JPH09248464A - Production of catalyst - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a catalyst high in catalytic activity and keeping stable activity over a long period of time by dispersing a metal component having catalytic activity in a high-molecular polymer and subjecting this high molecular polymer to heat treatment. SOLUTION: A metal component having catalytic activity such as platinic chloride or gold chloride is dispersed in a high-molecular polymer such as an epoxy resin or a polyester resin and the high-molecular polymer having the metal component dispersed therein is heat-treated to be pyrolyzed to obtain a porous carrier 1. As a result, the mutual action of metal fine particles 2 and the carrier becomes large and the movement or flocculation of metal fine particles 2 becomes hard to generate and metal fine particles 2 keep an initial particle size. Therefore, stable catalytic activity is kept over a long period of time and catalytic activity is also enhanced.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a catalyst, and more particularly to a method for producing a catalyst having high catalytic activity and capable of maintaining stable catalytic activity for a long period of time.

[0002]

2. Description of the Related Art Fuel cells have been developed as a clean and highly efficient power generator, but have not yet been generally used. This is because the fuel cell cannot maintain stable performance for a long period of time. Therefore, in order to further spread the fuel cell in the future, it is indispensable to provide a fuel cell capable of maintaining stable performance for a long period of time.

The biggest reason why a fuel cell cannot exhibit stable performance over a long period of time is that the performance of the electrode of the fuel cell deteriorates with time. Currently, the most practically used phosphoric acid fuel cell operates at about 100 to 200 ° C., but even in such a temperature range, the catalytically active component containing platinum as a main component used in the electrode aggregates. Therefore, it is difficult to obtain a stable output potential from the fuel cell for a long period of time.

Usually, a catalyst used in an electrode of a fuel cell is prepared by adding carbon black which has been fired in advance to an aqueous solution such as chloroplatinic acid and suspending it, and then evaporating to dryness and washing with water to form platinum on the surface of carbon black. It is manufactured by depositing the metal fine particles of. In the catalyst produced in this way, although metals such as platinum are fine particles, they are simply deposited on the surface of the carbon black that is a carrier, so it is easy to move on the surface of the carbon black due to the influence of heat and the like. The long-term operation causes the fine particles to aggregate and grow. Therefore, as the fuel cell is operated for a long period of time, the catalytic activity at the electrodes decreases, resulting in a decrease in the potential, making it difficult for the fuel cell to maintain its initial performance.

In order to solve this problem, nickel, cobalt and the like have been added to platinum, and improvements have been made by using these as alloys. In any case, a catalyst containing platinum or another metal as a main component is used. The active ingredient remains deposited on the surface of the carbon black as the carrier, and the essential solution has not been reached.

On the other hand, for example, in a system in which a reforming process for producing hydrogen by reforming methanol is carried out on an electrode plate, a catalyst effective for reforming methanol has a reaction temperature of 200 to 300 ° C.
Cu-Zn (-Al) system up to about 200 ~ 300 ℃
If it exceeds, it is a Zn-Cr system, and in any case, a catalyst system containing two or more kinds of metals has high catalytic activity. In addition to this system, in a catalytic reaction system in which a single metal exhibits sufficient catalytic activity, addition of another element to this metal as a cocatalyst often improves the catalytic activity. Generally, in these catalyst systems, two or more metals are in close proximity (or alloyed) on the support.
In some cases, the catalytic activity is improved.

However, using different raw materials,
When various metals having catalytic activity are added to the carrier to form a catalyst, sufficient contact cannot be made between two or more kinds of metals, so that the desired catalytic activity cannot be obtained and moreover, the catalytic activity does not change over time. There was a problem of lowering.

[0008]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is a method of producing a catalyst in which stable catalytic activity is maintained for a long period of time and improvement in catalytic activity is achieved. The purpose is to provide a method.

[0009]

A method for producing a catalyst according to the first invention of the present application is a method of dispersing a metal component having catalytic activity in a polymer, and a polymer having the metal component dispersed therein. It is characterized in that the step of heat treatment is sequentially performed.

In the present invention, since the fine metal particles, which are the conventional catalytically active component, are only deposited on the surface of the carrier such as carbon black, the problem of the conventional catalyst that it is easy to move on the surface of the carrier such as carbon black. It was done to solve the problem. As in the present invention, a metal component having a catalytic activity is dispersed in a high molecular polymer and then calcined to disperse and retain the metal fine particles in a carrier obtained by heat treating the high molecular polymer.

The catalyst obtained by the method for producing a catalyst according to the first aspect of the present invention has a large interaction between the fine metal particles having catalytic activity and the porous carrier formed by thermal decomposition of the high-molecular polymer by heat treatment. Since the metal fine particles are unlikely to move or aggregate, the metal fine particles easily maintain the initial particle size. Therefore, a highly active catalyst can be obtained for a long period of time.

FIG. 1 shows a conceptual diagram of a catalyst obtained by the method for producing a catalyst according to the first invention of the present application, and FIG. 2 shows a conceptual diagram of a catalyst obtained by a conventional method for producing a catalyst. 1 and 2
In the above, 1 indicates a carrier obtained by heat-treating a high-molecular polymer, and 2 indicates metal fine particles.

A method for producing a catalyst according to the second invention of the present application is
Dispersing a complex salt or double salt containing at least two kinds of metal components having catalytic activity in a high molecular weight polymer,
It is characterized in that the step of heat-treating the high molecular polymer in which the complex salt or the double salt is dispersed is sequentially performed.

In the second invention of the present application, a complex salt or double salt containing at least two kinds of catalytically active metal components or both a metal component having catalytic activity and a metal component acting as a cocatalyst in the molecule is a polymer. Dispersed in the polymer and heat treated with at least two metals present in close proximity in the complex or double salt. Therefore,
The produced (precipitated) metal fine particles have a form in which at least two kinds of metals are brought close to each other and are located on a carrier obtained by heat-treating a polymer. Then, the ratio of the number of atoms of at least two kinds of metals contained in one molecule of the complex salt or double salt used as a raw material becomes the abundance ratio of each metal element in the produced metal fine particles, and the number of complex salt or double salt before the heat treatment is determined. If they are aggregated, they become fine metal particles that uniformly contain at least two kinds of metal elements after heat treatment.

A second invention of the present application is, for example, a double salt represented by ΑBX _x , Α _a [B _b X _x ] _p , [C _c Y _y ].
_q [D _d Z _z ] _r , (A, B, C and D are metallic elements,
X and Z represent a negatively charged atomic group, and Y represents an electrically neutral or negatively charged atomic group) or the like, and a complex salt represented by, for example, K ₂ [PtC
l ₄ ], Cu ₂ [Zn (OH) ₆ ] and the like.

According to the second invention of the present application, in addition to the effect of the first invention of the present application, two or more kinds of metals are located close to each other, so that a catalyst having high catalytic activity can be obtained.

The method for producing a catalyst according to the third invention of the present application comprises: a polymer having at least one kind of functional group introduced therein, a functional group that specifically reacts with the functional group, and a metal component having catalytic activity. It is characterized in that a step of dispersing a compound containing a, a step of reacting the high-molecular polymer with the compound, and a step of heat-treating the high-molecular polymer reacted with the compound are sequentially performed.

According to the third invention of the present application, in addition to the function and effect of the first invention of the present application, the metal particles can be highly dispersed, and a catalyst having high catalytic activity can be obtained.

