JP2012115769A - Catalyst, and method of producing catalyst - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve catalytic activity and thermal stability of an alumina-supported Cu catalyst containing CuO and CuAlO.SOLUTION: A catalyst includes AlOand at least one metal component selected from Zr, Ti, Hf and Rf as a carrier. Firing is carried out at a first firing temperature to produce a first intermediate, and it is fired at a second firing temperature to produce the catalyst. CuO and CuAlOare supported on the carrier.

Description

The present invention relates to a catalyst containing CuO and CuAl ₂ O ₄ and a method for producing the same.

The copper zinc oxide catalyst (Cu / Zn-based oxide catalyst) shows high activity and excellent selectivity in the water gas shift reaction (CO + H ₂ O → CO ₂ + H ₂ ), compared with a catalyst using a noble metal as an active species. And it is widely used as a catalyst for water gas shift reaction. However, Cu / Zn-based oxide catalysts have problems in that they are low in oxidation resistance and sintering resistance and easily deteriorate, and development of catalysts for noble metal-less highly durable water gas shift reactions is being promoted. .

As described in Patent Document 1, Patent Document 2, and Non-Patent Document 1, for example, an alumina-supported Cu catalyst has been developed as a catalyst having copper oxide or the like as an active species in the same manner as the Cu / Zn-based oxide catalyst. Has been. The alumina-supported Cu catalyst is a catalyst in which CuO (copper (II) oxide) and CuAl ₂ O ₄ (copper aluminate) having a spinel crystal structure are supported using alumina as a carrier. For example, as described in Non-Patent Document 1, the alumina-supported Cu catalyst is produced by impregnating γ-alumina with Cu nitrate or the like and calcining at a high temperature of about 700 ° C. or higher.

However, the catalytic activity of the conventional alumina-supported Cu catalyst is not sufficiently high as compared with the conventional Cu / Zn-based oxide catalyst (for example, MDC7 manufactured by Zude Chemie). Has been done. For example, Patent Document 1 describes that a salt or oxide of Ce, Ba, Mn, Co, Zn, Ni, alkali metal and alkaline earth metal is further added to the catalyst in order to improve the catalytic activity. Patent Document 2 describes that Ti and Zn are further added to the catalyst.

Special Table 2000-507155 JP 2007-69105 A

Catalysis Communications 7, 228-231 (2006)

As a result of intensive studies, the inventors have made alumina containing CuO and CuAl ₂ O ₄ by making an oxide of a metal other than Al coexist in alumina used as a support in the production process of an alumina-supported Cu catalyst. It has been found that the catalytic activity and thermal stability of the supported Cu catalyst are improved.

The present invention includes a catalyst containing Al ₂ O ₃ and at least one metal component selected from Zr, Ti, Hf, and Rf as a support, and CuO and CuAl ₂ O ₄ supported on the support. provide.

The metal component may be Zr. The CuAl ₂ O ₄ preferably has a spinel crystal structure. The above-mentioned catalyst, in X-ray diffraction pattern by Cu-K [alpha line, a plurality of diffraction peaks attributed to CuO and CuAl ₂ O _4, and preferably has no diffraction peak attributable to α- alumina.

The method for producing a catalyst provided by the present invention includes calcining a mixture of an aluminum compound and a compound containing at least one metal component selected from Zr, Ti, Hf, and Rf at a first calcining temperature, A first step for producing an intermediate and a mixture of the first intermediate and the copper compound obtained in the first step are fired at a second firing temperature to produce a catalyst containing CuO and CuAl ₂ O _4. A first firing temperature is lower than the second firing temperature.

  In the above catalyst production method, the second calcination temperature is preferably 700 ° C. or higher and 1200 ° C. or lower. Moreover, it is preferable that a 1st baking temperature is 100 degreeC or more.

  ADVANTAGE OF THE INVENTION According to this invention, an alumina carrying | support Cu catalyst with high catalyst activity and thermal stability and its manufacturing method can be provided.

