JPH11151436A - Production of metallic colloid for catalyst and metallic colloid for catalyst produced by this production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce the metallic colloid for the catalyst high in catalyst metal concn. by dissolving a metal salt containing no halogen element and/or a metal complex containing no halogen element and polyvinyl pyrrolidone in a fixed amount of water and adding a specified amount of ethyl alcohol and refluxing the mixture. SOLUTION: In the production of the metallic colloid used for the production of the catalyst the metal salt containing no halogen element and/or the metal complex containing no halogen element and the polyvinyl pyrrolidone are dissolved in the fixed amount of the water, and the ethyl alcohol in (2/3)-(1/4) amount of a volume of the dissolution water amount is added, and the mixture is refluxed. A particle size of the incorporated catalytic metal is set within a range of 1-15 nm and a concn. of the catalytic metal is set within a range of 0.15 wt.% respectively. Dinitrodiammine platinum, dinitrodiammine platinum nitric acid soln., etc., are exemplified as the metal salt containing no halogen element and the metal complex containing no halogen element when platinum colloid is formed for example.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a metal colloid used for producing a catalyst and a metal colloid for a catalyst obtained by the method.

[0002]

2. Description of the Related Art Conventionally, metal colloids that function as catalysts can be used directly as chemical reaction catalysts, but have also been used for supporting catalysts on metal honeycombs or ceramic honeycombs. In particular, when this metal colloid is used as a supported catalyst, the catalyst can be supported in a complicated shape regardless of its shape, whether it is a metal honeycomb or a ceramic honeycomb. It has been widely used because it can be implemented in

The present inventors have conventionally used a metal salt or metal complex containing a halogen element represented by chloroplatinic acid or rhodium chloride, K-30 type polyvinylpyrrolidone (PVP), alcohol and water. Has produced metal colloids. Commonly known metal colloids include a solution in which chloroplatinic acid (IV) and rhodium chloride are dissolved in a certain amount of water, and K having a molecular weight of 40,000.
-30 type polyvinylpyrrolidone is converted to chloroplatinic acid (I
V) and a solution of rhodium chloride in water in the same amount of ethyl alcohol (volume ratio: ethyl alcohol / water =
1) is mixed and refluxed under a nitrogen stream for a certain period of time to produce a Pt-Rh bimetallic colloid. In this regard, J. Macromol. Sci.-Cem., A
13 (6), 727 (1979), J.Phys.Cem., 95 (19), 7448 (1991), J.
Phys. Cem., 98 (10), 2653 (1994) and the like.

[0004] However, when the metal colloid for catalyst obtained by the conventional production method is used for supporting a catalyst on a metal honeycomb or a ceramic honeycomb, some improvements are desired. One is that the metal colloid for catalyst obtained by the conventional production method contains a halogen element called chlorine. When the metal colloid for a catalyst contains a halogen element, when the metal colloid is supported on a carrier and used in a catalyst device, the halogen element in the catalyst layer causes corrosion of a structural material of the catalyst device. For the purpose of preventing such corrosion, a crystallized glass layer or the like is formed on the surface of the structural material of the catalyst device to cope with the problem. However, brittle materials, such as crystallized glass,
It is difficult to apply it to a catalyst device for automobile exhaust gas. The reason for this is that it is separated and falls off due to vibration and impact applied externally.

[0005] Furthermore, the concentration of the catalytic metal in the catalytic metal colloid obtained by the conventional production method is low, and if the concentration of the catalytic metal is to be increased, black is formed and precipitation occurs, so that the catalytic metal concentration can be increased. Did not. Therefore, the necessary amount of catalyst cannot be supported by one impregnation or application, and the impregnation or application is performed a plurality of times, which causes the manufacturing process to be lengthened and the manufacturing cost to increase.

In addition, even when the required amount of the metal colloid for a catalyst obtained by the conventional production method is supported on a metal honeycomb or a ceramic honeycomb, the catalytic ability calculated from the amount of the supported catalyst can be obtained. There is also a phenomenon that the catalyst colloid does not exist, and there has been a demand for a technique for solving the drawbacks of these conventional metal colloids for a catalyst and obtaining more excellent catalytic ability.