The functional group introduced into the high molecular polymer is
It may be introduced as a part of the main chain or side chain of the high-molecular polymer, or may be introduced as another additive substance.

The combination of functional groups that react specifically is
For example, -NH ₂ and -COOH (peptide bond), - O
Examples thereof include H and -COOH (ester bond), -Cl and aromatic (Friedel-Crafts reaction), acid and cation (ion exchange), base and anion (ion exchange), but are not limited thereto. Not a thing. The compounds containing different metals may be added at the same time or one by one. In the case of adding them one by one, if, for example, of the two functional groups A and B on the polymer side, only A selectively reacts with the functional group of the compound containing the metal to be added first, if the substance to be added later is As the functional group, not only a functional group that selectively reacts with only B but also a functional group that reacts with both A and B can be reacted with only B because A has already completed the reaction.

When the reaction between functional groups is strong and there is a risk of breaking the bond (Si-Si etc.) of the polymer, or by just trying to introduce it, for example, for some reason such as breaking the Si-Si bond, When the functional group cannot be introduced into the skeleton, it can be solved by separately arranging a metal using a carbon skeleton and then mixing with a polymer having a skeleton other than carbon.

Regarding the arrangement of the metal fine particles having catalytic activity to the high molecular polymer as a carrier, for example, by utilizing the steric hindrance of the monomer during the synthesis of the high molecular polymer,
If the functional groups in the polymer are kept away from each other, the dispersibility of the metal fine particles will be further improved.

The functional group introduced into the polymer is 1
In one case, when only one kind of metal is used, one kind of metal atom is easily collected in the functional group part introduced into the polymer, and a catalyst in which metal fine particles are uniformly and highly dispersed is obtained. However, it is difficult to arrange two or more kinds of metals in a desired arrangement. When it is desired to obtain a catalyst in which two or more kinds of metals are arranged in a desired arrangement, a plurality of kinds of functional groups are introduced into a polymer, and a group that selectively reacts with a specific functional group is added to each metal element. It may be added and mixed. In addition, a plurality of types of functional groups in the high molecular polymer,
Those existing on the same molecule or those existing on different molecules may be mixed.

When a functional group is introduced into a part of the main chain or side chain of a high molecular polymer, the following effects can be obtained in addition to the above-mentioned high dispersion effect.

(1) By manipulating the number of functional groups and the order of introduction, at least two metal atoms can be arranged in a desired arrangement.

(2) In (1), a metal atom is further added, and the metal atom arranged in the desired arrangement is further grown as a nucleus to obtain a catalyst in which the metal fine particles are arranged in the desired arrangement.

(3) For example, by adopting the structure shown in FIG. 3, the composition of the metal fine particles generated from this structural unit can be controlled to some extent, and in this case, alloying makes it possible to obtain the activity of the catalyst. It can also be applied to production and addition of co-catalyst. Note that 2 and 3 are different metal fine particles, and 4 is a main chain or side chain of a high-molecular polymer or a part of the structure of an additive substance.

The above (1) and (2) can also be used, for example, when arranging the catalytically active components used in each step of the sequential reaction in order.

The method for producing a catalyst according to the fourth invention of the present application comprises the steps of dispersing a metal component having catalytic activity in a polymer, heat treating the polymer having the metal component dispersed therein, It is characterized in that the step of removing the carbon component from the molecular polymer is sequentially performed.

According to the fourth invention of the present application, while exhibiting the same operation and effect as the first invention of the present application, a metal element having catalytic activity is dispersed in a high molecular weight polymer, fired by heat treatment, and then carbonized. By removing the components, pores are formed in the catalyst. As a result, more metal fine particles can be present on the surface of the carrier, so that the catalytic activity is improved.

In the method for producing the catalyst of the fourth invention of the present application,
It is preferable that Si is contained in the skeleton or side chain of the main chain of the high molecular polymer. At this time, a metal element having catalytic activity is dispersed in a high-molecular polymer containing Si and then fired by heat treatment in an inert gas to form a carrier mainly composed of a skeleton of carbon, silicon carbide, and silicon. However, among these components, by removing the carbon component that is relatively easy to selectively remove and is not suitable for use in an oxygen atmosphere, spaces (pores) are created in the carrier after the removal of the carbon component. At the very least, the catalytic activity is improved by allowing more metal fine particles to be present on the surface of the carrier. In addition, since the space after the carbon component is removed communicates with the outside air, it functions as a passage for the reaction gas. In removing the carbon component, it is preferable that the carbon be present in a certain amount of agglomeration. In the situation where carbon is surrounded by Si, the removal itself is difficult to perform, and even if the removal is possible, it changes as shown in Chemical Formula 1 and eventually the passage may be blocked.

[0032]

Embedded image To avoid this, in order to form continuous pores, in the side chain (or part of the main chain) of the high-molecular polymer containing Si,
It is advisable to introduce a straight chain hydrocarbon group having a long chain length, a hydrocarbon group having many branches, a hydrocarbon group containing a ring structure, and the like.
Further, a part of the side chain or the main chain may be replaced with a group such as a hydroxyl group that easily forms a hydrogen bond with hydrogen, and different carbon chains may be brought close to each other. In this case, it is necessary to pay attention because the surrounding of the metal fine particles attracted and collected by the hydroxyl group and the like are only carbon atoms, and therefore the metal fine particles are also removed at a high rate when the carbon chain is removed. It should be noted that a similar problem needs to occur when too many carbon chains are added.

FIG. 4 shows a schematic diagram of a catalyst obtained by the method for producing a catalyst of the fourth invention of the present application. In FIG.
Reference numeral 2 is metal fine particles, and 4 is a carrier mainly containing Si or SiC.

As a method of removing the carbon component in the carrier, it is preferable to remove it by steam reforming or reaction with carbon dioxide gas, as shown below as an example, not by burning carbon.

(Example 1) C + CO ₂ → 2CO (Example 2) C + H ₂ O → CO + Η ₂ (Example 3) C + 2H ₂ O → CO ₂ + 2Η ₂ According to this method, mainly carbon dioxide gas and water are generated. Unlike removal, there is an advantage that gases effective for chemical synthesis such as CO and H ₂ can be obtained at the same time. In addition, since it is not a combustion reaction, less heat is generated, and aggregation of metal fine particles can be suppressed more effectively. Incidentally, (Example 2) Reaction and (Example 3), the reaction conditions, equilibrium is established between the CO + 2H ₂ O and CO ₂ + 2Η _2,
In some cases, a mixed gas of CO, H ₂ O, CO ₂ and Η ₂ can be obtained.

The method for producing a catalyst according to the fifth invention of the present application is a step of dispersing a metal component having a catalytic activity and a carbon component in a polymer, and a polymer polymer in which the metal component and the carbon component are dispersed. It is characterized in that the step of heat-treating and the step of removing the carbon component are sequentially performed.

In the fifth invention of the present application, the same action and effect as those of the first and fourth inventions of the present application are shown, and a "carbon component", preferably a "substance having a carbon skeleton" is contained in the polymer. Pores are formed by dispersing with the metal component and removing the "carbon component" after firing by heat treatment. As a result, more metal fine particles can be present on the surface of the carrier, and the catalytic activity is increased.

