Carbon materials, methods for producing carbon materials, catalysts, dispersions, electrodes, batteries, and electrolysis apparatuses

Abstract

Disclosed is a carbon material which contains a fired product of a mixture that contains a first compound and a second compound, wherein: the first compound is a phthalocyanine compound that has bromine as a substituent; and the second compound contains at least one metal element that is selected from the group consisting of Fe, Co, Ni, Cu, Al and Zn.

Description

[Technical Field]

[0001] This disclosure relates to carbon materials, methods for producing carbon materials, catalysts, dispersions, electrodes, batteries, and electrolysis apparatus. [Background technology]

[0002] Carbon materials are used in a wide range of applications due to their properties such as high electrical conductivity, high thermal conductivity, low thermal expansion coefficient, lightness, and heat resistance. In recent years, the use of nitrogen-containing carbon materials as catalysts (oxygen reduction catalysts) for the positive electrodes of fuel cells and air batteries has been investigated (see Patent Document 1). Furthermore, nitrogen-containing carbon materials may possess carbon dioxide reduction activity or nitrogen reduction activity, and are attracting attention as catalysts (carbon dioxide reduction catalysts or nitrogen reduction catalysts) for the cathodes of electrolysis devices (see Non-Patent Documents 1 and 2). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2012-101155 [Patent Document 2] International Publication No. 2021 / 220495 [Non-patent literature]

[0004] [Non-Patent Document 1] Angew.Chem.Int.Ed., 2015, 54, 10758-10762 [Non-Patent Document 2] Nature Communications, 2019, 10, 341-348 [Overview of the project] [Problems that the invention aims to solve]

[0005] One aspect of the present disclosure aims to provide a novel carbon material that can be used in an oxygen reduction catalyst. Another aspect of the present disclosure aims to provide a carbon material that exhibits excellent oxygen reduction activity.

Means for Solving the Problems

[0006] Some aspects of the present disclosure provide the following [1] to

[17] .

[0007] [1] Containing a fired product of a mixture including a first compound and a second compound, where the first compound is a phthalocyanine compound having bromine as a substituent, and the second compound is a carbon material that is a compound containing at least one metal element selected from the group consisting of Fe, Co, Ni, Cu, Al, and Zn.

[0008] [2] The carbon material according to [1], wherein the phthalocyanine compound contains Fe, Co, or Zn as a central metal.

[0009] [3] The carbon material according to [1], wherein the phthalocyanine compound contains Zn as a central metal.

[0010] [4] The carbon material according to any one of [1] to [3], wherein the average number of bromines in the phthalocyanine compound is 4 or more.

[0011] [5] The phthalocyanine compound is in powder form, and the carbon material according to any one of [1] to [4], wherein the average particle diameter of the powder composed of the phthalocyanine compound is 300 nm or less.

[0012] [6] The carbon material according to any one of [1] to [5], wherein the second compound is a phthalocyanine compound or a porphyrin compound that does not have bromine as a substituent.

[0013] [7] The carbon material according to any one of [1] to [6], wherein the second compound is a compound containing Fe.

[0014] [8] The carbon material according to any one of [1] to [7], wherein the mass ratio of the content of the first compound to the content of the second compound in the mixture is 0.1 to 2000.

[0015] [9] A method for producing a carbon material according to any one of [1] to [8], A method for producing a carbon material, comprising the step of calcining a raw material containing the first compound and the second compound.

[0016]

[10] A catalyst used in the reduction reaction of oxygen, comprising a carbon material described in any of [1] to [8].

[0017]

[11] A dispersion containing a carbon material described in any of [1] to [8] and a dispersion medium for the carbon material.

[0018]

[12] A dispersion according to

[11] , containing a polymer electrolyte.

[0019]

[13] A dispersion according to

[11] or

[12] used for forming an electrode catalyst layer.

[0020]

[14] An electrode comprising an electrode catalyst layer containing a carbon material as described in any of [1] to [8].

[0021]

[15] The electrode according to

[14] , wherein the electrode catalyst layer contains a polymer electrolyte.

[0022]

[16] A battery comprising the electrodes described in

[14] or

[15] .

[0023]

[17] An electrolysis apparatus comprising the electrodes described in

[14] or

[15] . [Effects of the Invention]

[0024] According to one aspect of this disclosure, it is possible to provide novel carbon materials that can be used as oxygen reduction catalysts. [Modes for carrying out the invention]

[0025] In this specification, numerical ranges indicated using "~" represent a range that includes the numbers before and after "~" as the minimum and maximum values, respectively. Furthermore, unless otherwise explicitly stated, the units of the numbers before and after "~" are the same. In numerical ranges described in stages within this specification, the upper or lower limit of one stage of the range may be replaced with the upper or lower limit of another stage. Also, in numerical ranges described within this specification, the upper or lower limit of that range may be replaced with the values ​​shown in the examples (experimental examples). Additionally, individually described upper and lower limits can be combined in any way.

[0026] Preferred embodiments of this disclosure are described below. However, this disclosure is not limited to the embodiments described below.

[0027] <Carbon materials> One embodiment of the present disclosure is a carbon material containing a calcined product of a mixture comprising a first compound and a second compound, wherein the first compound is a phthalocyanine compound having bromine (Br) as a substituent (hereinafter also referred to as a "brominated phthalocyanine compound"), and the second compound is a compound containing at least one metal element selected from the group consisting of Fe, Co, Ni, Cu, Al, and Zn. The second compound is a different compound from the first compound, for example, a compound that does not contain bromine (Br).

[0028] The carbon material described above, containing the calcined product of the above mixture, exhibits excellent oxygen reduction activity. Therefore, the carbon material can be used as a catalyst for oxygen reduction reactions (oxygen reduction catalyst), and is used, for example, as a positive electrode catalyst in fuel cells, air batteries, etc. The carbon material can also be used as a cathode catalyst in oxygen electrolysis devices. The carbon material also tends to exhibit carbon dioxide reduction activity and nitrogen reduction activity, and may therefore be usable as a catalyst for carbon dioxide reduction reactions (carbon dioxide reduction catalyst) and nitrogen reduction reactions (nitrogen reduction catalyst). Specific applications include, for example, cathode catalysts for carbon dioxide electrolysis devices and nitrogen electrolysis devices. The oxygen reduction activity, carbon dioxide reduction activity, and nitrogen reduction activity of the carbon material can be confirmed by the method described in the Examples (Experimental Examples).

[0029] The first compound, a brominated phthalocyanine compound, has a structure represented by, for example, the following formula (1) or formula (2).

[0030] [ka]

[0031] [ka]

[0032] X in equations (1) and (2) 1 ~X 16 Each of these independently represents either a hydrogen atom or a halogen atom. However, X 1 ~X 16 At least one of them is a bromine atom.

[0033] In formula (2), M represents the central metal. Examples of central metals (M) include Fe, Co, Ni, Cu, and Zn. Phthalocyanine compounds containing a central metal are sometimes referred to using a prefix corresponding to the type of central metal, such as "iron phthalocyanine" (central metal: Fe), "cobalt phthalocyanine" (central metal: Co), "copper phthalocyanine" (central metal: Cu), and "zinc phthalocyanine" (central metal: Zn).

