Porous silicon oxycarbide composite material and method for producing the same

Abstract

A porous silicon oxycarbide composite material comprising porous silicon oxycarbide having a three-dimensional skeleton structure and a carbonaceous material retained by the three-dimensional skeleton structure, wherein the BET specific surface area is 100 m 2 / g or more, and the conductivity is 1.0×10 ‑6 S / cm or more.

Description

Technical Field

[0001] The present invention relates to a porous silicon oxycarbide composite material and a method for producing the porous silicon oxycarbide composite material.

[0002] This application claims priority based on Japanese Patent Application No. 2020-082098, filed in Japan on May 7, 2020, the contents of which are incorporated herein by reference. Background Art

[0003] Fuel cells are devices that generate electricity and heat through a chemical reaction between hydrogen and oxygen to produce water. There are various types of fuel cells, including phosphoric acid fuel cells (PAFC), molten carbonate fuel cells (MCFC), solid oxide fuel cells (SOFC), and polymer electrolyte fuel cells (PEFC). Polymer electrolyte fuel cells (PEFC) have a structure in which an anode (fuel electrode) is located on one side of a solid polymer electrolyte membrane, and a catalyst layer, which constitutes the cathode (air electrode), is located on the other side. Gas diffusion layers are bonded to the outside of each catalyst layer. The catalyst layer consists of a catalyst-supporting carrier in which a highly dispersed catalyst containing a precious metal is supported on the surface of nanometer-scale carrier particles.

[0004] Currently, carbon-based materials with high specific surface area and high electrical conductivity are used as catalyst carriers. However, degradation of catalyst performance due to corrosion of the carbon carrier, etc., is a major problem in both cathodes and anodes. Therefore, there is an urgent need to develop alternative materials with high specific surface area, high electrical conductivity, and excellent durability to carbon.

[0005] For example, Patent Document 1 discloses a method for producing porous silicon oxycarbide ceramics, wherein: (i) a silicon-containing organic compound is mixed with a dispersion in which a carbon-containing compound and a pore-forming agent are dispersed to prepare a mixed solution; (ii) the obtained mixed solution is polymerized at a temperature of 0 to 200°C, and the obtained product is calcined at a temperature of 200°C to 800°C, crushed, and classified to produce a primary calcined powder; and (iii) the primary calcined powder is calcined at a temperature of 800°C to 1150°C. In this production method, the BET specific surface area is set to 0.5 m 2 / g~50m 2 / g.

[0006] Patent Document 1 discloses a composite material containing the porous silicon oxycarbide ceramic and a conductive carbon material such as carbon black. The composite material contains 1 to 30% by mass of the conductive carbon material, which is believed to facilitate lowering of electrical resistance.

[0007] Non-patent document 1 discloses a method for producing porous silicon oxycarbide ceramics, which is achieved by mixing silicone resin, a pore-forming agent, a sintering shrinkage control agent, and graphite in an organic solvent, and sintering the resulting mixed solid at 1000°C after drying. In this production method, the BET specific surface area is set to 6.2 m 2 / g~32.3m 2 / g, the conductivity is set to 3×10 -2 ~9×10 -2 S / cm.

[0008] Non-patent document 2 reports a method for producing porous silicon oxycarbide ceramics, using a bis(trialkoxysilane) compound cross-linked with an alkylene group as a silicon-containing organic compound, polycondensing the compound by a sol-gel reaction in an alcohol solvent, and calcining the resulting porous alkylene group cross-linked polysilsesquioxane gel at 1000°C. In this production method, it is believed that the maximum BET specific surface area can be set to 452 m 2 / g.

[0009] Prior art literature

[0010] Patent Literature

[0011] Patent Document 1: Japanese Patent Application Laid-Open No. 2015-160762

[0012] Non-patent literature

[0013] Non-patent document 1: TC de Almeida e Silva et al. Catalysis Science & Technology v9, pp. 854-866 (2019).

[0014] Non-patent document 2: PR Aravind et al. Microporous and Mesoporous Materials v142, p511-517 (2011). Summary of the Invention

[0015] Problems to be solved by the invention

[0016] However, fuel cell electrodes designed to achieve high efficiency and high output require catalyst-supporting supports that simultaneously meet the requirements of a high specific surface area and high conductivity. Therefore, the BET specific surface areas reported in Patent Document 1 and Non-Patent Document 1 are insufficient and leave room for improvement. Furthermore, Patent Document 1 only discloses that the electrical resistance can be reduced by mixing a conductive carbon material into a porous silicon oxycarbide ceramic. It does not disclose examples of producing porous silicon oxycarbide ceramics mixed with a conductive carbon material, and therefore does not disclose quantitative evaluation of electrical conductivity.

[0017] The above-mentioned non-patent document 2 discloses that the BET specific surface area of porous silicon oxycarbide ceramics reaches 452 m 2 / g, but this is an example of realization using a special silicon-containing organic compound such as bis(trialkoxysilane) cross-linked with an alkylene group, and there is no disclosure or suggestion regarding electrical conductivity.

[0018] The present invention aims to provide a porous silicon oxycarbide composite material that is effective as a fuel cell electrode material and has both a large BET specific surface area and high electrical conductivity in a well-balanced manner, and to provide a method for producing the porous silicon oxycarbide composite material using an organic alkoxysilane of a type that is widely circulated as an industrial raw material.

[0019] Means for solving problems

[0020] To achieve the above objectives, the present invention ensures that the formation of a porous gel is not hindered during the sol-gel reaction in the presence of an organoalkoxysilane aqueous solution and a surfactant. A carbonaceous material or an organic polymer serving as a carbon source is also present to produce a precursor gel, which is then calcined. This results in the production of a porous silicon oxycarbide composite material with a well-developed microporous structure (mesopores) in the mesoscopic region and a carbonaceous material disposed at the nanometer level within a porous three-dimensional structural framework. This provides a porous silicon oxycarbide composite material that exhibits both a large BET specific surface area and high electrical conductivity in a well-balanced manner.

[0021] That is, the present invention provides the following means.

[0022] [1] A porous silicon oxycarbide composite material comprising porous silicon oxycarbide having a three-dimensional skeleton structure and a carbon-containing material retained by the three-dimensional skeleton structure.

[0023] BET specific surface area is 100m 2 / g or more, and the conductivity is 1.0×10 -6 S / cm or more.

[0024] [2] The porous silicon oxycarbide composite material as described in [1] above, wherein the total pore volume is 0.5 cm 3 / g or above.

[0025] [3] The porous silicon oxycarbide composite material according to [1] or [2] above, wherein the pore diameter is not less than 2 nm and not more than 200 nm.