In the method for producing the catalyst of the present invention, it is preferable that Si is contained in the skeleton or side chain of the polymer. At this time, a metal element having a catalytic activity and a carbon component are dispersed in a high-molecular polymer containing Si, and then the mixture is baked by a heat treatment in an inert gas to mainly contain carbon, silicon carbide,
A carrier composed of a silicon skeleton is formed, but among these components, the carbon component that is relatively easy to selectively remove and is not suitable for use in an oxygen atmosphere is removed. After that, spaces (pores) are created in the carrier and more metal fine particles are present on the surface of the carrier to improve the catalytic activity. In addition, since the space after the carbon component is removed communicates with the outside air, it functions as a passage for the reaction gas.

Here, schematic diagrams of the catalyst during and after its production are shown in FIGS. 5 and 6, respectively. 5 and 6, 2 is metal fine particles, 4 is mainly Si, S
Carriers containing iC as a main component, 5a and 5b represent added carbon components.

In order to form continuous pores, the side chain (or part of the main chain) of the Si-containing high-molecular polymer has a long-chain straight-chain hydrocarbon group or a highly branched hydrocarbon group. It is advisable to introduce a hydrocarbon group containing a ring structure.
Further, a part of the side chain or the main chain may be substituted with a group such as a hydroxyl group that easily forms a hydrogen bond with hydrogen, and different carbon skeletons may be brought close to each other. In this case, it is necessary to be careful because the surrounding of the metal fine particles attracted by the hydroxyl groups and the like are only carbon atoms, and therefore the metal fine particles are also removed at a high rate when the carbon skeleton is removed. It should be noted that the same problem may occur when too much carbon skeleton is added. A mixture containing a carbon component in addition to the polymer (raw material monomer) can be used even if a polymer or monomer that shares a carbon skeleton and a skeleton other than carbon in the molecule, or a mixture of a polymer having a carbon skeleton and a polymer having a skeleton other than carbon is used. It can be used as an aid when the pore formation is insufficient, and if the surface of carbon is modified with a functional group to facilitate the production of metal fine particles, the metal fine particles can be surely provided on the pore surface after carbon removal. Can be present.

As the shape of the "carbon component", preferably the "material having a carbon skeleton", there are carbon fiber, carbon powder, etc. for forming coarse pores (5a in FIG. 5), and for forming fine pores (in FIG. 5). Examples of 5b) include long-chain straight-chain hydrocarbons, hydrocarbons having a large number of branches as shown in Chemical Formula 2 or Chemical Formula 3, naphthalene, anthracene, or hydrocarbons having more rings. .

[0042]

Embedded image

Embedded image Usually, it is preferable to use both the "carbon component" for forming coarse pores and the "carbon component" for forming fine pores, but there is no problem even if only one is used. The "carbon component" for forming pores is obtained by substituting a part of the side chain with a group that easily hydrogen bonds with hydrogen such as a hydroxyl group.
The “carbon components” may be brought close to each other.

When carbon fibers are used, hollow ones are more efficient in removal. in this case,
Due to the reforming reaction of carbon, only a part of the outer shell of the carbon fiber is removed, and the hollow portion of the carbon fiber is connected to the outside air to increase the surface area. Since the carbon reforming reaction rate increases as the surface area increases, the carbon reforming reaction can be completed in a short time, and the effect on the resulting catalyst can be reduced.

The amount of the "carbon component", preferably the "substance having a carbon skeleton" dispersed with the metal component is not particularly limited, but the surface area per unit weight of the catalyst after removal of the "carbon component" is 1 m ² / g. Above, more preferably 1
It is preferable to add an amount of 0 m ² / g or more.

In the present invention, the "carbon component", preferably the "substance having a carbon skeleton", is dispersed in advance together with the metal component, so that the carbon content is reduced because, for example, there are many chains made of Si. Even if the formation of the pores cannot be expected by simply removing only the carbon component as a part of the high molecular weight polymer, the formation of the pores can be surely performed.

In the present invention, the catalyst obtained by the present invention is oxidizable if only the component having only the carbon skeleton is completely removed from the "carbon component", preferably the "substance having the carbon skeleton". Even when used in an atmosphere, the reaction system does not contain carbon oxides (CO, CO ₂ ) derived from the catalyst carrier.

A method for producing a catalyst according to a sixth aspect of the present invention is a step of dispersing a metal component having a catalytic activity and a metal component having a carbon modifying activity in a polymer, and the two metal components. It is characterized in that the step of heat-treating the high-molecular polymer having dispersed therein and the step of removing the carbon component from the heat-treated high-molecular polymer are performed in order.

In the sixth invention of the present application, the same action and effect as those of the first, fourth, and fifth inventions of the present application are exhibited, and in addition, the metal component having the modifying activity of carbon in the polymer has the catalytic activity. Pores are formed by dispersing with the metal component and removing the carbon component from the polymer after firing by heat treatment.

In the method for producing a catalyst of the sixth invention of the present application,
It is preferable that Si is contained in the polymer. In this case, a carrier mainly composed of carbon, silicon carbide, and silicon skeleton is prepared by dispersing a metal element having catalytic activity and a carbon component in a high-molecular polymer containing Si and then calcining by heat treatment in an inert gas. However, by removing the carbon component among these components, which is relatively easy to selectively remove and is not suitable for use in an oxygen atmosphere, a space ( Pores),
The catalytic activity is improved by allowing more metal fine particles to be present on the surface of the carrier. In addition, since the space after the carbon component is removed communicates with the outside air, it functions as a passage for the reaction gas.

Here, schematic diagrams of the catalyst during and after its production are shown in FIGS. 7 and 8, respectively.

In FIGS. 7 and 8, 2 is metal fine particles, 4 is a carrier mainly containing Si and SiC as main components, and 6 is metal fine particles having a carbon modifying activity.

The reforming reaction of carbon generally begins to proceed slowly from about 500 ° C. without a catalyst, but the reaction rate is remarkably improved by adding a catalyst. Therefore, the conditions for reforming carbon are moderated to reduce the thermal influence on the metal having catalytic activity. Metals having a carbon-modifying activity are mainly transition metals, especially VII
Group A, VIII or IB group elements are effective, and Ni is particularly effective.

As a method for dispersing a metal component effective for modifying carbon, it is preferable to form a solution in the same manner as a metal component having a catalytic activity and mix it with a high molecular weight polymer. Alternatively, the method of dispersing may be used.

The method for producing a catalyst according to the seventh invention of the present application comprises a step of dispersing a metal component having a catalytic activity, a carbon component and a metal component having a carbon modifying activity in a polymer, It is characterized in that a step of heat-treating a high-molecular polymer in which one metal component and a carbon component are dispersed and a step of removing the carbon component from the heat-treated high-molecular polymer are sequentially performed.

The seventh invention of the present application is the first, fourth, and
The effects of the inventions 5 and 6 are obtained.

In the present invention, in the high molecular polymer,
The “carbon component” described in the fifth invention, preferably the “substance having a carbon skeleton” is used as the metal component having catalytic activity and the sixth component.
The pores are formed by dispersing the carbon component with the metal component having a carbon-modifying activity described in the above invention, and removing the "carbon component" as described in the fourth invention after firing by heat treatment. In the method for producing a catalyst of the present invention, it is preferable that Si is contained in the polymer. At this time, a metallic element having catalytic activity and a carbon component are dispersed in a high-molecular polymer containing Si and then baked by heat treatment in an inert gas to mainly consist of a skeleton of carbon, silicon carbide and silicon. A carrier is formed, but among these components, by removing a carbon component that is relatively easy to selectively remove and is not suitable for use in an oxygen atmosphere, a space ( By causing more fine particles to exist on the surface of the carrier, the catalytic activity is improved.
In addition, since the space after the carbon component is removed communicates with the outside air, it functions as a passage for the reaction gas.

