JP2006096653A - Carbon gel composite material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a carbon-based composite material which carries a large carrying amount of a protein, a metal complex or a metal, and which is excellent in stability and activity of a carrying ingredient and is useful as a catalyst or the like. <P>SOLUTION: The carbon gel composite material has at least one carrying ingredient selected from the group consisting of carbon gel and the protein, the metal complex and the metal, wherein, if an X-ray diffraction peak is not found in a scanning region 2θ=0.5-10° (CuK<SB>α</SB>ray), and if the pore size value of the distribution peak top exists in the range of 1 nm or more and less than 10 nm in the pore size distribution as calculated by the adsorption and desorption isotherm while the pores consist of primary particles having the average particle diameter of 2-50 nm, 60% or more of the total pore volume is included in the pore size region of d±2 nm based on the pore size value (d), and if the pore size value of the distribution peak top exists in the range of 10 nm to 50 nm, 60% or more of the total pore volume is included in the pore size region of (0.75×D)-(1.25×D) nm based on the pore size value (D). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a composite material using a carbon gel as a carrier.

  Conventionally, various studies on porous bodies have been made, and application to a carrier such as a catalyst or an electrode material has been studied using its adsorptivity. Various porous bodies are known for such applications, and activated carbon is one of typical porous bodies.

  Such activated carbon is a porous body having a skeleton formed of carbon atoms, and has a high specific surface area. This high specific surface area has been conventionally activated in the production process, and is a material that becomes activated carbon. It was obtained by forming pores on the surface. As this activation treatment, for example, the raw material composition is heated to 600 to 1000 ° C. in an atmosphere of water vapor, carbon dioxide or the like, or the raw material composition is mixed with zinc chloride, potassium hydroxide or the like, and the inert atmosphere. Heating under is known. In the process of this activation treatment, a large number of pores are formed on the surface of the material to be activated carbon, and as a result, activated carbon having a high specific surface area is obtained, but the pore diameter is mainly 1 nm or less. Only the improvement of the surface area has a limit in improving the adsorptivity, and it has not been sufficient.

  In recent years, mesoporous carbons having so-called mesopores have been developed. A. Vinu et al., “Adsorption of Cytochrome C on New Mesoporous Carbon Molecular Sieves”, J. Phys. Chem. B, 2003, Vol. 107, p.8297-8299 (Non-Patent Document 1) discloses that cytochrome C is supported on a mesoporous carbon molecular sieve.

However, even when the mesoporous carbon molecular sieve as described in Non-Patent Document 1 is used as a carrier, there is a limit to the improvement in stability and activation with respect to the components carried there, and it is still insufficient. There wasn't.
A. Vinu et al., “Adsorption of Cytochrome C on New Mesoporous Carbon Molecular Sieves”, J. Phys. Chem. B, 2003, Vol. 107, p.8297-8299

  The present invention has been made in view of the above-described problems of the prior art, and supports a component such as a protein, a metal complex or a metal in a high loading amount and is excellent in stability and activity of the loading component. An object is to provide a carbon-based composite material useful as a catalyst or the like.

  As a result of intensive studies to achieve the above object, the inventors of the present invention consisted of primary particles having an average particle diameter of 2 to 50 nm, high uniformity of the pore diameter, and the pores having a periodic arrangement structure. However, the present inventors have found that the object can be achieved by using carbon gels having a three-dimensional network structure connected to each other as a carrier, and have completed the present invention.

That is, the present invention
In the scan region 2θ = 0.5 to 10 ° (CuK _α- ray), no X-ray diffraction peak is observed, the average particle size is composed of primary particles of 2 to 50 nm, and the pore size distribution is calculated from the adsorption / desorption isotherm. When the pore diameter value at the distribution peak top is in the range of 1 nm or more and less than 10 nm, 60% or more of the total pore volume is included in the pore diameter region of d ± 2 nm with respect to the pore diameter value (d). In addition, when the pore size value of the distribution peak top is in the range of 10 nm or more and 50 nm or less, (0.75 × D) to (1.25 × D) nm with respect to the pore size value (D). A carbon gel containing 60% or more of the total pore volume in the pore diameter region of
At least one supporting component selected from the group consisting of protein, metal complex and metal supported on the carbon gel;
It is a carbon gel composite material characterized by including.

  In the carbon gel composite material of the present invention, the pore size value of the distribution peak top of the carbon gel is preferably 1 to 20 nm.

  In the present invention, the pore size value of the distribution peak top of the carbon gel is more preferably 1 to 1.25 times the average molecular diameter of the supported component.

Furthermore, the specific surface area of the carbon gel is preferably 100 m ² / g or more, and the total pore volume of the carbon gel is preferably 0.1 to 50 ml / g.

  In addition, the protein carried on the carbon gel according to the present invention is preferably at least one protein selected from the group consisting of oxidoreductases and electron transfer proteins.

  Furthermore, the carbon gel used for the carbon gel composite material of the present invention may be one in which at least the vicinity of the surface is made of nitrogen-containing carbon. In this case, it is preferable that the atomic ratio (N / C) of the nitrogen atom to the carbon atom in the nitrogen-containing carbon is 0.01 to 0.4.

  According to the present invention, it is possible to provide a carbon gel composite material that supports a component such as a protein, a metal complex, or a metal in a high loading amount and that is excellent in stability and activity of the loading component and is useful as a catalyst or the like. Is possible.

  Hereinafter, the present invention will be described in detail with reference to preferred embodiments thereof, but the present invention is not limited to the following embodiments.

(Carbon gel)
The carbon-based porous material used as a carrier in the present invention is a carbon gel that satisfies the following conditions (i) to (iii).
(i) In X-ray diffraction measurement (XRD), no X-ray diffraction peak is observed in the scan region 2θ = 0.5 to 10 ° (CuK _α- ray).
(ii) It consists of primary particles having an average particle diameter of 2 to 50 nm.
(iii) In the pore diameter distribution calculated from the adsorption / desorption isotherm, when the pore diameter value at the top of the distribution peak is in the range of 1 nm or more and less than 10 nm, it is d ± 2 nm with respect to the pore diameter value (d). When the pore diameter region contains 60% or more of the total pore volume and the pore diameter value at the distribution peak top is in the range of 10 nm or more and 50 nm or less, the pore diameter value (D) is ( The pore diameter region of 0.75 × D) to (1.25 × D) nm contains 60% or more of the total pore volume.

Here, the X-ray diffraction peak means that a periodic structure having a d value corresponding to the peak angle is present in the sample. Therefore, in the carbon-based porous body in which one or more peaks are recognized in the scan region 2θ = 0.5 to 10 ° (CuK _α- ray), the pores are regularly arranged with a period of 0.9 to 17.7 nm. This is so-called mesoporous carbon (MPC). When the carrier is such a mesoporous carbon, sufficient improvement in stability and activation with respect to components such as an enzyme to be carried is not achieved.

