JP2001232196A - Catalyst and method for producing the same - Google Patents

Abstract

(57) [Problem] To efficiently reform a hydrocarbon-based fuel and reduce the concentration of carbon monoxide contained in the obtained hydrogen-containing gas. SOLUTION: An alkali metal or an alkaline earth metal is supported on a support made of a metal oxide such as zirconium dioxide, a noble metal such as platinum is supported on the support, and a 2B or 3B group element such as indium is supported. To form a catalyst. By using this catalyst, methanol can undergo a steam reforming reaction with high efficiency, and the concentration of carbon monoxide in a hydrogen-containing gas obtained by reforming methanol can be reduced. In addition, instead of supporting alkali metals or alkaline earth metals, an element belonging to alkali metals, alkaline earth metals, or rare earths is added to metal oxide to form a carrier, which carries a 2B or 3B group element together with a noble metal. Suitable catalysts are also suitable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a catalyst and a method for producing the same, and more particularly, to a reforming catalyst for reforming a hydrocarbon-based fuel into a hydrogen-containing gas containing hydrogen using water and a method for producing the same.

[0002]

2. Description of the Related Art A steam reforming reaction of methanol for reforming methanol into a hydrogen-containing gas containing hydrogen using steam is carried out by a decomposition reaction represented by the following formula (1) and a shift reaction represented by the following formula (2).

CH ₃ OH → CO + 2H ₂ (1) CO + H ₂ O → CO ₂ + H ₂ (2)

As a catalyst for efficiently carrying out such a reaction, a catalyst comprising a mixture of a heat-resistant porous inorganic compound, a base metal or a noble metal and an alkali metal or an alkaline earth metal (for example, JP-A-62-250948) is known. ) Or a catalyst comprising a support containing a rare earth element oxide and a noble metal supported thereon (for example, see JP-A-3-45501).
And a catalyst in which a noble metal is supported on a zirconium dioxide carrier to which an alkaline earth metal is added (for example, Japanese Patent Application Laid-Open No. 2-26801). These catalysts are intended to solve the problem of poor heat resistance and durability of a copper-based catalyst exhibiting high activity in the steam reforming reaction of methanol, and to further improve the performance as a catalyst.

[0005]

However, these catalysts have a problem that the obtained hydrogen-containing gas contains a high concentration of carbon monoxide. Since the shift reaction of the above formula (2) has a low reaction rate, the hydrogen-containing gas generally contains carbon monoxide. When obtaining a hydrogen-containing gas by steam reforming methanol for the purpose of supplying hydrogen to a device that operates as a fuel, the concentration of hydrogen in the hydrogen-containing gas should be as high as possible. The lower the carbon concentration, the better. In particular, when the apparatus receiving the supply of the hydrogen-containing gas reduces the efficiency by the carbon monoxide contained in the hydrogen-containing gas, for example, in the case of a fuel cell poisoned by the carbon monoxide contained in the hydrogen-containing gas, the hydrogen-containing gas The concentration of carbon monoxide in the gas must be low.

For a catalyst for reforming a hydrocarbon fuel such as methanol to a hydrogen-containing gas containing hydrogen, it is strongly desired to improve the reforming rate of the hydrocarbon fuel to a hydrogen-containing gas. It is rare. For the improvement of the reforming rate, the structure of the carrier, the substance forming the carrier, the substance carried on the carrier, and the like are important factors, and the identification of the optimum combination thereof is also considered to be an important factor.

An object of the catalyst of the present invention is to efficiently reform a hydrocarbon fuel or the like. Another object of the catalyst of the present invention is to efficiently reform methanol. An object of the catalyst of the present invention is to reduce the concentration of carbon monoxide contained in the obtained hydrogen-containing gas. An object of the method for producing a catalyst of the present invention is to produce a catalyst for efficiently reforming a hydrocarbon fuel and reducing the concentration of carbon monoxide contained in a hydrogen-containing gas obtained.

[0008]

Means for Solving the Problems and Their Functions and Effects The catalyst and the method for producing the same according to the present invention employ the following means in order to achieve at least a part of the above objects.

The first catalyst of the present invention comprises a metal oxide, a noble metal, at least one of elements belonging to Group 2B or 3B, and an element belonging to any of alkali metals, alkaline earth metals and rare earths. And at least one of them as a component.

The first catalyst of the present invention can be used as a reforming catalyst for reforming a hydrocarbon fuel, particularly methanol, to a hydrogen-containing gas containing hydrogen using water. When used as such a reforming catalyst, the noble metal alone functions as a reforming catalyst for reforming hydrocarbon-based fuels.
A metal oxide obtained by adding an element belonging to one of an alkaline earth metal and a rare earth is used as a carrier, an element belonging to Group 2B or 3B is supported on such a carrier together with a noble metal, or a group 2B is added together with a noble metal. Alternatively, by supporting an element belonging to Group 3B and an element belonging to any one of alkali metals, alkaline earth metals, and rare earths, it is possible to reform hydrocarbon fuel with high efficiency. Further, the concentration of carbon monoxide contained in the obtained hydrogen-containing gas can be reduced.

[0011] The second catalyst of the present invention comprises a support mainly composed of a metal oxide, a noble metal, at least one of elements belonging to Group 2B or 3B, and an alkali metal or an alkaline earth metal. The gist is to carry at least one of the elements.

The second catalyst of the present invention can be used as a reforming catalyst for reforming a hydrocarbon-based fuel, particularly methanol, to a hydrogen-containing gas containing hydrogen using water. When used as such a reforming catalyst, the noble metal alone functions as a reforming catalyst for reforming a hydrocarbon-based fuel.
By carrying an element belonging to Group B or 3B and an element belonging to an alkali metal or an alkaline earth metal,
The hydrocarbon-based fuel can be reformed with high efficiency, and the concentration of carbon monoxide contained in the obtained hydrogen-containing gas can be reduced.

The third catalyst according to the present invention is characterized in that at least one element selected from the group consisting of alkali metals, alkaline earth metals and rare earths is contained in a carrier made of a metal oxide, and then the noble metal is added to the carrier. The gist of the present invention is to support at least one of the elements belonging to Group 2B or 3B.