[0034] Brominated phthalocyanine compounds do not necessarily have the above-mentioned central metal (M), but when brominated phthalocyanine compounds have the above-mentioned central metal (M), superior oxygen reduction activity, carbon dioxide reduction activity, and nitrogen reduction activity are more likely to be obtained. From the viewpoint of obtaining even better oxygen reduction activity, brominated phthalocyanine compounds may contain Fe, Co, or Zn as the central metal (M), and from the viewpoint of obtaining even better oxygen reduction activity, they may contain Zn.

[0035] The halogen atom may consist solely of a bromine atom, or it may be a combination of a bromine atom and other halogen atoms (fluorine, chlorine, and iodine atoms). The halogen atom may contain both a bromine atom and a chlorine atom.

[0036] Among brominated phthalocyanine compounds, phthalocyanine compounds having bromine and chlorine as substituents and Zn as the central metal (brominated zinc chloride phthalocyanine) tend to yield even better oxygen reduction activity.

[0037] The mixture may contain one or more brominated phthalocyanine compounds.

[0038] The average number of bromine atoms in a brominated phthalocyanine compound, that is, the average number of bromine atoms in the brominated phthalocyanine compound (the number of bromine atoms per molecule), should be greater than 0, and from the viewpoint of easily obtaining superior oxygen reduction activity, carbon dioxide reduction activity, and nitrogen reduction activity, it may be 4 or more (for example, 4 to 16), 5 or more, 8 or more, or 11 or more, and may be 15 or less, or 13 or less.

[0039] The average number of chlorine atoms in a brominated phthalocyanine compound, that is, the average number of chlorine atoms in the brominated phthalocyanine compound (the number of chlorine atoms per molecule), may be greater than 0 and 11 or less, and may be 0.1 or more, 0.5 or more, or 1 or more, or may be 3 or less, or 2 or less, from the viewpoint of easily obtaining better oxygen reduction activity, carbon dioxide reduction activity, and nitrogen reduction activity.

[0040] The average halogen count of the brominated phthalocyanine compound, that is, the average total number of halogen atoms in the brominated phthalocyanine compound (total number of halogen atoms per molecule), is greater than 0 and is more likely to yield superior oxygen reduction activity, carbon dioxide reduction activity, and nitrogen reduction activity. From this viewpoint, it may be between 8 and 16, 11 or more, 15 or less, or 14 or less.

[0041] The number of halogen atoms can be determined, for example, by mass spectrometry using a matrix-assisted laser desorption / ionization time-of-flight mass spectrometer (such as the JMS-S3000 manufactured by JEOL Ltd.). Specifically, the number of each halogen atom can be calculated as a relative value per central metal element from the mass ratio of the central metal element to each halogen atom in the brominated phthalocyanine compound.

[0042] Brominated phthalocyanine compounds are, for example, in powder form. The finer the powder made from the brominated phthalocyanine compound, the finer the calcined product becomes, and the easier it is to obtain superior oxygen reduction activity, carbon dioxide reduction activity, and nitrogen reduction activity. From this viewpoint, the average particle size (average value of the major axis of the primary particles) of the powder made from the brominated phthalocyanine compound may be 300 nm or less (e.g., 10 to 300 nm), 200 nm or less (e.g., 10 to 200 nm), 100 nm or less (e.g., 10 to 100 nm), 70 nm or less (e.g., 10 to 70 nm), 60 nm or less (e.g., 10 to 60 nm), or 40 nm or less (e.g., 10 to 40 nm), or 40 nm or more (e.g., 40 to 200 nm) or 70 nm or more (e.g., 70 to 200 nm). The average aspect ratio of the powder made from the brominated phthalocyanine compound may be, for example, 1.0 to 3.0. Powders having such average particle size and average aspect ratio can be produced, for example, by methods described in International Publication No. 2021 / 220495, etc.

[0043] The second compound contains at least one metal element selected from the group consisting of Fe, Co, Ni, Cu, Al, and Zn. When the second compound contains Fe, better oxygen reduction activity, carbon dioxide reduction activity, and nitrogen reduction activity are more easily obtained. If the first compound contains a metal element (i.e., the brominated phthalocyanine compound has a central metal), the second compound may contain a different metal element than the metal element contained in the first compound.

[0044] In the second compound, the metal element may be a metal element included as the central metal of a phthalocyanine compound or a porphyrin compound. That is, the second compound may be a phthalocyanine compound without bromine as a substituent, or a porphyrin compound without bromine as a substituent. When the second compound is a phthalocyanine compound or a porphyrin compound without bromine as a substituent, it is easier to obtain superior oxygen reduction activity, carbon dioxide reduction activity, and nitrogen reduction activity. The phthalocyanine compound and the porphyrin compound may have halogen elements other than bromine (fluorine, chlorine, or iodine) as substituents.

[0045] The second compound may be a metal salt containing the above-mentioned metal element. Examples of metal salts include sulfates, nitrates, carbonates, phosphates, chromates, metal porphyrin complexes, metal phthalocyanine complexes, alkali metal salts, alkaline earth metal salts, earth metal salts, transition metal salts, ammonium salts, hydrogenates, oxoates, and the like.

[0046] Specific examples of the second compound include metal phthalocyanines such as iron phthalocyanine, cobalt phthalocyanine, nickel phthalocyanine, copper phthalocyanine, and aluminum chloride phthalocyanine, and chlorinated compounds obtained by substituting some of the hydrogen atoms of these with chlorine atoms (where M in formula (2) above is Fe, Co, Ni, Cu, Al, or Zn, and X 1 ~X 16 Examples include iron tetraphenylporphyrin chloride, tris(dibenzoylmethanato)ferrous sulfate (e.g., iron(II) sulfate heptahydrate), and iron chloride (e.g., iron(III) chloride hexahydrate, iron(II) chloride tetrahydrate).

[0047] The second compound is, for example, in powder form. The finer the powder made from the second compound, the finer the calcined product becomes, and the easier it is to obtain superior oxygen reduction activity, carbon dioxide reduction activity, and nitrogen reduction activity. From this viewpoint, the average particle size (average value of the major axis of the primary particles) of the powder made from the second compound may be 5000 nm or less (for example, 10 to 5000 nm), 500 nm or less, or 200 nm or less, or 30 nm or more, or 50 nm or more.

[0048] The second compound included in the mixture may be one or more types.

[0049] The mixing ratio of the first compound to the second compound, that is, the mass ratio of the content of the first compound C1 to the content of the second compound C2 in the mixture (C1 / C2), may be 0.1 to 2000, and may be 0.2 or more, 0.2 or more, 0.5 or more, 1 or more, 2 or more, or 10 or more, and may be 1000 or less, 500 or less, 100 or less, 50 or less, 10 or less, 10 or less, 2 or less, 1 or less, or 0.5 or less.

[0050] The mixture may consist only of the first compound and the second compound, or it may further contain components other than the first and second compounds (other components). The total content of the first and second compounds in the mixture may be 50% by mass or more, 80% by mass or more, or 90% by mass or more, based on the total mass of the mixture, from the viewpoint of making it easier to obtain a carbon material with superior oxygen reduction activity, carbon dioxide reduction activity and nitrogen reduction activity. The total content of the first and second compounds in the mixture may be 100% by mass, 99% by mass or less, or 95% by mass or less, based on the total mass of the mixture.