On the other hand, the carbon gel used in the present invention has no X-ray diffraction peak in the scan region 2θ = 0.5 to 10 ° (CuK _α ray), and the pores have a periodic arrangement structure. It has a three-dimensional network structure connected to each other. In the present invention, by using such a carbon gel as a carrier for components such as enzymes, the reason for this is not clear, but the stability and activation of the supported components are surprisingly improved.

In the present invention, an X-ray diffraction measurement (XRD) is not recognized as an X-ray diffraction peak when the ratio of the peak intensity to the background noise intensity is less than 3. That is, "scan region 2θ = 0.5~10 ° X-ray diffraction peak at (Cu K _alpha line) is not observed" means, in the scan area 2θ = 0.5~10 ° _(CuK α ray), background This means that no X-ray diffraction peak having a ratio of peak intensity to noise intensity of 3 or more is observed.

  The carbon gel according to the present invention is composed of primary particles having an average particle diameter of 2 to 50 nm, and more preferably is composed of primary particles having an average particle diameter of 4 to 20 nm. When the average particle size of the primary particles constituting the carbon gel is less than 2 nm, the size of the pores is often smaller than the size of the supported component, and the adsorptivity is reduced. On the other hand, when the average particle size exceeds 50 nm, The specific surface area is reduced and the adsorptivity is reduced.

  Further, the carbon gel according to the present invention is an aggregate composed of the primary particles, and in the pore diameter distribution calculated from the adsorption / desorption isotherm, (iii-1) the pore diameter value of the distribution peak top is 1 nm or more and less than 10 nm. In the range of the pore diameter value (d), the pore diameter region of d ± 2 nm contains 60% or more of the total pore volume, and (iii-2) distribution peak top When the pore diameter value is in the range of 10 nm or more and 50 nm or less, the pore diameter value (D) is all fine in the pore diameter region of (0.75 × D) to (1.25 × D) nm. 60% or more of the pore volume is included. If the uniformity of the pore diameter is worse than this, the components of pores other than the optimum pore diameter for supporting enzymes and the like increase, and the obtained effect is reduced.

  Furthermore, the pore size value of the distribution peak top of the carbon gel according to the present invention is preferably 1 to 20 nm. When the pore size value of the carbon gel is less than 1 nm, the pore size is often smaller than the size of the supported component, and the adsorptivity is reduced. On the other hand, when the pore size exceeds 50 nm, the specific surface area is reduced. And the adsorptivity decreases. Moreover, when the pore diameter value of the carbon gel exceeds 20 nm, there is a tendency that inconvenience is likely to occur when a part of the protein is supported.

  From the viewpoint of preventing a reduction in the amount of supported component, the pore size value of the distribution peak top of the carbon gel according to the present invention is preferably larger than the average molecular size of the supported component, More preferably, it is about 1 to 1.25 times.

The specific surface area of such carbon gel to the present invention is preferably 100 m ² / g or more, more preferably 500 to 1000 m ² / g. When the specific surface area of the carbon gel is less than 100 m ² / g, the contact area with the supporting component is reduced and the pores taking in the supporting component are reduced, so that the adsorptivity tends to be low.

  Furthermore, the total pore volume of the carbon gel according to the present invention is not particularly limited because it varies depending on the specific surface area and the pore diameter value of the distribution peak top, but is preferably 0.1 to 50 ml / g, More preferably, it is 0.2-2.5 ml / g.

The specific surface area and pore volume of the carbon gel according to the present invention can be determined by the general volumetric measurement described below. That is, carbon gel is put in a container and cooled to a liquid nitrogen temperature (−196 ° C.), nitrogen gas is introduced into the container, and the adsorption amount is obtained by a volume method. Next, by gradually changing the pressure of the introduced nitrogen gas, the nitrogen gas adsorption amount with respect to each equilibrium pressure is plotted to obtain a nitrogen adsorption / desorption isotherm. Using this nitrogen adsorption / desorption isotherm, the specific surface area and pore volume can be calculated by the SPE (Subtracting Pore Effect) method (K.Kaneko, C.Ishii, M.Ruike, H.Kuwabara, Carbon 30, 1075). , 1986). The SPE method is a method of calculating the specific surface area by removing the effect of the strong potential field of the micropore by performing micropore analysis by α _S -plot method, t-plot method, etc. This method is more accurate than the BET method in calculating the specific surface area of the porous porous body. In addition, the pore size distribution and the distribution peak top pore size value can be obtained by calculating by BJH analysis from the nitrogen adsorption / desorption isotherm obtained above (Barrett EP, Joyner LG, Halenda
PH, Journal of American Chemical Society 73, 373, 1951).

  The method for producing the carbon gel according to the present invention described above is not particularly limited, and the carbon gel according to the present invention can be appropriately obtained using a conventionally known method. Examples of a method for producing such a carbon gel include the method described below.

  That is, first, an organic gel is synthesized according to the method described in, for example, R.W.Pekala et al., J.Non-cryst.Solids, vol.145, p.90 (1992). That is, a phenol such as resorcinol and an aldehyde such as formaldehyde are reacted in the presence of an alkali catalyst or an acid catalyst and aged to obtain an organic gel composed of a phenol resin. Next, after drying the obtained organic gel, it is possible to obtain the carbon gel according to the present invention by baking it in an inert atmosphere and carbonizing it.

(Nitrogen-containing carbon gel)
The carbon gel used as a carrier in the present invention is basically composed of carbon as described above, but may be a nitrogen-containing carbon gel in which at least the vicinity of the surface is composed of nitrogen-containing carbon. When at least the vicinity of the surface of the carbon gel according to the present invention is nitrogen-containing carbon, the supported amount of the supported component is further improved, and the stability and activity of these supported components tend to be more excellent.

  The upper limit of the atomic ratio (N / C) of nitrogen atoms to carbon atoms in such nitrogen-containing carbon is preferably 0.4, and more preferably 0.3. On the other hand, the lower limit is preferably 0.01, and more preferably 0.05. When the atomic ratio of nitrogen atom to carbon atom (N / C) is less than 0.01, the nitrogen atom is decreased, and the function as an adsorption site capable of interacting with the supported component is decreased. There is a tendency that improvement in adsorptivity by nitrogen atoms cannot be obtained. On the other hand, when the atomic ratio (N / C) of nitrogen atoms to carbon atoms exceeds 0.4, the strength of the carbon skeleton is lowered and it is difficult to maintain the pore structure. It tends to decrease and the adsorptivity tends to decrease. In addition, the atomic ratio (N / C) of a nitrogen atom and a carbon atom in such nitrogen-containing carbon can be obtained by CHN elemental analysis or XPS.

  Thus, the method in particular of manufacturing the carbon gel containing nitrogen-containing carbon is not restrict | limited, It can obtain suitably using a conventionally well-known method. Examples of such a method for producing a nitrogen-containing carbon gel include (i) a method of introducing nitrogen atoms into the carbon skeleton constituting the carbon gel using nitrogen monoxide, which will be described below, and (ii) a thermal CVD method. A method of depositing nitrogen-containing carbon on the surface of the carbon gel is mentioned.