The third catalyst of the present invention can be used as a reforming catalyst for reforming a hydrocarbon-based fuel, particularly methanol, to a hydrogen-containing gas containing hydrogen using water. When used as such a reforming catalyst, noble metal alone functions as a catalyst for reforming hydrocarbon-based fuels,
At least one of the elements belonging to any of the alkali metals, alkaline earth metals and rare earths is contained in a carrier made of a metal oxide, and the carrier is loaded with an element belonging to Group 2B or 3B together with the noble metal. In addition, the hydrocarbon-based fuel can be reformed with high efficiency, and the concentration of carbon monoxide contained in the obtained hydrogen-containing gas can be further reduced. Further, since the carrier contains elements belonging to alkali metals, alkaline earth metals, and rare earths,
The function of a noble metal or an element belonging to Group 2B or 3B is not impaired.

The fourth catalyst according to the present invention is characterized in that at least one of the elements belonging to alkali metals or alkaline earth metals is supported on a support made of a metal oxide, and then the noble metal and the 2B or 3B group are supported on the support. The gist of the present invention is to support at least one of the elements belonging to

The fourth catalyst of the present invention can be used as a reforming catalyst for reforming a hydrocarbon-based fuel, particularly methanol, to a hydrogen-containing gas containing hydrogen using water. When used as such a reforming catalyst, noble metal alone functions as a catalyst for reforming hydrocarbon-based fuels,
Using metal oxide as carrier and 2B or 3B
By carrying an element belonging to the group III and an element belonging to the alkali metal or alkaline earth metal together with the noble metal, it is possible to reform the hydrocarbon-based fuel with high efficiency and to obtain the monoxide contained in the hydrogen-containing gas obtained. The carbon concentration can be lower. Further, since the element belonging to the alkali metal or the alkaline earth metal is first supported on the carrier, the function of the noble metal or the element belonging to Group 2B or 3B is not impaired.

In the second or fourth catalyst of the present invention, as the element belonging to the alkali metal or the alkaline earth metal, any metal may be used, but any one of potassium, magnesium and calcium is used. Is preferred.

[0018] The fifth catalyst of the present invention provides a carrier formed by a metal oxide to which at least one of elements belonging to any of alkali metals, alkaline earth metals and rare earths is added as a carrier additive. , A noble metal and at least one of the elements belonging to Group 2B or 3B.

The fifth catalyst of the present invention can be used as a reforming catalyst for reforming a hydrocarbon-based fuel, particularly methanol, to a hydrogen-containing gas containing hydrogen using water. When used as such a reforming catalyst, it functions as a catalyst for reforming a hydrocarbon-based fuel even if only a noble metal is supported using a metal oxide as a carrier, but it belongs to any of alkali metals, alkaline earth metals, and rare earths. By using a carrier formed of a metal oxide to which an element is added as a carrier additive, the performance as a reforming catalyst can be improved. In addition, by supporting an element belonging to Group 2B or 3B together with the noble metal on the carrier, the performance as a reforming catalyst can be improved. Therefore, a carrier formed of a metal oxide to which an element belonging to any of an alkali metal, an alkaline earth metal, and a rare earth is added as a carrier additive carries the element belonging to Group 2B or 3B together with the noble metal, thereby improving the properties. The performance as a catalyst can be further improved. Naturally, the concentration of carbon monoxide contained in the obtained hydrogen-containing gas can be further reduced.

In the fifth catalyst of the present invention, the carrier additive may be any element as long as it belongs to any one of alkali metals, alkaline earth metals and rare earths, but calcium and lanthanum are preferred. When calcium is used, the amount of the carrier additive is preferably in the range of 3 to 15 mol%, and when lanthanum is used, it is preferably in the range of 3 to 6 mol%.

In any of the first to fifth catalysts according to the present invention, the element belonging to Group 2B or 3B is
Any element belonging to these groups may be used, but zinc, gallium, and indium are preferable, and indium is particularly preferable. As the noble metal, any metal can be used as long as it is a noble metal, but platinum and palladium are preferable, and platinum is particularly preferable. As the metal oxide, any metal oxide may be used, but a basic metal oxide is preferable, and among them, cerium dioxide (CeO ₂ ),
Zirconium dioxide (ZrO ₂ ), titanium dioxide (Ti
O ₂ ) is preferred, and particularly zirconium dioxide (ZrO ₂ )
Is preferred. Therefore, it is particularly preferable to use zirconium dioxide (ZrO ₂ ) as a metal oxide, use platinum as a noble metal, and use indium as an element belonging to Group 2B or 3B.

In any one of the first to fifth catalysts of the present invention, the support is a monolithic support having a surface coated with the metal oxide or the metal oxide to which the support additive is added. It can also be. By using the monolithic carrier, the contact area per unit volume can be increased, so that the size of the reaction tank using the same can be reduced.

The first method for producing a catalyst according to the present invention is a method for producing a catalyst, wherein a carrier made of a metal oxide contains at least one element selected from the group consisting of alkali metals, alkaline earth metals and rare earths. And a carrier containing at least one of the elements belonging to any of the alkali metals, alkaline earth metals, and rare earths, wherein at least one of the noble metal and the element belonging to Group 2B or 3B is contained in the carrier. And a supporting step of supporting one and the other.

According to the first method for producing a catalyst of the present invention, at least one of the elements belonging to any of the alkali metals, alkaline earth metals and rare earths is contained in the metal oxide carrier. Later, on this carrier, precious metal and 2B
Obtained by reforming a hydrocarbon-based fuel with high efficiency without impairing the function of a noble metal or an element belonging to Group 2B or 3B, that is, a catalyst carrying at least one element belonging to Group 3B or Group 3B. A catalyst that lowers the concentration of carbon monoxide contained in the hydrogen-containing gas can be manufactured.

The second method for producing a catalyst according to the present invention is a method for producing a catalyst, wherein the first carrier comprises at least one element belonging to an alkali metal or an alkaline earth metal supported on a metal oxide carrier. And a second step of supporting the noble metal and at least one of the elements belonging to Group 2B or 3B on the carrier supporting at least one of the elements belonging to the alkali metal or alkaline earth metal.
And a supporting step.