[0051] Other components include, for example, organic compounds that do not contain metal elements. Examples of such organic compounds include phenolic resins, polyfurfuryl alcohol, furan, furan resin, phenolformaldehyde resin, epoxy resin, polyvinylidene chloride, polythiophene, polysulfone, polyvinyl alcohol, polyvinyl butyral, polyester, polylactic acid, polyether, polyetheretherketone, cellulose, carboxymethylcellulose, lignin, pitch, polycarbazole, polyacrylic acid, polyacrylic acid esters, polymethacrylic acid esters, and polymethacrylic acid.

[0052] Other components that can be used include carbon materials such as graphite, activated carbon, amorphous carbon, carbon black, coal, charcoal, coke, carbon nanotubes, fullerenes, and graphene.

[0053] The carbon material may consist solely of the above-mentioned calcined product, or it may contain components other than the above-mentioned calcined product. From the viewpoint of obtaining better oxygen reduction activity, the content of the above-mentioned calcined product in the carbon material may be 50% by mass or more, 80% by mass or more, or 90% by mass or more, based on the total mass of the carbon material. The content of the above-mentioned calcined product in the carbon material may be 100% by mass, 99% by mass or less, or 95% by mass or less, based on the total mass of the carbon material.

[0054] The carbon material may have a shape corresponding to the shape of the fired product. The shape of the carbon material is not particularly limited, but may be, for example, in powder form. The median diameter of the carbon material may be, for example, 0.01 to 50 μm, or 0.01 to 10 μm. The median diameter of the carbon material is the D50 particle size measured by a laser diffraction particle size distribution analyzer equipped with an airflow type dry disperser.

[0055] The average particle size of the carbon material may be, for example, 0.01 to 1 μm, may be 0.35 μm or less, or may be 0.1 μm or less, and may also be 0.05 μm or more. Among these, when the average particle size of the carbon material is 0.01 to 0.35 μm, there is a tendency that more excellent oxygen reduction activity is likely to be obtained. The average particle size is the average particle size of primary particles (average primary particle size), and can be calculated from the average value of 40 primary particles constituting the aggregate on the two-dimensional image after ultrasonic dispersion of the sample in cyclohexane and then photographing with a microscope.

[0056] The carbon material may have pores with a size corresponding to elements other than carbon (nitrogen (N), bromine (Br), chlorine (Cl), metal element (M), etc.) contained in the first compound and the second compound. That is, the carbon material may be a porous carbon material (for example, a powdery porous carbon material).

[0057] The specific surface area (BET specific surface area) of the carbon material may be, for example, 100 m 2 / g or more, may be 200 m 2 / g or more, or may be 300 m 2 / g or more. The specific surface area (BET specific surface area) of the carbon material may be 2000 m 2 / g or less, may be 1500 m 2 / g or less, or may be 1000 m 2 / g or less. From these viewpoints, the specific surface area (BET specific surface area) of the carbon material may be, for example, 100 to 2000 m 2 / g.

[0058] The carbon material described above is a material mainly containing carbon (C), but may contain elements other than carbon (nitrogen (N), bromine (Br), chlorine (Cl), metal element (M), etc.) contained in the first compound and the second compound.

[0059] The content of carbon (C) in the carbon material may be, for example, 60% by mass or more, may be 70% by mass or more, or may be 80% by mass or more. The content of carbon (C) in the carbon material is the content based on the total mass of the carbon material and can be measured by CHN elemental analysis using a combustion method.

[0060] The nitrogen (N) content in the carbon material may be such that, for example, the number of nitrogen atoms per carbon atom in the carbon material is 0.300 or less, or it may be 0.220 or less, or 0.140 or less. The nitrogen (N) content in the carbon material may be 0 ppm by mass, or it may be such that the number of nitrogen atoms per carbon atom in the carbon material is 0.005 or more, 0.010 or more, or 0.050 or more. The number of carbon atoms and nitrogen atoms in the carbon material can be measured by X-ray photoelectron spectroscopy (XPS).

[0061] The bromine (Br) content in the carbon material may be, for example, 100,000 ppm by mass or less, 50,000 ppm by mass or less, or 20,000 ppm by mass or less. The bromine (Br) content in the carbon material may be 0 ppm by mass, but may be 50 ppm or more by mass, 500 ppm or more by mass, or 2,000 ppm or more by mass. The bromine content in the carbon material is the content based on the total mass of the carbon material and can be measured by combustion ion chromatography (CIC).

[0062] The chlorine (Cl) content in the carbon material may be, for example, 30,000 ppm by mass or less, and may also be 10,000 ppm by mass or less, 5,000 ppm by mass or less, 1,000 ppm by mass or less, 500 ppm by mass or less, or 100 ppm by mass or less. The chlorine (Cl) content in the carbon material may be 0 ppm by mass, or 10 ppm by mass or more. The chlorine (Cl) content in the carbon material is the content based on the total mass of the carbon material and can be measured by combustion ion chromatography (CIC).

[0063] The content of metal elements (M) in the carbon material may be, for example, 20% by mass or less, 5% by mass or less, or 2% by mass or less. The content of metal elements (M) in the carbon material may be 0 ppm by mass, 0.005% by mass or more, 0.1% by mass or more, or 1% by mass or more. The content of metal elements is based on the total mass of the carbon material and can be measured by inductively coupled plasma emission spectrometry (ICP-OES).

[0064] <Method for manufacturing carbon materials> Another embodiment of the present disclosure is a method for producing a carbon material, comprising the step of calcining a raw material comprising a first compound and a second compound, wherein the first compound is a phthalocyanine compound having bromine as a substituent, and the second compound is a compound comprising at least one metal element selected from the group consisting of Fe, Co, Ni, Cu, Al, and Zn.

[0065] According to the above method, the carbon material of the above embodiment can be obtained. That is, according to the above method, a novel carbon material that can be used as an oxygen reduction catalyst can be obtained.

[0066] The mixture described above can be used as the raw material. That is, the first compound and the second compound described above can be used as the first compound and the second compound, and the examples are the same as those above. Furthermore, the example of the total amount of the first compound and the second compound used (based on the total mass of the raw material) is the same as the example of the total content of the first compound and the second compound (based on the total mass of the mixture) described above. Furthermore, the example of the ratio (mass ratio) of the amounts of the first compound and the second compound used is the same as the example of the mixing ratio (mass ratio) of the first compound and the second compound described above. Furthermore, the examples of other components that can be used as raw materials are the same as the examples of other components that may be included in the above mixture.

[0067] The firing temperature of the raw materials may be any temperature at which the raw materials can be carbonized, for example, 600°C or higher. From the viewpoint of obtaining carbon materials with superior oxygen reduction activity, carbon dioxide reduction activity, and nitrogen reduction activity, the firing temperature of the raw materials may be 700°C or higher, 800°C or higher, or 900°C or higher. From the viewpoint of suppressing high crystallization of the carbon material, the firing temperature of the raw materials may be, for example, 1500°C or lower, 1200°C or lower, or 1000°C or lower. From these viewpoints, the firing temperature of the raw materials may be, for example, 600 to 1500°C, or 700 to 1500°C.

[0068] The firing time for the raw materials may be, for example, 0.5 to 6 hours.