  First, (i) a method of introducing nitrogen atoms into the carbon skeleton constituting the carbon gel using nitric oxide (NO) will be described.

  The introduction of nitrogen atoms into the carbon skeleton constituting the carbon gel is carried out according to the method described in P.Chambrion et al., Energy & Fuels vol.11, p.681-685 (1997), for example. Is possible. That is, a carbon gel is placed in a quartz reaction tube and heated to about 950 ° C. under a helium stream. Thereafter, NO diluted with helium (concentration of about 1000 ppm) is introduced into the reaction tube, and reacted at a reaction temperature of about 600 to 900 ° C. The reaction time required for this reaction is not particularly limited, but if the reaction time is extended, the amount of nitrogen taken into the carbon skeleton is improved.

  Next, (ii) a method for depositing nitrogen-containing carbon on the surface of the carbon gel by a thermal CVD method will be described.

  In this method, a nitrogen-containing organic compound is introduced into the pores of the carbon gel, and the nitrogen-containing organic compound is thermally decomposed to precipitate nitrogen-containing carbon on the surface of the carbon gel. That is, first, a carbon gel is placed in a reaction tube and heated to a predetermined temperature while introducing an inert gas such as nitrogen or argon into the reaction tube. Next, while maintaining the heated state, a nitrogen-containing organic compound in a gaseous state is introduced into the reaction tube, and a CVD reaction is performed for a predetermined time while introducing the nitrogen-containing organic compound into the pores of the carbon gel. Thus, nitrogen-containing carbon having a skeleton formed of carbon atoms and nitrogen atoms can be deposited in the pores of the carbon gel. The deposition step by the thermal CVD method is usually performed in an inert atmosphere such as nitrogen or argon because carbon combustion occurs when the reaction atmosphere is an oxidizing atmosphere.

  The nitrogen-containing organic compound used here is not particularly limited as long as it is an organic compound containing a nitrogen atom, and examples thereof include nitrogen-containing heterocyclic compounds, amines, imines, and nitriles. Examples of the nitrogen-containing heterocyclic compound include a nitrogen-containing heterocyclic monocyclic compound and a nitrogen-containing condensed heterocyclic compound. Examples of the nitrogen-containing heterocyclic monocyclic compound include pyrrole and its derivatives, pyrazole and imidazole which are 5-membered ring compounds. Such as diazoles and derivatives thereof, triazoles and derivatives thereof, and pyridine and derivatives thereof as 6-membered ring compounds, diazines and derivatives thereof such as pyridazine, pyrimidine and pyrazine, triazines and melamine and cyanuric acid And triazine derivatives. Examples of the nitrogen-containing condensed heterocyclic compound include quinoline, phenanthroline, and purine.

  Examples of the amines include primary to tertiary amines, diamines, triamines, polyamines, and amino compounds. Examples of primary to tertiary amines include aliphatic amines such as methylamine, ethylamine, dimethylamine and trimethylamine, and aromatic amines such as aniline and derivatives thereof. Examples of diamines include ethylenediamine. Examples of the amino compound include amino alcohols such as ethanolamine. Examples of the imines include pyrrolidine and ethyleneimine. Furthermore, examples of the nitriles include aliphatic nitriles such as acetonitrile and aromatic nitriles such as benzonitrile. Other nitrogen-containing organic compounds include polyamides such as nylon, amino sugars such as galactosamine, nitrogen-containing polymer compounds such as polyacrylonitrile, amino acids and polyimides.

  In the deposition step by the thermal CVD method, when the nitrogen-containing organic compound is in a liquid state at room temperature, the nitrogen-containing organic compound can be introduced into the reaction tube as a gas state by vapor evaporation using a bubbler, a mass flow pump, or the like. it can. At this time, it is preferable to introduce a nitrogen-containing organic compound in a gaseous state using nitrogen or argon as a carrier gas. Furthermore, it is preferable to prevent backflow by installing a bubbler containing liquid paraffin or the like on the reaction tube outlet side so that the gas once circulated in the reaction tube does not flow back from the reaction tube outlet side.

  When the nitrogen-containing organic compound is in a solid state at room temperature, a heating evaporator (sublimation) can be installed on the inlet side of the reaction tube, and the nitrogen-containing organic compound can be introduced into the reaction tube as a gas state by heating. Moreover, the temperature of the evaporator at this time needs to be adjusted to a temperature at which the nitrogen-containing organic compound is not thermally decomposed.

  Further, when the nitrogen-containing organic compound has polymerizability, it may be preliminarily polymerized in the pores of the carbon gel and then thermally decomposed in an inert atmosphere in a reaction tube. it can.

  Further, when the nitrogen-containing organic compound is not vaporized by heating, a nitrogen-containing organic compound is previously introduced into the pores of the carbon gel by a solution adsorption method, an evaporation to dryness method, etc. By pyrolysis under an active atmosphere, nitrogen-containing carbon having a skeleton formed of carbon atoms and nitrogen atoms can be precipitated in the pores of the carbon gel.

  The reaction temperature in the precipitation step by the thermal CVD method is not particularly limited as long as the nitrogen-containing organic compound is thermally decomposed and carbonized, but is preferably 300 to 1000 ° C, and is in the range of 500 to 700 ° C. It is more preferable. When the reaction temperature is less than 300 ° C., thermal decomposition of the nitrogen-containing organic compound is difficult to occur, so that the deposition rate of nitrogen-containing carbon is slowed, and the reaction time and energy consumption tend to increase. Moreover, when reaction temperature exceeds 1000 degreeC, since nitrogen does not remain easily in carbon skeleton, it exists in the tendency for N / C atomic ratio to fall.

In such a deposition process, when precipitation amount of a nitrogen-containing carbon to deposit in the pores of the carbon gel is not particularly limited, where the specific surface area per carbon gel 1g and Ym ^2, (0.0001 × Y) It is preferable that it is more than g. When the amount of nitrogen-containing carbon deposited is less than (0.0001 × Y) g, the amount of deposited is small, so that the adsorptive improvement by nitrogen atoms tends to be not obtained.

  Further, the amount of precipitation has a correlation with the CVD reaction time, and the amount of precipitation can be controlled by adjusting the CVD reaction time. Further, the amount of precipitation varies depending on the CVD reaction temperature, the type of carbon gel, the type of nitrogen-containing organic compound, the flow rate when introducing the nitrogen-containing organic compound, etc. It is possible to control the amount of precipitation by adjusting.

(Carbon gel composite material)
The carbon gel composite material of the present invention uses the above-described carbon gel (including the nitrogen-containing carbon gel) as a carrier, and at least one component (support component) selected from the group consisting of a protein, a metal complex, and a metal. It is carried.