[0007]

SUMMARY OF THE INVENTION Accordingly, the present invention overcomes the above-mentioned disadvantages of the conventional metal colloids for catalysts, and in particular, the metal colloids for catalysts suitable for use on a carrier such as a metal honeycomb or a ceramic honeycomb. And a metal colloid for a catalyst obtained by the method.

In order to achieve this object, it is necessary to clarify the problems of conventional metal colloids for catalysts, and the present inventors have conducted intensive studies. As a result, he concluded that the following points should be resolved.

Regarding the problem of corrosion due to halogen elements, it is a natural premise that it is necessary to use a raw material containing no halogen element and to prepare a metal colloid for a catalyst.
However, even if the conventional manufacturing method is applied to raw materials that do not contain halogen elements, precipitation and black are very likely to occur, making it impossible to produce catalytic metal colloids themselves. The diameter could not be reduced.

Next, when the metal colloid for a catalyst is used for carrying a catalyst on a metal honeycomb or a ceramic honeycomb, it is necessary to perform impregnation or application several times.
A metal colloid for catalyst containing a higher concentration of metal for catalyst is required.

Further, in a conventional metal colloid solution for a catalyst, even when a required amount of a catalyst is supported on a metal honeycomb or a ceramic honeycomb, the phenomenon that a desired level of catalytic performance cannot be obtained from the amount of the supported catalyst is caused by a problem with the catalyst. Large clusters (hereinafter referred to as "aggregates") in which the particles of the catalyst metal distributed in the metal colloid aggregate more than necessary.
This is considered to be due to the fact that the contact reaction interface area is smaller than in the case where the catalyst metal particles are uniformly dispersed as fine catalyst metal particles. Therefore, it is necessary to finely and uniformly disperse the catalytic metal particles in the colloid solution to increase the contact reaction interface area.

[0012]

[Means for Achieving the Object] As a result of the inventors' research,
It has been found that the disadvantages of the conventional metal colloids for catalysts are caused by the low solubility of the catalyst metal complex and the high reduction rate of the catalyst metal depending on the composition of the solution used in the production process. On the other hand, the present inventors made an appropriate selection from starting materials that do not contain a halogen element, and changed the mixing ratio of the colloid solution according to the target metal colloid for the catalyst, so that the catalyst metal concentration was reduced. It has been found that high and fine and uniform dispersion is possible. Hereinafter, the present invention will be clarified while sequentially explaining the production process of the metal colloid for a catalyst.

[0013] In order to achieve these objects, the invention according to claim 1 is intended to dissolve a halogen-free metal salt and / or a metal complex containing no halogen element and polyvinylpyrrolidone in a certain amount of water. And 2/3 to 1/4 of the volume of dissolved water in ethyl alcohol, and refluxing the resulting mixture to obtain a halogen-free metal colloid for a catalyst. The use of a metal salt containing no halogen element and / or a metal complex containing no halogen element as a raw material is an essential requirement for producing a metal colloid for a catalyst containing no halogen element. The metal salt containing no halogen element and the metal complex containing no halogen element include the following.

In order to produce platinum colloid, dinitrodiammine platinum (II), dinitrodiammine platinum (I
I) nitric acid solution, cis-diamminediaquaplatinum (II)
Nitrate, trans-diamminediaquaplatinum (II) nitrate, tetranitroplatinic (II) acid, tetra (thiocyanato) platinum (II) acid, bis (oxalato) platinum (I
I) Acid, cis-dinitrodiaquaplatinum (II), tetraammineplatinum (II) hydroxide, hexaammineplatinum (IV) hydroxide and the like can be used.

In order to form a rhodium colloid, rhodium (III) nitrate, rhodium (III) sulfate, rhodium (III) acetate, rhodium (II) acetate, pentaammine aquarhodium (III) nitrate, pentaammine nitrorhodium (III) ), Triammine triaqua rhodium (III) nitrate, hexaammine aqua rhodium (III) nitrate and the like can be used.