According to the second method for producing a catalyst of the present invention, at least one element belonging to an alkali metal or an alkaline earth metal is supported on a porous metal oxide carrier, and then the carrier is loaded on the carrier. A catalyst that supports a noble metal and at least one element belonging to Group 2B or 3B, that is, reforms a hydrocarbon-based fuel with high efficiency without impairing the function of the noble metal or an element belonging to Group 2B or 3B. It is possible to produce a catalyst for reducing the concentration of carbon monoxide contained in the hydrogen-containing gas obtained together with the above.

[0027]

Next, embodiments of the present invention will be described with reference to examples.

A. Catalyst in which noble metal, element of group 2B or 3B and element of alkali metal or alkaline earth metal are supported on a support made of metal oxide

1. Preparation of Methanol Reforming Catalyst of Example and Methanol Reforming Catalyst of Comparative Example The preparation of a catalyst supporting a noble metal, a group 2B or 3B element, and an alkali metal or alkaline earth metal element is shown in FIG. It is performed based on the manufacturing process of the exemplified catalyst. First, a powder containing a porous metal oxide such as cerium dioxide (CeO ₂ ) or zirconium dioxide (ZrO ₂ ) is impregnated with a solution containing an element belonging to an alkali metal or an alkaline earth metal by impregnating the solution with an alkali metal or an alkaline earth metal. An alkaline earth metal is supported (step S10), and after drying, it is fired (step S12). The calcined powder thus obtained is impregnated with a solution of a noble metal and an element belonging to Group 2B or 3B to carry the noble metal and an element belonging to Group 2B or 3B (Step S14). Step S16) Forming into a predetermined shape (Step S1)
8) Complete. Specifically, it is as follows.

(1) Methanol reforming catalyst of the first embodiment 240 g of cerium dioxide (CeO ₂ ) powder was impregnated with an aqueous potassium nitrate solution to support 0.05 mol of potassium, and dried at 110 ° C. for 3 hours. , 300
Bake at ℃ for 1 hour. This calcined powder is impregnated with a dinitrodiamine platinum nitrate solution and an indium nitrate solution to carry 30 g (corresponding to 10 wt%) of platinum and indium respectively, and dried at a temperature of 110 ° C. for 3 hours.
Bake at 0 ° C. for 1 hour. And the obtained powder is 1
The methanol reforming catalyst of the first embodiment is obtained as pellets having a size of about 3 mm.

(2) Methanol reforming catalyst of the second embodiment 240 g of zirconium dioxide (ZrO ₂ ) powder was impregnated with an aqueous solution of calcium nitrate to make 0.05 m of calcium.
After being carried on the substrate and dried at a temperature of 110 ° C. for 3 hours, it is baked at 300 ° C. for 1 hour. The calcined powder is impregnated with a dinitrodiamine platinum nitrate solution and an indium nitrate solution to obtain 30 g of platinum and indium (10 wt.
%), Dried at a temperature of 110 ° C. for 3 hours, and then fired at a temperature of 500 ° C. for 1 hour. Then, the obtained powder is formed into a pellet having a size of about 1 to 3 mm,
The methanol reforming catalyst of the example is obtained.

(3) Methanol reforming catalyst of the third embodiment 240 g of zirconium dioxide (ZrO ₂ ) powder is impregnated with an aqueous solution of magnesium nitrate to reduce the amount of magnesium to 0.03 g.
After supporting 5 mol and drying at a temperature of 110 ° C. for 3 hours, it is baked at 300 ° C. for 1 hour. The calcined powder is impregnated with a palladium nitrate solution and a zinc nitrate solution to carry 30 g (corresponding to 10 wt%) of palladium and zinc respectively, and dried at a temperature of 110 ° C. for 3 hours.
For 1 hour. And the obtained powder is 1-3
The methanol reforming catalyst of the third embodiment is obtained as pellets having a size of about mm.

(4) Methanol reforming catalyst of the fourth embodiment 240 g of zirconium dioxide (ZrO ₂ ) powder is impregnated with an aqueous potassium nitrate solution to add 0.05 mol of potassium.
After being supported and dried at a temperature of 110 ° C. for 3 hours, 3
Bake at 00 ° C for 1 hour. This calcined powder is impregnated with a dinitrodiamine platinum nitrate solution and an indium nitrate solution to carry 30 g (corresponding to 10 wt%) of platinum and indium respectively, dried at 110 ° C. for 3 hours, and then dried at 500 ° C. Bake for 1 hour. The obtained powder is converted into pellets having a size of about 1 to 3 mm to obtain the methanol reforming catalyst of the fourth embodiment.

(5) Methanol reforming catalyst of the fifth embodiment 240 g of cerium dioxide (CeO ₂ ) powder is impregnated with an aqueous solution of calcium nitrate to obtain 0.05 mol of calcium.
After being supported and dried at a temperature of 110 ° C. for 3 hours, 3
Bake at 00 ° C for 1 hour. The calcined powder is impregnated with a dinitrodiamine platinum nitrate solution and a gallium nitrate solution to carry 30 g (corresponding to 10 wt%) of platinum and gallium respectively, and dried at a temperature of 110 ° C. for 3 hours.
Bake at 0 ° C. for 1 hour. And the obtained powder is 1
The methanol reforming catalyst of the fifth embodiment is obtained as pellets having a size of about 3 mm.

(6) Methanol reforming catalyst of the first comparative example 240 g of cerium dioxide (CeO ₂ ) powder was impregnated with a dinitrodiamine platinum nitrate solution and an indium nitrate solution to obtain 30 g (10 wt%) of platinum and indium, respectively.
Equivalent) After being supported and dried at a temperature of 110 ° C. for 3 hours, it is baked at a temperature of 500 ° C. for 1 hour. Then, the obtained powder is converted into pellets having a size of about 1 to 3 mm to obtain the methanol reforming catalyst of the first comparative example.

(7) Methanol reforming catalyst of the second comparative example 240 g of zirconium dioxide (ZrO ₂ ) powder was impregnated with a dinitrodiamine platinum nitrate solution and an indium nitrate solution to obtain 30 g of platinum and 10 g of indium, respectively.
(equivalent to t%) and dried at a temperature of 110 ° C. for 3 hours, and then fired at a temperature of 500 ° C. for 1 hour. The obtained powder is converted into pellets having a size of about 1 to 3 mm to obtain the methanol reforming catalyst of the second comparative example.