[0026] [4] The porous silicon oxycarbide composite material according to [1] above, wherein the content of the carbon-containing material is 2.5% by mass or more and 50% by mass or less.

[0027] [5] The porous silicon oxycarbon composite material according to [4], wherein the carbon-containing material is composed of one or more selected from carbon black, carbon nanofibers, carbon nanotubes, and low-crystalline nanocarbon.

[0028] [6] The porous silicon oxycarbide composite material according to [5], wherein the average diameter of the primary particles of the carbon-containing material is not less than 10 nm and not more than 200 nm.

[0029] [7] A fuel cell electrode comprising a layer containing the porous silicon oxycarbide composite material according to any one of [1] to [6].

[0030] [8] A method for producing a porous silicon oxycarbide composite material, characterized by:

[0031] Step (A) of adding an organoalkoxysilane to an acidic aqueous solution containing a surfactant and a pH adjuster to form a gel by a sol-gel reaction of the organoalkoxysilane,

[0032] step (B) of washing the gel with alcohol,

[0033] step (C) of drying the washed gel to form a porous silicon oxycarbide precursor, and

[0034] a step (D) of calcining the porous silicon oxycarbide precursor to obtain a porous silicon oxycarbide composite material;

[0035] In the step (A), a carbon-containing material or an organic polymer is further added to the acidic aqueous solution to form a gel containing the carbon-containing material or the organic polymer.

[0036] [9] The method for producing a porous silicon oxycarbide composite material according to [8] above, wherein in the step (A), the sol-gel reaction is carried out at a temperature of 25°C to 80°C.

[0037]

[10] The method for producing a porous silicon oxycarbide composite material according to [8] above, wherein the organoalkoxysilane is represented by the following formula (1) or formula (2).

[0038] R 1 -SiR 2x (OR 3 ) 3-x …(1)

[0039] (where R 1 is any one group selected from methyl, ethyl, vinyl and phenyl, R 2 Represents methyl, R 3 represents a methyl group or an ethyl group. Wherein the integer x is 0 or 1.

[0040] R 4 -(SiR 5 y (OR 6 ) 3-y )2…(2)

[0041] (where R 4 Contains any one group selected from methylene, ethylene, hexylene, vinylene, phenylene and biphenylene, R 5 Represents methyl, R 6 represents a methyl group or an ethyl group. In the formula, the integer y is 0 or 1.

[0042]

[11] The method for producing a porous silicon oxycarbide composite material according to [8] above, wherein the content of the surfactant relative to the acidic aqueous solution is 0.1% by mass or more and 50% by mass or less.

[0043]

[12] The method for producing a porous silicon oxycarbide composite material according to

[11] above, wherein the surfactant is a nonionic surfactant and / or a cationic surfactant.

[0044]

[13] The method for producing a porous silicon oxycarbide composite material according to [8] above, wherein the content of the pH adjuster relative to the acidic aqueous solution is 5% by mass or more and 50% by mass or less.

[0045]

[14] The method for producing a porous silicon oxycarbide composite material according to

[12] above, wherein the pH adjuster comprises any one selected from urea, ammonia, and sodium hydroxide.

[0046]

[15] The method for producing a porous silicon oxycarbide composite material as described in [8] above, wherein the mass ratio of the carbon-containing material or organic polymer to the organoalkoxysilane is 2.5-50:97.5-50.

[0047]

[16] The method for producing a porous silicon oxycarbon composite material as described in

[15] above, wherein the carbon-containing material is composed of one or more selected from carbon black, carbon nanofibers, carbon nanotubes and low-crystalline nanocarbon.

[0048]

[17] The method for producing a porous silicon oxycarbide composite material according to

[16] above, wherein the average diameter of the primary particles of the carbon-containing material is not less than 10 nm and not more than 200 nm.

[0049]

[18] The method for producing a porous silicon oxycarbide composite material as described in

[15] above, wherein the organic polymer is composed of one or more selected from phenol resin, polystyrene and polydivinylbenzene.

[0050]

[19] The method for producing a porous silicon oxycarbide composite material as described in [8] above, wherein in the step (B), the surfactant is removed from the acidic aqueous solution and the water in the acidic aqueous solution is replaced by the alcohol.

[0051]

[20] The method for producing a porous silicon oxycarbide composite material according to [8] above, wherein in the step (C), the washed gel is dried at room temperature and normal pressure.

[0052]

[21] The method for producing a porous silicon oxycarbide composite material as described in [8] above, wherein in the step (D), the porous silicon oxycarbide composite material is calcined at a temperature of not less than 700°C and not more than 1200°C.

[0053] Effects of the Invention

[0054] According to the present invention, it is possible to provide a porous silicon oxycarbide composite material that is effective as a fuel cell electrode material and has both a large BET specific surface area and high electrical conductivity in a well-balanced manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] [ Figure 1 ] Figure 1 This is a flowchart illustrating an example of a method for producing a porous silicon oxycarbide composite material according to an embodiment of the present invention.

[0056] [ Figure 2 ] Figure 2 This is a scanning electron microscope image of the porous silicon oxycarbide composite material exemplified in Example 1.

[0057] [ Figure 3 ] Figure 3 The porous silicon oxycarbide composite material exemplified in Example 1 is 29 Si-NMR spectroscopy.

[0058] [ Figure 4 ] Figure 4 This is a transmission electron microscope image of the porous silicon oxycarbide composite material (catalyst A) supporting platinum particles exemplified in Example 21.

[0059] [ Figure 5 ] Figure 5 These are the cyclic voltammetry (CV) measurement results of Catalyst A exemplified in Example 21.

[0060] [ Figure 6 ] Figure 6 This is a graph showing changes in the electrochemically active surface area (ECSA) of Catalyst A exemplified in Example 21 with respect to CV measurement cycles.

[0061] [ Figure 7 ] Figure 7 These are the CV measurement results of Catalyst B exemplified in Comparative Example 4.

[0062] [ Figure 8 ] Figure 8 This is a graph showing changes in the ECSA of Catalyst B exemplified in Comparative Example 4 with respect to CV measurement cycles. DETAILED DESCRIPTION

[0063] <Composition of Porous Silicon Oxycarbide Composite Material>

[0064] The porous silicon oxycarbide composite material according to the present embodiment includes porous silicon oxycarbide (SiOC) having a three-dimensional skeleton structure and a carbon-containing material held by the three-dimensional skeleton structure.

[0065] The form of the porous silicon oxycarbide composite material is not particularly limited and may be, for example, powder, particle, fiber, or needle-shaped. Among them, powder or particle forms are preferred.