In order to produce an iridium colloid, hexanitroiridium (III) acid, tris (oxalato) iridium (III) acid, pentaammineaquairidium (III) nitrate, nitropentaammineiridium (III) nitrite, hexaammine It is possible to use iridium (III) nitrate or the like.

To form a palladium colloid, tetranitropalladium (II) acid, palladium nitrate (I
I), palladium (II) sulfate, tetraamminepalladium (II) nitrate, tetraamminepalladium (I
I) sulfate, trans-diacianaminepalladium (II) nitrate, dinitrodiamminepalladium (I
I), bis (ethylenediamine) palladium (II) nitrate, diaqua (ethylenediamine) palladium (I
I) It is possible to use nitrates and the like.

In order to form a rhenium colloid, it is possible to use perrhenic acid, ammonium perrhenate, dioxobis (ethylenediamine) rhenium (V) nitrate, or the like.

In order to form gold colloid, ammonium disulfiteaurate (I), tetraammineaurate (II)
I) nitrate, tetranitrato gold (III) ammonium salt, diaqua (1.10-phenanthroline) gold (II)
I) It is possible to use nitrates and the like.

To produce a ruthenium colloid, trinitrate nitrosyldiaquaruthenium, ruthenium acetate, hexaammineruthenium (III) nitrate, hexaammineruthenium (II) nitrate, pentaammineaquaruthenium (III) nitrate, nitrosylpentaammineruthenium Nitrate, hydroxonitrosyltetraammineruthenium (III) nitrate, hydroxonitrosyltetraammineruthenium (II) nitrate and the like can be used.

In addition, when producing a composite catalyst metal colloid such as a bimetallic colloid or a trimetallic colloid, two or more of the above-mentioned metal salts and / or metal complexes are used in combination.

The polyvinylpyrrolidone (hereinafter sometimes referred to as “PVP”) used here is an aggregating agent for aggregating the catalytic metal particles to a certain size, and also as a dispersing agent for uniformly dispersing in the colloid. It plays the role of. Here, the role played by polyvinylpyrrolidone depends on the transmission electron microscope (TE) shown in FIG. 1 and FIG.
It becomes clear by comparing the observation photographs in M).

FIG. 1 shows a metal colloid for a catalyst manufactured by the conventional method without adding polyvinylpyrrolidone. It can be seen that the catalyst metal particles are largely agglomerated and fine catalyst metal particles are not dispersed. FIG. 2 shows a metal colloid for catalyst produced by adding polyvinylpyrrolidone. The particle diameter of the metal colloid is about 8 to 20 nm. I have. However, using only this polyvinylpyrrolidone has a uniform diameter of 1 to 15 nm, which is the object of the present invention, and cannot form finer catalytic metal particles.
Large clusters have also occurred. This indicates that the purpose of the present invention cannot be achieved only by adding polyvinylpyrrolidone.

With respect to polyvinylpyrrolidone, the invention according to claim 2 can be used in a conventional production method as polyvinylpyrrolidone used in the method for producing a halogen-free metal colloid for a catalyst according to claim 1. A K-25 type having a molecular weight of 25,000 or a K-60 type having a molecular weight of 220,000 is used. For the production of conventional metal colloids for catalysts, a molecular weight of 40
Only 000 K-30 types of polyvinylpyrrolidone have been used.

On the other hand, in the present invention, not only K-30 type polyvinylpyrrolidone but also K-25 type having a molecular weight of 25000 and K-60 type polyvinylpyrrolidone having a molecular weight of 220,000, which have not been conventionally used, can be used. Become. In the conventional manufacturing method, unless the K-30 type which exerts the effect of minimizing the catalyst metal particle diameter is used, the generated catalyst metal particle diameter cannot be reduced to 15 nm or less, which can withstand practical use. . On the other hand, when the manufacturing method according to the present invention is used, K-
Even if 25 type or K-60 type is used, catalyst metal particles having a diameter of 15 nm or less can be stably obtained. This becomes clear from the relationship between the type of polyvinylpyrrolidone and the diameter of the catalyst metal particles shown in Table 1.

