Carbon catalyst, electrode, and battery

Abstract

To provide a carbon catalyst which exhibits high catalytic activity while effectively avoiding problems attributable to iron, an electrode, and a battery.SOLUTION: A carbon catalyst has a ratio L / La of at least 12, where L / La means a ratio of an average carbon mesh surface size L, obtained by temperature-programmed desorption analysis capable of temperature raising to 1600°C, to the crystallite size La, obtained from a diffraction peak near a diffraction angle (2θ) of 43° in an X-ray diffraction pattern based on powder X-ray diffraction using a CuKα ray. The carbon catalyst has an iron content of 3000 ppm or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a carbon catalyst, an electrode, and a battery. [Background technology]

[0002] Patent Document 1 describes an oxygen reduction catalyst that includes composite particles in which particles of a titanium compound are dispersed in a carbon structure, and the composite particles have titanium, iron, carbon, nitrogen, and oxygen as constituent elements. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-123894 A Summary of the Invention [Problem to be solved by the invention]

[0004] On the other hand, it has not yet been fully elucidated what kind of carbon structure improves the catalytic activity of carbon materials. Also, it has been found that when a catalyst containing iron is used in the electrodes of a fuel cell, iron leaks from the catalyst and causes problems.

[0005] The present invention has been made in view of the above problems, and one of its objects is to provide a carbon catalyst, an electrode, and a battery that exhibit high catalytic activity while effectively avoiding problems caused by iron. [Means for solving the problem]

[0006] [1] A carbon catalyst according to one embodiment of the present invention for solving the above problems has an L / La ratio of 12 or more, which is the ratio of an average carbon network plane size L obtained by thermal desorption analysis capable of heating up to 1600°C to a crystallite size La obtained from a diffraction peak at a diffraction angle (2θ) of about 43° in an X-ray diffraction pattern obtained by powder X-ray diffraction using CuKα rays, and an iron content of 3000 ppm or less. According to the present invention, a carbon catalyst that exhibits high catalytic activity while effectively avoiding problems caused by iron is provided.

[0007] [2] The carbon catalyst according to [1] may have a crystallite size La of 10.00 nm or less. [3] The carbon catalyst according to [1] or [2] may have an average carbon net plane size L of 5 nm or more.

[0008] [4] The carbon catalyst according to any one of [1] to [3] may contain nitrogen atoms. [5] The carbon catalyst according to any one of [1] to [4] may have a ratio of a nitrogen atom concentration to a carbon atom concentration obtained by X-ray photoelectron spectroscopy of 0.0005 or more.

[0009] [6] The carbon catalyst according to any one of [1] to [5] has a BET specific surface area of ​​100 m 2 [7] The carbon catalyst according to any one of [1] to [6] may have a micropore volume of 0.05 cm3 or more. 3 [8] The carbon catalyst according to any one of [1] to [7] may have a micropore volume of 2.50 cm3 / g or more. 3 [9] The carbon catalyst according to any one of [1] to [8] may have a mesopore volume of 0.001 cm3 or less. 3

[10] The carbon catalyst according to any one of [1] to [9] may contain a non-noble metal other than iron.

[0010]

[11] An electrode according to an embodiment of the present invention for solving the above problems includes the carbon catalyst according to any one of [1] to

[10] . According to the present invention, an electrode that exhibits high catalytic activity while effectively avoiding problems caused by iron is provided.

[0011]

[12] A battery according to an embodiment of the present invention for solving the above problems includes the electrode according to

[11] . According to the present invention, a battery having an electrode that exhibits high catalytic activity while effectively avoiding problems caused by iron is provided. Effect of the Invention

[0012] According to the present invention, there are provided a carbon catalyst, an electrode, and a battery that exhibit high catalytic activity while effectively avoiding problems caused by iron. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is an explanatory diagram of a coronene model for the average carbon net surface size L. [Diagram 2] FIG. 11 is an explanatory diagram showing the results of evaluating the characteristics of a carbon catalyst in an example according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] An embodiment of the present invention will be described below. Note that the present invention is not limited to the example shown in this embodiment.

[0015] The carbon catalyst according to this embodiment (hereinafter referred to as "the catalyst") is a carbon material that exhibits catalytic activity. The catalyst is mainly composed of carbon. Specifically, the carbon content of the catalyst may be, for example, 70% by weight or more, preferably 75% by weight or more, more preferably 80% by weight or more, and particularly preferably 85% by weight or more. The carbon content of the catalyst may be, for example, 100% by weight or less, 95% by weight or less, or 90% by weight or less. The carbon content of the catalyst may be specified by any combination of any of the above-mentioned lower limit values ​​and any of the above-mentioned upper limit values. The carbon content of the carbon catalyst is obtained by elemental analysis (combustion method).

[0016] The present catalyst exhibits catalytic activity by itself. That is, the present catalyst exhibits catalytic activity without, for example, supporting a precious metal. The catalytic activity exhibited by the present catalyst is, for example, catalytic activity for reduction reaction and / or catalytic activity for oxidation reaction, more specifically, catalytic activity for oxygen reduction reaction and / or catalytic activity for hydrogen oxidation reaction, and is at least catalytic activity for oxygen reduction reaction.

[0017] The iron content of the catalyst may be, for example, 3000 ppm or less, preferably 2000 ppm or less, more preferably 1000 ppm or less, even more preferably 500 ppm or less, even more preferably 300 ppm or less, even more preferably 200 ppm or less, even more preferably 100 ppm or less, and particularly preferably 50 ppm or less. Note that 1 ppm means 0.0001% by weight. The iron content is obtained by inductively coupled plasma (ICP) emission spectrometry.

[0018] By having the iron content of the present catalyst be within the above-mentioned range, for example, even when the present catalyst is used as an electrode catalyst for a fuel cell, the occurrence of problems caused by iron can be effectively avoided.

[0019] The inventors of the present invention have conducted extensive research into technical means for improving the catalytic activity of a carbon catalyst while effectively avoiding problems caused by iron. As a result, they have independently found that a carbon catalyst having a carbon structure in which L / La, which is the ratio of an average carbon network plane size L to a crystallite size La, falls within a predetermined range, exhibits high catalytic activity, and have completed the present invention.

[0020] In other words, this catalyst has an L / La ratio of 12 or more, which is the ratio of the average carbon network plane size L obtained by temperature programmed desorption analysis that can be heated up to 1600°C to the crystallite size La obtained from a diffraction peak at a diffraction angle (2θ) of about 43° in an X-ray diffraction pattern obtained by powder X-ray diffraction using CuKα radiation.

[0021] The L / La of the present catalyst is preferably 13 or more, and particularly preferably 14 or more. The upper limit of L / La of the present catalyst is not particularly limited as long as the effects of the present invention are obtained, and may be, for example, 12500 or less, 10000 or less, 5000 or less, 1000 or less, 700 or less, 500 or less, 300 or less, 200 or less, or 100 or less. The L / La of the present catalyst may be specified by any combination of any of the above-mentioned lower limit values ​​and any of the above-mentioned upper limit values.