[0066] When the porous silicon oxycarbide composite material is in the form of powder or particles, the particle size of the porous silicon oxycarbide composite material is not particularly limited. The particle size D is the particle size at which the cumulative particle size in the volume-based cumulative particle size distribution reaches 50%. 50 For example, it is preferably from 0.1 μm to 100 μm, more preferably from 0.5 μm to 50 μm, and further preferably from 1 μm to 20 μm.

[0067] Particle size D of porous silicon oxycarbide composite material 50 It means the value measured according to JIS Z8825-1:2013, for example, it means the particle size D measured using a laser diffraction particle size distribution analyzer (manufactured by Shimadzu Corporation, SALD-7000). 50 .

[0068] [Porous silicon oxycarbide]

[0069] In porous silicon oxycarbide, due to the three-dimensional skeleton structure based on the siloxane network, a plurality of micropores are provided independently, or a part or all of the plurality of micropores are provided in a state of being interconnected.

[0070] The BET specific surface area of the porous silicon oxycarbide of this embodiment is 100 m 2 / g or more, preferably 100m 2 / g above 1500m 2 / g or less, more preferably 200m 2 / g above 1000m 2 / g or less. If the BET specific surface area is less than 100m 2 / g, the catalyst particle loading on the carrier surface becomes insufficient, and when the porous silicon oxycarbide is used as a fuel cell electrode, the desired characteristics such as output and efficiency cannot be obtained. In addition, the BET specific surface area is 1500m 2 When the pore size is less than 100 μg, the ratio of mesopores suitable for catalyst support becomes high, so the utilization rate of catalyst particles can be further improved.

[0071] The total pore volume of porous silicon oxycarbide is preferably 0.5 cm 3 / g or more, more preferably 0.5cm 3 / g above 3.0cm 3 / g or less, more preferably 0.6cm 3 / g above 2.0cm 3 / g or less. If the total pore volume of porous silicon oxycarbide is 0.5cm 3 / g or more, the reaction gas and electrolyte in the catalyst layer can be easily circulated, which can improve the catalyst efficiency. On the other hand, if the total micropore volume is 3.0cm 3 / g or less, good manufacturability can be achieved.

[0072] The pore diameter of the porous silicon oxycarbide is preferably from 2 nm to 200 nm, more preferably from 5 nm to 150 nm, and even more preferably from 10 nm to 100 nm. A pore diameter of from 2 nm to 200 nm facilitates the flow of reactant gases and electrolyte within the catalyst layer, improving catalyst efficiency. In particular, a pore diameter of less than 2 nm makes it difficult to supply reactant gases and electrolyte to the supported catalyst particles, significantly reducing catalyst particle utilization.

[0073] The BET specific surface area, total pore volume, and pore diameter of porous silicon oxycarbide can be calculated as measured values using a gas adsorption method. For example, these values are calculated by using a constant volume method to vary the relative pressure at the adsorption isotherm while adjusting the adsorption amount of a non-corrosive gas such as nitrogen or argon and the condensation shrinkage of the non-corrosive gas.

[0074] [Carbon-containing materials]

[0075] The content of the carbon-containing material in the porous silicon oxycarbide composite material is preferably from 2.5% to 50% by mass, more preferably from 3% to 30% by mass, and even more preferably from 5% to 20% by mass. A higher content of the carbon-containing material is preferred because it allows for higher electrical conductivity. However, if the content is too high, corrosion of the carbon-containing material may occur, which may reduce the durability of the catalyst cycle.

[0076] The content of the carbon-containing material in the porous silicon oxycarbide composite material means, for example, determining the ratio of the contained elements by elemental analysis, 29 The value is obtained by combining Si-NMR spectroscopy with thermogravimetric differential thermal analysis (TG-DTA) under atmospheric pressure.

[0077] The carbon-containing material is not particularly limited and may be, for example, one or more selected from carbon black, carbon nanofibers, carbon nanotubes, and low-crystalline nanocarbons. In particular, carbon black is preferred from the perspective of achieving high electrical conductivity and manufacturability.

[0078] When the carbon-containing material is composed of carbon black, the average diameter of the primary particles of the carbon-containing material is preferably from 10 nm to 200 nm, more preferably from 20 nm to 100 nm, and even more preferably from 30 nm to 50 nm. When the average diameter of the primary particles of the carbon-containing material is from 10 nm to 200 nm, good electrical conductivity can be achieved.

[0079] When the carbon-containing material is composed of carbon nanofibers or carbon nanotubes, the average diameter of the carbon-containing material is preferably from 10 nm to 200 nm, and the length of the carbon-containing material is preferably from 1 μm to 20 μm.

[0080] The morphology and size of the carbonaceous material retained in the porous silicon oxycarbon composite material can be measured, for example, by observation using a transmission electron microscope or a scanning electron microscope. Furthermore, the average diameter of the primary particles can be determined, for example, by using image analysis software for particle size distribution measurement based on microscope images.

[0081] [Characteristics of Porous Silicon Oxycarbide]

[0082] The electrical conductivity of porous silicon oxycarbide is 1.0×10 -6 S / cm or more, preferably 1.0×10 -4 S / cm or more 1.0×10 2 S / cm or less, more preferably 1.0×10 -3S / cm or higher and 10S / cm or lower. The higher the electrical conductivity of porous silicon oxycarbide, the better it can provide a fuel cell electrode catalyst. However, if the amount of carbonaceous material that contributes to improved electrical conductivity is set too high, corrosion of the carbon component may progress during the catalyst cycle, reducing durability.

[0083] <Method for producing porous silicon oxycarbide composite material>

[0084] The method for producing the porous silicon oxycarbide composite material according to this embodiment is as follows Figure 1 As shown, the present invention comprises a gel forming step (step (A)), a washing step (step (B)), a porous silicon oxycarbide precursor forming step (step (C)), and a calcining step (step (D)). It should be noted that, as long as the porous silicon oxycarbide composite material according to this embodiment can be obtained, other steps other than those described above may be provided before or after each step.

[0085] [Process (A)]

[0086] In step (A), for example, an organoalkoxysilane is added to an acidic aqueous solution containing a surfactant and a pH regulator, and a gel is formed by a sol-gel reaction of the organoalkoxysilane. For example, a hydrolyzate formed by hydrolyzing a hydrolyzable organoalkoxysilane is generated, and at the same time, the pH of the reaction system is further increased to carry out a polycondensation reaction of the organoalkoxysilane, thereby obtaining polysilsesquioxane. The pH suitable for the polycondensation reaction varies depending on the isoelectric point of the organoalkoxysilane used, but if the pH is too high, the reaction efficiency is sometimes reduced and the formation of the gel becomes difficult. The sol-gel reaction is preferably carried out at a temperature of 25°C to 80°C, more preferably at a temperature of 30°C to 70°C, and further preferably at a temperature of 40°C to 60°C. Thus, polysilsesquioxane can be obtained as a wet gel containing water as a solvent inside.