[0026]

[Table 1]

From Table 1, it can be seen that the use of the production method according to the present invention is preferable because the variation in the particle diameter of the catalyst metal and the particle diameter are small as compared with the conventional method. In addition, when the production method according to the present invention is used, it is understood that particles having a diameter of 15 nm or less can be produced using any of K-25, K-30 and K-60. Therefore, K-
The use of either 25, K-30 or K-60 is recommended.

Further, the catalyst metal particle diameters in Table 1 do not include those which have been formed into aggregates (having a diameter exceeding 50 nm) when formed by the conventional method. Therefore, if the aggregates are included, the diameter of the catalyst metal particles obtained by the conventional method becomes a large value that varies further. On the other hand, in the catalyst metal particle diameter obtained by the production method according to the present invention, no agglomerates are generated, and particles having a uniform and small variation are formed.

Further, K-25, K-30 or K-60
There is a difference in the amount of polyvinylpyrrolidone used depending on which one is used. For example, when attempting to obtain platinum-rhodium bimetal particles having a diameter of 1 to 5 nm, the amount of polyvinylpyrrolidone required for each type differs as shown in Table 2.

[0030]

[Table 2]

As shown in Table 2, the fact that the required amount of polyvinylpyrrolidone is different in order to obtain the desired particle size means that the type of polyvinylpyrrolidone used differs depending on the type of polyvinylpyrrolidone used.
The solution viscosities will be different. Which type of polyvinylpyrrolidone is used may be selected and used in consideration of the easiness of process control and the like.

Next, in considering the amount of polyvinylpyrrolidone added, the relationship between the amount of polyvinylpyrrolidone added and the particle size of the catalytic metal was examined, and FIG. 3 shows an example. The upper curve in FIG. 3 shows the transition of the maximum value of the catalyst metal particle diameter measured when the amount of added polyvinylpyrrolidone was changed, and the corresponding transition of the minimum value of the catalyst metal particle diameter. Is indicated by the lower curve. Therefore, the spread between the upper curve and the lower curve indicates a variation in the catalyst metal particle diameter according to the amount of polyvinylpyrrolidone added.

Considering the results shown in FIG. 3 and considering the economics, the metal salt containing no halogen element and / or
Or depending on the type of metal complex containing no halogen element,
K-30 may be set to 20 to 40 wt%. This is 2
This is because the variation in the particle diameter of the catalyst metal sharply decreases from around 0 wt%, and the variation is completely stabilized around 40 wt%. After similar verification, K-25 becomes 40
It is preferable that the use of K-60 is within the range of 8 to 16 wt% and K-60 is within the range of 8 to 16 wt%. As can be seen from FIG.
This is because even if polyvinylpyrrolidone is added at a value higher than these upper limits, it cannot contribute to the reduction in the size of the catalytic metal particles, and when it is lower than the lower limit, the variation in the diameter increases.

A preliminary adjustment is made so that the above-mentioned metal salt and / or metal complex containing no halogen element and polyvinylpyrrolidone are dissolved in a certain amount of water. In this dissolving procedure, the halogen salt-free metal salt and / or metal complex and polyvinylpyrrolidone are simultaneously added to a certain amount of water to dissolve the metal salt and / or metal complex and the polyvinylpyrrolidone. May be dissolved alone in water, and then both dissolved solutions may be mixed so that the resulting solution is dissolved in a certain amount of water. Here, the certain amount of water (hereinafter referred to as “dissolved water amount”) is appropriately determined in consideration of the final target concentration.

Subsequently, the addition of ethyl alcohol is performed. The amount of addition of the ethyl alcohol may be 2/3 to 1/4 of the volume of the amount of dissolved water. It may be adjusted according to. This ethyl alcohol acts as a reducing agent for the catalytic metal ions present in the solution. Here, Table 3 shows the relationship between the value of (ethyl alcohol addition amount) / (dissolved water amount) and the average catalyst metal particle diameter.