It is a figure which shows the measurement result of the X-ray diffraction which concerns on an Example and a comparative example. It is a figure which shows the measurement result of the X-ray diffraction which concerns on an Example and a comparative example. It is a figure which shows the result of the water gas shift reaction of the catalyst which concerns on Example 1, and has shown the result in case it is XW (Cu) = 20 wt%. It is a figure which shows the result of the water gas shift reaction of the catalyst which concerns on Example 2. FIG. It is a figure which shows the result of the water gas shift reaction of the catalyst which concerns on a comparative example. It is a figure which shows the result of the water gas shift reaction of the catalyst which concerns on an Example and a comparative example, and is comparing and showing the result in case the 2nd calcination temperature is 800 degreeC and it is XW (Cu) = 20 wt%. . It is a figure which shows the result of the water gas shift reaction of the catalyst which concerns on Example 1, and has shown the result in case it is XW (Cu) = 5 wt%. It is a figure which shows the result of the water gas shift reaction of the catalyst which concerns on Example 1, and has shown the result in case it is XW (Cu) = 10 wt%. It is a figure which shows the result of the water gas shift reaction of the catalyst which concerns on Example 1, and has shown the result in case it is XW (Cu) = 15 wt%. It is a figure which shows the result of the water gas shift reaction of the catalyst which concerns on Example 1, and has shown the result in case it is XW (Cu) = 20 wt%. It is a figure which shows the result of the water gas shift reaction of the catalyst which concerns on Example 1, and is comparing and showing the result in case 2nd baking temperature is 750 degreeC and it is XW (Cu) = 5-20 wt%. . It is a figure which shows the result of the water gas shift reaction of the catalyst which concerns on Example 1, and is comparing and showing the result in case the 2nd baking temperature is 800 degreeC and it is XW (Cu) = 5-20 wt%. .

(Alumina-supported Cu catalyst)
The catalyst disclosed in this specification includes Al ₂ O ₃ and at least one metal component selected from Zr (zirconium), Ti (titanium), Hf (hafnium), and Rf (razahodium) as a support. , An alumina-supported Cu catalyst in which CuO and CuAl ₂ O ₄ are supported on the carrier. More specifically, the metal component is one or more metal oxides of ZrO ₂ , TiO ₂ , HfO ₂ , RfO ₂ , or one or two of Zr, Ti, Hf, Rf. The composite oxide of the above and Al is preferably contained in the catalyst. Zr, Ti, Hf, and Rf are common in that all are metal elements belonging to Group 4 of the periodic table, but Zr and Ti can be suitably used from the viewpoint of cost and the like, and ZrO can be used in the catalyst. _2, it is preferably contained as TiO _2. Further, CuAl ₂ O ₄ in said catalyst preferably has a spinel crystal structure, Al ₂ O ₃ is is preferably contained in the above-mentioned catalyst mainly as γ- alumina. The catalyst preferably has a diffraction peak attributed to CuO and CuAl ₂ O ₄ and does not have a diffraction peak attributed to α-alumina in an X-ray diffraction pattern by Cu-Kα rays.

The above-mentioned alumina-supported Cu catalyst further includes at least one metal component selected from Zr, Ti, Hf, and Rf as a support in addition to Al ₂ O ₃ , so that CuO supported on the support can be obtained. And the catalytic activity obtained by CuAl ₂ O ₄ can be improved, and the thermal stability of the catalyst can be improved.