(8) Methanol reforming catalyst of the third comparative example 240 g of cerium dioxide (CeO ₂ ) powder was impregnated with a dinitrodiamine platinum nitrate solution and an indium nitrate solution to obtain 30 g (10 wt%) of platinum and indium, respectively.
Equivalent) After being supported and dried at a temperature of 110 ° C. for 3 hours, it is baked at a temperature of 500 ° C. for 1 hour. The calcined powder is impregnated with an aqueous solution of potassium nitrate to reduce potassium to 0.05 m.
After being carried on the substrate and dried at a temperature of 110 ° C. for 3 hours, it is baked at 300 ° C. for 1 hour. Then, the obtained powder is converted into pellets having a size of about 1 to 3 mm to obtain the methanol reforming catalyst of the third comparative example.

(9) Methanol reforming catalyst of the fourth comparative example 240 g of zirconium dioxide (ZrO ₂ ) powder was impregnated with a dinitrodiamine platinum nitrate solution and an indium nitrate solution to obtain 30 g of platinum and 10 g of indium, respectively.
(equivalent to t%) and dried at a temperature of 110 ° C. for 3 hours, and then fired at a temperature of 500 ° C. for 1 hour. The calcined powder is impregnated with an aqueous solution of calcium nitrate to carry 0.05 mol of calcium, dried at 110 ° C. for 3 hours, and calcined at 300 ° C. for 1 hour. The obtained powder is converted into pellets having a size of about 1 to 3 mm,
A methanol reforming catalyst of a comparative example is obtained.

2. Evaluation Method and Experimental Results For the methanol reforming catalysts of the first to fifth embodiments and the methanol reforming catalysts of the first to fourth comparative examples, the number of moles of water relative to the number of moles of methanol was determined. When the ratio (H ₂ O / CH ₃ OH) is 2.0 and the ratio of the number of oxygen atoms to the number of carbon atoms in methanol (O / C) is 0.2
3 was prepared, and the liquid space velocity (LHSV) of this mixed gas with respect to methanol was 2 [1 / h], and both the temperature of the mixed gas at the inlet and the temperature of the gas at the outlet of the reforming reaction layer were changed. Methanol was steam reformed under the condition of 250 ° C. The results are shown in Table 1 below. Table 1
In the formula, the methanol reforming ratio is the ratio of methanol that has produced a reforming reaction in the reaction layer.

[0040]

[Table 1]

As can be seen from the table, the first to fifth embodiments are described.
The methanol reforming catalysts of the examples were the first comparative example and the second comparative example.
It has a high methanol reforming rate as in the case of the catalyst supporting the noble metal of the comparative example and an element of the 2B group or 3B group,
The CO concentration is lower than the comparative example and the second comparative example. Therefore, the methanol reforming catalysts of the first to fifth embodiments carry an alkali metal or an alkaline earth metal in addition to a noble metal or a group 2B or 3B element,
It can be said that the steam reforming reaction of methanol can be performed with high efficiency, and the concentration of carbon monoxide in the obtained hydrogen-containing gas can be kept low.

Further, as a catalyst which carries an alkali metal or an alkaline earth metal in addition to a noble metal or a group 2B or 3B element, like the methanol reforming catalysts of the third comparative example and the fourth comparative example, When an alkali metal or an alkaline earth metal is supported after supporting a noble metal or a group 2B or 3B element, a reduction in the methanol reforming rate is observed. this is,
It is considered that the alkali metal or alkaline earth metal supported later hinders the function of the noble metal or the group 2B or 3B element as a methanol reforming catalyst. On the other hand, as in the case of the methanol reforming catalysts of the first to fifth embodiments, when an alkali metal or an alkaline earth metal is supported and then a noble metal or a group 2B or 3B element is supported, the alkali Precious metals and 2 by metals and alkaline earth metals
The group B or 3B element exhibits a good methanol reforming rate without inhibiting the function of the element as a methanol reforming catalyst, and exhibits one of the hydrogen-containing gases obtained by supporting an alkali metal or an alkaline earth metal. The carbon oxide concentration can be kept lower.

B. Catalyst in which a noble metal and an element belonging to Group 2B or 3B are supported on a carrier formed of a metal oxide to which an element belonging to an alkali metal, an alkaline earth metal or a rare earth is added as a carrier additive

1. Preparation of Methanol Reforming Catalyst of Example and Methanol Reforming Catalyst of Comparative Example The preparation of the methanol reforming catalyst of the example is performed based on the production process of the methanol reforming catalyst illustrated in FIG.
First, a slurry of a metal oxide such as zirconium dioxide (ZrO ₂ ) to which an element belonging to an alkali metal, an alkaline earth metal, or a rare earth is added as a carrier additive is fired in the shape of a carrier (step S20). At this time, for example, if a slurry is coated on a monolithic carrier such as a honeycomb tube and baked, it is suitable as a structure of the carrier. Subsequently, a solution of an element belonging to Group 2B or 3B is absorbed in the carrier obtained by firing, dried and calcined to allow the element belonging to Group 2B or 3B to be carried on the carrier (Step S22). next,
The noble metal solution is absorbed on the carrier supporting the element belonging to Group 2B or 3B, dried and calcined to support the noble metal on the carrier (Step S24) to complete the methanol reforming catalyst of the example.

(1) Methanol Reforming Catalyst of Sixth Embodiment 3 mol% of lithium nitrate (molar ratio of lithium to zirconium: 3:
97) The added zirconium dioxide slurry is
g / L, dried at 110 ° C. for 3 hours, and calcined at 300 ° C. to form a carrier. The carrier thus formed is allowed to absorb an indium nitrate solution to carry 30 g / L of indium, dried and fired. Then, a dinitrodiamine platinum nitrate solution is absorbed on a carrier supporting indium, platinum is supported at 30 g / L, dried, and calcined to obtain a methanol reforming catalyst of the sixth embodiment.

(2) Methanol reforming catalysts of the seventh to fifteenth embodiments In preparing the methanol reforming catalyst of the sixth embodiment, sodium (Na), potassium (K), rubidium (R) was used instead of lithium nitrate. Rb), cesium (Cs), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and lanthanum (La) were prepared in the same manner using nitrates, respectively. The methanol reforming catalyst of 15 examples is obtained.