[0022] The L / La in the above-mentioned range contributes to improving the catalytic activity of the present catalyst. That is, when L / La is equal to or greater than the above-mentioned lower limit, for example, the carbon structure of the present catalyst contains a structure having a moderate planarity, so that the active structure contained in the carbon structure is effectively increased, and as a result, the catalytic activity of the present catalyst is effectively improved. On the other hand, when L / La is equal to or less than the above-mentioned upper limit, for example, an electron conductive path is effectively formed in the carbon structure, so that the catalytic activity of the present catalyst is more effectively improved.

[0023] The crystallite size La of a carbon catalyst is obtained from a diffraction peak having a diffraction angle (2θ) of about 43° in an X-ray diffraction pattern obtained by powder X-ray diffraction of the carbon catalyst using CuKα radiation. Here, when a carbon catalyst has a structure in which hexagonal carbon mesh planes extending in the a-axis direction are connected among crystallites constituting curved carbon mesh planes that contribute to the catalytic activity of the carbon catalyst, a carbon (10) diffraction line (hereinafter referred to as "diffraction peak f") having a peak top at a diffraction angle (2θ) of about 43° (for example, within a range of 35° to 60°) in an X-ray diffraction pattern using CuKα radiation is obtained. 10 ") appears.

[0024] And this diffraction peak f 10 The crystallite size La is calculated by analyzing the diffraction peak f 10 The Bragg angle and full width at half maximum of La are substituted into the following Scherrer formula: La = Kλ / (βcosθ), where K is the Scherrer constant (0.94), λ is the wavelength of CuKα radiation (0.15418 nm), β is the full width at half maximum (radian), and θ is the Bragg angle (radian).

[0025] The crystallite size La of the present catalyst is not particularly limited as long as the effects of the present invention are obtained, but for example, it may be 10.00 nm or less, preferably 5.00 nm or less, more preferably 3.00 nm or less, even more preferably 2.50 nm or less, even more preferably 2.40 nm or less, even more preferably 2.35 nm or less, even more preferably 2.30 nm or less, even more preferably 2.25 nm or less, even more preferably 2.20 nm or less, and particularly preferably 2.15 nm or less.

[0026] In addition, the crystallite size La of the present catalyst may be, for example, 0.40 nm or more, 0.70 nm or more, 1.00 nm or more, 1.10 nm or more, 1.15 nm or more, 1.20 nm or more, 1.23 nm or more, or 1.25 nm or more. The crystallite size La of the present catalyst may be specified by any combination of any of the above-mentioned lower limit values ​​and any of the above-mentioned upper limit values.

[0027] The crystallite size La within the above range contributes to improving the catalytic activity of the catalyst. That is, if the crystallite size La is too large, the carbon structure spreads too much in the a-axis direction, which may cause a problem that the active structure contained in the carbon structure is reduced too much. On the other hand, if the crystallite size La is equal to or less than the upper limit value described above, the spread of the carbon structure in the a-axis direction is appropriately suppressed, so that the active structure contained in the carbon structure is effectively increased, and as a result, the catalytic activity of the catalyst is effectively improved. On the other hand, if the crystallite size La is too small, the crystallinity of the carbon structure in the a-axis direction is too low, so that the carbon structure has a disordered structure, which may cause a problem that the conductive path of electrons is difficult to form in the carbon structure. On the other hand, if the crystallite size La is equal to or more than the lower limit value described above, the conductive path of electrons is effectively formed in the carbon structure, so that the catalytic activity of the catalyst is more effectively improved.

[0028] The average carbon net plane size L of the carbon catalyst is obtained by a temperature programmed desorption (TPD) analysis capable of raising the temperature of the carbon catalyst up to 1600° C. That is, in this embodiment, the total amount of carbon edge planes of the carbon catalyst is calculated from the desorbed gas quantitative analysis result of the high-temperature TPD of the carbon catalyst using a temperature programmed desorption analyzer (high-temperature TPD device) capable of raising the temperature up to 1600° C., and the average carbon net plane size L obtained from the amount is calculated using the coronene model shown in Fig. 1. a0 in the formula shown in Fig. 1 represents 0.2461 nm, which is the lattice constant in the a-axis direction of graphite crystal.

[0029] The average carbon mesh plane size L of the present catalyst is not particularly limited as long as the effects of the present invention are obtained, but may be, for example, 5 nm or more, preferably 10 nm or more, more preferably 15 nm or more, even more preferably 20 nm or more, even more preferably 23 nm or more, even more preferably 25 nm or more, even more preferably 26 nm or more, even more preferably 27 nm or more, even more preferably 28 nm or more, and particularly preferably 29 nm or more.

[0030] The average carbon mesh surface size L of the present catalyst may be, for example, 5000 nm or less, 2000 nm or less, 1000 nm or less, 500 nm or less, 400 nm or less, 300 nm or less, 200 nm or less, 120 nm or less, 115 nm or less, or 113 nm or less. The average carbon mesh surface size L of the present catalyst may be specified by any combination of any of the above-mentioned lower limit values ​​and any of the above-mentioned upper limit values.

[0031] The average carbon mesh surface size L within the above range contributes to improving the catalytic activity of the catalyst. That is, when the average carbon mesh surface size L is too small, the continuity of the carbon structure is too low, so that the problem of the conductive path of electrons being difficult to form in the carbon structure may occur. On the other hand, when the average carbon mesh surface size L is equal to or greater than the above-mentioned lower limit, the continuity of the carbon structure is improved, and the catalytic activity of the catalyst is effectively improved. On the other hand, when the average carbon mesh surface size L is too large, the hexagonal mesh surfaces contained in the carbon structure are easily stacked, so that the carbon structure has a structure with too high planarity, and as a result, the problem of the carbon structure containing too many inactive structures may occur. On the other hand, when the average carbon mesh surface size L is equal to or less than the above-mentioned upper limit, the stacking of the hexagonal mesh surfaces in the carbon structure is not too many, and the inactive structures contained in the carbon structure are effectively reduced, so that the catalytic activity of the catalyst is more effectively improved.

[0032] The BET specific surface area of ​​the catalyst is not particularly limited as long as the effects of the present invention can be obtained. For example, 2 / g or more, 2 / g or more, and 2 / g or more is more preferable, and 2 / g or more is more preferable, 2 / g or more is more preferable, and 2 / g or more is more preferable, and 650m 2 / g or more is more preferable, and 2 It is particularly preferable that the molecular weight is 1 / g or more.

[0033] The BET specific surface area of ​​the catalyst is, for example, 4000 m 2 / g or less, and 2 / g or less, and 2 / g or less, and 2 / g or less. The BET specific surface area of ​​the catalyst may be specified by any combination of any of the above-mentioned lower limit values ​​and any of the above-mentioned upper limit values. The BET specific surface area is obtained by a nitrogen adsorption method.

[0034] The BET specific surface area within the above range contributes to improving the catalytic activity of the catalyst. That is, if the BET specific surface area is too small, the carbon structure is densely stacked, and the number of exposed carbon atoms is small, which may cause a problem that the carbon structure and the reactive active material are difficult to contact with each other. On the other hand, if the BET specific surface area is equal to or greater than the above-mentioned lower limit, the carbon structure and the reactive active material are effectively contacted with each other, which effectively improves the catalytic activity of the catalyst. On the other hand, if the BET specific surface area is too large, the carbon structure has a disordered structure, which may cause a problem that the conductive path of electrons is difficult to form in the carbon structure. On the other hand, if the BET specific surface area is equal to or less than the above-mentioned upper limit, the conductive path of electrons in the carbon structure is effectively formed, which more effectively improves the catalytic activity of the catalyst.

