystal structures of tricobalt tetraoxide (Co 3 O 4 ) and cobalt monoxide (CoO) were confirmed in the XRD spectrum.
  • tricobalt tetraoxide Co 3 O 4
  • CoO cobalt monoxide
  • the peaks of the strongest diffraction intensity among the peaks respectively corresponding to tricobalt tetraoxide (Co 3 O 4 ) and cobalt monoxide (CoO) are indicated by ⁇ and ⁇ , respectively.
  • the above confirmed respective diffraction peak intensities are obtained as described in Table 1, and the tricobalt tetraoxide content and the cobalt monoxide content are 62.3%, 37.7 It was calculated as%.
  • Example 4 (Preparation of oxygen reduction catalyst) An oxygen reduction catalyst (4) was prepared in the same manner as in Example 3, except that the mixed gas atmosphere used in the calcination was changed to a mixed gas atmosphere of nitrogen gas (gas flow rate 97 mL / min) and oxygen gas (gas flow rate 3 mL / min). Got). (Electrochemical measurement, XRD measurement, sulfur atom content) The electrochemical measurement, the XRD measurement and the sulfur atom content were measured and analyzed in the same manner as in Example 1, respectively. The XRD spectrum of the oxygen reduction catalyst (4) is shown in FIG. Only crystal structures of tricobalt tetraoxide (Co 3 O 4 ) and cobalt monoxide (CoO) were confirmed in the XRD spectrum.
  • the peaks of the strongest diffraction intensity among the peaks respectively corresponding to tricobalt tetraoxide (Co 3 O 4 ) and cobalt monoxide (CoO) are indicated by ⁇ and ⁇ , respectively.
  • the above confirmed respective diffraction peak intensities are obtained as described in Table 1, and the tricobalt tetraoxide content and the cobalt monoxide content are respectively 20.4%, 79. It was asked to be 6%.
  • Comparative Example 1 (Preparation of oxygen reduction catalyst) An oxygen reduction catalyst (c1) was prepared in the same manner as in Example 3, except that the mixed gas atmosphere used in the calcination was changed to a mixed gas atmosphere of nitrogen gas (gas flow rate 99 mL / min) and oxygen gas (gas flow rate 1 mL / min). Got). (Electrochemical measurement, XRD measurement, sulfur atom content) The electrochemical measurement, the XRD measurement and the sulfur atom content were measured and analyzed in the same manner as in Example 1, respectively. The obtained XRD spectrum is shown in FIG. Only crystal structures of cobalt monoxide (CoO), Co 9 S 8 and cobalt monosulfide (CoS) were confirmed in the XRD spectrum.
  • CoO cobalt monoxide
  • Co 9 S 8 cobalt monosulfide
  • the peaks of the strongest diffraction intensity among the peaks respectively corresponding to cobalt monoxide (CoO), Co 9 S 8 and cobalt monosulfide (CoS) are shown by ⁇ , ⁇ and ⁇ , respectively.
  • the intensity of the strongest diffraction peak of the identified crystal was obtained as described in Table 1.
  • the cobalt monoxide content was determined to be 100%.
  • the crystal structure of tricobalt tetraoxide (Co 3 O 4 ) was not confirmed in the XRD spectrum of the oxygen reduction catalyst (c1), and the tricobalt tetraoxide content was determined to be 0%.
  • Comparative example 2 (Preparation of oxygen reduction catalyst) An oxygen reduction catalyst was prepared in the same manner as in Example 3, except that the mixed gas atmosphere used in the calcination was changed to a mixed gas atmosphere of nitrogen gas (gas flow rate 100 mL / min) and oxygen gas (gas flow rate 0.5 mL / min). I got (c2). (Electrochemical measurement, XRD measurement, sulfur atom content) The electrochemical measurement, the XRD measurement and the sulfur atom content were measured and analyzed in the same manner as in Example 1, respectively. The obtained XRD spectrum is shown in FIG. In the XRD spectrum, only crystal structures of cobalt monoxide (CoO), Co 9 S 8 and cobalt monosulfide (CoS) were confirmed.
  • CoO cobalt monoxide
  • Co 9 S 8 cobalt monosulfide
  • the peaks of the strongest diffraction intensity among the peaks respectively corresponding to cobalt monoxide (CoO), Co 9 S 8 and cobalt monosulfide (CoS) are shown by ⁇ , ⁇ and ⁇ , respectively.
  • the intensity of each of the confirmed diffraction peaks was obtained as described in Table 1.
  • the cobalt monoxide content was determined to be 100%.
  • the crystal structure of tricobalt tetraoxide (Co 3 O 4 ) was not confirmed in the XRD spectrum of the oxygen reduction catalyst (c2), and the tricobalt tetraoxide content was determined to be 0%.
  • the above respective diffraction peak intensities, the content rate of cobalt tetraoxide, the content rate of cobalt monoxide, the natural potential and the sulfur atom content confirmed in the XRD measurement are collectively shown in Table 1.
  • Comparative example 3 (Preparation of oxygen reduction catalyst) An oxygen reduction catalyst (c3) was obtained in the same manner as in Comparative Example 2 except that the firing temperature was changed to 400 ° C. (Electrochemical measurement, XRD measurement, sulfur atom content) The electrochemical measurement, the XRD measurement and the sulfur atom content were measured and analyzed in the same manner as in Example 1, respectively. The obtained XRD spectrum is shown in FIG. In the XRD spectrum, crystal structures of Co 9 S 8 , cobalt monosulfide (CoS) and tricobalt tetrasulfide (Co 3 S 4 ) were confirmed.
  • Co 9 S 8 cobalt monosulfide
  • Co 3 S 4 tricobalt tetrasulfide
  • the peaks of the strongest diffraction intensities among the peaks respectively corresponding to Co 9 S 8 , cobalt monosulfide (CoS) and tricobalt tetrasulfide (Co 3 S 4 ) are shown by ⁇ , ⁇ and ⁇ , respectively. .
  • the intensity of the strongest diffraction peak of the identified crystal was obtained as described in Table 1.
  • the crystal structure of tricobalt tetraoxide (Co 3 O 4 ) was not confirmed in the XRD spectrum of the oxygen reduction catalyst (c3), and both the tricobalt tetraoxide content and the cobalt monoxide content were determined to be 0%.
  • the above respective diffraction peak intensities, the content rate of cobalt tetraoxide, the content rate of cobalt monoxide, the natural potential and the sulfur atom content confirmed in the XRD measurement are collectively shown in Table 1.
  • Comparative example 4 (Oxygen reduction catalyst)
  • the cobalt monosulfide (CoS) used as a raw material in Example 1 was used as it is as an oxygen reduction catalyst (c4).
  • (Electrochemical measurement, XRD measurement, sulfur atom content) The electrochemical measurement, the XRD measurement and the sulfur atom content were measured and analyzed in the same manner as in Example 1, respectively.
  • the obtained XRD spectrum is shown in FIG. In the XRD spectrum, only the crystal structures of Co 9 S 8 , cobalt monosulfide (CoS) and tricobalt tetrasulfide (Co 3 S 4 ) were confirmed.
  • Comparative example 5 (Oxygen reduction catalyst) A commercially available tricobalt tetraoxide (Co 3 O 4 ) (manufactured by Kishda Chemical, grade for analysis of organic elements) was used as it was as an oxygen reduction catalyst (c5). (Electrochemical measurement, XRD measurement, sulfur atom content) The electrochemical measurement, the XRD measurement and the sulfur atom content were measured and analyzed in the same manner as in Example 1, respectively. The XRD spectrum of the oxygen reduction catalyst (c5) is shown in FIG. In the XRD spectrum, the peak of the strongest diffraction intensity among peaks corresponding to tricobalt tetraoxide (Co 3 O 4 ) is indicated by ⁇ .
  • Comparative example 6 (Oxygen reduction catalyst) A commercially available cobalt monoxide (CoO) (manufactured by Wako Pure Chemical Industries, Ltd.) was used as it was as an oxygen reduction catalyst (c6). (Electrochemical measurement, XRD measurement, sulfur atom content) The electrochemical measurement, the XRD measurement and the sulfur atom content were measured and analyzed in the same manner as in Example 1, respectively. The XRD spectrum of the oxygen reduction catalyst (c6) is shown in FIG. In the XRD spectrum, the peak of the strongest diffraction intensity among the peaks corresponding to cobalt monoxide (CoO) is indicated by ⁇ .
  • CoO cobalt monoxide
  • the oxygen reduction catalyst having a crystal structure of tricobalt tetraoxide (Co 3 O 4 ) and a sulfur atom content in the range of 1.0 to 15.0 mass% has a high natural potential.
  • the oxygen reduction catalyst of the present invention has a crystal structure of tricobalt tetraoxide (Co 3 O 4 ) and contains a sulfur atom in a specific amount range, and has a high oxygen reduction ability, and a catalyst containing an oxygen reduction catalyst It can be suitably used for a fuel cell electrode having a layer.