Alumina-supported Cu catalyst containing CuO and CuAl ₂ O _4, by the CuO and CuAl ₂ O ₄ coexist, it is possible to obtain a high catalytic activity. More specifically, it has been reported that CuAl ₂ O ₄ is produced to form fine particles of CuO, thereby improving the catalytic activity (Non-patent Document 1). CuAl ₂ O ₄ can be produced by performing a treatment such as baking the catalyst precursor at a high temperature and reacting a part of CuO with Al ₂ O ₃ . On the other hand, in order to obtain catalytic activity, CuO needs to remain in the catalyst. Therefore, it is necessary to suppress the reaction that generates CuAl ₂ O ₄ to some extent. In addition, when calcination is performed at a high temperature, the carrier Al ₂ O ₃ undergoes a phase transition from γ-alumina to α-alumina, which also reduces the catalytic activity.

In the alumina-supported Cu catalyst disclosed in the present specification, in addition to Al ₂ O ₃ , at least any one metal component selected from Zr, Ti, Hf, and Rf is further included as a support. In the case of firing at a lower temperature, the reaction of generating CuAl ₂ O ₄ is suppressed and the coexistence state of CuO and CuAl ₂ O ₄ is maintained, and Al ₂ O ₃ contained as a carrier is γ− Phase transition from alumina to α-alumina is suppressed. As a result, the catalyst activity can be improved and the thermal stability of the catalyst can be improved.

Since the above-mentioned alumina-supported Cu catalyst disclosed in the present specification improves the catalytic activity and thermal stability derived from Cu obtained by the conventional alumina-supported Cu catalyst, the conventional alumina-supported Cu catalyst has a catalytic activity. (For example, water gas shift reaction, methanol synthesis reaction (main reaction formula: CO + 2H ₂ → CH ₃ OH and CO ₂ + 3H ₂ → CH ₃ OH + H ₂ O), hydrogen generation reaction from methanol, NOx removal reaction) It can be used suitably.

The method for producing a catalyst disclosed in this specification includes calcining a mixture of an aluminum compound and a compound containing at least one metal component selected from Zr, Ti, Hf, and Rf at a first calcining temperature, A first step for producing one intermediate and a mixture of the first intermediate and the copper compound obtained in the first step are fired at a second firing temperature to produce a catalyst containing CuO and CuAl ₂ O ₄ The first firing temperature is lower than the second firing temperature.

According to this catalyst manufacturing method, Al ₂ O ₃ and at least one metal component selected from Zr, Ti, Hf, and Rf are included as a support, and CuO and CuAl ₂ O ₄ are supported on the support. Alumina-supported Cu catalyst can be produced.

  In the first step, a first intermediate containing Al and at least one metal component selected from Zr, Ti, Hf, and Rf is manufactured. As the aluminum compound used in the first step, aluminum nitrate, sulfate, chloride, aluminate and the like can be suitably used, and nitrate is more preferable. As the compound containing the metal component, nitrates, sulfates, chlorides, and the like of at least one metal component selected from Zr, Ti, Hf, and Rf can be suitably used. preferable.

  In the first step, the aluminum compound and the compound containing the metal component may be mixed by, for example, either dry or wet methods. The mixing method can be appropriately selected depending on the aluminum compound to be used and the compound containing the metal component. It is preferable to mix the aluminum compound and the compound containing the metal component in a wet manner, and it is more preferable to use a coprecipitation method from the viewpoint of producing a more homogeneous first intermediate.

  When the mixing ratio XA (M) of the compound containing the metal component is expressed by the following formula (1) using the number A (M) of metal component atoms and the number A (Al) of aluminum atoms, The ratio XA (M) is preferably 0 <XA (M) ≦ 10%, and more preferably 1% ≦ XA (M) ≦ 5%.

  XA (M) [%] = A (M) × 100 / (A (M) + A (Al)) (1)

  The firing performed in the first step is preferably performed in an oxidizing atmosphere (for example, in an air atmosphere), whereby at least one selected from Al oxide, Zr, Ti, Hf, and Rf. A first intermediate containing an oxide of a metal component or a composite oxide thereof can be produced.

In the second step, the mixture of the first intermediate and the copper compound obtained in the first step is fired at a second firing temperature to produce a catalyst containing CuO and CuAl ₂ O ₄ .