[0069] The atmospheric gas used during firing may be an inert gas, an oxidizing gas, a reducing gas, or a mixture thereof. Examples of inert gases include argon, helium, and nitrogen. Examples of oxidizing gases include carbon dioxide. Examples of reducing gases include hydrogen and ammonia. From the viewpoint of the porosity of the resulting carbon material, the atmospheric gas may contain at least one selected from the group consisting of nitrogen, ammonia, and carbon dioxide. For example, if the specific surface area is to be improved, an ammonia-containing gas may be used. Mixing ammonia with helium tends to improve the total volume of either mesopores or micropores. The concentration of ammonia in the ammonia-containing gas may be, for example, 0.1 to 50 volume percent.

[0070] The calcination of the raw materials may be carried out by a single heat treatment, or by two or more heat treatments. For example, heat treatment may be performed at a temperature below 600°C followed by heat treatment at a temperature of 600°C or higher.

[0071] When performing heat treatment in two or more stages, the second stage may be carried out under a different atmosphere than the first stage. By using a different gas atmosphere for the second stage, the specific surface area, the total volume of mesopores and micropores, etc., can be easily controlled.

[0072] In one embodiment of this disclosure, the obtained calcined product may be washed. That is, the calcined product constituting the carbon material may be a calcined product after washing. The washing method is not particularly limited and examples include water washing, acid washing, alkaline washing, etc. The washing method may be acid washing from the viewpoint of controlling the content of metal elements. Examples of acids include hydrochloric acid and sulfuric acid.

[0073] (catalyst) Another embodiment of the present disclosure is a catalyst (e.g., an electrocatalyst) containing the carbon material of the above embodiment. The catalyst of the embodiment may be an oxygen reduction catalyst, a carbon dioxide reduction catalyst, or a nitrogen reduction catalyst. The oxygen reduction catalyst may be a two-electron reduction catalyst that catalyzes the two-electron reduction reaction of oxygen, or a four-electron reduction catalyst that catalyzes the four-electron reduction reaction of oxygen, but tends to exhibit better catalytic activity when used as a four-electron reduction catalyst. Since the carbon material of the above embodiment exhibits catalytic activity as an oxygen reduction catalyst under both acidic and basic conditions, the oxygen reduction catalyst of this embodiment can be used under both acidic and basic conditions.

[0074] (dispersion) Another embodiment of the present disclosure is a dispersion containing the carbon material of the above embodiment and a dispersion medium for the carbon material. This dispersion is used for the formation of an electrode catalyst layer, etc. That is, one aspect of the dispersion is an ink composition for forming an electrode catalyst layer.

[0075] As described above, the carbon material of the above embodiment can function as an oxygen reduction catalyst, a carbon dioxide reduction catalyst, or a nitrogen reduction catalyst. Therefore, the dispersion is useful for forming an electrode catalyst layer for an oxygen reduction electrode (e.g., a positive electrode catalyst layer for fuel cells, air batteries, etc., and a cathode catalyst layer for oxygen electrolyzers), an electrode catalyst layer for a carbon dioxide reduction electrode (e.g., a cathode catalyst layer for carbon dioxide electrolyzers), or an electrode catalyst layer for a nitrogen reduction electrode (e.g., a cathode catalyst layer for nitrogen electrolyzers).

[0076] As the dispersion medium, known dispersion media used for forming electrode catalyst layers in the above-mentioned batteries and electrolysis apparatus can be used. For example, water, lower alcohols (methanol, ethanol, isopropyl alcohol, n-propyl alcohol, etc.) and mixtures thereof can be used. The content of the dispersion medium may be adjusted as appropriate so that the viscosity of the dispersion is suitable for the coating apparatus. The content of the dispersion medium in the dispersion may be, for example, 60 to 99.5% by mass based on the total mass of the dispersion.

[0077] The dispersion may consist only of a carbon material and a dispersion medium, but it may also contain known materials used for forming the electrode catalyst layer of the battery or electrolysis apparatus. The dispersion may further contain, for example, a binder for the carbon material. Known organic polymer compounds can be used as the binder, and polymer electrolytes may be used from the viewpoint of forming ion conduction paths. Examples of polymer electrolytes include perfluorosulfonic acid polymers such as Nafion®.

[0078] If the dispersion contains solids other than carbon materials (e.g., the binder mentioned above), the carbon material content may be 40 to 80% by mass, based on the total amount of solids in the dispersion. The binder content may be 20 to 60% by mass, based on the total amount of solids in the dispersion. If the dispersion contains a polymer electrolyte, the polymer electrolyte content may be 20 to 60% by mass, based on the total amount of solids in the dispersion. The total amount of solids refers to the sum of components other than the dispersion medium contained in the dispersion.

[0079] The dispersion may further contain carbon materials other than the carbon materials of the above embodiments, but the content of carbon materials other than the carbon materials of the above embodiments may be 40% by mass or less based on the total amount of all carbon materials.

[0080] (electrode) Another embodiment of the present disclosure is an electrode comprising an electrode catalyst layer containing the carbon material of the above embodiment. This electrode may be an oxygen reduction electrode (e.g., the positive electrode of a fuel cell or air battery, or the cathode of an oxygen electrolyzer), a carbon dioxide reduction electrode (e.g., the cathode of a carbon dioxide electrolyzer), or a nitrogen reduction electrode (e.g., the cathode of a nitrogen electrolyzer). The configuration of the electrode other than the electrode catalyst layer may be a configuration that is conventionally known with respect to oxygen reduction electrodes, carbon dioxide reduction electrodes, nitrogen reduction electrodes, etc. The electrode of one embodiment may further comprise, for example, a gas diffusion layer, a microporous layer, etc.

[0081] The electrode catalyst layer may consist solely of carbon material, but may also contain components other than carbon material depending on its application. Examples of components other than carbon material include binders such as the polymer electrolytes mentioned above. The range of carbon material, binder, and polymer electrolyte content in the electrode catalyst layer (based on the total mass of the electrode catalyst layer) may be the same as the range of carbon material, binder, and polymer electrolyte content in the dispersion liquid of the above embodiment (based on the total amount of solids in the dispersion liquid).

[0082] The electrode catalyst layer described above can be formed using the dispersion of the above embodiment. For example, the electrode catalyst layer may be obtained by coating the dispersion onto a support and drying it. The coating method is not particularly limited, and general methods such as bar coaters, spray coaters, and screen printers can be used.

[0083] The above electrode may be part of a membrane electrode assembly (MEA) that constitutes a fuel cell. The MEA comprises, for example, a positive electrode catalyst layer and a negative electrode catalyst layer, an electrolyte membrane disposed between the positive electrode catalyst layer and the negative electrode catalyst layer, and a pair of gas diffusion layers disposed on the side of the positive electrode catalyst layer and the negative electrode catalyst layer opposite to the electrolyte membrane side.

[0084] (battery) Another embodiment of the present disclosure is a battery comprising the electrodes of the above embodiment. This battery is, for example, a battery comprising the electrodes of the above embodiment as an oxygen reduction electrode (positive electrode), and may be a fuel cell or an air battery. Examples of fuel cells include polymer electrolyte fuel cells (PEFCs), phosphate fuel cells (PAFCs), alkaline fuel cells (AFCs), molten carbonate fuel cells (MCFCs), solid electrolyte fuel cells (SOFCs), and microbial fuel cells (MFCs). The battery configuration other than the positive electrode may adopt configurations that are conventionally known with respect to fuel cells, air batteries, etc. The battery of one embodiment may be, for example, a fuel cell comprising a membrane-electrode assembly (MEA) including the above electrodes.