  First, the carbon gel composite material of the present invention carrying a protein will be described. The protein used herein is not particularly limited, and various electron transfer proteins, various oxidoreductases, various transferases, hydrolytic enzymes such as proteolytic enzymes (such as subtilisin and lipase), carboxy (carboxylyase), Examples include elimination enzymes such as aldehydes, various isomerases, ligases, and the like. Among these, at least one protein selected from the group consisting of an electron transfer protein and an oxidoreductase is preferable from the viewpoint of enabling efficient exchange of electrons. Examples of such electron transfer proteins include cytochrome C and ferredoxin. Examples of the oxidoreductase include (i) an oxidoreductase that uses an electron transfer protein as an electron acceptor or an electron donor, ferredoxin NADP reductase, cytochrome C oxidase, and the like (ii) an electron transfer molecule (coenzymes, methyl As oxidoreductases that use viologens, ABTS, etc.) as electron acceptors or electron donors, laccase, diaphorase, lipoxyamide dehydrogenase, alcohol dehydrogenase, glucose oxidase (including oxidases that use other sugars as substrates), glucose dehydrogenase (In addition, dehydrogenase containing sugar as a substrate is included), (iii) Other examples of oxidoreductases include manganese peroxidase.

  The amount of the protein supported on the carbon gel in the carbon gel composite material of the present invention is not particularly limited, but the enzyme activity is shown from the viewpoint that the protein becomes sufficiently active in the obtained carbon gel composite material. The amount of protein supported is preferably about 0.01 to 80 parts by weight with respect to 100 parts by weight of the carbon gel.

  Further, the method for obtaining the carbon gel composite material of the present invention by loading the protein on the carbon gel is not particularly limited, and methods such as a sublimation method and an impregnation method can be used, but the following impregnation method is more preferable. It is. That is, first, the protein is dissolved in water or a buffer so as to have a concentration at which precipitation does not occur (preferably 0.1 mg / ml to 1000 mg / ml). The carbon gel is suspended at a temperature (preferably 0 ° C. to 50 ° C.) at which the solution does not freeze and the protein is not denatured, and the protein and carbon are at least 5 minutes or more, preferably 30 minutes or more. By contacting the gel, the protein is immobilized in the pores of the carbon gel, and the carbon gel composite material of the present invention is obtained.

  The concentration at which the carbon gel is suspended in the solution is not particularly limited, but is preferably about 0.1 to 1000 mg / ml. In addition, after the supporting step, there may be a step of further separating the carbon gel composite material from the solution by performing a centrifugal separation or the like, and a state in which the liquid component is removed by drying or the like. You may have the process of obtaining a carbon gel composite material.

  Next, the carbon gel composite material of the present invention carrying a metal complex will be described. The metal complex used here is not particularly limited, and is selected from the group consisting of Pt, Pd, Ru, Os, Ir, Rh, Au, Fe, Ni, Cr, Mn, Co, Cu, Ti, Zn, and V. A metal complex having at least one metal as a central metal and having an organic ligand is preferable. Such an organic ligand is not particularly limited, and examples thereof include porphyrin, phthalocyanine, salen, bipyridyl and the like.

  The amount of the metal complex supported on the carbon gel in the carbon gel composite material of the present invention is not particularly limited. From the viewpoint that the metal complex becomes sufficiently active in the obtained carbon gel composite material, the carbon gel 100 It is preferable that the supported amount of the metal complex is about 0.1 to 40 parts by weight with respect to parts by weight.

  Further, the method for obtaining the carbon gel composite material of the present invention by loading the metal complex on the carbon gel is not particularly limited, but for example, the following method is suitably employed. That is, first, a solution in which the metal complex is dissolved and / or dispersed in a solvent is prepared. Next, the carbon gel is suspended in the solution, and the metal complex in the solution is supported on the carbon gel to obtain the carbon gel composite material of the present invention.

  The solvent used here is not particularly limited as long as it can dissolve and / or disperse the metal complex. For example, nitrile solvents such as propionitrile; chlorinated solvents such as dichloromethane and chloroform Alcohol solvents such as methanol, ethanol and 1-butanol; alkyl ketone solvents such as acetone and 2-butanone; aromatic hydrocarbon solvents such as benzene, toluene and xylene; ether solvents such as tetrahydrofuran and dioxane; Examples include ester solvents such as ethyl acetate.

  The concentration of the metal complex in the solution is not particularly limited, but is preferably about 0.1 to 30 mM. Further, the concentration at which the carbon gel is dissolved and / or dispersed in the solution is not particularly limited, but is preferably about 0.1 to 35 mg / ml.

  There are no particular restrictions on the adsorption method and conditions when the metal complex is supported on the carbon gel. For example, the carbon complex is put into the solution and stirred at a temperature of about 10 to 100 ° C. for a predetermined time. It can be supported. In addition, after the supporting step, there may be a step of further separating the carbon gel composite material from the solution by performing a centrifugal separation or the like, and a state in which the liquid component is removed by drying or the like. You may have the process of obtaining a carbon gel composite material.

  Next, the carbon gel composite material of the present invention carrying a metal will be described. The metal used here is not particularly limited, and various kinds of precious metals and base metals are used. The state when such a metal is supported on the carbon gel is a metal ion even in the state of metal fine particles. It may be in the state.

  First, a carbon gel composite material in which the metal is supported in the form of fine metal particles will be described. The metal used in this case is not particularly limited as long as it forms fine particles, but Pt, Pd, Ru, Os, Ir, Rh, Au, Fe, Ni, Cr, Mn, Co, Cu, At least one metal selected from the group consisting of Ti, Zn and V is preferable, and at least one noble metal selected from the group consisting of Pt, Pd, Ru, Os, Ir, Rh and Au from the viewpoint of catalytic activity and the like. Is preferred.

  The average particle size of the metal fine particles in the carbon gel composite material of the present invention is not particularly limited, but is preferably 10 nm or less, and more preferably 1 to 5 nm. Further, the amount of the metal fine particles supported on the carbon gel in the carbon gel composite material of the present invention is not particularly limited, but from the viewpoint that the metal fine particles show sufficient activity in the obtained carbon gel composite material. It is preferable that the supported amount of metal fine particles is about 0.1 to 70 parts by weight with respect to 100 parts by weight of the gel.

  In addition, the method for obtaining the carbon gel composite material of the present invention by supporting metal fine particles on the carbon gel is not particularly limited, but for example, the following method is preferably employed. That is, first, a solution of a metal (preferably a metal salt) constituting the metal fine particles is prepared. Next, a suspension containing the carbon gel and the metal solution is prepared, mixed thoroughly, and then added with a reducing agent to reduce and deposit metal on the surface of the carbon gel, thereby supporting the metal fine particles. The inventive carbon gel composite material is obtained.

  The solvent used here is not particularly limited as long as it dissolves the metal (preferably metal salt), but water is preferably used. Also, the reducing agent is not particularly limited, hydrogen compounds such as hydrogen peroxide and sodium borohydride, phosphorus compounds such as hypophosphorous acid compounds, sulfur compounds such as sodium sulfide, hydrazine derivatives such as hydrated hydrazine, etc. A conventionally known reducing agent can be appropriately selected and used.