[0036]

[Table 3]

According to Table 3, as the amount of ethyl alcohol increases, the reduction rate of the catalyst metal ion increases, and the aggregation of the catalyst metal particles and the formation of black tend to occur.
Agglomerates are easily generated, and as a result, the contact reaction interface area is small and the catalytic function is inferior. Therefore, by reducing the amount of ethyl alcohol as a reducing agent, the reduction rate is adjusted to be slow, and together with the aggregation and dispersion effects of polyvinylpyrrolidone, to prevent the formation of aggregates,
Fine catalyst metal particles having a uniform diameter are formed, and a metal colloid for catalyst containing the fine catalyst metal particles can be produced.

The appropriate amount of the ethyl alcohol is 2/3 to 1/4 of the amount of water used for dissolving the metal salt or metal complex and polyvinylpyrrolidone. this is,
When using the production method according to the present invention, the same tendency is observed in all of colloidal platinum, iridium colloid, and bimetal colloid. If the amount is less than 1/4, the reducing power is insufficient and the formation of catalytic metal particles is too slow. If the amount is more than 2/3, the reduction rate is high, and the formation of aggregates of the catalytic metal particles and black is likely to occur. This is because a large cluster is likely to be generated.

The metal colloid for catalyst produced by the production method according to claim 1 or 2 in consideration of the conditions described above has a higher concentration of catalyst metal particles finer than the conventional metal colloid for catalyst. Although it is included, a case where a higher concentration is required may be considered. In such a case, as a final concentration adjustment, it is possible to volatilize and concentrate the ethyl alcohol used for the reduction reaction under a reduced-pressure atmosphere to obtain a higher-concentration metal colloid for a catalyst.

As described above, using a metal salt containing no halogen element and / or a metal complex containing no halogen element, polyvinyl pyrrolidone, which is a flocculant and a dispersant, is appropriately selected and added in an optimum range. In addition, by controlling the reduction rate of catalytic metal ions by adjusting the ratio of the reducing agent ethyl alcohol to water, the concentration of catalytic metal in the catalytic metal colloid can be increased without black or sedimentation. This has made it possible to further reduce the catalyst metal particle diameter, thereby making it possible to match the amount of supported catalyst with the calculated catalytic performance.
The catalyst metal particles can be made finer without containing a halogen element, and the amount of the supported catalyst can be made to coincide with the calculated catalytic performance.

According to a third aspect of the present invention, there is provided the production method according to the first or second aspect, wherein the diameter of the catalyst metal particles contained is 1 to 15 nm and the concentration of the catalyst metal is 0.1 to 5 wt%. It is a metal colloid for a catalyst not containing a halogen element obtained by the method. There is no conventional metal colloid for a catalyst containing such a fine particle diameter and a high concentration of a catalyst metal, and the catalyst metal containing no halogen element by using the production method according to claim 1 or 2. Since it is a colloid, the problem that the halogen element of the catalyst layer after being supported on the carrier causes corrosion of the structural material of the catalyst device cannot be solved or cannot be solved.

[0042]

DETAILED DESCRIPTION OF THE INVENTION Using the above-described method, various metal halide colloids containing no halogen element were produced. Observation of the particle diameter of the metal colloid for catalyst produced below is performed by TEM, and the concentration is analyzed by chemical quantitative analysis. This is because the TEM observation sample of the metal colloid for the catalyst is dried and sample preparation is performed, so that the same sample has a different concentration state, and the particle distribution and the concentration in the TEM observation do not have a proportional relationship.

First Embodiment First, 1.92 g of cis-diamminediaquaplatinum (II) nitrate and 4 g of polyvinylpyrrolidone (K-30) were dissolved in 4.1 ml of water. To this solution, 2.5 ml of ethyl alcohol was added, and reflux was performed for 5 hours using a reflux condenser to prevent evaporation of water and volatilization of ethyl alcohol. As a result, a platinum colloid for a catalyst as shown in the TEM observation photograph of FIG. 4 was obtained. At this time, the platinum particle diameter was 1.0 to 3.0 nm, the platinum concentration in the platinum colloid was 2.7 wt%, and no precipitation or black was generated.