[0085] (Electrolysis device) Another embodiment of this disclosure is an electrolysis apparatus equipped with the electrodes of the above embodiment. This electrolysis apparatus may be an electrolysis apparatus (oxygen electrolysis apparatus) equipped with the electrodes of the above embodiment as the oxygen reduction electrode (cathode), an electrolysis apparatus (carbon dioxide electrolysis apparatus) equipped with the electrodes of the above embodiment as the carbon dioxide reduction electrode (cathode), or an electrolysis apparatus (nitrogen electrolysis apparatus) equipped with the electrodes of the above embodiment as the nitrogen reduction electrode (cathode). An oxygen electrolysis apparatus can also be called a hydrogen peroxide synthesis apparatus because it synthesizes hydrogen peroxide in conjunction with the decomposition of oxygen. The configuration of the battery other than the cathode can be a configuration that is conventionally known with respect to oxygen electrolysis apparatuses, carbon dioxide electrolysis apparatuses, nitrogen electrolysis apparatuses, etc. [Examples]

[0086] The contents of this disclosure will be explained in more detail below using experimental examples, but this disclosure is not limited to the experimental examples below.

[0087] <Method for measuring halogen count> The halogen counts (average bromine count and average chlorine count) of the materials used in the experimental examples were determined by mass spectrometry using a JEOL Ltd. JMS-S3000.

[0088] <Method for measuring average particle size> The average particle size (average primary particle size) of the material used in the experimental example was calculated from the average value of 40 primary particles constituting the aggregates in the two-dimensional image obtained by ultrasonically dispersing the material in cyclohexane and then photographing it with a microscope.

[0089] <Experimental Example 1> As raw material 1, raw material powder A was prepared, consisting of CI Pigment Green 58 (zinc phthalocyanine with bromine and chlorine substituents, average number of bromine atoms: 11-16, average number of chlorine atoms: 0-5, average particle size: 10-60 nm, "BrCl-ZnPc (A)" in Table 1) manufactured by DIC Corporation. As raw material 2, iron phthalocyanine ("FePc" in Table 1, manufactured by Tokyo Chemical Industry Co., Ltd., iron(II) phthalocyanine, product code: P0774, average particle size: 110 nm, the same applies hereafter) was prepared. Next, a raw material mixture was prepared by mixing raw material powder A (raw material 1) and iron phthalocyanine (raw material 2) in a mass ratio of 10:1 (raw material 1:raw material 2).

[0090] 1.0 g of the raw material mixture was placed on a calcination boat (CC brand Nikkatoh SSA-S 5B; 99.6% alumina) and set in the center of a quartz reaction tube. Nitrogen was circulated at 500 ml / min for 20 minutes to purge any remaining air from the tube. Then, under a nitrogen flow (500 ml / min), the temperature was raised to 600°C (calcination temperature) at a rate of 10°C / min in a tubular furnace and held for 2 hours. After that, it was cooled to room temperature under a nitrogen flow before the carbon material, which was the calcined product of the raw material mixture, was removed.

[0091] <Experimental Examples 2 and 3> Carbon materials were prepared in the same manner as in Experimental Example 1, except that the firing temperature was changed from 600°C to 900°C or 1000°C.

[0092] <Experimental Examples 4-11> Carbon materials were prepared in the same manner as in Experimental Example 2, except that the mixing ratio (mass ratio) of raw material powder A (raw material 1) and iron phthalocyanine (raw material 2) was changed to the ratio shown in Table 1 (raw material 1:raw material 2).

[0093] <Experimental Example 12> A carbon material was prepared in the same manner as in Experimental Example 2, except that cobalt phthalocyanine (labeled "CoPc" in Table 2, manufactured by Tokyo Chemical Industry Co., Ltd., cobalt(II) phthalocyanine, product code: P0887, average particle size: 200 nm) was used as raw material 2 instead of iron phthalocyanine.

[0094] <Experimental Example 13> A carbon material was prepared in the same manner as in Experimental Example 2, except that copper phthalocyanine (CuPc in Table 2, manufactured by Tokyo Chemical Industry Co., Ltd., copper(II) phthalocyanine (β-type), product code: P1006, average particle size: 70 nm) was used as raw material 2 instead of iron phthalocyanine.

[0095] <Experimental Example 14> A carbon material was prepared in the same manner as in Experimental Example 2, except that nickel phthalocyanine ("NiPc" in Table 2, manufactured by Sigma-Aldrich, nickel(II) phthalocyanine, product number: 360635, average particle size: 90 nm) was used as raw material 2 instead of iron phthalocyanine.

[0096] <Experimental Example 15> A carbon material was prepared in the same manner as in Experimental Example 2, except that aluminum chloride phthalocyanine (Al(Cl)Pc in Table 2, manufactured by Tokyo Chemical Industry Co., Ltd., chloroaluminum phthalocyanine, product code: C1167, average particle size: 240 nm) was used as raw material 2 instead of iron phthalocyanine.

[0097] <Experimental Example 16> A carbon material was prepared in the same manner as in Experimental Example 2, except that iron tetraphenylporphyrin chloride (FeTPP in Table 2, manufactured by Tokyo Chemical Industry Co., Ltd., iron(III) tetraphenylporphyrin chloride, product code: I0937, average particle size: 180 nm) was used as raw material 2 instead of iron phthalocyanine.

[0098] <Experimental Example 17> A carbon material was prepared in the same manner as in Experimental Example 2, except that chlorinated iron phthalocyanine ("16Cl-FePc" in Table 2, manufactured by Cosmo Bio, product number: 097, average particle size: 130 nm), in which all 16 hydrogen atoms were replaced with chlorine atoms, was used as raw material 2.

[0099] <Experimental Example 18> A carbon material was prepared in the same manner as in Experimental Example 2, except that iron(II) sulfate heptahydrate ("FeSO4" in Table 2, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., average particle size: 430 nm) was used as raw material 2 instead of iron phthalocyanine.

[0100] <Experimental Example 19> A carbon material was prepared in the same manner as in Experimental Example 2, except that tris(dibenzoylmethanato)ferrous iron (TDBM-Fe in Table 2, manufactured by Tokyo Chemical Industry Co., Ltd., tris(dibenzoylmethanato)ferrous iron, product code: T1686, average particle size: 260 nm) was used as raw material 2 instead of iron phthalocyanine.

[0101] <Experimental Example 20> Raw material powder B was prepared from CI Pigment Green 59 (zinc phthalocyanine with bromine and chlorine substituents, average number of bromine atoms: 8-13, average number of chlorine atoms: 0-5, average particle size: 10-60 nm, "BrCl-ZnPc (B)" in Table 3) manufactured by DIC Corporation. A carbon material was prepared in the same manner as in Experimental Example 2, except that raw material powder B was used instead of raw material powder A as raw material 1.