[0035] The micropore volume of the present catalyst is not particularly limited as long as the effects of the present invention can be obtained. For example, the micropore volume is 0.05 cm 3 / g or more, 3 / g or more, and 3 / g or more is more preferable, and 0.15 cm 3 More preferably, it is 0.20 cm / g or more. 3 More preferably, it is 0.25 cm / g or more. 3 More preferably, it is 0.30 cm / g or more. 3 More preferably, it is 0.35 cm / g or more. 3 It is particularly preferable that the molecular weight is 1 / g or more.

[0036] The micropore volume of the catalyst is, for example, 2.50 cm 3 / g or less, and 3 / g or less, and 1.50 cm 3 / g or less is more preferable, and 1.40 cm 3 / g or less, and more preferably 1.30 cm 3 / g or less, and more preferably 1.20 cm 3 / g or less is more preferable, and 1.15 cm 3 / g or less is more preferable, and 3 / g or less, and more preferably 1.05 cm 3 / g or less is more preferable, and 1.00 cm 3 More preferably, it is 0.95 cm / g or less. 3 / g or less is particularly preferred. The micropore volume of the present catalyst may be specified by any combination of any of the above-mentioned lower limit values ​​and any of the above-mentioned upper limit values.

[0037] In this embodiment, the micropores are pores having a diameter of less than 2 nm, and the micropore volume is the total volume of the micropores contained in the catalyst. The micropore volume is obtained by a nitrogen adsorption method.

[0038] The micropore volume within the above range contributes to improving the catalytic activity of the present catalyst. That is, if the micropore volume is too small, the carbon structure is densely stacked, and the number of exposed carbon atoms is small, which may cause a problem that the carbon structure and the reactive active material are difficult to contact with each other. On the other hand, if the micropore volume is equal to or greater than the above-mentioned lower limit, the carbon structure and the reactive active material are effectively contacted with each other, which effectively improves the catalytic activity of the present catalyst. On the other hand, if the micropore volume is too large, the carbon structure has a disordered structure, which may cause a problem that the conductive path of electrons is difficult to form in the carbon structure. On the other hand, if the micropore volume is equal to or less than the above-mentioned upper limit, the conductive path of electrons in the carbon structure is effectively formed, which more effectively improves the catalytic activity of the present catalyst.

[0039] The mesopore volume of the present catalyst is not particularly limited as long as the effects of the present invention can be obtained. For example, 3 / g or more, and 3 / g or more, and 0.01 cm 3 / g or more, and 3 / g or more, and 3 It is particularly preferable that the molecular weight is 1 / g or more.

[0040] The mesopore volume of the catalyst is, for example, 5.00 cm 3 / g or less, and 3 / g or less, and 3 / g or less is more preferable, and 2.00 cm 3 / g or less, and more preferably 1.70 cm 3 / g or less is more preferable, and 3 / g or less is more preferable, and 1.50 cm 3 / g or less is more preferable, and 1.45 cm 3 / g or less, and more preferably 1.43 cm 3 / g or less is particularly preferred. The mesopore volume of the present catalyst may be specified by any combination of any of the above-mentioned lower limit values ​​and any of the above-mentioned upper limit values.

[0041] In this embodiment, the mesopores are pores having a diameter of 2 nm or more and 50 nm or less, and the mesopore volume is the total volume of the mesopores contained in the catalyst. The mesopore volume is obtained by a nitrogen adsorption method.

[0042] A mesopore volume within the above-mentioned range contributes to improving the catalytic activity of the present catalyst. That is, if the mesopore volume is too small, the transport of substances (e.g., water and / or ion exchange substances) having a size of about several tens of nanometers entering and leaving the carbon structure is hindered, which may cause a problem of inhibiting the catalytic reaction. In contrast, if the mesopore volume is equal to or greater than the above-mentioned lower limit, the transport of substances to the carbon structure is smooth, which effectively improves the catalytic activity. On the other hand, if the mesopore volume is too large, the carbon catalyst becomes too bulky, which may cause a problem of significantly reducing the catalytic activity of the carbon catalyst per certain volume. In contrast, if the mesopore volume is equal to or less than the above-mentioned lower limit, the catalytic activity per certain volume is effectively maintained, which may more effectively improve the catalytic activity of the present catalyst.

[0043] The catalyst preferably contains nitrogen atoms. That is, in this case, the catalyst contains, for example, nitrogen atoms doped into the carbon structure. Specifically, the ratio of the nitrogen atom concentration (atomic %) to the carbon atom concentration (atomic %) (hereinafter referred to as "N / C ratio") of the catalyst obtained by X-ray photoelectron spectroscopy (XPS) may be, for example, 0.0005 or more, preferably 0.0007 or more, may be 0.0010 or more, preferably 0.0020 or more, more preferably 0.0030 or more, even more preferably 0.0040 or more, even more preferably 0.0050 or more, and particularly preferably 0.0055 or more.

[0044] The N / C ratio of the present catalyst may be, for example, 0.2000 or less, 0.1000 or less, 0.0500 or less, 0.0400 or less, 0.0300 or less, 0.0200 or less, or 0.0150 or less. The N / C ratio of the present catalyst may be specified by any combination of any of the above-mentioned lower limit values ​​and any of the above-mentioned upper limit values.

[0045] The N / C ratio within the above range contributes to improving the catalytic activity of the catalyst. That is, when the N / C ratio is too small, the amount of nitrogen contained in the carbon structure is small, so that the effect of doping electrons from nitrogen to carbon is small, and as a result, the catalytic activity cannot be sufficiently improved. On the other hand, when the N / C ratio is equal to or greater than the above-mentioned lower limit, the effect of doping electrons from nitrogen to carbon is obtained, and the catalytic activity of the catalyst is effectively improved. On the other hand, when the N / C ratio is too large, the carbon structure becomes disordered, and the problem of the conductive path of electrons in the carbon structure being difficult to form may occur. On the other hand, when the N / C ratio is equal to or less than the above-mentioned upper limit, the conductive path of electrons in the carbon structure is effectively formed, and the catalytic activity of the catalyst is more effectively improved.

[0046] The catalyst may contain a non-precious metal other than iron. Here, the non-precious metal is a metal other than a precious metal. The precious metal is ruthenium (Ru), palladium (Pd), rhodium (Rh), silver (Ag), osmium (Os), iridium (Ir), platinum (Pt) and gold (Au).

[0047] The non-precious metal contained in the present catalyst is not particularly limited as long as the effects of the present invention can be obtained. For example, the non-precious metal may be a non-precious metal belonging to Groups 2 to 14 of the periodic table, and preferably a non-precious metal belonging to Periods 3 to 5 of Groups 2 to 14 of the periodic table.

[0048] Specifically, the non-precious metal contained in the present catalyst is more preferably one or more selected from the group consisting of magnesium (Mg), aluminum (Al), calcium (Ca), titanium (Ti), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo) and tin (Sn), and particularly preferably one or more selected from the group consisting of Mg, Al, Ca, Cu, Zn, Y, Zr, Mo and Sn.