Here, schematic diagrams of the catalyst during and after its production are shown in FIGS. 9 and 10, respectively.

9 and 10, 2 is metal fine particles, 4 is a carrier mainly containing Si and SiC as main components, 5a and 5b are added carbon components, and 6 is metal fine particles having a carbon modifying activity. Show.

As described above, the reforming reaction of carbon begins to proceed slowly from about 500 ° C. without a catalyst, but the reaction rate is remarkably improved by adding the catalyst. As the metal having a carbon reforming activity and functioning as a catalyst, mainly transition metals, particularly elements of Group VII Group, Group VIII or Group IB are effective, and Ni is particularly effective.

The method for dispersing the metal component effective for modifying the carbon may be a method in which it is solubilized in the same manner as the metal component having the catalytic activity and mixed with the high molecular weight polymer. It is preferable that the “carbon component” be surely brought into contact with the “carbon component” so as to be effectively utilized by devising such as by preliminarily supporting the “carbon skeleton”. It is also possible to introduce a functional group into a continuous portion of a carbon chain in a polymer containing Si and collect molecules (or metal ions) containing a metal element involved in the carbon reforming reaction therein. To be In this case, this operation is preferably performed before mixing with the solution containing the metal component having catalytic activity. This is because the functional group portion introduced into the Si-containing polymer has a biased charge, and the ions containing the metal component having catalytic activity are collected in the functional group portion. This is because the metal fine particles of (3) become large and the catalytic activity decreases. Furthermore, by modifying the surface of the "carbon skeleton" with a functional group, and attracting ions containing a metal component having catalytic activity to the functional group, the "from the carbon skeleton" It is also possible to make sure that the fine metal particles are present on the surface of the fine pores of the carrier when the "substantial substance" is removed. However, if the ions containing the metal component having catalytic activity are excessively collected, the metal fine particles generated after the calcination by the heat treatment will be large and the specific surface area will be lowered, and the catalytic activity will be lowered.

In the fourth to seventh inventions of the present application, the carbon skeleton portion may remain without being completely removed as long as a sufficient surface area is obtained on the surface of the carrier. In this case, the remaining carbon skeleton functions as an electric conduction path, and thus serves as a catalyst having an electric conductor function.

In the first to seventh inventions of the present application, the high molecular polymer converted into a carrier is a polymer or a monomer having a carbon skeleton and a skeleton other than carbon in the molecule,
Examples thereof include a mixture of a polymer having a carbon skeleton and a polymer having a skeleton other than carbon, a mixture obtained by adding carbon in addition to the polymer (raw material monomer), and the like. When a polymer or monomer that shares a carbon skeleton and a skeleton other than carbon in the molecule is used as a high-molecular polymer, a homogeneous carrier can be obtained, but a mixture of a polymer having a carbon skeleton and a polymer having a skeleton other than carbon is used. In such a case, it can be applied without problems when the monomers of the respective polymers cannot be copolymerized, but care must be taken because the carrier tends to become heterogeneous unless a proper mixing method is selected.

In the first to seventh inventions of the present application, the high molecular polymer which is converted into a carrier may be one having only a carbon skeleton, and a substance other than carbon such as N, B or Si may be contained in the main chain or side chain. It may be contained, or may be a mixture of two or more kinds thereof. The polymer having a suitable composition is appropriately selected in consideration of the use environment and the like as the carrier. In the case where a polymer other than carbon is contained in the main chain or side chain, such as N, B or Si, the properties of strength, conductivity, etc. can be adjusted appropriately in the finally formed carrier. It is also possible to form pores by removing only this, and it is also suitable for use in an oxidizing atmosphere.

In addition, in the catalyst obtained by the method for producing a catalyst according to the present invention, the polymer containing Si is further corrosive resistant due to SiC generated by thermal decomposition by heat treatment and residual C. It is preferable because it has heat resistance and electronic conductivity.

Generally, pure silicon carbide (SiC) has properties as a semiconductor and is unsuitable for use as an electrode. However, in the silicon carbide obtained by the present invention, carbon atoms are partially adjacent to each other. There are many regions with defects and defective regions, and these regions function as current paths, so the conductivity is increased.

Therefore, for example, in an electrode of a fuel cell,
Although high catalytic ability, corrosion resistance to phosphoric acid, etc., conductivity as an electrode, etc. are required, the catalyst obtained by the present invention can effectively cope with such use environment.

For example, FIG. 11 shows a schematic view of a catalyst produced by the method for producing a catalyst according to the first invention of the present application, in which the high molecular polymer contains Si. FIG.
In 1, a reference numeral 1 is a carrier containing Si and C as main components, which is generated by decomposition or alteration of a high-molecular polymer containing Si by heat treatment, and 2 is a fine metal particle. Although Si, C, and SiC are mainly produced in the carrier 1, there may be components that are not included in these, and the carrier 1 does not clearly have these forms and contains Si and C. It may be other compound crystal or amorphous.

On the other hand, when heat treatment is performed in an oxygen atmosphere,
Si reacts with oxygen to change to silicon dioxide (SiO ₂ ), and the carbon-free region and the cracks caused by the volume change accompanying the oxidation of Si contribute to the improvement of the surface area and secure the gas flow path. .

A schematic diagram of the structure of this catalyst is shown in FIG.
In FIG. 12, 3 is a carrier whose main component is SiO ₂ produced by firing, and 2 is metal fine particles.

In addition, in the high-molecular polymer containing Si, III
By partially introducing an element of group III or group VB, the conductivity of silicon carbide or SiO ₂ after firing by heat treatment can be increased.

In the method for producing a catalyst according to the first to seventh inventions of the present application, examples of the polymer include epoxy resin, polyester resin, phenol resin, polysilane resin, polysiloxane resin, polyimide resin and silicone resin. You can As the form of the high molecular weight polymer, when the high molecular weight polymer is a soluble solid or a highly viscous liquid, it may be used as a solution. At this time,
As the solvent, a substance that dissolves the high molecular polymer and other additive substances is selected. In addition, when the polymer itself is a liquid, it may be used as it is, but when other additive substances are added, the additive substance may not dissolve in the polymer polymer. In this case, the additive substance is dissolved. Use possible solvents simultaneously. Furthermore, when the monomer is available at a very low cost, or when the polymer is solid and does not easily form a solution, the monomer (including the polymer for block copolymerization) may be polymerized to obtain a polymer. In this case, since a catalytically active component such as a metal can be incorporated during the polymerization of the monomer, it becomes possible to highly disperse the catalytically active component.

To solidify the high molecular weight polymer, a solidifying agent (including a polymerizing agent) may be used, or a heat treatment (including firing or evaporation to dryness at room temperature) may be performed. When the solidifying agent is used, the high molecular weight polymer can be solidified relatively quickly, and therefore, aggregation of the metal component having catalytic activity can be prevented and high dispersion can be achieved. However, since the solidifying agent may remain as an impurity, it is necessary to appropriately set the amount of the solidifying agent added. Further, when the high-molecular polymer is solidified by heat treatment, the solidification rate may be slow, or exposure to a high temperature before solidification may hinder the formation of fine particles such as metal components having catalytic activity. Be careful.