  The concentration of the metal in the suspension is not particularly limited, but is preferably about 0.01 to 100 mM. The concentration of the carbon gel in the suspension is not particularly limited, but is preferably about 0.01 to 50 mg / ml.

  There is no particular limitation on the adsorption method and conditions when the metal in the suspension is supported on the carbon gel. For example, the metal is made into the carbon gel by stirring the suspension at about 20 to 100 ° C for a predetermined time. It can be supported. In addition, after the supporting step, there may be a step of further separating the carbon gel composite material from the solution by performing a centrifugal separation or the like, and a state in which the liquid component is removed by drying or the like. You may have the process of obtaining a carbon gel composite material. Furthermore, there is no particular limitation on the method and conditions for reducing the metal supported on the carbon gel composite material. For example, a method of reducing the carbon gel composite material in a hydrogen stream at about 150 to 300 ° C. for a predetermined time is suitably employed. Is done.

  Next, a carbon gel composite material in which the metal is supported in the form of metal ions will be described. The metal ion used in this case may be any metal ion capable of forming a coordination bond with the nitrogen atom in the carbon skeleton, and Fe, Ni, Cr, Mn, Co, Cu, Ti, Zn, and At least one metal selected from the group consisting of V is preferred.

  The amount of the metal ion supported on the carbon gel in the carbon gel composite material of the present invention is not particularly limited, but from the viewpoint that the metal ion becomes sufficiently active in the obtained carbon gel composite material, the carbon gel 100 It is preferable that the supported amount of metal ions is about 0.1 to 50 parts by weight with respect to parts by weight.

  Further, the method for obtaining the carbon gel composite material of the present invention by loading metal ions on the carbon gel is not particularly limited, but for example, the following method is preferably employed. That is, first, a solution in which the metal (preferably a metal salt) is dissolved in a solvent is prepared. Next, the carbon gel is suspended in the solution, and the metal ions in the solution are supported on the carbon gel to obtain the carbon gel composite material of the present invention.

  The solvent used here is not particularly limited as long as it can dissolve a metal (preferably a metal salt), and examples thereof include acetic acid, water, ethylene glycol, DMSO, and DMF.

  The concentration of the metal in the solution is not particularly limited, but is preferably about 0.01 to 100 mM. Moreover, the concentration when the carbon gel is dispersed in the solution is not particularly limited, but is preferably about 0.01 to 100 mg / ml.

  There is no particular limitation on the adsorption method and conditions when the metal ions are supported on the carbon gel. For example, the metal gel is charged into the solution and preferably stirred at a temperature of about 25 to 200 ° C. for a predetermined time under reduced pressure. Ions can be supported on the carbon gel. In addition, after the supporting step, there may be a step of performing centrifugation or the like to separate the carbon gel composite material from the solution and taking it out, and the carbon gel in a state where the liquid component is removed by drying or the like You may have the process of obtaining a composite material, and also may have the process of heat-processing a carbon gel composite material at about 400-1000 degreeC for about predetermined time in inert atmosphere (for example, Ar).

  The method of using the carbon gel composite material of the present invention is not particularly limited, and for example, it can be applied by a general method of use in various applications such as a catalyst carrier.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

(Synthesis Examples 1-4)
First, an organic gel was synthesized according to the method described in RWPekala et al., J. Non-cryst. Solids, vol. 145, p. 90 (1992). Specifically, 5.5 g of Resorcinol (Wako Pure Chemical Industries) and 26.5 mg of sodium carbonate (Wako Pure Chemical Industries) were dissolved in 16.9 g of distilled water, and then 8.1 g of 37% formaldehyde aqueous solution (Wako Pure Chemical Industries) was added and mixed by stirring. did. The mixed solution became light yellow and transparent. In addition, the molar ratio of each said component is as follows.
Resorcinol: sodium carbonate: formaldehyde = 200: 1: 400.

  Subsequently, an organic gel was obtained while controlling the pore diameter by further diluting the mixed solution prepared above with water. That is, together with the mixed solution prepared above, a solution obtained by further diluting it with water 3 to 12 times (volume ratio) was prepared (Synthesis Example 1: No dilution, Synthesis Example 2: Dilution factor 3 times, Synthesis Example 3). : 6 times dilution ratio, Synthesis Example 4: 12 times dilution ratio), these solutions were put in a vial and sealed, and allowed to stand at room temperature for 24 hours, at 50 ° C. for 24 hours, and at 90 ° C. for 72 hours. A hydrated organic gel was obtained.

  Next, the organic gel obtained above was dried as follows. That is, first, a hydrated organic gel was immersed in acetone (Wako Pure Chemicals) as an exchange solvent in order to remove moisture in the organic gel. The water in the organic gel diffused into acetone, so that the water in the organic gel was completely replaced with acetone. At this time, the substitution rate of water was further improved by exchanging acetone as a substitution solvent several times with a new one. Subsequently, the immersion solvent was changed to n-pentane (Wako Pure Chemical Industries), and the solvent exchange-immersion process was repeated until the acetone in the organic gel was completely replaced with n-pentane in the same manner as described above. And the dried organic gel was obtained by air-drying the organic gel solvent-substituted by n-pentane.

  Next, the dried organic gel obtained above was carbonized as follows to obtain a carbon gel. That is, the organic gel was carbonized by heating the dried organic gel at 1000 ° C. under a nitrogen stream (flow rate 300 ml / min). The heating time at that time was 6 hours.

(Comparative Synthesis Example 1)
One-dimensional fine pore mesoporous carbon (MPC) was synthesized as follows. That is, first, 4 g of a triblock copolymer (Pluonic P123) was added to 30 ml of water and stirred for 3 hours to obtain a uniform solution. 120 ml of 2M HCl aqueous solution was added thereto, and the mixture was further stirred for 2 hours. 9 g of tetraethyl orthosilicate was added to this solution and stirred at 313 K for 24 hours. After the stirring was completed, the solid content was precipitated by allowing to stand at 373 K for 48 hours.

  Next, the produced solid content was filtered, further washed thoroughly with ion exchange water, and then dried in air at 373K. Further, the organic material (P123) was decomposed and removed by firing the obtained dried sample in air at 823 K, to obtain a silica mesoporous material (SBA-15) serving as a pore template.

  Next, 1.25 g of sucrose dissolved in 5 g of water and 0.14 g of sulfuric acid were added to 1 g of the silica mesoporous material (SBA-15) obtained above and mixed, and heated at 373 K for 6 hours and further at 433 K for 6 hours. did. Due to the dehydration action of sulfuric acid, a part of sucrose was carbonized and a brown powder was obtained. To this reaction product, 0.3 g of sucrose dissolved in 5 g of water and 0.03 g of sulfuric acid were added and mixed, and heated at 373 K for 6 hours and further at 433 K for 6 hours as in the previous operation. The obtained powder was heated at 1173 K under a nitrogen stream to completely carbonize sucrose present in the pores.