[0087] The content of the surfactant in the acidic aqueous solution is preferably 0.1% by mass to 50% by mass, more preferably 0.5% by mass to 35% by mass, and even more preferably 2% by mass to 15% by mass.

[0088] As surfactant, there is no particular limitation, and examples thereof include nonionic surfactants and / or cationic surfactants. By appropriately selecting and using any one or both of nonionic surfactants and cationic surfactants as surfactants, the desired BET specific surface area and micropore size can be obtained. As nonionic surfactants, for example, polyethylene glycol type (ether type, ester ether type), polyol type, etc. can be mentioned. As polyethylene glycol type nonionic surfactants, for example, Pluronic (registered trademark) type can be mentioned. As cationic surfactants, for example, amine salt type, quaternary ammonium salt type, etc. can be mentioned. By setting the content of surfactant relative to the acidic aqueous solution to 0.1% by mass or more and 50% by mass or less, a porous gel with a large BET specific surface area and well-developed mesopores can be formed.

[0089] The content of the pH adjuster relative to the acidic aqueous solution is preferably 5% by mass to 50% by mass, more preferably 5.5% by mass to 35% by mass, and even more preferably 6% by mass to 23% by mass. By setting the content of the pH adjuster relative to the acidic aqueous solution to 5% by mass to 50% by mass, a porous polysilsesquioxane gel having high skeletal strength and flexibility can be formed.

[0090] The pH adjuster is not particularly limited, and examples thereof include substances containing any one selected from urea, ammonia, and sodium hydroxide.

[0091] The acidic aqueous solution is not particularly limited, and examples thereof include aqueous solutions of hydrochloric acid, nitric acid, acetic acid, and the like.

[0092] The organoalkoxysilane is preferably represented by the following formula (1) or formula (2): By using the organoalkoxysilane represented by the following formula (1) or formula (2), porous silicon oxycarbide having a desired three-dimensional skeleton structure can be easily formed.

[0093] R 1 -SiR 2 x (OR 3 ) 3-x …(1)

[0094] (where R 1 is any one group selected from methyl, ethyl, vinyl and phenyl, R 2 Represents methyl, R 3 represents a methyl group or an ethyl group. Wherein the integer x is 0 or 1.

[0095] R 4 -(SiR 5 y (OR 6 ) 3-y )2…(2)

[0096] (where R 4 Contains any one group selected from methylene, ethylene, hexylene, vinylene, phenylene and biphenylene, R 5 Represents methyl, R 6 represents a methyl group or an ethyl group. In the formula, the integer y is 0 or 1.

[0097] Specific examples of the organoalkoxysilane represented by the above formula (1) include methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, methylethyldimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, methylvinyldimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, and methylphenyldimethoxysilane. Specific examples of the organoalkoxysilane represented by the formula (2) include bis(trimethoxysilyl)methane, bis(triethoxysilyl)methane, bis(methyldimethoxysilyl)methane, bis(methyldiethoxysilyl)methane, 1,2-bis(trimethoxysilyl)ethane, 1,2-bis(triethoxysilyl)ethane, 1,2-bis(methyldimethoxysilyl)ethane, 1,2-bis(methyldiethoxysilyl)ethane, 1,6-bis(trimethoxysilyl)hexane, 1,6-bis(triethoxysilyl)hexane, 1,6-bis(methyldimethoxysilyl)hexane, 1,6-bis(methyldiethoxysilyl)ethane, These ethane derivatives include 1,2-bis(trimethoxysilyl)ethane, 1,2-bis(triethoxysilyl)ethane, 1,2-bis(methyldimethoxysilyl)ethane, 1,2-bis(methyldiethoxysilyl)ethane, 1,4-bis(trimethoxysilyl)benzene, 1,4-bis(triethoxysilyl)benzene, 1,4-bis(methyldimethoxysilyl)benzene, 1,4-bis(methyldiethoxysilyl)benzene, 4,4'-bis(trimethoxysilyl)biphenyl, 4,4'-bis(triethoxysilyl)biphenyl, 4,4'-bis(methyldimethoxysilyl)biphenyl, and 4,4'-bis(methyldiethoxysilyl)biphenyl. Cis / trans geometric isomers exist in the above ethane derivatives, but any isomer can be used.

[0098] In step (A), a carbon-containing material or an organic polymer is further added to the above-mentioned acidic aqueous solution to form a gel containing the carbon-containing material or the organic polymer. By adding a carbon-containing compound or an organic polymer to the sol-gel reaction of the alkoxysilane, the precursor formed in step (C) can be fired in step (D). The carbon-containing material is configured at the nanometer level in the porous three-dimensional structural skeleton, which can impart excellent conductivity to the porous carbon oxide, which is originally an insulator. The organic polymer is thermally decomposed by firing in step (D) and is retained in the porous carbon oxide as low-crystalline nanocarbon, which can impart conductivity.

[0099] In the above-mentioned step (A), the carbon-containing material or the conductive organic polymer is preferably added to the acidic aqueous solution in a mass ratio of the carbon-containing material or the organic polymer to the organoalkoxysilane of 2.5 to 50:97.5 to 50. In addition, the mass ratio of the carbon-containing material or the organic polymer to the organoalkoxysilane is more preferably 3 to 30:70 to 97, and further preferably 5 to 20:80 to 95. By setting the mass ratio of the carbon-containing material or the organic polymer to the organoalkoxysilane to a value within the above-mentioned range, it is possible to achieve both a larger BET specific surface area and a higher electrical conductivity. If the amount of the carbon-containing material or the organic polymer added is too much, separation from the sol-gel reaction system occurs, which hinders the formation of a gel composed of polysilsesquioxane, and is therefore not preferred.

[0100] The carbon-containing material is not particularly limited and may be, for example, one or more selected from carbon black, carbon nanofibers, carbon nanotubes, and low-crystalline nanocarbons. In particular, carbon black is preferred from the perspective of achieving high electrical conductivity and manufacturability.

[0101] The organic polymer is not particularly limited, and can be composed of, for example, one or more selected from phenol resin, polystyrene, and polydivinylbenzene.

[0102] [Process (B)]

[0103] In step (B), the gel obtained in the above step (A) is washed with alcohol. The alcohol that can be used for washing is not particularly limited, and examples thereof include methanol, ethanol, 1-propanol, and 2-propanol. In this way, unnecessary surfactants can be removed from the acidic aqueous solution, and the water in the acidic aqueous solution can be replaced with alcohol. In addition, after washing with alcohol, it can be further replaced with a hydrocarbon solvent such as hexane or heptane. In this step (B), water, which is a high surface tension solvent, is replaced with an alcohol or hydrocarbon solvent, which is a low surface tension solvent. This can suppress the shrinkage of the siloxane network in the drying step at room temperature and pressure in the later-described step (C), making it easier to form a porous gel structure.