The equivalent ratio of the high molecular weight polymer to the metal component is selected according to the purpose of use, and the metal compound used is one capable of breaking the bond and depositing a metal atom on the carrier. Any covalent substance may be used if it is present.

As the feedstock of the metal component having catalytic activity, inorganic salts such as palladium chloride, chloroplatinic acid, gold chloride, chlorides of transition metals, organometallic salts such as palladium acetylacetonate and platinum acetylacetonate, or The complex salts and double salts mentioned above can be mentioned.

The metal contained in the metal component dispersed in the polymer may exist in the liquid in the form of ultrafine particles in a colloidal state as in the case of being supplied as a complex or a double salt, or may be present in an ion. It may exist in a dissociated state. When the metal component is supplied in the form of a colloidal complex or double salt, a plurality of metal atoms in the complex or double salt move together, so that the abundance ratio of the metal atom in the metal fine particles to be formed is desired. It becomes possible to make it a ratio. Further, when the metal in the metal component is in a state of being dissociated into ions, it may be preliminarily deposited as metal fine particles by a reducing agent, or may be generated as metal fine particles in the heat treatment step of the polymer. Care should be taken when adding the reducing agent, because the reducing agent may remain as impurities.

As the compound used as the reducing agent,
Alcohols such as benzyl alcohol and dextrin,
Aldehydes such as formalin, benzaldehyde and phthalaldehyde, hydrogen gas and hydrazine can be preferably used.

The high molecular weight polymer and its manufacturing method and the metal component and its reducing agent are, for example, Japanese Patent Application No. 7-21995.
However, it is not particularly limited.

In addition, a carbon skeleton having a graphite structure or the like or silicon carbide (generated when a high-molecular polymer containing Si such as polysilane) is used in the carrier after removing the carbon component.
When remains, they function as conductors or semiconductors, so the carrier can be made electrically conductive,
For example, it can be used as an electrode material.

When heat treating a high-molecular polymer in which a metal or a metal salt is dispersed for thermal decomposition, the thermal decomposition may be performed in an oxidizing atmosphere or in an inert atmosphere. By thermal decomposition in an atmosphere, although the porosity of the carrier is slightly lowered, it can be generally used. Specifically, after polymerizing or curing at least a part of a polymer containing a metal having catalytic activity, it is sprayed into a furnace in an inert atmosphere in a mist with a spray dryer to thermally decompose the polymer. Alternatively, the polymer is simply pyrolyzed in a furnace in an inert atmosphere, but is not particularly limited. Further, the obtained catalyst may be heat-treated in steam or hydrogen stream. On the other hand, when the thermal decomposition is performed in an oxidizing atmosphere, it is necessary to note that the entire carrier may be burned out unless proper heat treatment conditions are set. By properly setting the heat treatment conditions, only the carbon skeleton is removed (water or carbon dioxide is used as the oxidizing gas), or it is transformed into a carrier composed of oxides of substances other than carbon (combustion in air) can do. However, when the carbon skeleton is removed, the metal fine particles are not completely held on the carrier before the heat treatment, so that if the carbon skeleton is removed during the heat treatment, aggregation of the metal fine particles easily occurs. Therefore, this case can be solved by performing heat treatment in an inert atmosphere in advance to form stable metal fine particles and then performing thermal decomposition again in an oxidizing atmosphere.

The size of the fine metal particles after thermal decomposition is preferably composed of a single atom and has a particle size of 100 nm, but it is appropriately set depending on the application. Generally, the particle size of the fine particles is determined by adjusting the properties of the high-molecular polymer, the curing / polymerization temperature, the thermal decomposition temperature, the time, and the like.

Further, the loading amount of the metal fine particles loaded on the carrier is usually 0.1 to 50 wt% with respect to the catalyst, but when used in the electrode of the fuel cell, it is 1 with respect to the catalyst.
It is adjusted to 0 to 50 wt%, preferably 15 to 30 wt%.

The catalyst obtained according to the present invention cannot be continuously used in an oxidizing atmosphere unless the use conditions are appropriately set when the carrier is composed of a carbon skeleton. However, when the catalyst contains a large amount of graphite structure, It has properties as a good conductor. Further, when the carrier is composed of carbon and another element (for example, Si), continuous use in an oxidizing atmosphere is possible.

[0083]

BEST MODE FOR CARRYING OUT THE INVENTION (Example 1 and Comparative Example 1)

Embedded image

Embedded image In 500 ml of acetone, 1 g of the compound represented by the chemical formula 4 (weight average molecular weight 7000), 1 g of the compound represented by the chemical formula 5 (weight average molecular weight 21,000), and Cu [Z
n (OH) ₄ ] 0.25 g and terephthalaldehyde 1 g were weighed and mixed to obtain an acetone solution A.

Next, the acetone solution A was heated at 100 ° C. for 1 hour to be solidified, and the acetone was volatilized to form Cu.
-Zn alloy fine particle dispersed resin B was obtained. Then, the Cu-Zn alloy fine particle dispersed resin B is applied to a refractory substrate (alumina) to a thickness of 15 μm by the doctor blade method, and 1
Heat treatment was performed for 12 hours under an argon atmosphere at 000 ° C. Then, switch the atmosphere to carbon dioxide and let stand for 12 hours.
After modifying the carbon component in the carrier to form pores, it was naturally cooled to obtain a Cu-Zn alloy fine particle dispersion material C.

Finally, the Cu-Zn alloy fine particle dispersion material C was calcined in air at 400 ° C. for 1 hour to form Cu-Zn on the carrier.
A catalyst in which a system oxide was highly dispersed and supported was obtained (Example 1). On the other hand, instead of Cu [Zn (OH) ₄ ], Cu
A catalyst was obtained under the same conditions as in Example 1 except that a mixture of 0.18 g of Cl _{2 and} 0.18 g of ZnCl ₂ was used (Comparative Example 1).

Here, FIG. 13 shows a schematic diagram of the catalyst of Example 1, and FIG. 14 shows a schematic diagram of the catalyst of Comparative Example 1. In FIGS. 13 and 14, 7 is a carrier, 8 is a fine particle containing Cu and Εn substantially evenly, 9 is a fine particle containing an excess of Ε compared to Cu, 10 is a fine particle containing an excess of Cu compared to Zn, Reference numeral 11 is a fine particle composed of only Cu atoms, and 12 is a fine particle composed of only Zn atoms.

As a result of TEM-EDX, there was almost no difference in the particle size of the produced oxide particles or fine particles between Example 1 and Comparative Example 1, and it was about 10 nm. However, in Example 1, the oxides of Cu and Zn coexisted almost uniformly (about 4: 6 to 6: 4) in most of the generated fine particles, whereas in Comparative Example 1, 99%. Or more C
In addition to the fact that particles consisting only of u (0) and Zn (0) were confirmed, fine particles containing a large excess of either one occupied the majority, and both oxides were mixed as in Example 1. The fine particles contained almost uniformly accounted for about 20% of the whole.

Next, using the catalysts of Example 1 and Comparative Example 1, methanol synthesis from synthesis gas (CO: H ₂ = 1: 2) was carried out.