  The copper mixing ratio XW (Cu) is expressed by the following formula (2) using W (Cat) as the weight of the catalyst obtained after the second step and W (Cu) as the weight of the copper contained in the catalyst. When expressed, the mixing ratio XW (Cu) is preferably 1 wt% ≦ XW (Cu) ≦ 30 wt%, and more preferably 5 wt% ≦ XW (Cu) ≦ 20 wt%.

XW (Cu) [wt%] = W (Cu) × 100 / W (Cat) (2)

Also in the second step, as in the first step, the firing is preferably performed in an oxidizing atmosphere, whereby CuO and CuAl ₂ O ₄ , oxides of Al as carriers, Zr, Ti, Hf, An alumina-supported Cu catalyst containing an oxide of at least one metal component selected from Rf or a composite oxide thereof can be produced.

  In the above catalyst production method, the second calcination temperature is preferably 700 ° C. or higher and 1200 ° C. or lower, and particularly preferably 700 ° C. or higher and 900 ° C. or lower. What is necessary is just to set 1st baking temperature to temperature lower than 2nd baking temperature, and it is preferable to set in the range of 100 degreeC or more. For example, when the second baking temperature is 700 ° C., it is preferably set in a range of 100 ° C. or more and less than 700 ° C.

In the examples, the case where the metal component M contained as a support is zirconium (Zr) will be described as an example.
(material)
In the first step and the second step, the following reagents were used as raw materials. Moreover, the ultrapure water refine | purified with the Milli-Q water manufacturing apparatus (made by Nippon Millipore Corporation) was used as a solvent.
_{Al (NO 3) 3 · 9H} 2 O: special grade, Kanto Chemical Co. _{ZrO (NO 3) 2 · 2H} 2 O: special grade, Kanto Chemical Co. _{Cu (NO 3) 2 · 3H} 2 O: special grade, Kanto Ammonia water manufactured by Chemical Co., Ltd.

(Manufacture of Cu / AZr1 catalyst)
(First step)
Example 1 describes an alumina-supported Cu catalyst (hereinafter referred to as a Cu / AZr1 catalyst in the present specification and the like) in which XA (M) = 1%. Example 1 illustrates and describes a method for producing 8.0 g of the first intermediate under the condition of XA (M) = 1%.

Weigh 58.614 g of Al (NO ₃ ) ₃ .9H ₂ O as an aluminum compound, weigh 0.418 g of ZrO (NO ₃ ) ₂ .2H ₂ O as a compound containing a metal component, and place it in a 500 ml beaker. Ultrapure water was added as a solvent, and the total weight of the aqueous solution was adjusted to 300 g. While this aqueous solution was vigorously stirred with a stir bar, aqueous ammonia was added dropwise to adjust pH = 8.5. In addition, when dropping the ammonia water, the above ammonia water is dropped as a reagent until the pH reaches about 8, and thereafter, the above ammonia water is diluted 5 times for fine adjustment. Was dripped. After the obtained gel was allowed to stand for 2 hours, centrifugation and washing were repeated until the pH of the supernatant became 7 or less. After removing water, it was dried at 150 ° C. overnight (about 12 hours), and the obtained solid (mixture of AlOOH and Zr (OH) ₄ ) was pulverized in an alumina mortar for about 10 minutes. The pulverized solid was put in a firing furnace, heated to the first firing temperature at a temperature rising rate of 5 ° C./min, and fired at the first firing temperature for 3 hours. The first firing temperature was 500 ° C. As a result, a first intermediate (a mixture of γ-Al ₂ O ₃ and ZrO ₂ ) was obtained. A box furnace was used as the firing furnace, and firing was performed in an air atmosphere.