(3) Methanol Reforming Catalyst of Fifth Comparative Example The methanol reforming catalyst of the fifth comparative example is prepared and prepared in the same manner as the methanol reforming catalyst of the sixth embodiment without adding a carrier additive. . That is, the surface of a cordierite monolithic carrier was coated with a slurry of zirconium dioxide (ZrO ₂ ) with no addition to a concentration of 240 g / L, dried at a temperature of 110 ° C. for 3 hours, and then fired at a temperature of 300 ° C. A carrier was formed, the carrier was allowed to absorb an indium nitrate solution, 30 g / L of indium was carried thereon, dried and calcined, and further, a dinitrodiamine platinum nitrate solution was absorbed to remove platinum.
After drying at 0 g / L, the mixture was dried and calcined to obtain a methanol reforming catalyst of the fifth comparative example.

Table 2 below shows a list of carrier additives, metal oxides, and supported metals of the methanol reforming catalysts of the sixth to fifteenth embodiments and the methanol reforming catalyst of the fifth comparative example.

[0049]

[Table 2]

2. Evaluation method and evaluation The ratio of the number of moles of water to the number of moles of methanol (H ₂ O / CH ₃
OH) is 2.0 and a mixed gas is prepared in which the ratio of the number of oxygen atoms to the number of carbon atoms in methanol (O / C) is 0.21, and this mixed gas is subjected to a liquid hourly space velocity (LHSV) against methanol. ) Was 2 [1 / h], and methanol was steam reformed under the conditions that the temperature of the mixed gas at the inlet of the reforming reaction layer was 250 ° C. and the temperature of the gas at the outlet was 250 ° C.
The result is shown in FIG. As shown in the figure, it can be seen that the methanol reforming catalysts of the sixth to fifteenth examples exhibited a better methanol reforming rate than the methanol reforming catalyst of the comparative example. In particular, the twelfth embodiment, the thirteenth embodiment,
The methanol reforming catalyst of the fifteenth embodiment, that is, the methanol reforming catalyst using calcium (Ca), strontium (Sr), or lanthanum (La) as a carrier additive, is a methanol reforming catalyst using another carrier additive. It shows a higher methanol reforming rate than that of. This indicates that calcium (Ca), strontium (Sr), and lanthanum (La) are particularly suitable as carrier additives.

Since the methanol reforming catalyst of the fifteenth embodiment, that is, the reforming catalyst using a carrier to which lanthanum (La) is added, has a good methanol reforming rate, it belongs to the rare earth element having the same characteristics as lanthanum. It is considered that the reforming catalyst using the carrier to which other elements are added also shows a good methanol reforming rate similarly to the methanol reforming catalyst of the fifteenth embodiment.
That is, among elements belonging to rare earths, elements belonging to lanthanoids such as scandium (Sc) and yttrium (Y), cerium (Ce) and praseodymium (Pr), and elements belonging to actinoids such as actium (Ac) and thorium (Th) It is considered that a good methanol reforming rate is similarly exhibited even when a carrier to which any one of the above elements is added is used.

As described above, the use of a carrier prepared by adding an alkali metal, an alkaline earth metal, or a rare earth as a carrier additive to zirconium dioxide as a metal oxide can improve the methanol reforming rate. This is considered to be due to the fact that the basic properties of the carrier are improved and the specific surface area of the carrier is improved. The methanol reforming catalyst of the first to fifth embodiments described above, that is, noble metal or 2B
The methanol reforming catalyst comprising an alkali metal or an alkaline earth metal supported before carrying an element belonging to Group III or 3B also exhibits a good methanol reforming rate in the sixth to fifteenth embodiments. It is considered that, similarly to the methanol reforming catalyst, when the alkali metal or alkaline earth metal enhances the basic properties of the carrier, the specific surface area of the carrier is improved. That is, the step of supporting an alkali metal or an alkaline earth metal on a metal oxide and firing the same is a step of increasing the basic properties of the support made of the metal oxide. You can do it. From these considerations and the experimental results of the methanol reforming catalyst of the fifteenth embodiment, a methanol reforming catalyst obtained by supporting a rare earth element such as lanthanum before supporting a noble metal or an element belonging to Group 2B or 3B is also good. It is considered to show a high methanol reforming rate. In order to prepare this methanol reforming catalyst, a step S10 of impregnating the metal oxide with a solution of an alkali metal or an alkaline earth metal in the catalyst manufacturing process of FIG. What is necessary is just to impregnate a solution and carry it. As an example of a method of including at least one of the elements belonging to any of alkali metals, alkaline earth metals, and rare earths in a carrier made of a metal oxide, a method of supporting the carrier or a slurry of the metal oxide may be used. Although the method of firing the metal oxide after the addition has been described, the method is not limited to these methods, and any method of inclusion may be used.

3. Evaluation of Addition of Carrier Additive Carrier addition in the methanol reforming catalyst of the twelfth embodiment using calcium (Ca) as a carrier additive and the methanol reforming catalyst of the fifteenth embodiment using lanthanum (La) as a carrier additive The relationship between the amount of the carrier additive and the methanol reforming rate was evaluated by changing the amount of the additive in the range of 0 to 20 mol / L. The methanol reforming catalyst used in the evaluation was prepared in the same manner as the preparation of the methanol reforming catalyst of the twelfth and fifteenth embodiments described above, except for the amount of the carrier additive added. As the conditions for measuring the methanol reforming rate, the same mixed gas as the mixed gas used in the method for evaluating a methanol reforming catalyst in the above-described sixth to fifteenth embodiments was used under the same conditions. The experimental results are shown in FIG. As shown in the figure, the methanol reforming catalyst of the twelfth embodiment using calcium (Ca) as a carrier additive is 3 to 15 mo.
The methanol reforming rate in the 15th embodiment using lanthanum (La) as a carrier additive showed a good methanol reforming rate in the range of 1 to 3 mol / L. Show.