The methanol synthesis was carried out at a reaction temperature of 250 ° C. in a fixed bed flow type tubular reactor using 1 g of a catalyst.
Total pressure: 2 μPa, flow rate 100 ml / min (standard state conversion)
Was carried out under the conditions of In general, Cu is used for a while after the start of the reaction.
The oxidation state of is not stable at a value suitable for methanol synthesis, and the catalytic activity is low, so an objective evaluation cannot be performed. Therefore, a comparison was made 2 hours after the start of the reaction.

As a result, in the catalyst of Comparative Example 1, C
The conversion of O to methanol was about 5%, whereas the catalyst of Example 1 showed a conversion of CO to methanol of 20%.

Therefore, the catalyst of Example 1 was the same as Comparative Example 1
It can be seen that it has a higher catalytic activity than that of the above catalyst.

(Example 2 and Comparative Example 2)

[Chemical 6] Bis (cyclopentadienyl) in 500 ml of acetone
After dissolving 0.6 g of ruthenium Ru (C ₅ Η ₅ ) ₂ and 1.2 g of a compound represented by Chemical Formula 6 (monomers were mixed so that the average of n is about 10 and m is 50 to 500) 1 g of concentrated sulfuric acid was added and the reaction was carried out at 50 ° C. for 5 hours while refluxing to remove the chlorine of the compound represented by the chemical formula-6.
An acetone solution D substituted with (C ₅ H ₄ ) Ru (C ₅ Η ₅ ) was obtained. Next, 1.8 g of barium hydroxide was added to the acetone solution D to precipitate barium sulfate, and the supernatant D
Got ' Next, 10 g of the compound represented by Chemical Formula 4 (weight average molecular weight 7000) was added to the supernatant D ′, and Chemical Formula 5
The compound (weight average molecular weight 21,000)
g and 1 g of terephthalaldehyde are weighed and mixed, completely dissolved and then heated at 100 ° C. for 1 hour to solidify and volatilize water, acetone and hydrogen chloride etc.
u Fine particle dispersed resin E was obtained.

Next, the Ru fine particle-dispersed resin E was deposited on the refractory substrate (alumina) to a thickness of 15 by the doctor blade method.
It was applied to a thickness of μm and heat-treated for 12 hours in an argon atmosphere at 1000 ° C. Then, the atmosphere was switched to carbon dioxide gas and left for 12 hours to modify the carbon component in the carrier to form pores. Then, it was naturally cooled to obtain a Ru fine particle dispersion material F.

Finally, the Ru fine particle dispersion material F was subjected to reduction treatment in a hydrogen stream at 200 ° C. for 1 hour to obtain a catalyst in which metal Ru was supported in a highly dispersed state on the carrier (Example 2). At this time, almost no change was observed in the silicon carbide during silicon reduction or the carrier mainly composed of silicon.

On the other hand, a catalyst was obtained under the same conditions as in Example 2 except that 1.2 g of polyethylene was used instead of the compound represented by Chemical Formula 6 (Comparative Example 2).

As a result of TE M-EDX, most of the Ru fine particles produced had a particle size of 2 nm or less in Example 2. However, in Comparative Example 2, most Ru fine particles had a particle size of more than 5 nm.

Next, using the catalysts of Example 2 and Comparative Example 2, Fischer-Tropsch synthesis was carried out.

In the Fischer-Tropsch synthesis, a fixed bed flow type tubular reactor using 1 g of a catalyst was used, the reaction temperature was 240 ° C., the total pressure was 1 μPa, the synthesis gas composition CO / H ₂ = 1/2, the flow rate was 100 ml. / Minute (standard state conversion).

As a result, at 1 hour after the start of the reaction, the CO conversion of the catalyst of Example 2 was 45%, whereas the CO conversion of the catalyst of Comparative Example 2 was 2%.
It was 9%. The hydrocarbon selectivities were both 99% or more, and the chain growth probability obtained from the distribution of produced hydrocarbons was 0.94 for the catalyst of Example 2 and 0.95 for the catalyst of Comparative Example 2, which is almost the same. There was no difference.

From the above, it can be seen from the CO conversion that the catalyst of Example 2 has a higher catalytic activity than the catalyst of Comparative Example 2.

(Example 3 and Comparative Example 3)

Embedded image 0.5 g of bis (cyclopentadienyl) nickel Ni (C ₅ Η ₅ ) ₂ in 500 ml of acetone, represented by the chemical formula 7
The compound (-COOH and -COCl are the same number as a whole,-(C < ₂ >) _2- is twice as many as -COOH and -COCl, a, b, c, d are 10 on average, and e is 10 to 100). After dissolving 5 g, 1 g of concentrated sulfuric acid was added and the mixture was refluxed at 50 ° C. for 5 hours to react with chlorine of the compound represented by the chemical formula 7 — (C ₅ Η ₄ ) Ni (C ₅ Η ₅ ) Acetone solution G substituted with was obtained.

Then, 1.8 g of barium hydroxide was added to the acetone solution G to precipitate barium sulfate, and the supernatant liquid G was added.
Got ' Next, CuCl ₂ is added to the supernatant liquid G ′ by 0.2
g, a compound represented by Chemical Formula 4 (weight average molecular weight 700
0), 1 g of the compound represented by the chemical formula 5 (weight average molecular weight 12,000) and 1 g of terephthalaldehyde are weighed and mixed, and heated at 100 ° C. for 1 hour to solidify, and water, acetone and hydrogen chloride are also added. Volatilize Ni etc.
A Cu fine particle dispersed resin Η was obtained.

Next, by the doctor blade method, Ni-
A Cu fine particle dispersion resin Η was applied on a refractory substrate (alumina) to a thickness of 15 µm, heat-treated in an argon atmosphere at 1000 ° C for 12 hours, and then naturally cooled to obtain a Ni-Cu fine particle dispersion material Ι.

Finally, the Ni-Cu fine particle dispersion material I was subjected to reduction treatment in a nitrogen stream containing 20% of carbon monoxide at 200 ° C. for 1 hour to obtain a catalyst (Example 3).

On the other hand, a catalyst was obtained under the same conditions as in Example 3 except that 0.5 g of polyethylene was used instead of the compound represented by Chemical Formula 7 (Comparative Example 3).

As a result of TE E1-EDX, in Example 3, fine particles of Ni and Cu having a particle size of 2 nm or less were supported in a highly dispersed state while being close to each other while being independent of each other. On the other hand, in Comparative Example 3, the particle size is 3 on the carrier.
There were almost no Ni and Cu fine particles of nm or less, and the composition of each Ni and Cu particle was mixed in a nonstoichiometric ratio.

Next, an electrode was manufactured using the catalysts of Example 3 and Comparative Example 3, and methanol was flown to the fuel electrode side of an organic solid oxide fuel cell using Nafion as an electrolyte to perform a power generation test. In this power generation test, if the catalyst works,
After reforming on Cu to generate hydrogen and dissociate on Ni,
Ions are ionized and protons are supplied to the electrolytic solution. Also, although Cu alone has a lower catalytic activity than the Cu-Zn based catalyst, C
Since the hydrogen generated on u is consumed on Ni in the immediate vicinity, the apparent equilibrium is inclined to the hydrogen deficiency side, and the reaction is performed faster than when Cu and Ni are used separately.

In this power generation test, the current density was set to 100.
When it was set to m Α / cm ² , 730 mV was obtained with the electrode using the catalyst of Example 3. On the other hand, in the electrode using the catalyst according to Comparative Example 3, the Cu catalyst, which should decompose alcohol, is inferior in catalytic activity because it is mixed with Ni, so that sufficient hydrogen is not supplied and the internal resistance increases. And only 670 mV was obtained.