[0102] <Experimental Example 21> In a 300 ml flask, 91 g of sulfuryl chloride (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 109 g of aluminum chloride (manufactured by Kanto Chemical Co., Ltd.), 15 g of sodium chloride (manufactured by Tokyo Chemical Industries, Ltd.), 30 g of copper phthalocyanine (manufactured by Tokyo Chemical Industries, Ltd.), and 230 g of bromine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were charged. The mixture was then heated to 130°C and held at 130°C for 4 hours. The reaction mixture (reaction solution) was removed and placed in water to precipitate. After the precipitate was filtered, washed with water, and dried, a crude pigment powder was obtained. 12 g of the crude pigment powder, 240 g of Japanese sea salt (manufactured by Nihonkaisui Co., Ltd.), and 35 g of diethylene glycol were charged into a double-arm kneader and kneaded at 80°C for 18 hours. The resulting mixture was then placed in 700 g of water. After stirring for 1 hour, the mixture was filtered, washed with hot water, dried, and pulverized to obtain raw material powder C (copper phthalocyanine with bromine and chlorine substituents, average number of bromine atoms: 11-16, average number of chlorine atoms: 0-5, average particle size: 10-60 nm, "BrCl-CuPc" in Table 3).

[0103] A carbon material was prepared in the same manner as in Experimental Example 2, except that raw material powder C was used instead of raw material powder A as raw material 1.

[0104] <Experimental Example 22> A carbon material was prepared in the same manner as in Experimental Example 21, except that cobalt phthalocyanine (labeled "CoPc" in Table 3, manufactured by Tokyo Chemical Industry Co., Ltd., cobalt(II) phthalocyanine, product code: P0887, hereinafter the same) was used as raw material 2 instead of iron phthalocyanine.

[0105] <Experimental Example 23> In a 300 ml flask, 91 g of sulfuryl chloride (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 109 g of aluminum chloride (manufactured by Kanto Chemical Co., Ltd.), 15 g of sodium chloride (manufactured by Tokyo Chemical Industries, Ltd.), 30 g of iron phthalocyanine, and 230 g of bromine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were charged, and the mixture was heated to 130°C and held at 130°C for 4 hours. The reaction mixture (reaction solution) was taken out and placed in water to precipitate, and the precipitate was filtered, washed with water, and dried to obtain crude pigment powder. 12 g of crude pigment powder, 240 g of Japanese sea salt (manufactured by Nihonkaisui Co., Ltd.), and 35 g of diethylene glycol were charged into a double-arm kneader and kneaded at 80°C for 18 hours, after which the resulting mixture was taken out and placed in 700 g of water. After stirring for 1 hour, the mixture was filtered, washed with hot water, dried, and pulverized to obtain raw material powder D (iron phthalocyanine with bromine and chlorine substituents, average number of bromine atoms: 11-16, average number of chlorine atoms: 0-5, average particle size: 10-60 nm, "BrCl-FePc" in Table 3).

[0106] A carbon material was prepared in the same manner as in Experimental Example 2, except that raw material powder D was used instead of raw material powder A as raw material 1.

[0107] <Experimental Example 24> In a 300 ml flask, 91 g of sulfuryl chloride (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 109 g of aluminum chloride (manufactured by Kanto Chemical Co., Ltd.), 15 g of sodium chloride (manufactured by Tokyo Chemical Industries, Ltd.), 30 g of cobalt phthalocyanine (manufactured by Tokyo Chemical Industries, Ltd.), and 230 g of bromine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were charged. The mixture was then heated to 130°C and held at 130°C for 4 hours. The reaction mixture (reaction solution) was removed and placed in water to precipitate. After the precipitate was filtered, washed with water, and dried, a crude pigment powder was obtained. 12 g of the crude pigment powder, 240 g of Japanese sea salt (manufactured by Nihonkaisui Co., Ltd.), and 35 g of diethylene glycol were charged into a double-arm kneader and kneaded at 80°C for 18 hours. The resulting mixture was then placed in 700 g of water. After stirring for 1 hour, the mixture was filtered, washed with hot water, dried, and pulverized to obtain raw material powder E (cobalt phthalocyanine with bromine and chlorine substituents, average number of bromine atoms: 11-16, average number of chlorine atoms: 0-5, average particle size: 10-60 nm, "BrCl-CoPc" in Table 3).

[0108] A carbon material was prepared in the same manner as in Experimental Example 2, except that raw material powder E was used instead of raw material powder A as raw material 1.

[0109] <Experimental Example 25> 5 g of raw material powder A and 100 g of propylene glycol monomethyl ether acetate were placed in a 150 mL vial and ultrasonically treated at 31 kHz for 8 hours using a Honda Electronics W-113MKII tabletop ultrasonic cleaner. By filtration, washing with water, drying, and grinding in a mortar, raw material powder F (zinc phthalocyanine with bromine and chlorine substituents, average bromine number: 11-16, average chlorine number: 0-5, average particle size: 210 nm, "BrCl-ZnPc (F)" in Table 3) was obtained.

[0110] A carbon material was prepared in the same manner as in Experimental Example 2, except that raw material powder F was used instead of raw material powder A as raw material 1.

[0111] <Experimental Example 26> 5 g of raw material powder A and 100 g of cyclohexane were placed in a 150 mL vial and ultrasonically treated at 31 kHz for 8 hours using a Honda Electronics W-113MKII tabletop ultrasonic cleaner. By filtration, washing with water, drying, and grinding in a mortar, raw material powder G (zinc phthalocyanine with bromine and chlorine substituents, average number of bromine atoms: 11-16, average number of chlorine atoms: 0-5, average particle size: 70 nm, "BrCl-ZnPc (G)" in Table 3) was obtained.

[0112] A carbon material was prepared in the same manner as in Experimental Example 2, except that raw material powder G was used instead of raw material powder A as raw material 1.

[0113] <Experimental Example 27> 12 g of raw material powder A, 240 g of Japanese sea salt (manufactured by Nippon Kaisui Co., Ltd.), and 35 g of diethylene glycol were placed in a double-arm kneader and kneaded at 80°C for 18 hours. After kneading, the resulting mixture was transferred to 700 g of water. After stirring for 1 hour, the mixture was filtered, washed with hot water, dried, and pulverized to obtain raw material powder H (zinc phthalocyanine with bromine and chlorine substituents, average number of bromine atoms: 11-16, average number of chlorine atoms: 0-5, average particle size: 40 nm, "BrCl-ZnPc (H)" in Table 3).

[0114] A carbon material was prepared in the same manner as in Experimental Example 2, except that raw material powder H was used instead of raw material powder A as raw material 1.

[0115] <Experimental Example 28> Carbon materials were prepared in the same manner as in Experimental Example 2, except that zinc phthalocyanine (ZnPc in Table 3, manufactured by DIC Corporation, hereinafter the same) was used instead of the raw material mixture.

[0116] <Experimental Example 29> A carbon material was prepared in the same manner as in Experimental Example 2, except that iron phthalocyanine was used instead of the raw material mixture.

[0117] <Experimental Example 30> A carbon material was prepared in the same manner as in Experimental Example 2, except that zinc phthalocyanine was used instead of raw material powder A.

[0118] <Experimental Example 31> The carbon material was prepared in the same manner as in Experimental Example 2, except that a mixed gas of ammonia and helium (ammonia concentration: 10 vol%) was used as the flowing gas instead of nitrogen.

[0119] <Experimental Example 32> 0.5 g of the carbon material obtained in Experimental Example 2 and 50 ml of 1 mol / L hydrochloric acid were placed in a 110 ml vial and stirred at 70°C for 1 hour, after which the mixture was filtered and washed with water. The same procedure was repeated two more times, and the resulting residue was dried overnight in a 90°C oven to prepare the carbon material.