C. Comparison of noble metal with elements belonging to group 2B or 3B In the methanol reforming catalysts of the first to fifteenth examples, platinum or palladium is used as the noble metal, and indium, zinc, or gallium is used as the element belonging to group 2B or 3B. However, rhodium, iridium, ruthenium and the like can be used as the noble metal in addition to platinum and palladium. In addition, as an element belonging to Group 2B or 3B, cadmium, mercury, aluminum, or the like can be used in addition to indium, zinc, and gallium. Among these various noble metals and elements belonging to Group 2B or 3B, platinum and indium are particularly preferable because of a better methanol reforming rate than those using other noble metals or elements belonging to Group 2B or 3B. Is obtained. The reason will be described.

1. Preparation of Methanol Reforming Catalyst of Example and Methanol Reforming Catalyst of Comparative Example (1) Methanol Reforming Catalyst of Sixteenth Example A dinitrodiamine platinum nitrate solution and an indium nitrate solution were added to 100 g of cerium dioxide (CeO ₂ ) powder. After being impregnated to carry 10 wt% of platinum and indium, respectively, and dried at 110 ° C. for 3 hours,
For 1 hour, and then put in a hydrogen reducing atmosphere at a temperature of 400 to 500 ° C. for 2 hours to reduce hydrogen. The obtained powder is converted into pellets having a size of about 1 to 3 mm to obtain the methanol reforming catalyst of the sixteenth embodiment.

(2) Methanol Reforming Catalyst of Seventeenth Embodiment In the preparation of the methanol reforming catalyst of the sixteenth embodiment,
Cerium oxide (CeO _Two) Instead of zirconium dioxide
(ZrO_Two) And replace with indium nitrate solution
In the same manner using a zinc nitrate solution.
Obtain a methanol reforming catalyst.

(3) Methanol Reforming Catalyst of Eighteenth Embodiment In the preparation of the methanol reforming catalyst of the sixteenth embodiment, a palladium nitrate solution and a gallium nitrate solution were used instead of the dinitrodiamine platinum nitrate solution and the indium nitrate solution. To prepare the methanol reforming catalyst of the eighteenth embodiment.

(4) Methanol Reforming Catalyst of Nineteenth Embodiment In the preparation of the methanol reforming catalyst of the sixteenth embodiment,
Cerium oxide (CeO _Two) Instead of zirconium dioxide
(ZrO_Two) And dinitrodiamine platinum nitrate
Palladium nitrate solution instead of solution and indium nitrate solution
Liquid and an indium nitrate solution.
The methanol reforming catalyst of the example is obtained.

(5) Methanol Reforming Catalyst of Twentieth Embodiment In the preparation of the methanol reforming catalyst of the sixteenth embodiment,
Cerium oxide (CeO _Two) Instead of zirconium dioxide
(ZrO_Two) And substitute for indium nitrate solution
Prepared in the same manner using a gallium nitrate solution.
The methanol reforming catalyst of the example is obtained.

2. Evaluation method and experimental results The ratio of the number of moles of water to the number of moles of methanol (H ₂ O / CH ₃ OH) was 2.0 with respect to the methanol reforming catalysts of the sixteenth to twentieth embodiments described above. To prepare a mixed gas in which the ratio of the number of oxygen atoms to the number of carbon atoms in methanol (O / C) is 0.23, and this mixed gas has a liquid hourly space velocity (LHSV) for methanol of 2 [1 / h. ]
And the temperature of the mixed gas at the inlet of the reforming reaction layer is 300
The methanol was steam reformed under the condition that the temperature of the gas at the outlet was 250 ° C. The results are shown in Table 3 below. In addition,
In Table 3, the methanol reforming ratio is the ratio of methanol that has undergone a reforming reaction in the reaction layer, and the CO selectivity is the amount of generated monoxide relative to the sum of the amount of generated carbon monoxide and the amount of generated carbon dioxide. The ratio of the amount of carbon [the amount of generated CO / (the amount of generated CO +
Generated CO ₂ amount)].

[0061]

[Table 3]

As can be seen from Table 3, the methanol reforming catalysts of the sixteenth embodiment to the twentieth embodiment all show a high methanol reforming rate and a low CO selectivity. In particular, the methanol reforming catalyst of the sixteenth embodiment, that is, a methanol reforming catalyst using platinum as a noble metal and using indium as an element belonging to Group 2B or 3B exhibits a high methanol reforming rate and a low CO selectivity. . From this, platinum is used as a noble metal and the group 2B or 3
It is understood that indium is preferably used as an element belonging to Group B.

The methanol reforming catalysts of the above-described sixteenth to twentieth embodiments correspond to the noble metal and the group 2B or 3B.
The first to fifth embodiments which carry an element belonging to an alkali metal or an alkaline earth metal in addition to the element belonging to the group B
Although it does not correspond to the methanol reforming catalyst of the example, it is considered to be the same from the viewpoint of comparing the type of noble metal and its function in the catalyst and comparing the type of element belonging to Group 2B or 3B and its function. The experimental results using the methanol reforming catalysts of the sixteenth to twentieth examples, that is, it is preferable to use platinum as a noble metal and to use indium as an element belonging to Group 2B or 3B, Noble metal and 2B or 3
It is believed that a methanol reforming catalyst that carries an element belonging to an alkali metal or an alkaline earth metal in addition to the element belonging to Group B can also provide similar results. The methanol reforming catalysts of the sixteenth embodiment to the twentieth embodiment are characterized in that a noble metal and a 2B or 3B metal are added to a carrier obtained by adding an element belonging to any of alkali metals, alkaline earth metals and rare earths as a carrier additive. It does not correspond to the methanol reforming catalysts of the sixth to fifteenth embodiments supporting an element belonging to the group III, but since the components of the carrier are slightly different,
This is considered to be the same from the viewpoint of comparing the type of the noble metal to be supported and its function and comparing the type of the 2B or 3B group and its function. That is, the experimental results using the methanol reforming catalysts of the sixteenth to twentieth embodiments, that is, the experimental results that it is preferable to use platinum as a noble metal and to use indium as an element belonging to Group 2B or 3B, are as follows. Similar results are obtained with a methanol reforming catalyst in which a noble metal and an element belonging to Group 2B or 3B are supported on a carrier obtained by adding an element belonging to any of alkali metals, alkaline earth metals and rare earths as a carrier additive. It is thought to bring.