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Abstract

L'invention fournit un catalyseur de réduction d'oxygène qui consiste en un composé cobalt de capacité de réduction d'oxygène élevée en raison d'une teneur en atomes de soufre selon une plage que quantité prédéfinie. Le catalyseur de réduction d'oxygène de l'invention présente une structure cristalline de tétroxyde de tricobalt （Ｃｏ3Ｏ4）identifiée par mesure de diffraction des rayons X, et une teneur en atomes de soufre comprise entre 1,0 et 15,0% en masse.
PCT/JP2019/000194 2018-01-16 2019-01-08 Catalyseur de réduction d'oxygène Ceased WO2019142696A1 (fr)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005317288A (ja) * 2004-04-27 2005-11-10 Japan Science & Technology Agency 白金フリー硫化物系燃料電池触媒とその製造方法
JP2009043620A (ja) * 2007-08-09 2009-02-26 Toyota Motor Corp 燃料電池用電極触媒、酸素還元型触媒の性能評価方法、及びそれを用いた固体高分子型燃料電池
WO2013008501A1 (fr) * 2011-07-14 2013-01-17 昭和電工株式会社 Catalyseur de réduction de l'oxygène, son procédé de production et pile à combustible à membrane polymère échangeuse de protons

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005317288A (ja) * 2004-04-27 2005-11-10 Japan Science & Technology Agency 白金フリー硫化物系燃料電池触媒とその製造方法
JP2009043620A (ja) * 2007-08-09 2009-02-26 Toyota Motor Corp 燃料電池用電極触媒、酸素還元型触媒の性能評価方法、及びそれを用いた固体高分子型燃料電池
WO2013008501A1 (fr) * 2011-07-14 2013-01-17 昭和電工株式会社 Catalyseur de réduction de l'oxygène, son procédé de production et pile à combustible à membrane polymère échangeuse de protons

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