[0049] The content of non-precious metals other than iron in the present catalyst (when the present catalyst contains multiple non-precious metals, the total content of the multiple non-precious metals) may be, for example, 50 ppm or more, 100 ppm or more, 1000 ppm or more, 10000 ppm or more, or 100000 ppm or more. The content of non-precious metals other than iron in the present catalyst may be, for example, 500000 ppm or less, 400000 ppm or less, 300000 ppm or less, or 200000 ppm or less. The content of non-precious metals other than iron in the present catalyst may be specified by any combination of any of the above-mentioned lower limit values ​​and any of the above-mentioned upper limit values. The content of non-precious metals is obtained by inductively coupled plasma (ICP) atomic emission spectrometry.

[0050] The non-iron non-precious metal contained in the present catalyst contributes to improving the catalytic activity of the present catalyst. That is, for example, when the present catalyst contains a non-iron non-precious metal derived from the raw material for carbonization described below, a unique carbon structure including catalytic active sites can be effectively formed by performing the carbonization in the presence of the non-precious metal.

[0051] When the present catalyst contains a non-precious metal derived from the raw material for carbonization described later, the present catalyst contains the non-precious metal due to the non-precious metal being contained in the raw material for carbonization. In this case, the present catalyst contains the non-precious metal inside the skeleton constituting the porous structure. Even when the present catalyst is a carbonized material produced through a metal removal treatment described later after carbonization, the non-precious metal derived from the raw material for carbonization remains inside the skeleton of the present catalyst. Of the non-precious metals contained in the present catalyst, the weight of the non-precious metal contained inside the skeleton of the present catalyst may be greater than the weight of the non-precious metal contained on the surface of the skeleton of the present catalyst.

[0052] The non-precious metals in the framework of the catalyst can be detected, for example, by subjecting the framework to a surface etching process and analyzing the cross section exposed by the etching process. That is, in this case, when one particle of the catalyst is etched, the non-precious metals are detected on the cross section of the particle exposed by the etching process. The non-precious metals contained in the catalyst can be detected, for example, by inductively coupled plasma (ICP) optical emission spectrometry of the catalyst.

[0053] The carbon material constituting the present catalyst is preferably a carbonized material obtained by carbonizing a raw material containing an organic matter, as described below. In this regard, when the present catalyst is a carbonized material obtained by carbonizing a raw material containing an organic matter and a non-precious metal other than iron, the non-precious metal is contained in the carbon structure of the present catalyst, but the catalytic activity of the present catalyst is considered to be mainly due to the active sites contained in the carbon structure itself rather than the non-precious metal. This is supported by the fact that even when the present catalyst containing the non-precious metal derived from the raw material for carbonization is subjected to a metal removal treatment to reduce the content of the non-precious metal, the catalytic activity of the present catalyst after the metal removal treatment does not decrease significantly compared to that before the metal removal treatment.

[0054] The present catalyst may not contain a precious metal. That is, as described above, the present catalyst does not need to contain a precious metal because it exhibits catalytic activity by itself without supporting a precious metal. However, the present catalyst may be used as a carbon support for supporting a metal catalyst such as a precious metal.

[0055] Furthermore, when the present catalyst contains non-precious metals other than iron, the content of metals other than Mg, Al, Ca, Ti, Mn, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, and Sn in the present catalyst, or the content of metals other than Mg, Al, Ca, Cu, Zn, Y, Zr, Mo, and Sn, may be, for example, 3000 ppm or less, 2000 ppm or less, 1000 ppm or less, 500 ppm or less, 300 ppm or less, 200 ppm or less, 100 ppm or less, or 50 ppm or less.

[0056] The method for producing the present catalyst is not particularly limited as long as it is a method that can obtain the present catalyst having the above-mentioned properties, but is preferably a method that includes carbonizing a raw material containing an organic substance. The organic substance contained in the raw material is not particularly limited as long as it can be carbonized. The organic compound contained in the organic substance may be a polymer (e.g., a thermosetting resin and / or a thermoplastic resin) and / or an organic compound with a smaller molecular weight.

[0057] Specifically, examples of organic substances include polyacrylonitrile, polyacrylonitrile-polyacrylic acid copolymer, polyacrylonitrile-polymethyl acrylate copolymer, polyacrylonitrile-polymethacrylic acid copolymer, polyacrylonitrile-polymethacrylic acid-polymethallylsulfonic acid copolymer, polyacrylonitrile-polymethyl methacrylate copolymer, phenol resin, polyfurfuryl alcohol, furan, furan resin, phenol formaldehyde resin, melamine, melamine resin, and epoxy. Resins, nitrogen-containing chelating resins (for example, one or more selected from the group consisting of polyamine type, iminodiacetic acid type, aminophosphoric acid type, and aminomethylphosphonic acid type), polyamideimide resins, pyrrole, polypyrrole, polyvinylpyrrole, 3-methylpolypyrrole, acrylonitrile, polyvinylidene chloride, thiophene, oxazole, thiazole, pyrazole, vinylpyridine, polyvinylpyridine, pyridazine, pyrimidine, piperazine, pyran, morpholine, imidazole, 1-methylimidazole, 2 -Methylimidazole, quinoxaline, aniline, polyaniline, succinic dihydrazide, adipic dihydrazide, polysulfone, polyaminobismaleimide, polyimide, polyvinyl alcohol, polyvinyl butyral, benzimidazole, polybenzimidazole, polyamide, polyester, polylactic acid, polyether, polyetheretherketone, cellulose, carboxymethylcellulose, lignin, chitin, chitosan, pitch, silk, wool, polyamino acid, nucleic acid, DNA, RNA, hydrazine The organic solvent may be one or more selected from the group consisting of benzene, hydrazide, urea, salen, polycarbazole, polybismaleimide, triazine, polyacrylic acid, polyacrylic acid ester, polymethacrylic acid ester, polymethacrylic acid, polyurethane, polyamidoamine, polycarbodiimide, naphthalene, naphthalene analogues, anthracene, anthracene analogues, hydroxybenzene, hydroxybenzene analogues, carbazole, quinoline, cyanuric acid, naphthoic acid, methylene blue, and phthalocyanine.

[0058] The organic matter is preferably a nitrogen-containing organic matter. The nitrogen-containing organic matter includes, for example, a nitrogen-containing organic compound. The nitrogen-containing organic compound is not particularly limited as long as it is an organic compound that contains a nitrogen atom in its molecule.

[0059] The present catalyst is preferably a carbonized material obtained by carbonizing a raw material containing an organic substance and a non-precious metal. In this case, the present catalyst may be a carbonized material that has been subjected to a metal removal treatment after carbonization. The metal removal treatment is a treatment for reducing the amount of non-precious metals derived from the raw material contained in the carbonized material. Specifically, the metal removal treatment is preferably, for example, a washing treatment with an acid and / or an electrolytic treatment.

[0060] Carbonization is carried out by heating the raw material at a temperature at which the organic matter contained in the raw material is carbonized. The carbonization temperature is not particularly limited as long as the raw material is carbonized at the temperature, and is preferably 900°C or higher, more preferably 1000°C or higher, even more preferably 1100°C or higher, and particularly preferably 1200°C or higher.