(Second step)
Using Cu (NO ₃ ) ₂ .3H ₂ O as the copper compound, 0.40 g, 0.84 g, 1.34 g, and 1.50 g, respectively, so that XW (Cu) = 5, 10, 15, and 20 wt%. 90 g was weighed and placed in a 100 ml beaker, and ultrapure water was added to make 60 ml, and four types of Cu-containing aqueous solutions were prepared. The first intermediate was dried at 150 ° C. for 1 hour, weighed 2.0 g, and added to each Cu-containing aqueous solution. The Cu-containing aqueous solution was stirred at room temperature for 30 minutes using a stirrer and then heated to evaporate to dryness to obtain a solid. The obtained solid was further dried overnight at 150 ° C., and then ground and mixed for about 10 minutes using an agate mortar. The pulverized and mixed solid matter was put into a firing furnace, heated to the second firing temperature at a heating rate of 5 ° C./min, and fired at the second firing temperature for 8 hours. A box furnace was used as the firing furnace, and firing was performed in an air atmosphere. The second firing temperature was set to 700, 750, 800, 850, and 900 ° C. Thus, Catalyst 1 to Catalyst 14 which are Cu / AZr1 catalysts were produced.

(First step)
In Example 2, an alumina-supported Cu catalyst having XA (M) = 5% (hereinafter referred to as a Cu / AZr5 catalyst in this specification and the like) will be described. In Example 2, referring to Example 1, Al (NO ₃ ) ₃ · 9H ₂ O and ZrO (NO ₃ ) ₂ · 2H ₂ when XA (M) = 5% based on the above formula (1) The weight of O was calculated, 53.271 g of Al (NO ₃ ) ₃ .9H ₂ O and 1.977 g of ZrO (NO ₃ ) ₂ .2H ₂ O were weighed and placed in a 500 ml beaker. Subsequent steps were performed in the same manner as in Example 1. This produced a first intermediate.

(Second step)
A Cu-containing aqueous solution was prepared under the condition of XW (Cu) = 20 wt%, and the second step was performed in the same manner as in Example 1. The second firing temperature was 700, 800, and 900 ° C., respectively. Thus, Catalyst 15 to Catalyst 17 which are Cu / AZr5 catalysts were produced.

(Comparative example)
As a comparative example, a conventional alumina-supported Cu catalyst (hereinafter referred to as a Cu / Al 2 O 3 catalyst in the present specification and the like) in which a carrier does not contain a group 4 element such as Zr was manufactured. In the comparative _{example, Al (NO 3) 3 ·} 9H 2 O only to 60.045g weighed as starting materials in the first step, was placed in a 500ml beaker. Subsequent steps were performed in the same manner as in Example 1. Thus, a carrier of γ-alumina was produced. Using γ-alumina produced in the first step as a carrier, γ-alumina is immersed in a Cu (NO ₃ ) ₂ .3H ₂ O aqueous solution in the same manner as in the second step in Example 1, and impregnated with a copper compound. After supporting, a treatment such as firing was performed. The Cu-containing aqueous solution was prepared under the condition of XW (Cu) = 20 wt%, and the second firing temperature was 700, 800, and 900 ° C., respectively. As a result, Catalysts 18 to 20 which are Cu / Al2O3 catalysts were produced.

(Reference example)
As a reference example, MDC7 (composition ratio: CuO = 43 wt%, ZnO = 47 wt%, alumina = 10 wt%), which is a Cu / Zn-based oxide catalyst manufactured by Zude Chemie, was used as the catalyst 21. MDC7 is a commercially available catalyst and is widely used in comparing the catalytic activity of the water gas shift reaction.

(XRD analysis)
Of the alumina-supported Cu catalysts obtained in Examples 1 and 2 and the comparative example, the catalyst produced under the conditions of XW (Cu) = 20 wt% and the second calcination temperature = 800,900 ° C. (catalysts 13, 14, 16, 17, 19, 20) were analyzed by XRD (X-ray diffraction) using Cu-Kα rays. The results are shown in FIG. 1 and FIG. FIG. 1 illustrates the catalysts 13, 16, and 19 having a second calcination temperature of 800 ° C., and FIG. 2 illustrates the catalysts 14, 17, and 20 having a second calcination temperature of 900 ° C., respectively. Table 1 below shows the peak position 2θ and the peak intensity ratio I of each crystal.