[0120] <Experimental Example 33> A carbon material was prepared in the same manner as in Experimental Example 20, except that raw material powder B (raw material 1) and iron phthalocyanine (raw material 2) were mixed in a mass ratio of 500:1 (raw material 1:raw material 2). 0.5 g of the obtained carbon material and 50 ml of 1 mol / L hydrochloric acid were placed in a 110 ml vial and stirred at 70°C for 1 hour, after which the mixture was filtered and washed with water. The same procedure was repeated two more times, and the resulting residue was dried overnight in a 90°C oven to produce the carbon material.

[0121] <Analysis> The BET specific surface area of ​​carbon materials in Experimental Examples 1-33 was measured by nitrogen adsorption. The measurements were performed using a fully automatic specific surface area analyzer, Macsorb HMmodel-1208 (manufactured by Mountec Co., Ltd.), in accordance with the "Method for measuring gas adsorption amount by single-point method" specified in Annex 2 of Japanese Industrial Standard JIS Z 8830-1990. The results are shown in Tables 1-3.

[0122] <Rating> (Evaluation of oxygen reduction activity) [Acidic conditions] The oxygen reduction activity of the carbon materials in Experimental Examples 1-33 under acidic conditions was evaluated using the following method. As a reference example, the oxygen reduction activity of platinum-supported carbon (product name: TEC10E10E, manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.), which is conventionally used as a catalyst for oxygen reduction electrodes in fuel cells, was also evaluated.

[0123] First, 4.1 mg of carbon material or platinum-supported carbon, 1680 μL of IPA (isopropyl alcohol), 420 μL of ultrapure water, and 30 μL of 5% Nafion (Sigma-Aldrich; catalog number 510211) were measured into a vial and mixed by irradiating with ultrasound for 5 minutes to obtain a dispersion. 4 μL of the dispersion was dropped onto the disk portion of a platinum ring GC disk electrode (RRDE) (BAS, catalog number 012613, ring outer diameter: 7.0 mm, ring inner diameter: 5.0 mm, disk outer diameter: 4.0 mm), and allowed to stand for about 10 minutes to dry. This was repeated a total of two times, and a total of 8 μL of the dispersion was applied to the catalytic electrode for measurement (disk electrode area: 0.126 cm²). 2 Catalyst load: 123 μg / cm³ 2 ) was obtained.

[0124] Next, the oxygen reduction activity of the catalytic electrode was evaluated using a three-electrode electrochemical cell method, with an Ag / AgCl electrode (BAS Corporation; part number 012167) as the reference electrode and a Pt coil electrode (BAS Corporation; part number 012961) as the counter electrode. Specifically, first, the measurement system was stabilized by cycling through the range of -0.1 to 0.7 V (vs. Ag / AgCl) in a 0.1 M HClO4 aqueous solution saturated with nitrogen (N2) at a scanning speed of 100 mV / s. Next, linear sweep voltammetry (LSV) measurements were performed in a 0.1 M HClO4 aqueous solution saturated with oxygen (O2) while rotating the catalytic electrode at 1600 rpm. The LSV measurement was performed by scanning from noble potential to base potential at 10 mV / s in the range of -0.1 to 0.7 V (vs. Ag / AgCl). The potential of the ring electrode was set to 0.9V (vs. Ag / AgCl), which is a potential that can sufficiently oxidize hydrogen peroxide.

[0125] The voltammogram obtained by measurement with an Ag / AgCl electrode is converted to an RHE reference using the following formula (a), and the disk current value I at 0.2V (vs. RHE) is obtained. Disk Ring current value I Ring And, the reaction initiation potential E onset We found that in equation (a) below, E observed This is the potential relative to the Ag / AgCl electrode, and E 0 Ag / AgCl The ratio was set to 0.195, and the pH was set to 1.0. E RHE =E 0 Ag / AgCl +0.0590 pH+E observed …(a)

[0126] Furthermore, to confirm the proportion of two-electron reduction reactions (reactions that produce hydrogen peroxide) among the catalyzed oxygen reduction reactions, the hydrogen peroxide production rate (%H2O2) was determined based on the following equation (a1). The capture rate N was calculated based on the following equations (a2) to (a5), using the outer radius r1 of the disk portion of the disk electrode, the inner radius r2 of the ring portion of the ring electrode, and the inner radius r3 of the ring portion of the ring electrode. • %H2O2 (unit: %) = 2 × I Ring / N / (I Disk +I Ring / N) …(a1) N = 1 - F(α / β) + β 2 / 3 [1-F(α)]-(1+α+β) 2 / 3 {1-F[(α / β)(1+α+β)]} …(a2) ·α=(r² / r¹) 3 -1 …(a3) ·β=(r3 / r1) 3 -(r2 / r1) 3 …(a4) ·F(θ)=[3 1 / 2 / (4π)]In[(1+θ 1 / 3 ) / (1+θ)]+[3 / (2π)]arctan[(2θ 1 / 3 -1) / 3 1 / 2 ] + 1 / 4 …(a5)

[0127] In this evaluation, 0.1 mA / cm 2The potential at which the reduction current flows is defined as the reaction initiation potential, and the disk current value at 0.2V (vs. RHE) is I Disk -1.5mA / cm 2 The following conditions are met, and if the reaction initiation potential is 0.5V or higher, the carbon material is judged to have oxygen reduction activity under acidic conditions, and the disk current value at 0.2V (vs. RHE) I Disk -4.0mA / cm 2 The following conditions were observed, and it was determined that carbon materials possessed excellent oxygen reduction activity under acidic conditions when the reaction initiation potential was 0.7V or higher. Furthermore, among the carbon materials determined to possess oxygen reduction activity, those with a hydrogen peroxide production rate (%H2O2) of 30% or higher were deemed particularly useful as catalysts for two-electron reduction reactions, and those with a hydrogen peroxide production rate (%H2O2) of 15% or less were deemed particularly useful as catalysts for four-electron reduction reactions. The results are shown in Tables 1 to 3.

[0128] [Basic conditions] The oxygen reduction activity of carbon materials under basic conditions for Experimental Examples 1-27 and 31-33 was evaluated in the same manner as the measurement method under acidic conditions described above, except that a 0.1M KOH aqueous solution was used instead of a 0.1M HClO4 aqueous solution, the range was changed from -0.1 to 0.7V (vs. Ag / AgCl) to -0.7 to 0.1V (vs. Ag / AgCl), and the potential of the ring electrode was set to 0.2V (vs. Ag / AgCl). However, the value substituted for pH in the above formula (a) to convert the voltammogram to the RHE standard was set to 13.

[0129] In this evaluation, 0.1 mA / cm 2 The potential at which the reduction current flows is defined as the reaction initiation potential, and the disk current value at 0.4V (vs. RHE) is I Disk -2.8mA / cm 2 The following conditions are met, and if the reaction initiation potential is 0.6V or higher, the carbon material is judged to have oxygen reduction activity under basic conditions, and the disk current value at 0.4V (vs. RHE) is I Disk -4.0mA / cm 2The following conditions were observed, and it was determined that carbon materials possessed excellent oxygen reduction activity under basic conditions when the reaction initiation potential was 0.85V or higher. Furthermore, among the carbon materials determined to possess oxygen reduction activity, those with a hydrogen peroxide production rate (%H2O2) of 30% or higher were deemed particularly useful as catalysts for two-electron reduction reactions, and those with a hydrogen peroxide production rate (%H2O2) of 15% or less were deemed particularly useful as catalysts for four-electron reduction reactions. The results are shown in Tables 1 to 3.