[0061] The carbonization temperature may be, for example, 3000°C or lower, preferably 2500°C or lower, more preferably 2000°C or lower, and particularly preferably 1900°C or lower. The carbonization temperature may be specified by any combination of any of the above-mentioned lower limit values ​​and any of the above-mentioned upper limit values. The rate of temperature rise to the carbonization temperature is not particularly limited, and may be, for example, 0.5°C / min or higher and 300°C / min or lower. The carbonization is preferably performed in an inert atmosphere such as a nitrogen atmosphere.

[0062] The catalyst may be a carbon material obtained by supporting a non-precious metal on a carbonized material obtained by carbonizing a raw material containing an organic matter and a non-precious metal. In this case, the catalyst contains a first non-precious metal derived from the raw material of the carbonization and a second non-precious metal supported after the carbonization. The first non-precious metal and the second non-precious metal may be the same type of non-precious metal or different types of non-precious metals.

[0063] The first non-precious metal and the second non-precious metal are not particularly limited as long as the effects of the present invention can be obtained. For example, each of them may be independently a non-precious metal belonging to Groups 2 to 14 of the periodic table, and preferably a non-precious metal belonging to Periods 3 to 5 of Groups 2 to 14 of the periodic table.

[0064] Specifically, the first non-precious metal and the second non-precious metal are each preferably, independently, one or more selected from the group consisting of, for example, Mg, Al, Ca, Ti, Mn, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, and Sn, and particularly preferably one or more selected from the group consisting of Mg, Al, Ca, Cu, Zn, Y, Zr, Mo, and Sn.

[0065] Also, for example, it is preferable that the first non-precious metal is one or more selected from the group consisting of Mg, Al, Ca, Ti, Mn, Co, Ni, Cu, Zn, and Sn, and the second non-precious metal is one or more selected from the group consisting of Y, Zr, Nb, and Mo, and it is particularly preferable that the first non-precious metal is one or more selected from the group consisting of Mg, Al, Ca, Cu, Zn, and Sn, and the second non-precious metal is one or more selected from the group consisting of Y, Zr, and Mo.

[0066] When the catalyst comprises a first non-precious metal of a specific kind (e.g., one selected from the group described above) and a second non-precious metal of a specific kind different from the first non-precious metal (e.g., one selected from the group described above and different from the first non-precious metal), the weight of the first non-precious metal contained inside the skeleton of the catalyst may be greater than the weight of the first non-precious metal contained on the surface of the skeleton of the catalyst, and the weight of the second non-precious metal contained on the surface of the skeleton of the catalyst may be greater than the weight of the second non-precious metal contained inside the skeleton of the catalyst.

[0067] The electrode according to this embodiment (hereinafter referred to as "this electrode") contains the present catalyst. That is, the present electrode may contain, for example, an electrode substrate and the present catalyst supported on the electrode substrate. The present electrode is preferably a battery electrode. Specifically, the present electrode is preferably an electrode of, for example, a fuel cell (e.g., a polymer electrolyte fuel cell, a microbial fuel cell), an air cell, a water electrolysis cell (e.g., a polymer electrolyte water electrolysis cell), a redox flow cell, or a halogen cell.

[0068] The electrode may be either a cathode or an anode, but is preferably a cathode, i.e., the electrode is a cathode or an anode, preferably a cathode, of a fuel cell, an air cell, a water electrolyzer, a redox flow battery, or a halogen battery.

[0069] The battery according to this embodiment (hereinafter referred to as "this battery") includes this electrode. Specifically, this battery is preferably a fuel cell (e.g., a polymer electrolyte fuel cell, a microbial fuel cell), an air battery, a redox flow battery, or a halogen battery that includes this electrode. This battery preferably has a membrane electrode assembly (MEA) that includes this electrode.

[0070] The present battery is a battery having the present electrode as a cathode or an anode, and preferably a battery having the present electrode as a cathode. That is, the present battery is a fuel cell, an air battery, a redox flow battery, or a halogen battery having the present electrode as a cathode or an anode, and preferably a fuel cell, an air battery, a redox flow battery, or a halogen battery having the present electrode as a cathode.

[0071] Next, a specific example according to this embodiment will be described. EXAMPLES

[0072] [Example 1] 0.5 g of polyvinylpyridine (PVP) was dissolved in 200 mL of DMF, and 18.03 g of tin(II) chloride (SnCl2) was added to prepare a homogeneous solution. This solution was vacuum dried at 80°C for one day to obtain the raw material for carbonization.

[0073] The obtained raw material was placed in a quartz tube, and in an image furnace, the temperature was raised to 1200° C. at a rate of 50° C. / min in a nitrogen atmosphere, and the raw material was held at 1200° C. for 1 hour, thereby performing carbonization.

[0074] Next, silicon nitride balls having a diameter of 10 mm were set in a planetary ball mill (P-7, manufactured by Fritsch Japan KK), and the carbonized material obtained by the carbonization was pulverized by the planetary ball mill.

[0075] 100 mL of concentrated hydrochloric acid was added to the ground carbonized material, and the mixture was heated under reflux for 2 hours. The solution containing the carbonized material was then filtered using a filter membrane and washed with distilled water until the filtrate became neutral. The collected carbonized material was vacuum dried.

[0076] The carbonized material that had been subjected to the metal removal treatment as described above was placed in a quartz tube, and heat-treated in an image furnace by heating in a nitrogen atmosphere at 1200° C. and holding for 30 minutes, thereby obtaining the carbon catalyst of Example 1.

[0077] [Example 2] The preparation of raw materials, carbonization of the raw materials, and pulverization of the carbonized material obtained by the carbonization were carried out in the same manner as in Example 1 described above, except that 0.5 g of cyanuric acid was used instead of PVP and 10.56 g of zinc (II) chloride (ZnCl2) was used instead of tin chloride.

[0078] 20 mL of concentrated hydrochloric acid was added to the ground carbonized material and stirred for 30 minutes. The carbonized material was then precipitated and the solution was removed. This process was repeated several times, after which distilled water was added and stirred. The solution containing the carbonized material was filtered using a filtration membrane and washed with distilled water until the filtrate became neutral. The recovered carbonized material was vacuum dried.

[0079] The carbonized material that had been subjected to the metal removal treatment as described above was placed in a quartz tube, and heat-treated in an image furnace by heating in a nitrogen atmosphere at 1200° C. and holding for 30 minutes, thereby obtaining the carbon catalyst of Example 2.

[0080] [Example 3] A carbon catalyst of Example 3 was obtained in the same manner as in Example 2 above, except that 0.5 g of polyacrylonitrile (PAN) was used instead of cyanuric acid, and 25.34 g of copper chloride (II) (CuCl2) was used instead of zinc chloride.

[0081] [Example 4] A carbon catalyst of Example 4 was obtained in the same manner as in Example 2 described above, except that 0.5 g of polyvinylidene chloride (PVDC) was used instead of cyanuric acid, 34.67 g of copper (II) chloride (CuCl2) was used instead of zinc chloride, and 20 mL of concentrated nitric acid was used instead of concentrated hydrochloric acid.