As shown in FIGS. 1 and 2, CuO and spinel crystals were observed in the X-ray diffraction patterns of the catalysts of Examples 1 and 2 (Catalysts 13, 14, 16, and 17) and Comparative Examples (Catalysts 19 and 20). A diffraction peak attributed to the structure CuAl ₂ O ₄ was observed. In Examples 1 and 2 (catalysts 13, 14, 16, and 17), the peak of CuAl ₂ O ₄ was smaller than in the comparative examples (catalysts 19 and 20). This is presumably because the reaction in which CuAl ₂ O ₄ was generated was suppressed by including Zr in the support. Further, when calcined at a high temperature of 900 ° C., in the comparative example (catalyst 20), α-alumina peaks (remarkably, peaks at 2θ = 25.57, 35.14, 43.34) were observed. However, in Examples 1 and 2 (catalysts 14 and 17), no α-alumina peak was observed. This is accomplished by including Zr to the carrier, it is contemplated that because is suppressed Al ₂ O ₃ wherein the carrier is a phase transition to the α- alumina from γ- alumina. When the second calcination temperature was 800 ° C., no α-alumina peak was observed in any of the catalysts (catalysts 13, 16, 19).

(Water gas shift reaction)
Using a fixed bed flow type reaction tube, a water gas shift reaction was performed, and the catalytic activities of Catalysts 1 to 21 according to Examples 1 and 2, Comparative Example, and Reference Example were evaluated. The amount of the catalyst was 0.10 g, the catalyst layer temperature was 150 to 400 ° C., and a balance gas having the following composition was passed through a water bubbling tank and then supplied to the catalyst layer of the reaction tube. The water bubbling tank was heated to 46 ° C. by a ribbon heater, and when the following balance gas was supplied to the bubbling tank at 100 ml / min, a reaction gas having the following composition was obtained. This reaction gas was supplied to the catalyst layer at a flow rate of 111 ml / min.

<Balance gas composition>
CO: 1 mol%
N ₂ : 99 mol%
<Reaction gas composition>
CO: 1 mol%
H ₂ O: 10 mol%
N ₂ : 89 mol%

The product gas was dried by passing through a silica gel layer, and then analyzed by micro-GC 3000A manufactured by Agilent. The column was detected by TCD using MS5A and Porapak-Q. The reaction gas was similarly analyzed by gas chromatography, and the hydrogen production rate was calculated from the obtained CO concentration and H ₂ concentration. Hydrogen production rate _{(H 2} yield) was calculated by the following equation (3). It was also confirmed by gas chromatography that CH ₄ was not contained in the product gas.

H ₂ yield [%] = (H ₂ concentration in product gas) × 100 / (CO concentration in reaction gas) (3)

The results of the water gas shift reaction are shown in Tables 2 to 5 and FIGS. 3 to 12, “H ₂ Yield” on the vertical axis represents the H ₂ yield (%), and the horizontal axis represents the catalyst layer temperature of the water gas shift reaction.

3 to 5 show Cu / AZr1 catalyst (catalysts 11, 13, and 14), Cu / AZr5 catalyst (catalysts 15 to 17), Cu / Al2O3 produced under the conditions of the second firing temperature = 700, 800, and 900 ° C. It is a figure which shows the result of the water gas shift reaction of a catalyst (catalysts 18-20) with the result of the catalyst 21 which is a reference example. FIG. 6 shows a comparison of the results when XW (Cu) = 20 wt% under the condition that the second baking temperature is 800 ° C. As shown in FIGS. 3 to 6, at any reaction temperature of the water gas shift reaction, the catalysts 11, 13, 14 and the catalysts 15 to 17 have a higher catalytic activity than the catalysts 18 to 20, and particularly the highest activity. As shown in FIG. 6 in which the catalytic activity at the second calcination temperature of 800 ° C. is compared, the catalytic activity was particularly improved in the catalyst 13 which is a Cu / AZr1 catalyst. Moreover, when the 2nd calcination temperature was 900 degreeC, the catalyst 11,13,14 and the catalyst 15-17 showed the catalyst activity remarkably high compared with the catalyst 18-20.