[0104] [Process (C)]

[0105] In step (C), the washed gel is dried to form a porous silicon oxycarbide precursor. Examples of methods for this step (C) include supercritical drying using carbon dioxide at 80°C and 14 MPa, drying at room temperature and atmospheric pressure, and vacuum drying at a temperature between 20°C and 80°C. Among these, drying at room temperature and atmospheric pressure is preferred because of its low production cost and the ability to produce a high-density porous silicon oxycarbide precursor with well-developed mesopores when forming a polysilsesquioxane having high skeletal strength and flexibility.

[0106] [Process (D)]

[0107] In step (D), the porous silicon oxycarbide precursor containing the carbonaceous material or organic polymer is calcined to obtain a porous silicon oxycarbide composite material. During this step, carbon atoms are donated from the organic groups of the polysilsesquioxane to form the silicon oxycarbide skeleton. Furthermore, carbon atoms are also donated to the skeleton from the carbonaceous material or organic polymer dispersed at the nanometer level in the gel. The organic polymer is thermally decomposed by calcination and retained as low-crystalline nanocarbon in the porous silicon oxycarbide.

[0108] Firing can be carried out by a well-known and customary method without any particular limitation, for example, by heating at 5°C per minute in an inert gas atmosphere and maintaining the highest temperature reached for a certain period of time to thereby carry out firing. The highest temperature for firing is preferably above 700°C and below 1200°C, more preferably above 750°C and below 1100°C, and particularly preferably above 800°C and below 1000°C. The maintenance time of the highest temperature can be appropriately determined based on the effective time for obtaining a porous silicon oxycarbide composite material. As an example, it is preferably 5 minutes to 16 hours, more preferably 10 minutes to 10 hours, and particularly preferably 30 minutes to 3 hours. Firing can also be carried out in two or more stages. That is, in the first stage, firing can be carried out at a temperature lower than the highest reached temperature for a certain period of time, and then firing can be carried out by heating again. Firing can be performed at normal pressure.

[0109] Examples of the inert gas include nitrogen, helium, and argon. The inert gas may contain a reducing gas such as hydrogen.

[0110] The calcination can be carried out using a fixed bed or fluidized bed carbonization furnace. The heating method and type of the carbonization furnace are not particularly limited as long as the furnace has the function of heating to a predetermined temperature. Examples of carbonization furnaces include Riedhammer furnaces, tunnel furnaces, and single furnaces.

[0111] In this step (D), a carbonaceous material or an organic polymer can be further mixed with the porous silicon oxycarbide precursor, and the mixture can be calcined. In the case of mixing an organic polymer with the porous silicon oxycarbide precursor in step (D), the organic polymer is calcined and thermally decomposed as in step (A), and the low-crystalline nanocarbon is retained in the porous silicon oxycarbide.

[0112] Example

[0113] The following describes examples of the present invention. However, the present invention is not limited to the following examples.

[0114] (Example 1)

[0115] 6 g of 5 mM acetic acid aqueous solution (manufactured by Kanto Chemical Co., Ltd.), 0.8 g of Pluronic (registered trademark) F-127 (manufactured by BASF), 0.5 g of urea (manufactured by Kanto Chemical Co., Ltd.), and 0.24 g of Ketjenblack (manufactured by Lion Specialty Chemicals Co., Ltd., product name "EC-600") were placed in a vial and stirred at room temperature for 10 minutes. 5 g of methyltrimethoxysilane (manufactured by Kanto Chemical Co., Ltd.) was added thereto and stirred at room temperature for 30 minutes. Thereafter, the mixture was reacted at 60°C for 4 days to obtain a wet gel. The obtained wet gel was washed with methanol (manufactured by Kanto Chemical Co., Ltd.), dried at room temperature and normal pressure for 3 days, and then further dried at 80°C and normal pressure for 6 hours to obtain 3.5 g of a porous silicon oxycarbide precursor. 1 g of the porous silicon oxycarbide precursor was placed in a tubular furnace and calcined under a nitrogen atmosphere at a heating rate of 10°C / min to 1000°C and held for 2 hours. 0.8 g of the resulting solid was pulverized with a paint conditioner to obtain a particle size (D 50 ) 1 μm powder. The scanning electron microscope image of the obtained powder is shown in Figure 2 In addition, using Figure 3 The powder shown 29 Si-NMR spectroscopy detected the presence of Si bonded to C, confirming the formation of a porous silicon oxycarbide composite material.

[0116] (Example 2)

[0117] The same operation as in Example 1 was carried out except that Pluronic F-127 was changed to 1.0 g and urea was changed to 0.4 g to obtain 3.5 g of a porous silicon oxycarbide precursor. The precursor was then calcined to obtain a porous silicon oxycarbide composite material at a yield of 76%.

[0118] (Example 3)

[0119] The same operation as in Example 1 was carried out except that the amount of Pluronic F-127 was changed to 0.65 g to obtain 3.4 g of a porous silicon oxycarbide precursor. The precursor was then calcined to obtain a porous silicon oxycarbide composite material at a yield of 75%.

[0120] (Example 4)

[0121] The same operation as in Example 1 was carried out except that the amount of Pluronic F-127 was changed to 0.40 g to obtain 3.3 g of a porous silicon oxycarbide precursor. The precursor was then calcined to obtain a porous silicon oxycarbide composite material at a yield of 74%.

[0122] (Example 5)

[0123] The same operation as in Example 1 was carried out except that the amount of Pluronic F-127 was changed to 0.37 g to obtain 3.4 g of a porous silicon oxycarbide precursor. The precursor was then calcined to obtain a porous silicon oxycarbide composite material at a yield of 72%.

[0124] (Example 6)

[0125] The same operation as in Example 1 was carried out except that Pluronic F-127 was changed to 0.34 g and urea was changed to 6 g to obtain 3.5 g of a porous silicon oxycarbide precursor. The precursor was then calcined to obtain a porous silicon oxycarbide composite material at a yield of 78%.

[0126] (Example 7)

[0127] The same operation as in Example 1 was performed except that the 5 mM acetic acid aqueous solution was changed to 10 g, the urea was changed to 6 g, and Pluronic F-127 was changed to 0.40 g of hexadecyltrimethylammonium chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) to obtain 3.5 g of porous silicon oxycarbide precursor. The porous silicon oxycarbide composite material was obtained with a yield of 77% by performing a calcination step.