After 5000 hours, a voltage drop of 40 mV was observed in the electrode using the catalyst of Example 3, and a voltage drop of 35 mV was observed in the electrode using the catalyst of Comparative Example 3.

(Examples 4 to 8 and Comparative Examples 4 to 6) 50
The compound represented by the chemical formula 4 was added to 1 ml of 0 ml of acetone.
g, 1 g of the compound represented by the chemical formula 5, 0.5 g of sodium chloroplatinate (Na ₂ [PtCl ₄ ]), and 1 g of terephthalaldehyde were weighed and mixed to obtain an acetone solution J.

Then, the acetone solution J was added at 100 ° C. for 1 hour.
Along with heating for solidification, acetone was volatilized to obtain a platinum fine particle dispersed resin H.

Next, the platinum fine particle dispersed resin H was applied on the refractory substrate (alumina) to a thickness of 15 by the doctor blade method.
It was applied to a thickness of μm and heat-treated for 12 hours in an argon atmosphere at 1000 ° C. Then, after cooling, it was heated to 900 ° C. in nitrogen containing 10% hydrogen and immediately spontaneously cooled to obtain a platinum fine particle dispersion material I.

Then, the platinum fine particle dispersion material I was mixed with 5 in air.
The catalyst was calcined at 00 ° C. for 1 hour to obtain a catalyst in which platinum was supported on a SiO ₂ carrier in a highly dispersed state (Example 4).

On the other hand, a catalyst was obtained by a heat treatment under the same conditions as in Example 1 except that the same platinum fine particle dispersion material I was fired in an argon atmosphere (Comparative Example 4).

Further, the platinum fine particle dispersion material I is 1 MPa, 1
A catalyst was obtained by treating under a steam flow of 000 ° C. for 24 hours (Example 5). Further, a catalyst in which the treatment was continued for only 1 hour was also obtained (Comparative Example 5).

Furthermore, before heating the acetone solution J,
A catalyst was obtained in the same manner as in Comparative Example 2 except that 30 Ig of nickel chloride was added to the acetone solution J (Example 6).

Further, 0.3 g of polystyrene was added to the acetone solution J, and after dissolution and mixing, 0.3 g of a diameter of 20 μm was added.
Two kinds of catalysts were obtained under the same conditions as in Example 5 and Comparative Example 5 except that the carbon fiber of Example 5 was added (Example 5
The catalyst under the same conditions as in Example 7 and the catalyst under the same conditions as in Comparative Example 5 are Comparative Examples 6).

Further, a catalyst was obtained under the same conditions as in Comparative Example 6 except that the carbon fiber supporting 20 mg of Ni was used in advance (Example 8).

Table 1 shows the platinum contents and specific surface areas of Examples 4-8 and Comparative Examples 4-6. The platinum content is shown as a ratio to the catalyst.

[0120]

[Table 1] As is clear from Table 1, in Examples 4 to 8 and Comparative Examples 5 and 6, the platinum content is high because there are components removed from the carrier. In addition, Examples 4 to 8
In Table 1, it is understood that the specific surface area is larger than that of each comparative example.

Further, a power generation test of a fuel cell was conducted using an electrode plate prepared by using a material in which each catalyst and an equal weight of carbon black were kneaded. The power generation test was carried out by a half-cell test in which the rate of the hydrogen was limited.

Table 2 shows the test results (initial potential, potential change, average particle size of platinum) at 5,000 hours at 200 mA / cm ² .
Shown in

[0123]

[Table 2] The effect of the reforming catalyst can be seen from the comparison between Example 6 and Comparative Example 5 and the comparison between Example 8 and Comparative Example 6. Since the carbon component was removed, there is a tendency for Pd to agglomerate a little more easily. However, since the amount of Pd that can be used is large, it has sufficient catalytic activity and the voltage drops compared to the comparative example. You can see that it is smaller.

(Examples 9 to 11 and Comparative Examples 7 to 8)

Embedded image

Embedded image 10 g of the polysiloxane represented by the chemical formula 8 (weight average molecular weight 15,000), 10 g of the compound represented by the chemical formula 9 (weight average molecular weight 18,000), 5 g of sodium chloroplatinate and 10 g of terephthalaldehyde were mixed. Then, it was heated at 100 ° C. for 1 hour to obtain a resin K in which platinum fine particles were dispersed.

Then, a resin K having platinum fine particles dispersed therein was applied to a refractory substrate (alumina) to a thickness of 15 μm by the doctor blade method, and this was heated in an argon atmosphere at 1000 ° C. for 12 hours, and then 10%. The mixture was heated to 900 ° C. in a reaction tube while circulating hydrogen (residual nitrogen). Further, it was naturally cooled to room temperature in the furnace to obtain a catalyst containing 10% by weight of platinum (Example 9).

In addition, the polysilane represented by the chemical formula 4 is 1
0 g, 10 g of the compound represented by the chemical formula 5, 5 g of sodium chloroplatinate and 10 g of terephthalaldehyde were mixed and then heated at 100 ° C. for 1 hour to obtain a resin L in which platinum fine particles were dispersed.

Next, the resin L in which the fine platinum particles were dispersed was sprayed and pyrolyzed by a spray dryer in a heating furnace at 1000 ° C. in which nitrogen was passed at a pressure of 10 Torr.
Further, after heating in a nitrogen atmosphere at 1000 ° C. under normal pressure for 12 hours, it was heated to 900 ° C. in a reaction tube while flowing 10% hydrogen (residual nitrogen). Then, it was naturally cooled in the furnace to room temperature to obtain a catalyst containing 10% by weight of platinum (Example 10).

Furthermore, an epoxy resin (CEL2021:
Manufactured by Daicel) 20 g, sodium chloroplatinate 1 g, nickel nitrate 0.5 g, cobalt nitrate 0.5 g, terephthalaldehyde 5 g, diphenyldihydroxysilane 5
g, and 1 g of aluminum acetal acetonate were mixed, left at room temperature for 5 hours, and then heated at 100 ° C. for 1 hour to obtain a resin M in which fine metal particles were dispersed.

Next, the resin M in which the fine metal particles are dispersed is
After heating in an argon atmosphere at 1000 ° C for 24 hours,
It was crushed with a ball mill to obtain a powder. Then, this powder was stirred in a nitric acid aqueous solution at 50 ° C. to elute nickel and cobalt not alloyed with aluminum and platinum from the powder.

Finally, the mixture was filtered, washed with distilled water, and dried at 400 ° C. in a nitrogen stream to obtain a catalyst containing 10% by weight of metal fine particles (Example 11).

Further, a slurry prepared by adding acetylene black as a carbon carrier in an amount of 3.8 times the weight of sodium chloroplatinate to an aqueous solution saturated with sodium chloroplatinate was stirred at a temperature of 80 ° C. in an oven. After evaporating and removing water therein, it was washed with distilled water and dried in an oven at 150 ° C. for 24 hours to obtain carbon N carrying 10% by weight of platinum.

Then, after heating carbon N to 900 ° C. in a reaction tube in which 10% hydrogen (remaining nitrogen) was passed,
A catalyst was obtained by naturally cooling to room temperature in the furnace (Comparative Example 7).