Second Embodiment First, 0.85 g of rhodium nitrate and 4 g of polyvinylpyrrolidone (K-30) were dissolved in 5.2 ml of water. 2.5 ml of ethyl alcohol was added to this solution, and reflux was performed for 4 hours using a reflux condenser to prevent evaporation of water and volatilization of ethyl alcohol. As a result, a rhodium colloid for a catalyst as shown in the TEM observation photograph of FIG. 5 was obtained.
At this time, the rhodium particle diameter was 1.0 to 1.5 nm, the rhodium concentration in the rhodium colloid was 0.6 wt%, and no precipitation or black occurred.

Third Embodiment First, 0.21 g of rhodium nitrate and 1.8 g of dinitrodiammineplatinum (I
I) Nitric acid solution and 0.5 g of polyvinylpyrrolidone (K-
30) was dissolved in 97.5 ml of water. 2
5 ml of ethyl alcohol was added, and the mixture was refluxed for 5 hours using a reflux condenser to prevent evaporation of water and volatilization of ethyl alcohol. As a result, TE in FIG.
A bimetal colloid of platinum-rhodium (a molar ratio of platinum to rhodium was 7: 3) for a catalyst as shown in the M observation photograph was obtained. At this time, the platinum-rhodium particle diameter was 1.0.
２．５2.5 nm, the bimetal concentration in the platinum-rhodium colloid was 3.3 wt%, and no precipitation or black generation occurred.

Fourth Embodiment First, 0.85 g of rhodium nitrate and 2.1 g of cis-diamminediaquaplatinum (II) nitrate and 3.6 g of polyvinylpyrrolidone (K-60) are added to 3.5 ml of water. Dissolved. To this solution, 2.5 ml of ethyl alcohol was added, and reflux was performed for 2 hours using a reflux condenser to prevent evaporation of water and volatilization of ethyl alcohol. As a result, FIG.
A bimetallic colloid of platinum-rhodium (a molar ratio of platinum to rhodium was 7: 3) for a catalyst as shown in the TEM observation photograph of No. 7 was obtained. At this time, the platinum-rhodium particle diameter was 1.0 to 2.5 nm, the bimetal concentration in the platinum-rhodium colloid was 3.3 wt%, and no precipitation or black was generated.

Fifth Embodiment First, 0.18 g of pentaammineaquairidium (III) nitrate and 1.5 g of cis-diamminediaquaplatinum (II) nitrate are dissolved in 7.4 ml of water, and separately dissolved in 3 ml of water. 0.3 g of polyvinylpyrrolidone (K-30) was dissolved in 4.0 ml of water, and the two solutions were mixed. 4.1 ml of ethyl alcohol was added to the mixed solution, and reflux was performed for 2 hours using a reflux condenser to prevent evaporation of water and volatilization of the ethyl alcohol. As a result, a bimetal colloid of platinum-iridium for a catalyst (a molar ratio of platinum to iridium was 7: 3) was obtained as shown in the TEM observation photograph of FIG. At this time, the platinum-iridium particle diameter was 3.0 to 5.0 nm, the bimetal concentration in the platinum-iridium colloid was 3.3 wt%, and no precipitation or black was generated.

Sixth Embodiment First, 0.041 g of pentaammineaqua iridium (III) nitrate was added.
27 g of rhodium nitrate and 0.91 g of cis-diamminediaquaplatinum (II) nitrate are dissolved in 6.8 ml of water and separately 1.0 g of polyvinylpyrrolidone (K-3
0) was dissolved in 1.0 ml of water, and the two solutions were mixed. 2.5 ml of ethyl alcohol was added to the mixed solution, and reflux was performed for 5 hours using a reflux condenser to prevent evaporation of water and evaporation of the ethyl alcohol. As a result, a trimetal colloid of platinum-rhodium-iridium (a molar ratio of platinum, rhodium and iridium was 7: 2: 1) for a catalyst as shown in the TEM observation photograph of FIG. 9 was obtained. At this time, the platinum-rhodium-iridium particle diameter was 3.0 to 5.0 nm, the trimetal concentration in the platinum-rhodium-iridium colloid was 3.3 wt%, and no precipitation or black was generated.