Although the methanol reforming catalysts of the sixteenth and twentieth embodiments were calcined and then placed in a hydrogen reducing atmosphere and reduced with hydrogen, the same results were obtained with and without hydrogen reduction. I confirmed.

D. Comparison of metal oxides forming carrier In the methanol reforming catalysts of the first to fifteenth embodiments, zirconium dioxide (ZrO ₂ ) is used as the metal oxide.
And cerium dioxide (CeO ₂ ), but various metal oxides such as titanium dioxide (TiO ₂ ), aluminum oxide (Al ₂ O ₃ ), and silicon dioxide (SiO ₂ ) may be used. Can also. Among these various metal oxides, zirconium dioxide (ZrO ₂ ) is particularly preferred because a better methanol reforming rate can be obtained as compared with those using other metal oxides.
The reason is described below.

1. Preparation of Methanol Reforming Catalyst of Example Cerium dioxide (CeO ₂ ), zirconium dioxide (ZrO ₂ ), titanium dioxide (TiO ₂ ),
Aluminum oxide (Al ₂ O ₃ ), silicon dioxide (SiO
₂ ), the respective methanol reforming catalysts using platinum as a noble metal and using indium as a group 2B or 3B element were used as the methanol reforming catalysts of the 21st to 25th embodiments.

(1) The methanol reforming catalyst of the twenty-first embodiment was prepared by coating a cordierite monolithic carrier with a slurry of cerium dioxide (CeO ₂ ) at 240 g / l, drying at 110 ° C. for 3 hours, The support is obtained by firing at 1 ° C. for 1 hour. An indium nitrate solution is absorbed on the carrier to support 30 g / l of indium, which is dried and fired. Thereafter, a dinitrodiamine platinum nitrate solution is absorbed into the fired product to carry 30 g / l of platinum, dried at 110 ° C. for 3 hours, and fired at 300 ° C. for 1 hour to complete.

(2) The methanol reforming catalysts of the twenty-second to twenty-fifth embodiments were prepared by coating the slurry of cerium dioxide (CeO ₂ ) on the monolith carrier in the preparation of the methanol reforming catalyst of the twenty-first embodiment. It is prepared and prepared in the same manner except that each slurry of zirconium (ZrO ₂ ), titanium dioxide (TiO ₂ ), aluminum oxide (Al ₂ O ₃ ), and silicon dioxide (SiO ₂ ) is replaced with a coating on a monolithic carrier. .

2. Evaluation Method and Experimental Results The ratio of the number of moles of water to the number of moles of methanol (H ₂ O / CH ₃ OH) was 2.0 with respect to the methanol reforming catalysts of the above-mentioned 21st to 25th embodiments. To prepare a mixed gas in which the ratio of the number of oxygen atoms to the number of carbon atoms in methanol (O / C) is 0.21, and this mixed gas has a liquid hourly space velocity (LHSV) of 2 [1 / h ]
And the temperature of the mixed gas at the inlet of the reforming reaction layer is 250
The methanol was steam reformed under the condition that the temperature of the gas at the outlet was 250 ° C. The results are shown in the graph of FIG.
Note that the numerical values shown in the graph indicate the emission concentrations of carbon monoxide.

As shown, as the metal oxide,
Cerium (CeO_Two) And zirconium dioxide (Zr
O_Two), Titanium dioxide (TiO_TwoTwenty-first embodiment using)
The methanol reforming catalyst of the thirty-third embodiment is a metal oxidation catalyst.
Aluminum oxide (Al _TwoO_Three) Or silicon dioxide
(SiO_Two) Of the 24th and 25th embodiments using
Shows better methanol reforming rate than the ethanol reforming catalyst
You. As a result, cerium dioxide (Ce) is used as the metal oxide.
O_Two) And zirconium dioxide (ZrO)_Two),titanium dioxide
(TiO_Two), Especially cerium dioxide (Ce)
O_Two) Or zirconium dioxide (ZrO)_Two) Can be used
It turns out to be effective.

Next, the durability of the methanol reforming catalyst of the twenty-first embodiment using cerium dioxide (CeO ₂ ) as the metal oxide and the methanol reforming catalyst of the twenty- _second embodiment using zirconium dioxide (ZrO ₂ ) are shown. Think. As an experiment, both methanol reforming catalysts were treated at a temperature of 400 ° C., 500 ° C., and 600 ° C. for 8 hours in a hydrogen reducing atmosphere in which a mixed gas of hydrogen and nitrogen in a ratio of 1: 9 was passed. Was subjected to steam reforming of methanol under the same conditions as the experimental conditions for obtaining the graph. The results of this experiment are shown in the graph of FIG. As a comparison target, the values of the samples not subjected to the treatment in the hydrogen atmosphere, that is, the values of the methanol reforming catalyst of the twenty-first embodiment and the methanol reforming catalyst of the twenty-second embodiment shown in FIG. 5 are shown as Fresh. FIG.
As can be seen from the graph, the methanol reforming catalyst of the twenty- _second embodiment using zirconium dioxide (ZrO ₂ ) as the metal oxide is more durable than the methanol reforming catalyst of the twenty-first embodiment using cerium dioxide (CeO ₂ ). It turns out that performance is high.

The methanol reforming catalysts of the above-mentioned twenty-first to twenty-fifth embodiments are each composed of a noble metal and a 2B group or a 3B group.
The first to fifth embodiments which carry an element belonging to an alkali metal or an alkaline earth metal in addition to the element belonging to the group B
The carrier corresponding to the methanol reforming catalyst of the embodiment, or a carrier obtained by adding an element belonging to any of alkali metals, alkaline earth metals, and rare earths as a carrier additive to a noble metal,
It does not correspond to the methanol reforming catalysts of the sixth to fifteenth embodiments supporting elements belonging to Group B or Group 3B, but is similar from the viewpoint of comparing the types of metal oxides and their functions. Therefore, it is considered that the result of the experiment will give similar results.