Further, in the same manner as in Comparative Example 7, powder O containing nickel and cobalt in addition to platinum was obtained. The powder O contained 50% nickel and 50% cobalt in atomic ratio with respect to platinum. Then, the mixture was further stirred in a nitric acid aqueous solution at 50 ° C. to elute nickel and cobalt not alloyed with platinum from the powder O. Finally, it was filtered, washed with distilled water, and dried at 400 ° C. in a nitrogen stream to obtain a catalyst containing 10% by weight of metal fine particles (Comparative Example 8).

Further, a power generation test of a fuel cell was conducted using an electrode plate prepared by using a material in which each catalyst and an equal weight of carbon black were kneaded. The power generation test was carried out by a half-cell test in which the rate of the hydrogen was limited.

Table 3 shows the test results (initial potential, potential change, average platinum particle size) at 200 mA / cm ² and 5000 hours.
Shown in

[0136]

[Table 3] As is clear from Table 3, in Examples 9 to 11,
It can be understood that the increase in the particle size of platinum or the platinum alloy after 5000 hours was small and the change in the potential was suppressed to be small as compared with Comparative Examples 7 to 8.

[0137]

As described above in detail, in the present invention, a metal component having a catalytic activity is dispersed in a polymer, and then the polymer in which the metal component is dispersed is heat-treated. Since the metal fine particles have a strong interaction with the carrier and are hard to aggregate, it is possible to obtain a catalyst having a large catalytic surface area and a high catalytic activity.
Further, in the present invention, a metal group is dispersed in a high molecular polymer in the form of a complex salt, or a functional group which specifically reacts with this functional group is introduced into the high molecular polymer into which at least one kind of functional group is introduced. Since the compound containing the catalytically active metal component is dispersed to react the polymer with the compound, and then the polymer is heat-treated, the generated metal fine particles have a strong interaction with the carrier and are less likely to aggregate. Therefore, it is possible to obtain a catalyst having a high catalytic activity in which the metal having a catalytic activity has a large surface area and the metal fine particles are homogeneously and highly dispersed.

Further, in the present invention, since the carbon component is removed again from the polymer after heat treatment, or the carbon component is removed after the carbon component is added to the polymer in advance, the pores in the carrier are It is possible to obtain a catalyst having a high catalytic activity, in which the surface area of the developed metal having a catalytic activity is further increased.

Further, in the present invention, since the metal component having a carbon-modifying activity and, if necessary, the carbon component are also simultaneously added to the high-molecular polymer, the pores are further developed in the carrier and the catalytic activity is improved. It is possible to obtain a catalyst having a large metal surface area and high catalytic activity.

Therefore, in the present invention, the amount of metal used to obtain the same catalytic activity can be reduced and stable catalytic activity can be maintained for a long period of time, as compared with the conventional method for producing a catalyst. Further, since it is possible to provide a catalyst having an improved catalytic activity, it is possible to achieve a very beneficial effect in industry.

[Brief description of drawings]

FIG. 1 is a diagram showing a concept of a catalyst obtained by a method for producing a catalyst according to the present invention.

FIG. 2 is a diagram showing the concept of a catalyst obtained by a conventional method for producing a catalyst.

FIG. 3 is a diagram showing a structural unit.

FIG. 4 is a diagram schematically showing a catalyst obtained by the method for producing a catalyst of the present invention.

FIG. 5 is a diagram schematically showing a catalyst in the process of being produced by the method for producing a catalyst of the present invention.

FIG. 6 is a diagram schematically showing a catalyst after being manufactured by the method for manufacturing a catalyst of the present invention.

FIG. 7 is a diagram schematically showing a catalyst in the process of being produced by the method for producing a catalyst of the present invention.

FIG. 8 is a diagram schematically showing a catalyst after being manufactured by the method for manufacturing a catalyst of the present invention.

FIG. 9 is a diagram schematically showing a catalyst in the process of being manufactured by the method for manufacturing a catalyst of the present invention.

FIG. 10 is a view schematically showing a catalyst after being manufactured by the method for manufacturing a catalyst of the present invention.

FIG. 11 is a diagram schematically showing a catalyst in which a high molecular polymer contains Si.

FIG. 12 is a diagram schematically showing a catalyst in which a high molecular polymer contains Si and which is finally calcined in an oxygen atmosphere.

FIG. 13 is a diagram schematically showing the catalyst of Example 1.

FIG. 14 is a diagram schematically showing the catalyst of Comparative Example 1.

[Explanation of symbols]

1 ... Carrier 2 ... Metal fine particles 3 ... Carrier having SiO ₂ as a main component produced by calcination 4 ... Main chain or side chain of high-molecular polymer 5a, 5b .... Added carbon component 6 ... Metal fine particles having carbon modifying activity 7 ... Carrier 8 ... Fine particles containing Cu and Εn almost evenly 9 ・ ・ ・ …… Fine particles containing excess Ζ compared with Cu 10 …… Fine particles containing Cu in excess as compared with Zn 11 Fine particles made of only Cu atoms 12 Fine particles made of Zn atoms only

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Toshiro Hiraoka 1 Komukai Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Toshiba Research and Development Center Co., Ltd. (72) Inventor Toshiyuki Ohashi Komukai-Toshiba, Kawasaki-shi, Kanagawa Town No. 1 Toshiba Corporation Research & Development Center

Claims (9)

[Claims] 1. A method for producing a catalyst, which comprises sequentially performing a step of dispersing a metal component having catalytic activity in a polymer and a step of heat-treating the polymer having the metal component dispersed therein. 2. A step of dispersing a complex salt or a double salt containing at least two kinds of metal components having catalytic activity in the high molecular polymer, and a step of heat-treating the high molecular polymer in which the complex salt or the double salt is dispersed. A method for producing a catalyst, which comprises: 3. A step of dispersing a compound containing a functional group capable of specifically reacting with the functional group and a metal component having catalytic activity in a polymer having at least one functional group introduced therein, A method for producing a catalyst, which comprises sequentially performing a step of reacting a molecular polymer with the compound and a step of heat-treating a high molecular polymer reacted with the compound. 4. A step of dispersing a metal component having a catalytic activity in a polymer, a step of heat-treating the polymer having the metal component dispersed therein, and a step of removing a carbon component from the polymer. A method for producing a catalyst, which is carried out in order. 5. A step of dispersing a metal component having a catalytic activity and a carbon component in a polymer, a step of heat-treating the polymer in which the metal component and the carbon component are dispersed, and the removal of the carbon component. A method for producing a catalyst, which comprises sequentially performing the steps of: 6. A step of dispersing a metal component having a catalytic activity and a metal component having a carbon-modifying activity in the polymer, and a step of heat-treating the polymer having the two metal components dispersed therein. A method for producing a catalyst, which comprises sequentially performing the step of removing a carbon component from the heat-treated high molecular weight polymer. 7. A step of dispersing a metal component having a catalytic activity, a carbon component and a metal component having a carbon modifying activity in a polymer, and a polymer in which the two metal components and the carbon component are dispersed. A method for producing a catalyst, which comprises sequentially performing a step of heat-treating a polymer and a step of removing the carbon component from the heat-treated polymer. 8. The method for producing a catalyst according to claim 5, wherein the carbon component is removed by a steam reforming reaction or a reaction with carbon dioxide gas. 9. The method for producing a catalyst according to claim 1, wherein the high molecular polymer contains Si.