7-12 is a figure which shows the result of the water gas shift reaction of a Cu / AZr1 catalyst with the result of the catalyst 21 which is a reference example. FIGS. 7 to 10 show the results when XW (Cu) = 5 to 20 wt%, respectively. FIGS. 11 and 12 show XW (Cu) under the conditions where the second firing temperature is 750 and 800 ° C., respectively. ) = 5 to 20 wt%, the results are shown in comparison.

  As shown in FIGS. 7 to 12, at any reaction temperature of the water gas shift reaction, the catalyst 5 according to Example 1 exhibited catalytic activity equivalent to or higher than that of the catalyst 21 (MDC7). When the reaction temperature is in the range of 300 ° C. or higher, the catalyst (catalyst 5, 6, 8-10, 12 and 13) showed catalytic activity comparable to that of the catalyst 21. When the Cu loading XW (Cu) is 15 wt%, any catalyst (catalysts 8 to 10) having a second firing temperature of 750 ° C. to 850 ° C. has a catalytic activity equal to or higher than that of the catalyst 21. Indicated.

  As described above, according to the examples of the present invention, the catalytic activity and thermal stability of the alumina-supported Cu catalyst can be improved, and the catalytic activity equal to or higher than that of MDC7, which is a Cu / Zn-based oxide catalyst. It has been found that it is possible to provide an alumina-supported Cu catalyst having the same. The MDC 7 used as a reference example contains 43 wt% of CuO, which is about 34 wt% when converted to the weight ratio of Cu. However, the alumina-supported Cu catalyst (Cu) further containing Zr according to this embodiment as a support. / AZr1 catalyst) has a Cu loading of 5 to 20 wt%. According to this example, a high catalytic activity equivalent to or higher than that of MDC7 can be obtained with a smaller amount of Cu supported than MDC7. According to this embodiment, it is possible to provide a highly active and highly durable copper-based catalyst that can be suitably used for water gas shift reaction, methanol synthesis reaction, hydrogen generation reaction from methanol, NOx removal reaction, and the like. .

  As mentioned above, although the Example of this invention was described in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

  The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

Claims (7)

A catalyst comprising Al ₂ O ₃ and at least one metal component selected from Zr, Ti, Hf, and Rf as a support, and CuO and CuAl ₂ O ₄ supported on the support.   The catalyst according to claim 1, wherein the metal component is Zr. The catalyst according to claim 1, wherein the CuAl ₂ O ₄ has a spinel crystal structure. The X-ray diffraction pattern by Cu-Kα rays has a diffraction peak attributed to CuO and CuAl ₂ O ₄ and does not have a diffraction peak attributed to α-alumina. The catalyst according to 1. A first step of producing a first intermediate by firing a mixture of an aluminum compound and a compound containing at least one metal component selected from Zr, Ti, Hf, and Rf at a first firing temperature;
And a second step of producing a catalyst containing CuO and CuAl ₂ O ₄ by firing the mixture of the first intermediate and the copper compound obtained in the first step at a second firing temperature,
The method for producing a catalyst, wherein the first firing temperature is lower than the second firing temperature.   The catalyst production method according to claim 5, wherein the second calcination temperature is 700 ° C or higher and 1200 ° C or lower.   The catalyst production method according to claim 5 or 6, wherein the first calcination temperature is 100 ° C or higher.

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