[0049]

Comparative Example A conventionally known bimetallic colloid of platinum-rhodium was produced. First, 0.0026 g of rhodium chloride and 0.012 g of chloroplatinic acid (IV) were added to 25 m
of water, separately dissolved 0.151 g of polyvinylpyrrolidone (K-30) in 25 ml of ethyl alcohol, and the two solutions were mixed. This mixed solution was refluxed for 2 hours using a reflux condenser to prevent evaporation of water and volatilization of ethyl alcohol. As a result, a bimetallic colloid of platinum-rhodium for a catalyst (a molar ratio of platinum to rhodium was 7: 3) was obtained as shown in the TEM observation photograph of FIG. At this time, the platinum-rhodium particle diameter was 3.0 to 20.0 nm, and the bimetal concentration in the platinum-rhodium colloid was 0.01% by weight. When this result is compared with the metal colloid produced by the method according to the present invention described above, it can be seen that the metal concentration is clearly low and the platinum-rhodium particle diameter varies.

[0050]

As described above, according to the present invention, one or more metal salts or metal complexes containing no halogen element are used to properly select polyvinylpyrrolidone which is a flocculant and a dispersant. By making the ratio of the reducing agent ethyl alcohol and water appropriate, it is possible to increase the concentration of the catalyst metal in the metal colloid for the catalyst without causing black or sedimentation. Since it can be performed only once, and the catalyst metal particle diameter has been made finer, it has become possible to make the amount of supported catalyst coincide with the calculated catalytic performance. Further, since it is a metal colloid for a catalyst that does not contain a halogen element, which has not been known in the related art, it is possible to solve the problem that the halogen element in the catalyst layer causes corrosion of the structural material of the catalyst device.

[Brief description of the drawings]

FIG. 1 is a TEM observation photograph of the particle structure of a metal colloid for a catalyst produced without using polyvinylpyrrolidone.

FIG. 2 is a TEM observation photograph of a particle structure of a metal colloid for a catalyst using polyvinylpyrrolidone.

FIG. 3 is a graph showing the relationship between the amount of polyvinylpyrrolidone added and the catalyst metal particle diameter.

FIG. 4 is a TEM observation photograph of the particle structure of a platinum colloid for a catalyst.

FIG. 5: TE of particle structure of rhodium colloid for catalyst
It is an M observation photograph.

FIG. 6 is a TEM observation photograph of a particle structure of a platinum-rhodium colloid for a catalyst.

FIG. 7 is a TEM observation photograph of the particle structure of a platinum-rhodium colloid for a catalyst.

FIG. 8 is a TEM observation photograph of the particle structure of a platinum-iridium colloid for a catalyst.

FIG. 9 is a TEM observation photograph of the particle structure of a platinum-rhodium-iridium colloid for a catalyst.

FIG. 10 is a TEM observation photograph of the particle structure of a platinum-rhodium colloid for a catalyst produced by a conventional method.

Claims (3)

[Claims] 1. A metal salt containing no halogen element and / or
Alternatively, a metal complex containing no halogen element and polyvinylpyrrolidone are dissolved in a certain amount of water, and 2/3 to 1/4 of the volume of the dissolved water is added, and the mixture is refluxed. A method for producing a metal colloid for catalyst containing no halogen element. 2. Polyvinylpyrrolidone has a molecular weight of 250.
K-25 type of 00 or K- of molecular weight 220000
The method for producing a metal colloid for catalyst according to claim 1, which is of 60 types. 3. The catalyst metal particle diameter contained is 1 to 15 nm.
And a metal colloid for a catalyst which does not contain a halogen element and which is obtained by the production method according to claim 1 or 2, and has a catalyst metal concentration of 0.1 to 5 wt%.