[0082] [Example 5] The carbon catalyst of Example 5 was obtained in the same manner as in Example 3 above, except that 17.94 g of magnesium chloride (MgCl2·6H2O) was used instead of copper chloride.

[0083] [Example 6] A carbon catalyst was obtained in the same manner as in Example 1, except that 0.5 g of PAN was used instead of PVP and 10.56 g of zinc chloride (II) (ZnCl2) was used instead of tin chloride. This carbon catalyst was heated to 900°C at a rate of 50°C / min in an ammonia atmosphere and held at 900°C for 1 hour, thereby performing a nitrogen doping treatment.

[0084] Furthermore, 100 mg of the nitrogen-doped carbon catalyst was immersed in 130 mL of an aqueous solution containing 1.3 mg of yttrium chloride (YCl3·6H2O), thereby impregnating the carbon catalyst with the yttrium chloride.

[0085] Thereafter, the aqueous solution containing the carbon catalyst and yttrium chloride was dried at 60° C., heated to 1000° C. at a rate of 50° C. / min in a hydrogen atmosphere, and the aqueous solution was held at 1000° C. for 0.5 hours to perform hydrogen reduction. In this way, the carbon catalyst of Example 6 was obtained.

[0086] [Example 7] A carbon catalyst of Example 7 was obtained in the same manner as in Example 6 above, except that 1.2 mg of molybdenum chloride (MoCl5) was used instead of yttrium chloride.

[0087] [Example 8] A carbon catalyst of Example 8 was obtained in the same manner as in Example 6 above, except that 1.0 mg of zirconium chloride (ZrCl4) was used instead of yttrium chloride.

[0088] [Example 9] 0.5g of novolac phenolic resin was dissolved in 80g of acetone, and 11.20g of copper chloride (II) (CuCl2) was added to prepare a homogeneous solution. This solution was vacuum dried at 80℃ for one day to obtain the raw material for carbonization.

[0089] The obtained raw material was placed in a quartz tube, and in an image furnace, the temperature was raised to 1200° C. at a rate of 50° C. / min in a nitrogen atmosphere, and the raw material was held at 1200° C. for 1 hour, thereby performing carbonization.

[0090] Next, silicon nitride balls having a diameter of 10 mm were set in a planetary ball mill (P-7, manufactured by Fritsch Japan KK), and the carbonized material obtained by the carbonization was pulverized by the planetary ball mill.

[0091] 20 mL of concentrated nitric acid was added to the ground carbonized material and stirred for 30 minutes. The carbonized material was then precipitated and the solution was removed. This process was repeated several times, after which distilled water was added and stirred. The solution containing the carbonized material was filtered using a filtration membrane and washed with distilled water until the filtrate became neutral. The recovered carbonized material was vacuum dried.

[0092] The carbonized material that had been subjected to the metal removal treatment as described above was placed in a quartz tube, and heat-treated by heating in an image furnace in a nitrogen atmosphere at 1200° C. for 30 minutes, thereby obtaining the carbon catalyst of Example 9.

[0093] [Example 10] 1.5 g of naphthoic acid was dissolved in 80 g of acetone, and 23.23 g of aluminum chloride (III) (AlCl3) and 23.75 g of zinc chloride (II) (ZnCl2) were added to prepare a homogeneous solution. This solution was vacuum dried at 80°C for a whole day and night to obtain a raw material for carbonization. Thereafter, the carbon catalyst of Example 10 was obtained in the same manner as in Example 9 above, except that 20 mL of nitric hydrofluoric acid (HNO3:HF=1 mol:1 mol) was used instead of concentrated nitric acid.

[0094] [Example C1] 0.5g of novolac phenolic resin was dissolved in 80g of acetone, and 1.08g of copper phthalocyanine was added and ultrasonically stirred for 30 minutes. Next, the acetone solvent was removed using a rotary evaporator, and the mixture was dried under reduced pressure at 70℃ overnight to obtain the raw material for carbonization.

[0095] The obtained raw material was heated to 800° C. at a rate of 10° C. / min in a nitrogen atmosphere in an image furnace, and the raw material was held at 800° C. for 1 hour, thereby carbonizing the raw material.

[0096] Thereafter, the carbonized material was crushed and washed with an acid in the same manner as in Example 2 described above to obtain the carbon catalyst of Example C1.

[0097] [Example C2] A carbon catalyst of Example C2 was obtained in the same manner as in Example 2 above, except that 0.5 g of carbazole was used instead of cyanuric acid, and 8.50 g of zinc chloride and 8.29 g of aluminum chloride (III) (AlCl3) were further added to 10.56 g of zinc chloride.

[0098] [Powder X-ray diffraction] Powder X-ray diffraction (XRD) measurement of the carbon catalyst of each example was carried out using an X-ray diffractometer (XRD-6100, manufactured by Rigaku Corporation). Note that CuKα rays were used as incident X-rays, the voltage and current applied to the X-ray tube were set to 40 kV and 15 mA, respectively, and the measurement angle range (2θ) was set to the range of 5° to 90°.

[0099] Here, as described above, when the carbon catalyst has a structure in which the hexagonal carbon network planes extending in the a-axis direction are connected among the crystallites constituting the curved carbon network planes that contribute to the catalytic activity of the carbon catalyst, in an X-ray diffraction pattern using CuKα rays, a diffraction peak f 10 Specifically, in this embodiment, the diffraction peak f 10 was defined as the diffraction peak whose diffraction angle (2θ) was 43.5°±1.0° and whose full width at half maximum was 7.5°±6.5°.

[0100] And this diffraction peak f 10 The crystallite size La was calculated by analyzing the diffraction peak f 10 The Bragg angle and full width at half maximum of La were substituted into the following Scherrer formula: La = Kλ / (βcosθ), where K is the Scherrer constant (0.94), λ is the wavelength of CuKα radiation (0.15418 nm), β is the full width at half maximum (radian), and θ is the Bragg angle (radian).

[0101] [Temperature Programmed Desorption Analysis] A temperature programmed desorption analysis of the carbon catalyst of each example was performed using a temperature programmed desorption analyzer (high-temperature TPD device) capable of heating up to 1600°C. The high-temperature TPD device is a device that can heat the graphite crucible, which is the object to be heated, to a high temperature of 1600°C or higher by high-frequency electromagnetic induction heating. Details of this high-temperature TPD device are described in Carbon magazine (Takafumi Ishi, SuSumu Kashihara, Yasuto Hoshikawa, Jun-ichi Ozaki, Naokatsu Kannari, Kazuyuki Takai, Toshiaki Enoki, Takashi Kyotani, Carbon, Volume 80, December 2014, Pages 135-145).

[0102] A carbon catalyst was placed in this high-temperature TPD device, and 5 × 10 -5 The carbon catalyst was heated under a high vacuum of less than 1 Pa, and the desorbed gas was measured using a quadrupole mass spectrometer (QMS).

[0103] Specifically, 1 mg of the carbon catalyst was first filled into a graphite crucible and then set in a quartz reaction tube attached to a high-temperature TPD device. Next, the inside of the device was evacuated with a turbo molecular pump until the pressure reached 5×10 -5 After evacuation to a pressure of 1 Pa, the sample was heated from room temperature to 1600°C at a heating rate of 10°C / min. During this heating, the desorbed gas was detected, and the correlation between temperature (horizontal axis) and detection intensity (vertical axis) was recorded. The amount of desorbed gas was then calculated. In other words, the integral value (detection intensity area) of the gas detection intensity from room temperature, where the heat treatment was started, to the temperature (1600°C) to be quantified was calculated.