In the methanol reforming catalysts of the first to fifteenth embodiments described above, the metal oxide is impregnated or impregnated with a nitrate of an element belonging to any of alkali metals, alkaline earth metals and rare earths or a solution thereof. Although added, the chemical form of the element belonging to any of the alkali metals, alkaline earth metals and rare earths is not limited to nitrate, but may be any chemical form. That is, when impregnating, a salt that is soluble in a solvent such as water may be used, and when adding, a salt that is soluble in a slurry of a metal oxide may be used.

Further, an alkali metal, an alkaline earth metal,
The solvent in the solution of the element belonging to any of the rare earth elements, the noble metal, the element belonging to the group 2B or the group 3B and the solvent for preparing the slurry of the metal oxide may be any solvent capable of dissolving the respective metal or element. A solvent may be used. The solvent is preferably neutral in view of the reaction to the dissolved metals and elements, and the prepared metal oxide. Considering that no residue remains when fired, the solvent volatilizes by firing ( For example, water is preferred.

The methanol reforming catalyst of each embodiment described above was used as a methanol reforming catalyst for reforming methanol as a hydrocarbon fuel into a hydrogen-containing gas containing hydrogen using water. Hydrogen fuels other than the above, such as saturated hydrocarbons such as methane and ethane, unsaturated hydrocarbons such as ethylene and propylene, and other alcohols such as ethanol, are used to generate hydrogen using a shrine. It can be used as a catalyst for reforming into a contained hydrogen-containing gas.

The embodiments of the present invention have been described with reference to the embodiments. However, the present invention is not limited to these embodiments, and various embodiments may be made without departing from the scope of the present invention. Of course, it can be carried out.

[Brief description of the drawings]

FIG. 1 is a production process diagram illustrating the production of a catalyst comprising a noble metal, a group 2B or 3B element, and an alkali metal or alkaline earth metal element.

FIG. 2 shows that a carrier formed of a metal oxide to which an element belonging to an alkali metal, an alkaline earth metal, or a rare earth is added as a carrier additive carries a noble metal and an element belonging to Group 2B or 3B. FIG. 4 is a manufacturing process diagram illustrating a state of manufacturing a catalyst.

FIG. 3 shows a carrier formed of a metal oxide to which an element belonging to an alkali metal, an alkaline earth metal, or a rare earth is added as a carrier additive, on which a noble metal and an element belonging to Group 2B or 3B are supported. 4 is a graph illustrating an experimental result of a catalyst.

FIG. 4 is a graph illustrating the experimental results of the relationship between the added amount and the methanol reforming rate when calcium and lanthanum are used as carrier additives.

FIG. 5 is a graph illustrating an experimental result of a relationship between a type of a metal oxide and a methanol reforming rate.

FIG. 6 shows cerium dioxide (Ce) as a metal oxide.
4 is a graph illustrating the results of a durability performance test using O ₂ ) and zirconium dioxide (ZrO ₂ ).

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Claims (19)

[Claims] 1. A metal oxide, a noble metal, at least one of elements belonging to Group 2B or 3B, and at least one of elements belonging to any of alkali metals, alkaline earth metals and rare earths. A catalyst contained as a component. 2. A carrier comprising a metal oxide as a main component, a precious metal, at least one of elements belonging to Group 2B or 3B, and at least one of elements belonging to alkali metal or alkaline earth metal. Catalyst. 3. A carrier comprising a metal oxide containing at least one of the elements belonging to any of an alkali metal, an alkaline earth metal and a rare earth, and then the precious metal and a 2B or 3B group are added to the carrier. A catalyst comprising at least one of the elements belonging to the following. 4. After supporting at least one of the elements belonging to alkali metals or alkaline earth metals on a carrier made of a metal oxide, the carrier comprises a noble metal and one of the elements belonging to Group 2B or 3B. A catalyst comprising at least one supported thereon. 5. The catalyst according to claim 2, wherein the element belonging to the alkali metal or alkaline earth metal is at least one of potassium, magnesium, and calcium. 6. A carrier formed of a metal oxide to which at least one of elements belonging to any of an alkali metal, an alkaline earth metal and a rare earth is added as a carrier additive, a noble metal and a 2B or A catalyst supporting at least one of the elements belonging to Group 3B. 7. The catalyst according to claim 6, wherein the carrier additive is calcium or lanthanum. 8. The catalyst according to claim 6, wherein the carrier is a porous metal oxide to which 3 to 15 mol% of calcium is added as the carrier additive. 9. The catalyst according to claim 6, wherein the carrier is a porous metal oxide to which 3 to 6 mol% of lanthanum is added as the carrier additive. 10. The catalyst according to claim 1, wherein the element belonging to Group 2B or 3B is at least one of zinc, gallium, and indium. 11. The catalyst according to claim 1, wherein the noble metal is one of platinum and palladium. 12. The catalyst according to claim 1, wherein the metal oxide is a basic metal oxide. 13. The method according to claim 1, wherein the metal oxide is one of cerium dioxide (CeO ₂ ), zirconium dioxide (ZrO ₂ ), and titanium dioxide (TiO ₂ ).
The catalyst according to any one of claims 1 to 7. 14. The catalyst according to claim 1, wherein the metal oxide is zirconium dioxide (ZrO ₂ ), the noble metal is platinum, and the metal oxide belongs to the 2B group or 3B group. The element is a catalyst that is indium. 15. The monolithic carrier having a surface coated with the metal oxide or a metal oxide to which the carrier additive is added.
The catalyst according to any one of the above. 16. The catalyst according to claim 1, wherein the catalyst is a reforming catalyst for reforming a hydrocarbon-based fuel into a hydrogen-containing gas containing hydrogen using water. 17. The catalyst according to claim 16, wherein the hydrocarbon-based fuel is methanol. 18. A method for producing a catalyst, comprising: a carrier comprising a metal oxide containing at least one element selected from the group consisting of alkali metals, alkaline earth metals, and rare earths; A support step of supporting the noble metal and at least one of the elements belonging to Group 2B or 3B on the carrier containing at least one of the elements belonging to any of metals, alkaline earth metals and rare earths. Method for producing catalyst. 19. A method for producing a catalyst, comprising: a first supporting step of supporting at least one element belonging to an alkali metal or an alkaline earth metal on a support made of a metal oxide; The carrier supporting at least one of the elements belonging to the metal,
A second supporting step of supporting at least one of elements belonging to Group B or Group 3B.