[0130] [Table 1]

[0131] [Table 2]

[0132] [Table 3]

[0133] (Evaluation of carbon dioxide reduction activity) The carbon dioxide reduction activity of the carbon materials in Experimental Examples 1-33 was evaluated using the following method.

[0134] First, a catalytic electrode for measurement was prepared in the same manner as for evaluating oxygen reduction activity. Next, using an Ag / AgCl electrode (BAS Corporation; product number 012167) as the reference electrode and a Pt coil electrode (BAS Corporation; product number 012961) as the counter electrode, the carbon dioxide reduction activity of the catalytic electrode for measurement was evaluated using a three-electrode electrochemical cell method. Specifically, first, the measurement system was stabilized by cycling in the range of -1.8 to -0.7 V (vs. Ag / AgCl) at a scanning speed of 100 mV / s in a 0.5 M KHCO3 (potassium bicarbonate) aqueous solution saturated with argon (Ar), and then a voltammogram was obtained by performing LSV measurement while rotating the catalytic electrode for measurement at 1600 rpm. Next, a voltammogram was obtained by performing LSV measurement in a 0.5 M KHCO3 aqueous solution saturated with carbon dioxide (CO2), while rotating the catalytic electrode for measurement at 1600 rpm. LSV measurements were performed by scanning the range from -0.8 to -0.1 V (vs. RHE) from noble potential to base potential at 5 mV / s. The voltammogram of the carbon dioxide reduction reaction was obtained by subtracting the voltammogram under argon saturation from the voltammogram under carbon dioxide saturation. The obtained voltammogram was converted to an RHE standard using equation (a) above to determine the current value at -0.7 V (vs. RHE). However, the value substituted for pH in equation (a) above to convert the voltammogram to an RHE standard was set to 8.36. In the voltammogram of the carbon dioxide reduction reaction, a larger negative current value indicates higher carbon dioxide reduction activity.

[0135] In this evaluation, the current value at -0.7V (vs. RHE) in the voltammogram of the carbon dioxide reduction reaction was -0.05 mA / cm². 2 The carbon material is judged to have carbon dioxide reduction activity (evaluation A or B) if the following conditions are met: the current value at -0.7V (vs. RHE) in the voltammogram of the carbon dioxide reduction reaction is -0.4mA / cm². 2 If the value was less than [value missing], the carbon material was judged to have excellent carbon dioxide reduction activity (evaluation A). The evaluation results are shown in Table 4. Experiments in which the carbon material was judged to have no carbon dioxide reduction activity were evaluated as C.

[0136] (Evaluation of nitrogen reduction activity) The nitrogen reduction activity of carbon materials in Experimental Examples 1-33 was evaluated using the following method.

[0137] First, a catalytic electrode for measurement was prepared in the same manner as for evaluating oxygen reduction activity. Next, using an Ag / AgCl electrode (BAS Corporation; product number 012167) as the reference electrode and a Pt coil electrode (BAS Corporation; product number 012961) as the counter electrode, the nitrogen reduction activity of the catalytic electrode for measurement was evaluated using a three-electrode electrochemical cell method. Specifically, first, the measurement system was stabilized by cycling in the range of -1.7 to -0.5 V (vs. Ag / AgCl) at a scanning speed of 100 mV / s in a 0.1 M Na2SO4 (sodium sulfate) aqueous solution saturated with argon (Ar), and then a voltammogram was obtained by performing LSV measurement while rotating the catalytic electrode for measurement at 1600 rpm. Next, a voltammogram was obtained by performing LSV measurement in a 0.1 M Na2SO4 aqueous solution saturated with nitrogen (N2), while rotating the catalytic electrode for measurement at 1600 rpm. LSV measurements were performed by scanning the range from -0.8 to 0V (vs. RHE) from noble potential to base potential at 5mV / s. The voltammogram of the nitrogen reduction reaction was obtained by subtracting the voltammogram under argon saturation from the voltammogram under nitrogen saturation. The obtained voltammogram was converted to an RHE standard using equation (a) above to determine the current value at -0.8V (vs. RHE). However, the value substituted for pH in equation (a) above to convert the voltammogram to an RHE standard was set to 5.8. In the voltammogram of the nitrogen reduction reaction, a larger negative current value indicates higher nitrogen reduction activity.

[0138] In this evaluation, the current value at -0.8V (vs. RHE) in the voltammogram of the nitrogen reduction reaction was -0.02 mA / cm². 2 The carbon material is judged to have nitrogen reduction activity (evaluation A or B) if the following conditions are met: the current value at -0.8V (vs. RHE) in the voltammogram of the nitrogen reduction reaction is -0.3mA / cm². 2 If the value was less than [value], the carbon material was judged to have excellent nitrogen reduction activity (evaluation A). The results are shown in Table 4. Experiments in which the carbon material was judged to have no nitrogen reduction activity were evaluated as C.

[0139] Table 4

Claims

1. It contains a calcined product of a mixture containing the first compound and the second compound, The first compound is a phthalocyanine compound having bromine and chlorine as substituents. The second compound is a compound containing at least one metal element selected from the group consisting of Fe, Co, Ni, Cu, Al, and Zn. The phthalocyanine compound contains Fe, Co, Ni, Cu, or Zn as the central metal. The average bromine number of the phthalocyanine compound is 4 or more and less than 16. The average number of chlorine atoms in the phthalocyanine compound is greater than 0 and 11 or less. The average halogen number of the phthalocyanine compound is 8 or more and 16 or less. BET specific surface area is 100-2000 m² ２ A carbon material that is / g.

2. The carbon material according to claim 1, wherein the phthalocyanine compound comprises Fe, Co, or Zn as the central metal.

3. The carbon material according to claim 1, wherein the phthalocyanine compound contains Zn as the central metal.

4. The phthalocyanine compound is in powder form, The carbon material according to claim 1, wherein the average particle size of the powder comprising the phthalocyanine compound is 300 nm or less.

5. The carbon material according to claim 1, wherein the second compound is a phthalocyanine compound or a porphyrin compound that does not have bromine as a substituent.

6. The carbon material according to claim 1, wherein the second compound is a compound containing Fe.

7. The carbon material according to claim 1, wherein the mass ratio of the content of the first compound to the content of the second compound in the mixture is 0.1 to 2000.

8. A method for producing a carbon material according to any one of claims 1 to 7, A method for producing a carbon material, comprising the step of calcining a raw material containing the first compound and the second compound.

9. A catalyst used in the reduction reaction of oxygen, comprising a carbon material according to any one of claims 1 to 7.

10. A dispersion comprising a carbon material according to any one of claims 1 to 7 and a dispersion medium for the carbon material.

11. The dispersion according to claim 10, comprising a polymer electrolyte.

12. The dispersion according to claim 10, used for forming an electrode catalyst layer.

13. An electrode comprising an electrode catalyst layer containing the carbon material described in any one of claims 1 to 7.

14. The electrode according to claim 13, wherein the electrode catalyst layer contains a polymer electrolyte.

15. A battery comprising the electrode described in claim 13.

16. An electrolysis apparatus comprising the electrodes described in claim 13.

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