[0128] (Example 8)

[0129] The same operation as in Example 7 was carried out except that the amount of urea was changed to 3 g to obtain 3.2 g of a porous silicon oxycarbide precursor. The precursor was then calcined to obtain a porous silicon oxycarbide composite material at a yield of 71%.

[0130] (Example 9)

[0131] The same operation as in Example 8 was carried out except that the amount of hexadecyltrimethylammonium chloride was changed to 0.06 g to obtain 3.1 g of a porous silicon oxycarbide precursor. The precursor was then calcined to obtain a porous silicon oxycarbide composite material at a yield of 76%.

[0132] (Example 10)

[0133] The same operation as in Example 8 was carried out except that KETJENBLACK was replaced with 1.5 g of phenol resin (manufactured by DIC Corporation, product name "Phenolite IF-3300") to obtain 3.6 g of porous silicon oxycarbide precursor. The porous silicon oxycarbide composite material was obtained at a yield of 65% by performing a calcination step.

[0134] (Example 11)

[0135] The same operation as in Example 10 was carried out except that the amount of the phenol resin was changed to 2.5 g to obtain 3.5 g of a porous silicon oxycarbide precursor. The precursor was then calcined to obtain a porous silicon oxycarbide composite material at a yield of 67%.

[0136] (Example 12)

[0137] The same operation as in Example 8 was carried out except that 0.24 g of carbon nanotubes (manufactured by Cnanotechnology, product name "Flotube7000") was used instead of phenol resin to obtain 3.2 g of porous silicon oxycarbide precursor. The porous silicon oxycarbide composite material was obtained at a yield of 43% by performing a calcination step.

[0138] (Example 13)

[0139] The same operation as in Example 8 was carried out except that the amount of KETJENBLACK was changed to 0.15 g to obtain 3.5 g of a porous silicon oxycarbide precursor. The precursor was then calcined to obtain a porous silicon oxycarbide composite material at a yield of 70%.

[0140] (Example 14)

[0141] The same operation as in Example 8 was carried out except that the amount of KETJENBLACK was changed to 0.4 g to obtain 3.4 g of a porous silicon oxycarbide precursor. The precursor was then calcined to obtain a porous silicon oxycarbide composite material at a yield of 78%.

[0142] (Example 15)

[0143] The same operation as in Example 8 was carried out except that 4 g of methyltrimethoxysilane was used and 1 g of vinyltrimethoxysilane (manufactured by Kanto Chemical Co., Ltd.) was used to obtain 3.5 g of a porous silicon oxycarbide precursor. The porous silicon oxycarbide composite material was obtained with a yield of 79% by performing a calcination step.

[0144] (Example 16)

[0145] The same operation as in Example 15 was carried out except that 1 g of phenyltrimethoxysilane (manufactured by Kanto Chemical Co., Ltd.) was used instead of vinyltrimethoxysilane to obtain 3.4 g of a porous silicon oxycarbide precursor. The porous silicon oxycarbide composite material was obtained by calcining at a yield of 80%.

[0146] (Example 17)

[0147] The same operation as in Example 1 was carried out except that the calcination was carried out at 700° C. to obtain 3.5 g of a porous silicon oxycarbide precursor. The calcination step was then carried out to obtain a porous silicon oxycarbide composite material at a yield of 77%.

[0148] (Example 18)

[0149] 5g of 5mM aqueous nitric acid solution (manufactured by Kanto Chemical Co., Ltd.), 5g of 1,2-bis(methyldiethoxysilyl)ethane (manufactured by Gelest Inc.), and 0.24g of Ketjenblack were placed in a vial and stirred at room temperature for 30 minutes. 3g of polyoxyethylene-2-ethylhexyl ether (manufactured by NOF Corporation, nonionic EH-208) was added to the solution and stirred for 3 minutes. 2g of 0.6M tetraethylamine hydroxide (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the solution and stirred at room temperature for 30 seconds. Thereafter, the solution was reacted at 80°C for 4 days to obtain a wet gel. The obtained wet gel was washed with methanol, dried at room temperature and atmospheric pressure for 3 days, and then further dried at 80°C and atmospheric pressure for 6 hours to obtain 3.0g of a porous silicon oxycarbide precursor. 1 g of the porous silicon oxycarbide precursor was calcined under a nitrogen atmosphere at a heating rate of 10°C / min to 1000°C and held for 2 hours. Then, 0.7 g of the obtained solid was pulverized with a paint mixer to obtain a particle size (D 50 )1μm porous silicon oxycarbide composite material.

[0150] (Example 19)

[0151] 5 g of 1,2-bis(methyldiethoxysilyl)ethane (trans isomer, manufactured by Gelest Inc.), 0.24 g of Ketjenblack, and 5 g of polyoxyethylene-2-ethylhexyl ether were placed in a vial and stirred at room temperature for 30 minutes. To this, 5 g of a 5 mM aqueous nitric acid solution was added and stirred for 10 minutes. Furthermore, 5 g of 0.6 M tetraethylamine hydroxide was added and stirred at room temperature for 30 seconds. The same procedures as in Example 18 were followed, except that 2.9 g of a porous silicon oxycarbide precursor was obtained. This was then calcined to obtain a porous silicon oxycarbide composite material with a yield of 79%.

[0152] (Example 20)

[0153] 1.8 g of 3M aqueous hydrochloric acid solution (manufactured by Kanto Chemical Co., Ltd.), 7.5 g of isopropyl alcohol (manufactured by Kanto Chemical Co., Ltd.), 5 g of 1,2-bis(triethoxysilyl)ethane (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.24 g of Ketjenblack, and 0.01 g of polyoxyethylene-2-ethylhexyl ether were placed in a vial and stirred at room temperature for 10 minutes. 3.5 g of 13.4 M ammonium hydroxide (manufactured by Kanto Chemical Co., Ltd.) was added to this and stirred at room temperature for 30 minutes. Thereafter, the mixture was reacted at 60°C for 4 days to obtain a wet gel. The obtained wet gel was washed with methanol, dried at room temperature and atmospheric pressure for 3 days, and then further dried at 80°C and atmospheric pressure for 6 hours to obtain 2.4 g of a porous silicon oxycarbide precursor. 1 g of the porous silicon oxycarbide precursor was calcined under a nitrogen atmosphere at a heating rate of 10°C / min to 1000°C and held for 2 hours. 0.7 g of the resulting solid was pulverized with a paint mixer to obtain a particle size (D 50 )1μm porous silicon oxycarbide composite material.