[0104] On the other hand, a calibration curve showing the correlation between the amount of gas desorption and the detection intensity area was created using a specified amount of standard gas. When analyzing the desorbed gas from the sample with QMS, in order to strictly distinguish between gas species of the same mass contained in the desorbed gas (CO, N2, C2H4, etc. for mass number 28), the fragment intensity ratios for various gas species (H2, H2O, CO, CO2, N2, HCN, O2, CH4, C2H6, C3H6, C3H8) were examined and used to qualitatively identify the desorbed gas. Then, based on the detection intensity area obtained by the measurement, the calibration curve, and the fragment intensity ratio, the amount of gas desorbed (emitted) from the carbon catalyst was quantified. In addition, to confirm the validity of the created calibration curve, measurements were performed on Ketjen Black EC600JD (Lion Specialty Chemicals Co. Ltd.) and it was confirmed that the edge hydrogen amount was within the range of 1000 [μmol / g] to 1500 [μmol / g].

[0105] Here, the actual size of the carbon net planes constituting the carbon can be evaluated from the average carbon net plane size L obtained from the amount of carbon edge planes. In this embodiment, the total amount of carbon edge planes is calculated from the desorbed gas quantification results of high-temperature TPD of the carbon catalyst, and the average carbon net plane size L obtained from the amount is calculated using the coronene model shown in Fig. 1. a0 in the formula shown in Fig. 1 represents 0.2461 nm, which is the lattice constant in the a-axis direction of graphite crystal.

[0106] In addition, it is known that the phenolic hydroxyl group among oxygen-containing compounds decomposes into carbon monoxide by heating, and the hydrogen atoms derived from the hydroxyl group remain on the carbon edge. Therefore, the amount of hydrogen determined by high-temperature TPD may include the contribution of hydrogen derived from the phenolic hydroxyl group. Therefore, in order to accurately calculate the total amount of edge faces, it is necessary to consider the phenolic hydroxyl group. For example, both ether (-O-) and phenolic hydroxyl group (-OH) are functional groups that are desorbed as CO at around 700°C. After the phenolic hydroxyl group is desorbed as CO, H remains at the edge site. Therefore, for the phenolic hydroxyl group, H2 was desorbed at a temperature of 1000°C or higher after CO was desorbed. In addition, the phenolic hydroxyl group differs from the ether in that two types of gas (CO and H2) are desorbed from one functional group. It is not possible to distinguish between ether and phenolic hydroxyl group from the desorption of CO observed in TPD analysis. Therefore, the amount of carbon edge sites and L were calculated for each case, which was classified into two cases: when the CO elimination originated only from ether and when it originated only from phenolic hydroxyl groups.

[0107] It was assumed that CO is released from the phenolic hydroxyl group or ether in the high-temperature TPD. The total amount of CO on the edge surface of the carbon catalyst (N edge ) was calculated. If all the CO released was from ether, N edge The amount is maximized. Therefore, N edge (Max) was calculated by the following formula: N edge (Max)[mol / g]=CO[mol / g]+CO2[mol / g]+H2[mol / g]×2. In addition, if all the CO released is derived from phenolic hydroxyl groups, N edge takes the minimum value. Therefore, N edge (Min) was calculated by the following formula: edge (Min) [mol / g] = CO2 [mol / g] + H2 [mol / g] × 2. In the formula, CO [mol / g], CO2 [mol / g], and H2 [mol / g] are the amounts of carbon monoxide, carbon dioxide, and hydrogen desorbed gases, respectively, determined by high-temperature TPD.

[0108] On the other hand, the average carbon network size L is calculated by the following formula using the atomic weight of carbon atoms of 12 g / mol and the lattice constant of the graphite crystal in the a-axis direction of 0.2461 nm: L [nm] = 2 × 1 / 12 × 0.2461 / N edge [mol / g]. Here, the maximum value of L, "L(Max)", and the minimum value, "L(Min)", are calculated by the following two formulas: "L(Max)" [nm] = 2 × 1 / 12 × 0.2461 / N edge (Min)[mol / g];, “L(Min)”[nm]=2×1 / 12×0.2461 / N edge (Max) [mol / g].

[0109] As described above, since it is difficult to separate ether and phenolic hydroxyl groups from the average carbon net surface size L, two values, a maximum value and a minimum value, are calculated. However, while "L(Max)" is the case when only phenolic hydroxyl groups are present and "L(Min)" is the case when only ether is present, it is difficult to imagine a state in which only one of these exists in an actual material. Therefore, the average carbon net surface size L of the carbon catalyst is defined as the median "L(av.)" between "L(Max)" and "L(Min)". "L(av.)" is obtained by dividing the sum of "L(Min)", obtained as the minimum possible value of the average carbon net surface size L, and "L(Max)", obtained as the maximum possible value, by 2. This "L(av.)" was obtained as the average carbon net surface size L of the carbon catalyst.

[0110] [X-ray photoelectron spectroscopy (XPS)] An X-ray photoelectron spectrometer (AXIS NOVA, manufactured by KRATOS) was used to measure the photoelectron spectrum from the core levels of carbon and nitrogen atoms on the surface of the carbon catalyst of each example. AlKα radiation (10 mA, 15 kV, pass energy 40 eV) was used as the X-ray source. In the obtained photoelectron spectrum, the binding energy was corrected so that the peak top of the C1s peak derived from the 1s orbital of the carbon atom was located at 284.5 eV.

[0111] In the XPS wide scan analysis, the atomic concentrations (atomic %) of carbon atoms and nitrogen atoms on the surface of the carbon catalyst were obtained from the peak area and detection sensitivity coefficient in the photoelectron spectrum. The N / C ratio was calculated by dividing the nitrogen atomic concentration (atomic %) by the carbon atom concentration (atomic %). The atomic concentrations (atomic %) were calculated assuming that the carbon catalyst contains carbon atoms, nitrogen atoms, oxygen atoms, sulfur atoms, boron atoms, chlorine atoms, and metal atoms contained in the carbonization raw material.

[0112] [Specific surface area and pore volume] The specific surface area and pore volume of the carbon catalyst of each example were measured by a nitrogen adsorption method using a specific surface area / pore distribution measuring device (BELSORP MAX, manufactured by Microtrack BEL Co., Ltd.).

[0113] First, 0.01 g of carbon catalyst was heated at 200°C for 6.7 × 10 -2 The carbon catalyst was held at 100 Pa for 2 hours to remove moisture adsorbed on the carbon catalyst. Next, a nitrogen adsorption isotherm at 77 K was obtained by the BET method. This nitrogen adsorption isotherm at 77 K was obtained by measuring the change in the amount of nitrogen adsorbed on the carbon catalyst with the change in nitrogen gas pressure at a temperature of 77 K. From the nitrogen adsorption isotherm at a temperature of 77 K, the BET specific surface area (m 2 The micropore volume (cm3 / g) was also obtained from the nitrogen adsorption isotherm at 77K by the MP method. 3 / g) was calculated by the DH method. 3 / g) was obtained.