  The silica mesoporous carbon composite thus obtained was treated with 5 wt% hydrofluoric acid at room temperature to dissolve only the silica component to obtain one-dimensional pore mesoporous carbon (MPC).

<X-ray diffraction measurement (XRD)>
When X-ray diffraction was measured for the carbon gels obtained in Synthesis Examples 1 to 4 and the mesoporous carbon obtained in Comparative Synthesis Example 1, the scan regions 2θ = 0. An X-ray diffraction peak at 5 to 10 ° (CuK _α- ray) was not confirmed. Therefore, in the carbon gels obtained in Synthesis Examples 1 to 4, the pores do not have a periodic arrangement structure, but the pores are interconnected, and a three-dimensional network structure is obtained. It was confirmed to have.

  On the other hand, in the mesoporous carbon obtained in Comparative Synthesis Example 1, a main peak was observed at 2θ = 0.96 °, and weak peaks were observed at 1.68 ° and 1.94 °. These peaks are derived from a two-dimensional hexagonal structure (p6 mm), and are due to (100), (110), and (200) diffraction, respectively. The d value of each peak is 9.1, 5.2, 4.6 nm. In addition, since these X-ray diffraction peaks were also observed in SBA-15 as a template, it was confirmed that the mesoporous carbon obtained in Comparative Synthesis Example 1 reflects the pore structure of SBA-15. It was done. It is known that the two-dimensional hexagonal structure is formed from an array of cylinder pores. Therefore, the mesoporous carbon obtained in Comparative Synthesis Example 1 reflecting the pore structure of SBA-15 is one-dimensional fine. It was confirmed to have holes.

<Measurement of pore size distribution, etc.>
The carbon gel obtained in Synthesis Examples 1 to 4 was subjected to nitrogen adsorption / desorption measurement, and the pore size distribution of the carbon gel was determined based on the obtained nitrogen adsorption / desorption isotherm. The obtained results are as shown in FIG. 1, and the pore diameters of the carbon gels obtained in Synthesis Examples 1 to 4 exist in the range of 2 to 15 nm. When the pore size value of the distribution peak top is in the range of 1 nm or more and less than 10 nm with respect to the pore size value of the distribution peak top, the pore size value of the distribution peak top is in the range of d ± 2 nm with respect to the pore diameter value (d). When the value is in the range of 10 nm to 50 nm, 60% or more of the total pore volume is included in the range of (0.75 × D) to (1.25 × D) nm with respect to the pore diameter value (D). It was confirmed that the pores were highly uniform. Moreover, the pore diameter value of the distribution peak top and the average particle diameter of the primary particles of the carbon gels obtained in Synthesis Examples 1 to 4 were as shown in Table 1.

  Further, when the pore size distribution was similarly obtained for the mesoporous carbon obtained in Comparative Synthesis Example 1, it was the same shape as the carbon gel obtained in Synthesis Example 2, and the pore size value at the distribution peak top was It was 7.5 nm.

(Example 1 and Comparative Examples 1-2)
Manganese peroxidase (MnP, molecular diameter 6.8 nm) derived from white rot fungi as an enzyme was dissolved in distilled water to prepare an enzyme solution having an enzyme concentration of 1 mg / ml. Next, the carbon gel obtained in Synthesis Example 2 was used as the porous body in Example 1, and the mesoporous carbon (MPC) obtained in Comparative Synthesis Example 1 was used in Comparative Example 1. Each was added gently at 4 ° C. overnight to immobilize the enzyme in the porous body. Thus, the porous body which fixed the enzyme was isolate | separated and collect | recovered from the enzyme solution by centrifugation, and washing | cleaning was repeated 3 times with 5 ml distilled water (washing liquid).

<Measurement of enzyme immobilization amount and leakage amount>
The amount of enzyme in the enzyme solution before and after immobilization was determined from the absorbance at 280 nm, and the amount of enzyme immobilized on the porous body obtained based on the result was calculated. Further, the amount of enzyme leaked into the cleaning solution was also measured in the same manner. The obtained results are shown in Table 2.

  As is clear from the results shown in Table 2, a sufficient amount of enzyme (MnP) was immobilized on both the carbon gel obtained in Synthesis Example 2 and the mesoporous carbon obtained in Comparative Synthesis Example 1, and the leakage amount was It was about the same.

<Thermal stability test of immobilized enzyme>
The thermal stability of the enzyme (MnP) immobilized on the porous body (Example 1, Comparative Example 1) and the enzyme solution (Comparative Example 2) was evaluated as follows. That is, first, after suspending 10 mg of the enzyme-immobilized porous body in 0.5 ml of 50 mM succinate buffer (pH = 4.5), heat treatment was performed at 60 ° C. for a predetermined time (30 minutes or 60 minutes). Then, it was sufficiently cooled in ice, and the porous body was recovered by centrifugation (Example 1, Comparative Example 1).

  Similarly, an enzyme solution prepared by dissolving MnP in a 50 mM succinate buffer (pH = 4.5) at a concentration of 1 mg / ml was prepared, and the enzyme solution was heat-treated at 60 ° C. and then sufficiently cooled in ice. (Comparative example 2).

Next, 1 ml of a substrate solution (0.5 mM MnSO ₄ , 2 mM sodium oxalate, 0.1 mM H ₂ O ₂ , 25 mM succinate buffer (pH = 4.5)) is added to each of the porous body and the enzyme solution. The mixture was added and stirred at 37 ° C. for 15 minutes, then cooled, and the residual activity was determined by measuring the absorbance of the supernatant at 270 nm. In addition, it measured similarly also about the case where the heat processing at 60 degreeC was not performed, and calculated | required the residual activity as a relative activity with respect to the activity before heat processing. The obtained results are shown in Table 3.

  As is apparent from the results shown in Table 3, in the enzyme solution obtained in Comparative Example 2 that was not immobilized on the porous body, the enzyme was almost inactivated by heat treatment for 30 minutes, whereas in Synthesis Example 2, When immobilized on any of the obtained carbon gel and the mesoporous carbon obtained in Comparative Synthesis Example 1, the thermal stability of the enzyme was sufficiently high.

<Specific activity test of immobilized enzyme>
As the porous material, the carbon gel obtained in Synthesis Example 2 was used in Example 1, and the mesoporous carbon (MPC) obtained in Comparative Synthesis Example 1 was used in Comparative Example 1, and 50 mg of enzyme (MnP) was used in the same manner as described above. A sample was obtained by immobilizing to a 100 mg porous body. Next, the porous body on which the enzyme is immobilized is packed in a glass column (5 mmφ), and a substrate solution (0.5 mM MnSO ₄ , 2 mM sodium oxalate, 0.1 mM H ₂ O ₂ , 25 mM succinate buffer (pH = 4.5)) was allowed to flow down at various flow rates, and the reaction was continuously performed at 37 ° C. The apparent reaction activity was evaluated by measuring the amount of the reaction product contained in the reaction solution flowing out from the column per minute by measuring the absorbance at 270 nm. The obtained results are shown in FIG.