[0154] (Comparative Example 1)

[0155] Under Ar circulation, 18.6 g of novolac-type phenol resin (PSM4261 manufactured by Qun-Ei Chemical Industry Co., Ltd.) was dissolved in 60 ml of diethylene glycol (manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight 106) as a pore-forming agent, and 108.6 g of tetraethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise while stirring. Thereafter, 4.68 g of p-toluenesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) was added as an acid catalyst to initiate polymerization. The solution was heated to a temperature of 115°C, which was near the boiling point, at a heating rate of 25°C / hour, and then kept under reflux for 20 hours. Next, the temperature was raised to 200°C and kept in a vacuum for 24 hours, thereby heat-curing and desolventizing the product. The resulting polymer was kept at 600°C in an Ar atmosphere for 1 hour, thereby performing a primary calcination. Thereafter, the product was kept at a temperature of 1000°C in an Ar atmosphere for 3 hours, thereby performing a secondary calcination to obtain the porous carbon oxide silicon as the target.

[0156] (Comparative Example 2)

[0157] 3.0 g of a porous silicon oxycarbide precursor was obtained in the same manner as in Example 1 except that urea was not used. The precursor was then subjected to a calcination step to obtain a porous silicon oxycarbide composite material at a yield of 35%.

[0158] (Comparative Example 3)

[0159] 3.5 g of a porous silicon oxycarbide precursor was obtained in the same manner as in Example 1 except that the amount of KETJENBLACK added was changed to 0.10 g. This was then subjected to a calcination step to obtain a porous silicon oxycarbide composite material at a yield of 69%.

[0160] The above-mentioned Examples 1 to 20 and Comparative Examples 1 to 3 were measured by the following method.

[0161] [Determination of BET specific surface area, micropore volume and micropore diameter]

[0162] 0.04 g of the porous silicon oxycarbide composite material or porous silicon oxycarbide powder was weighed and placed in a sample vial. The sample was then pretreated by vacuum drying at 100°C for 6 hours. After pretreatment, nitrogen was adsorbed onto the sample at -196°C while varying the relative pressure using a specific surface area / pore distribution analyzer (Microtrac BEL Corp., "BELSORP-miniII").

[0163] [Determination of electrical conductivity]

[0164] The porous silicon oxycarbide composite material or porous silicon oxycarbide powder was introduced into a powder resistance measurement system (Mitsubishi Chemical Analytech, device name "MCP-PD51"). The sample was pressurized to 12 kN using the included hydraulic pump. The resistivity was then measured using a resistivity meter (Mitsubishi Chemical Analytech, device name "Loresta GX"). The electrical conductivity was calculated from the resistivity using the following formula. These measurement results are shown in Table 1.

[0165] Conductivity (S / cm) = (Powder resistance (Ω·cm)) -1

[0166] [Table 1]

[0167]

[0168] As shown in Table 1, in Examples 1 to 20, the BET specific surface area of the porous silicon oxycarbide composite material is 100 m 2 / g or more, micropore volume is 0.5cm 3 / g or more, micropore diameter of 2nm or more and 200nm or less, conductivity of 1.0×10 -6 These results show that a porous silicon oxycarbide composite material having a large BET specific surface area and high electrical conductivity can be obtained.

[0169] On the other hand, in Comparative Example 1, the BET specific surface area of porous silicon oxycarbide was 70 m 2 / g, micropore volume is 0.2cm 3 / g, the pore size is 10nm. In addition, the electrical conductivity is 1.0×10 -9Therefore, it can be seen that when the synthesis of the porous silicon oxycarbide precursor accompanying the sol-gel reaction is not performed, both the BET specific surface area and the electrical conductivity are significantly smaller than those in any of Examples 1 to 20.

[0170] In Comparative Example 2, the BET specific surface area of the porous silicon oxycarbide composite material is 50 m 2 / g, micropore volume is 0.2cm 3 / g, and the micropore diameter is 5nm. In addition, the electrical conductivity is 2.6×10 -3 S / cm. Therefore, it can be seen that when urea as a pH adjuster is not used, the BET specific surface area is significantly smaller than that of any of Examples 1 to 20.

[0171] In Comparative Example 3, the BET specific surface area of the porous silicon oxycarbide composite material was 370 m 2 / g, micropore volume is 1.8cm 3 / g, and the micropore diameter is 35nm. In addition, the electrical conductivity is 1.6×10 -8 Therefore, it can be seen that when the amount of KETJENBLACK used is significantly reduced compared to Example 1, the electrical conductivity is significantly lower than that of any of Examples 1 to 20.

[0172] (Example 21)

[0173] [Production of Catalysts Containing Precious Metals]

[0174] 0.43 g of chloroplatinic acid hexahydrate was dissolved in 60 mL of ultrapure water, 3.1 g of sodium bisulfite was added thereto to allow the reduction reaction to proceed, and then 280 mL of ultrapure water was added for dilution. Next, a 5% aqueous sodium hydroxide solution was added, and 35% hydrogen peroxide (24 mL) was added dropwise while adjusting the pH to about 5 to obtain a dispersion containing platinum colloid. Next, the dispersion was fractionated in such a manner that the amount of platinum after the carrier became 15% of the total mass of the carrier, 0.4 g of the porous carbon oxide composite material synthesized in Example 1 was added thereto as a carrier, and the mixture was mixed at 90°C for 3 hours. After cooling, solid-liquid separation was performed, and the powder obtained was thoroughly washed with ultrapure water to remove chloride ions, and then dried at 60°C in the atmosphere for 12 hours to obtain catalyst A loaded with platinum on the porous carbon oxide composite material carrier. The transmission electron microscope image of catalyst A is shown in FIG. Figure 4 It was confirmed that platinum particles with a particle size of about 5 nm were supported.

[0175] [Electrode production]

[0176] A 5 mm diameter glassy carbon (GC) electrode was ground using wrapping film and aluminum slurry, then ultrasonically cleaned with ultrapure water. Catalyst A was added to a 60% ethanol aqueous solution and dispersed using an ultrasonic homogenizer. This was added dropwise to a GC disc and allowed to dry at room temperature for 12 hours. After drying, a 5% Nafion (registered trademark) solution was added dropwise to the catalyst on the GC disc to achieve a dry film thickness of 50 nm, and the solution was dried at room temperature for 12 hours.

[0177] [Electrode evaluation based on electrochemical measurement]

[0178] The electrode evaluation was carried out using an electrochemical measurement system HZ-5000 manufactured by Hokuto Electric Co., Ltd. After nitrogen was purged in a 0.1M perchloric acid aqueous solution for 30 minutes, the reference electrode was cleaned 50 times using a reversible hydrogen electrode (RHE) in a potential range of 0.05 to 1.2 V and a scan rate of 150 mV / s. Thereafter, cyclic voltammetry (CV) was performed in a potential range of 0.05 to 1.2 V and a scan rate of 100 mV / s as a formal measurement. The analysis of the electrochemically active surface area (ECSA) was carried out using the adsorption wave of hydrogen visible below 0.4 V. Furthermore, in order to confirm the stability of the catalyst above 1.0 V, the potential range of 1.0 to 1.5 V was scanned 500 times, and then CV was measured in a potential range of 0.05 to 1.2 V.