[0114] [Evaluation of catalytic activity] The catalytic activity of the carbon catalyst was evaluated using a rotating ring-disk electrode apparatus (RRDE-3A rotating ring-disk electrode apparatus ver. 1.2, manufactured by BAS Co., Ltd.) and a dual electrochemical analyzer (CHI700C, manufactured by ALS Co., Ltd.).

[0115] That is, first, a three-electrode rotating ring-disk electrode device having a working electrode containing a carbon catalyst was prepared. Specifically, 5 mg of the carbon catalyst, 50 μL of 5% Nafion (registered trademark) (Sigma-Aldrich Corporation, Nafion perfluorinated ion exchange resin, 5% solution (product number: 510211)), 400 μL of water, and 100 μL of isopropyl alcohol were mixed to prepare a slurry. Next, this slurry was subjected to ultrasonic treatment for 10 minutes, and then to homogenization treatment for 2 minutes. The obtained slurry was then mixed with a 100-μL ethanol solution containing 0.1 mg of carbon catalyst per unit area of ​​the electrode. 2 The carbon catalyst was applied to a working electrode (RRDE-3A ring-disk electrode, platinum ring-gold disk electrode, disk diameter 4 mm, manufactured by BAS Inc.) so as to obtain a working electrode supported with the carbon catalyst. The working electrode was then dried.

[0116] A platinum electrode (Pt counter electrode 23 cm, manufactured by BAS Co., Ltd.) was used as the counter electrode, and a reversible hydrogen electrode (RHE) (a storage-type reversible hydrogen electrode, manufactured by EC Frontier Co., Ltd.) was used as the reference electrode. In this way, a rotating ring-disk electrode device was obtained that had a working electrode containing a carbon catalyst, a platinum electrode as the counter electrode, and a reversible hydrogen electrode (RHE) as the reference electrode. A 0.1 M aqueous solution of perchloric acid was used as the electrolyte.

[0117] Then, the catalytic activity of the carbon catalyst was measured using the rotating ring-disk electrode apparatus described above. That is, linear sweep voltammetry in a nitrogen atmosphere (N2-LSV) and linear sweep voltammetry in an oxygen atmosphere (O2-LSV) were performed using a three-electrode rotating ring-disk electrode apparatus having a working electrode containing a carbon catalyst.

[0118] In the N2-LSV, nitrogen bubbling was performed for 10 minutes to remove oxygen from the electrolyte.Then, the electrode was rotated at 1600 rpm, and the current density was recorded as a function of potential when the potential was swept at a sweep rate of 20 mV / sec (N2-LSV).

[0119] In the O2-LSV, oxygen was bubbled for 10 minutes to fill the electrolyte with saturated oxygen.Then, the electrode was rotated at 1600 rpm, and the current density was recorded as a function of potential when the potential was swept at a sweep rate of 20 mV / sec (O2-LSV).

[0120] The N2-LSV was subtracted from the O2-LSV to obtain an oxygen reduction voltammogram. In the obtained oxygen reduction voltammogram, the values ​​were assigned signs so that the reduction current was negative and the oxidation current was positive.

[0121] From the oxygen reduction voltammogram thus obtained, the catalytic activity of the carbon catalyst itself was shown to be −10 μA / cm 2 The voltage at which the reduction current flowed (oxygen reduction onset potential EO2) (V vs. NHE) was recorded.

[0122] [result] Fig. 2 shows the results of evaluating the characteristics of the carbon catalyst of each example. As shown in Fig. 2, the oxygen reduction onset potential EO2 (V vs. NHE) of the carbon catalysts of Examples 1 to 10 was higher than that of the carbon catalysts of Examples C1 and C2. That is, the carbon catalysts of Examples 1 to 10 exhibited higher catalytic activity than the carbon catalysts of Examples C1 and C2.

[0123] In particular, the carbon catalysts of Examples 1 to 8 exhibited a larger oxygen reduction onset potential EO2 (V vs. NHE) than the carbon catalysts of Examples 9 and 10. That is, the carbon catalysts of Examples 1 to 8 exhibited even higher catalytic activity than the carbon catalysts of Examples 9 and 10.

[0124] Furthermore, the L / La (ratio of the average carbon mesh plane size L to the crystallite size La) of the carbon catalysts of Examples 1 to 10 was larger than that of the carbon catalysts of Examples C1 and C2. Furthermore, the average carbon mesh plane size L of the carbon catalysts of Examples 1 to 10 was significantly larger than that of the carbon catalysts of Examples C1 and C2. On the other hand, the crystallite size La of the carbon catalysts of Examples 9 and 10 among Examples 1 to 10 was smaller than that of the carbon catalysts of Examples 1 to 8. The N / C ratios of the carbon catalysts of Examples 9 and 10 were zero. That is, the carbon catalysts of Examples 9 and 10 did not contain nitrogen atoms.

[0125] The BET specific surface area (S BET ) was significantly smaller than those of the carbon catalysts of the other examples. In addition, the carbon catalyst of Example 9 had a larger micropore volume (V micro On the other hand, the carbon catalyst of Example C1 had a significantly smaller micropore volume (V micro )

Claims

1. the ratio L / La of the average carbon network plane size L (av.) obtained by thermal desorption analysis capable of heating up to 1600°C to the crystallite size La obtained from a diffraction peak that is a carbon (10) diffraction line having a peak top at a diffraction angle (2θ) of around 43° in an X-ray powder diffraction pattern obtained by CuKα ray diffraction, is 12 or more; The iron content is 3000 ppm or less, The average carbon mesh plane size L (av.) is calculated by the following formula (I): (In the above formula (I), L(Max) and L(Min) are calculated by the following formulas (II) and (III), respectively. (N edge (Max) in the above formula (III) and N edge (Min) in the above formula (II) are calculated by the following formulas (IV) and (V), respectively: (CO [mol / g] in the above formula (IV), CO 2 [mol / g] and H 2 [mol / g] in the above formulas (IV) and (V) are the amounts of desorbed carbon monoxide, carbon dioxide and hydrogen gases, respectively, determined by the thermal desorption analysis.) Carbon catalyst.

2. The crystallite size La is 10.00 nm or less; The carbon catalyst according to claim 1 .

3. The average carbon net plane size L(av.) is 5 nm or more. The carbon catalyst according to claim 1 .

4. containing a nitrogen atom, The carbon catalyst according to claim 1 .

5. the ratio of nitrogen atom concentration to carbon atom concentration obtained by X-ray photoelectron spectroscopy is 0.0005 or more; The carbon catalyst according to claim 1 .

6. BET specific surface area is 100m ２ / g or more, The carbon catalyst according to claim 1 .

7. Micropore volume of 0.05 cm ３ / g or more, The carbon catalyst according to claim 1 .

8. Micropore volume is 2.50 cm ３ / g or less, The carbon catalyst according to claim 1 .

9. Mesopore volume is 0.001 cm ３ / g or more, The carbon catalyst according to claim 1 .

10. Contains non-precious metals other than iron, The carbon catalyst according to claim 1 .

11. A carbon catalyst comprising the carbon catalyst according to any one of claims 1 to 10. electrode.

12. 12. The electrode of claim 11 , battery.

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