  As is clear from the results shown in FIG. 2, in the low flow rate region, when mesoporous carbon was used (Comparative Example 1), the reaction activity was almost the same as when carbon gel was used (Example 1). In the case of using mesoporous carbon (Comparative Example 1) as the flow rate of the water increased, the amount of reaction product gradually decreased. On the other hand, when carbon gel was used (Example 1), it was confirmed that the initial activity was generally maintained even in this flow rate region and the activity was excellent.

  In addition, in the enzyme immobilized on the porous body, in addition to the activity of the enzyme itself, the diffusion of the substrate and the reactant in the pore greatly affects the apparent reaction activity. Since the activity in the low flow rate region was almost the same in this test, the activity of the immobilized enzyme itself is considered to be almost the same. However, since there was a difference in the apparent activity in the high flow rate region where the diffusion of the substrate and the like becomes the reaction rate limiting, the three-dimensional pores formed in the carbon gel compared to the one-dimensional pores formed in the mesoporous carbon. Since the diffusion of the substrate and the reactant occurs with higher efficiency, it is considered that the reactivity in the high flow rate region was higher when the carbon gel was used (Example 1).

(Example 2)
Hexahydroxyplatinic acid (1.5 g) was dispersed in an aqueous solution, and 100 ml of a 6% aqueous sulfurous acid (H ₂ SO ₃ ) solution was added thereto and stirred for 1 hour. Thereafter, the obtained dispersion was immersed in an oil bath heated to 120 ° C. to remove residual sulfurous acid, and cooled to obtain a Pt chemical solution (Pt concentration: 4 g / L).

Next, 3 g of the carbon gel (specific surface area: 760 m ² / g, pore size distribution: distribution peak top pore size value: 11.5 nm shown in FIG. 3) obtained in Synthesis Example 4 was weighed, and the above Pt chemical solution 187 ml was added, 20% H ₂ O ₂ aqueous solution was added and immersed in an oil bath heated to 120 ° C., and Pt was supported on the carbon gel. The carbon gel supporting Pt in this way is reduced in a hydrogen stream at 150 to 500 ° C. (preferably 200 to 400 ° C.) for 1 to 3 hours through filtration, drying and pulverization processes, and Pt is supported on the carbon gel. Pt / carbon gel catalyst (A) was obtained.

Subsequently, the Pt / carbon gel catalyst (A) obtained above was weighed, and the polymer content was 5 wt. % Nafion solution (manufactured by Aldrich, solvent: mixed solvent of ethanol and water), the carbon gel weight in the catalyst and the polymer solid weight in the Nafion solution are mixed and kneaded to obtain a catalyst. Ink (A) was prepared. This catalyst ink (A) was applied onto a Teflon sheet (registered trademark) so that the amount of Pt was 0.3 mg / cm ² and dried to obtain a catalyst sheet (A). The catalyst sheet (A) is thermocompression bonded to one side of a Nafion 112 membrane (made by DuPont, film thickness: about 50 μm), the Teflon sheet is peeled off, and a cathode catalyst layer (cathode catalyst layer) is formed on the surface of the Nafion membrane. A transfer was formed.

On the other hand, the Pt / carbon gel catalyst (A) except that carbon black (manufactured by Lion, Ketjen Black, specific surface area: 800 m ² / g, pore size distribution: shown in FIG. 3) was used instead of the carbon gel. A Pt / carbon black catalyst (B) was prepared in the same manner as in the method obtained. Next, the catalyst sheet (P) except that the Pt / carbon black catalyst (B) was used in place of the Pt / carbon gel catalyst (A) and that the Pt amount was 0.1 mg / cm ^2. A catalyst sheet (B) was obtained in the same manner as in the method obtained from A). Then, the catalyst sheet (B) is transferred onto the surface of the Nafion 112 film opposite to the surface onto which the cathode catalyst layer has been transferred in the same manner as in the method for obtaining the cathode catalyst layer, and the anode catalyst layer is then transferred to the anode catalyst layer. Formed.

Using the electrolyte membrane / electrode assembly (Membrane-Electrode-Assembly, hereinafter referred to as “MEA”) produced in this manner, a small fuel cell (electrode area 13 cm ² ) was produced.

(Example 3)
An MEA was prepared in the same manner as in Example 2 except that a carbon gel having a specific surface area of 640 m ² / g, a distribution peak top pore size value of 30 nm, and an average primary particle size of 8.5 nm was used. And the small fuel cell was produced using the MEA. In this carbon gel, an X-ray diffraction peak in the scan region 2θ = 0.5 to 10 ° (CuK _α ray) was not confirmed.

(Comparative Example 3)
An MEA was produced in the same manner as in Example 2 except that the mesoporous carbon (specific surface area: 780 m ² / g) obtained in Comparative Synthesis Example 1 was used instead of the carbon gel, and the MEA was used to make a small size. A fuel cell was fabricated.

(Comparative Example 4)
An MEA was prepared in the same manner as in Example 2 except that the Pt / carbon black catalyst (B) was used instead of the Pt / carbon gel catalyst (A) as the cathode side catalyst, and the MEA was used to make a small size. A fuel cell was fabricated.

<Power generation characteristics of small fuel cells>
The discharge test of the small fuel cell obtained in Examples 2-3 and Comparative Examples 3-4 was performed as follows. That is, pure hydrogen gas having a dew point of 75 ° C. as the anode gas (pressure 0.15 MPa, flow rate 100 mL / min), air having a dew point of 65 ° C. as the cathode gas (pressure 0.15 MPa, flow rate 500 mL / min), and a battery temperature of 80 ° C. A power generation experiment was conducted under the conditions of (1) and (4) the relationship between the discharge current and the battery voltage (IV characteristics) was examined. The obtained results are shown in FIG.

  As is clear from the results shown in FIG. 4, the fuel cell using the carbon gel composite material of the present invention (Examples 2 to 3) as an electrode catalyst is higher than the fuel cells obtained in Comparative Examples 3 to 4. It was confirmed to show voltage characteristics. As described above, the present inventors infer that the high voltage characteristic is achieved by the carbon gel composite material of the present invention as follows.

  (i) Since the holes in the mesoporous carbon used in Comparative Example 3 have a one-dimensional structure, supply of reactants such as oxygen when the holes are blocked by Nafion or water generated in the fuel cell reaction Is easily disturbed. On the other hand, since the carbon gel according to the present invention has a three-dimensional pore network structure, it is not easily affected by pore blockage.

  (ii) When carbon black is used in Comparative Example 4, the Pt catalyst is basically not supported in pores of 1 nm or less that occupy most of the surface area, and Nafion enters even if supported. Since Pt cannot be used, the Pt is not used effectively. Therefore, in comparison with the case of using a carbon gel having the same carrier surface area, when carbon black is used, the substantial surface area of Pt is reduced and the voltage characteristics are lowered.