[0179] This measurement step is regarded as one round, and 10 rounds or more (scanning of 5000 cycles or more) are performed. The CV measurement results of catalyst A are shown in FIG. Figure 5 The current value remained constant during each measurement cycle. Figure 6 The change in ECSA with respect to the measurement cycle is shown in . The evaluation up to 8000 cycles showed that the decrease in ECSA stopped at about 20% of the initial value, confirming that Catalyst A showed little degradation and had high potential stability.

[0180] (Comparative Example 4)

[0181] Instead of using 0.4 g of the porous silicon oxycarbide composite material synthesized in Example 1 as a carrier, 0.4 g of KETJENBLACK was used as a carrier. The same operations as in Example 21 were followed to prepare a catalyst containing a precious metal (preparation of catalyst B), prepare an electrode, and evaluate the electrode based on electrochemical measurements.

[0182] The CV measurement results of catalyst B are shown in Figure 7 As the potential was scanned, the current value increased in the vicinity of 0.2 to 0.6 V, and a redox peak of the quinone group generated by carbon degradation appeared in the vicinity of 0.6 V. Figure 8The change in ECSA over the measurement cycles is shown in Figure 2. Evaluation up to 8000 cycles revealed that the ECSA had decreased to approximately 50% of the initial value, confirming that Catalyst B, which uses a carbon-based material as a support, exhibited lower high-potential stability and inferior durability compared to the results for Catalyst A shown in Example 21.

[0183] Industrial applicability

[0184] The porous silicon oxycarbide composite material of the present embodiment has both a large BET specific surface area and high electrical conductivity, and is therefore suitable as an electrode material used in a catalyst layer of a fuel cell electrode.

Claims

1. A porous silicon oxycarbide composite material comprising porous silicon oxycarbide having a three-dimensional skeleton structure and a carbon-containing material held by the three-dimensional skeleton structure. BET specific surface area is 100m 2 / g or more, and the conductivity is 1.0×10 -6 S / cm or more, The carbon-containing material is composed of one or more selected from carbon black, carbon nanofibers, carbon nanotubes and low-crystalline nanocarbon.

2. The porous silicon oxycarbide composite material according to claim 1, wherein the total pore volume is 0.5 cm 3 / g or above. 3 . The porous silicon oxycarbide composite material according to claim 1 , wherein the pore diameter is from 2 nm to 200 nm. 4 . The porous silicon oxycarbide composite material according to claim 1 , wherein the content of the carbon-containing material is 2.5% by mass or more and 50% by mass or less. The porous silicon oxycarbon composite material according to claim 1 , wherein the average diameter of primary particles of the carbon-containing material is from 10 nm to 200 nm. 6 . A fuel cell electrode comprising a layer comprising the porous silicon oxycarbide composite material according to claim 1 .

7. A method for producing a porous silicon oxycarbide composite material, characterized in that: have: step (A) of adding an organoalkoxysilane to an acidic aqueous solution containing a surfactant and a pH adjuster to form a gel by a sol-gel reaction of the organoalkoxysilane, step (B) of washing the gel with alcohol, step (C) of drying the washed gel to form a porous silicon oxycarbide precursor, and a step (D) of calcining the porous silicon oxycarbide precursor to obtain a porous silicon oxycarbide composite material; In the step (A), a carbon-containing material or an organic polymer is further added to the acidic aqueous solution to form a gel containing the carbon-containing material or the organic polymer. 8 . The method for producing a porous silicon oxycarbide composite material according to claim 7 , wherein in the step (A), the sol-gel reaction is carried out at a temperature of 25° C. to 80° C.

9. The method for producing a porous silicon oxycarbide composite material according to claim 7, wherein the organoalkoxysilane is represented by the following formula (1) or formula (2): R 1 -SiR 2 x (OR 3 ) 3-x …(1) in, Where R 1 is any one group selected from methyl, ethyl, vinyl and phenyl, R 2 Represents methyl, R 3 represents a methyl group or an ethyl group, wherein the integer x is 0 or 1, R 4 -(SiR 5 y (OR 6 ) 3-y )2…(2) Among them, R 4 Contains any one group selected from methylene, ethylene, hexylene, vinylene, phenylene and biphenylene, R 5 Represents methyl, R 6 represents a methyl group or an ethyl group, wherein the integer y is 0 or 1. 10 . The method for producing a porous silicon oxycarbide composite material according to claim 7 , wherein the content of the surfactant relative to the acidic aqueous solution is 0.1% by mass or more and 50% by mass or less. 11 . The method for producing a porous silicon oxycarbide composite material according to claim 10 , wherein the surfactant is a nonionic surfactant and / or a cationic surfactant. 12 . The method for producing a porous silicon oxycarbide composite material according to claim 7 , wherein the content of the pH adjuster relative to the acidic aqueous solution is 5% by mass or more and 50% by mass or less. 13 . The method for producing a porous silicon oxycarbide composite material according to claim 11 , wherein the pH adjuster comprises any one selected from urea, ammonia, and sodium hydroxide. 14 . The method for producing a porous silicon oxycarbide composite material according to claim 7 , wherein the mass ratio of the carbon-containing material or organic polymer to the organoalkoxysilane is 2.5-50:97.5-50. 15 . The method for producing a porous silicon oxycarbon composite material according to claim 14 , wherein the carbon-containing material is composed of one or more selected from the group consisting of carbon black, carbon nanofibers, carbon nanotubes, and low-crystalline nanocarbon. 16 . The method for producing a porous silicon oxycarbide composite material according to claim 15 , wherein the average diameter of primary particles of the carbon-containing material is from 10 nm to 200 nm. 17 . The method for producing a porous silicon oxycarbide composite material according to claim 14 , wherein the organic polymer is composed of one or more selected from phenol resin, polystyrene, and polydivinylbenzene.

18. The method for producing a porous silicon oxycarbide composite material according to claim 7, wherein in the step (B), the surfactant is removed from the acidic aqueous solution, and water in the acidic aqueous solution is replaced with the alcohol.

19. The method for producing a porous silicon oxycarbide composite material according to claim 7, wherein in the step (C), the washed gel is dried at room temperature and normal pressure.

20. The method for producing a porous silicon oxycarbide composite material according to claim 7, wherein in the step (D), the porous silicon oxycarbide composite material is fired at a temperature of 700°C to 1200°C.

Images