Example 4
Carbon gel (specific surface area: 680 m ² / g, distribution peak top pore size value: 3 nm, average primary particle size: 8.2 nm) was weighed and transferred to an eggplant flask. Next, a 2.9 mg / L concentration Co-tetraphenylporphyrin (CoTPP) / toluene solution was prepared, and 400 mL of the solution per 1 g of the carbon gel was charged into the eggplant flask. Then, the solvent is removed by reducing the pressure while the obtained dispersion is bathed in water at 50 ° C., further dried overnight at 100 ° C., then taken out and pulverized, and CoTPP / carbon in which CoTPP is supported on the carbon gel. A gel (A) catalyst was prepared. In this carbon gel, an X-ray diffraction peak in the scan region 2θ = 0.5 to 10 ° (CuK _α ray) was not confirmed.

(Example 5)
CoTPP / carbon was prepared in the same manner as in Example 4 except that the carbon gel obtained in Synthesis Example 1 (specific surface area: 640 m ² / g, distribution peak top pore size value: 5.2 nm) was used as the carbon gel. A gel (B) catalyst was prepared.

(Example 6)
CoTPP / carbon was used in the same manner as in Example 4 except that the carbon gel obtained in Synthesis Example 4 (specific surface area: 760 m ² / g, distribution peak top pore size value: 11.5 nm) was used as the carbon gel. A gel (C) catalyst was prepared.

(Comparative Example 5)
CoTPP / carbon was used in the same manner as in Example 4 except that carbon black (manufactured by Lion, Ketjen Black, specific surface area: 800 m ² / g, pore size distribution: shown in FIG. 3) was used instead of the carbon gel. A black catalyst was prepared.

<Model test of oxygen reduction reaction>
An electrode (working electrode) in which each catalyst obtained in Examples 4 to 6 and Comparative Example 5 was dispersed and adhered on a glassy carbon electrode (GC electrode) was prepared, and a model test of the oxygen reduction reaction was performed as follows. went. The obtained results are shown in FIG.

(1) Cell configuration test electrode of model experiment: The working electrode was prepared by the following procedure.
(i) The GC surface of the rotating electrode (the apparent surface area of the GC electrode: 0.20 cm ² ) was polished into a mirror surface.
(ii) 60 mg of each catalyst and 10 ml of ultrapure water were mixed and subjected to a dispersion treatment with ultrasonic waves for 3 minutes.
(iii) After 15 μl of the obtained suspension was dropped onto the GC electrode, it was dried in air at 80 ° C. for 10 minutes.
(iv) A Nafion / ethanol aqueous solution was further dropped onto the obtained GC electrode, dried at room temperature for 15 minutes, and then vacuum dried at 80 ° C. for 30 minutes. At this time, the Nafion coating amount was about 3.2 μg in terms of dry polymer weight.
(v) The obtained GC electrode was naturally cooled outside the furnace and then attached to the apparatus.
Counter electrode: Pt plate Reference electrode: RHE (reversible hydrogen electrode).

(2) Model experiment procedure
(i) An electrolytic cell containing a 0.05M sulfuric acid aqueous solution was immersed in a constant water bath at 25 ° C.
(ii) The electrolyte was degassed by bubbling with Ar (about 20 minutes or more).
(iii) Sweep speed: 10 mV / s, sweep range: 50 mV to 1000 mV, electrode rotation speed: 1000 rpm, 10 reciprocation potentials were set to 1 cycle, and the 10th reciprocal voltammogram was recorded.
(iv) The bubbling gas was switched to oxygen and the gas was replaced for 30 minutes or more. Thereafter, the potential sweep was repeated under the same conditions as in (iii).
(v) The potential at which the current difference from the voltammogram in Ar becomes 0.2 mA / cm ² or more on the reduction side was examined, and plotted against the time from the start of potential scanning under oxygen saturation. .

  As is apparent from the results shown in FIG. 5, when carbon black having a small pore size capable of containing tetraphenylporphyrin (TPP, average molecular diameter: about 1 nm) is used (Comparative Example 5), a catalyst is used. Although the activity decreased rapidly with time, it was confirmed that when the carbon gel composite material of the present invention was used (Examples 4 to 6), the decrease in the catalyst activity was suppressed. Moreover, when the carbon gel which has many pores about 1 to 1.25 times the average molecular diameter of the complex is used (Examples 4 to 5), the stability of the catalytic activity may be further improved. confirmed.

  As described above, according to the present invention, it is possible to obtain a carbon gel composite material that supports a component such as a protein, a metal complex, or a metal in a high loading amount and that is excellent in stability and activity of the loading component. it can. Therefore, according to the present invention, it is possible to provide a carbon gel composite material useful for various uses such as a catalyst.

It is a graph which shows the pore size distribution of the carbon gel obtained by the synthesis examples 1-4. 4 is a graph showing specific activities of the carbon gel composite material obtained in Example 1 and the mesoporous carbon composite material obtained in Comparative Example 1. 4 is a graph showing the pore size distribution of carbon gel and carbon black used in Example 2. It is a graph which shows the result of the discharge test of the small fuel cell obtained in Examples 2-3 and Comparative Examples 2-3. It is a graph which shows the result of the oxygen reduction reaction test about the catalyst obtained in Examples 4-6 and Comparative Example 5.

Claims (8)

In the scan region 2θ = 0.5 to 10 ° (CuK _α- ray), no X-ray diffraction peak is observed, the average particle size is composed of primary particles of 2 to 50 nm, and the pore size distribution is calculated from the adsorption / desorption isotherm. When the pore diameter value at the distribution peak top is in the range of 1 nm or more and less than 10 nm, 60% or more of the total pore volume is included in the pore diameter region of d ± 2 nm with respect to the pore diameter value (d). In addition, when the pore size value of the distribution peak top is in the range of 10 nm or more and 50 nm or less, (0.75 × D) to (1.25 × D) nm with respect to the pore size value (D). A carbon gel containing 60% or more of the total pore volume in the pore diameter region of
At least one supporting component selected from the group consisting of protein, metal complex and metal supported on the carbon gel;
A carbon gel composite material comprising:   The carbon gel composite material according to claim 1, wherein a pore diameter value of the distribution peak top of the carbon gel is 1 to 20 nm.   The carbon gel composite material according to claim 1 or 2, wherein a pore diameter value of the distribution peak top of the carbon gel is 1 to 1.25 times an average molecular diameter of the supported component. The carbon gel composite material according to claim 1, wherein a specific surface area of the carbon gel is 100 m ² / g or more.   The carbon gel composite material according to any one of claims 1 to 4, wherein the total pore volume of the carbon gel is 0.1 to 50 ml / g.   The carbon gel composite according to any one of claims 1 to 5, wherein at least one protein selected from the group consisting of an oxidoreductase and an electron transfer protein is supported on the carbon gel. material.   The carbon gel composite material according to claim 1, wherein at least the vicinity of the surface of the carbon gel is made of nitrogen-containing carbon.   The carbon gel composite material according to claim 7, wherein an atomic ratio (N / C) of nitrogen atoms to carbon atoms in the nitrogen-containing carbon is 0.01 to 0.4.

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