JP6308834B2 - Catalyst for producing hydrogen and method for producing hydrogen using the catalyst - Google Patents

Description

  The present invention relates to a honeycomb-shaped non-noble metal catalyst for producing hydrogen by decomposing ammonia and a method for producing hydrogen using the catalyst.

  A number of ammonia catalysts using noble metals have been proposed as techniques for decomposing ammonia to produce hydrogen. For example, as a catalyst for decomposing ammonia generated from a coke oven to obtain hydrogen, a catalyst in which a nickel-lanthanum-platinum group element is supported on a carrier has been proposed (Patent Document 1). Further, an ammonia decomposition catalyst (Patent Document 2) in which a honeycomb ceramic molded body mainly composed of cordierite, mullite or silicon carbide is coated with a catalyst component containing a transition metal element, a composite oxide of cerium oxide and zirconium oxide An ammonia oxidation / decomposition catalyst in which at least one metal selected from the group consisting of Group 6A, Group 7, Group 8, Group 1B is supported on a catalyst carrier comprising: There has been proposed an ammonia decomposition catalyst (Patent Document 4) in which ruthenium and a promoter are supported on a carrier in which a powder is formed into a spherical shape, a cylindrical shape, or a honeycomb shape. On the other hand, non-noble metal-based ammonia decomposition catalysts have also been proposed from the viewpoint of rare resource replacement. For example, an ammonia decomposition catalyst containing a high proportion of cobalt (Patent Document 5), an ammonia decomposition catalyst having nickel supported on zeolite or silica alumina (Patent Document 6), and the like have been proposed.

JP 05-329372 A JP2012-005926A JP 2012-101157 A JP 2011-78888 A JP2011-224554A JP 2010-284640 A

  As a reaction method for decomposing ammonia to produce hydrogen, direct decomposition reaction method for producing hydrogen by circulating ammonia directly into an ammonia decomposition catalyst reactor and heating the reactor, ammonia and oxygen-containing gas as raw material gas There is an auto-thermal reforming method in which ammonia decomposition reaction is advanced using ammonia combustion heat. In particular, the autothermal reforming method enables a simple reactor design that does not require an external heat source, and has the advantage that the reaction efficiency can be maintained high even in the case of a high linear velocity reaction.

  When performing ammonia decomposition reaction by the autothermal reforming method using a conventional ammonia decomposition catalyst, the present inventors are very dangerous if the supply of ammonia is interrupted due to abnormal operation or the like and only air is supplied. I found that there was a new problem that could be in a state. That is, the catalyst in the reaction is in a state reduced by hydrogen generated by ammonia decomposition, but when the supply of ammonia is stopped due to an operation abnormality or the like and only air is supplied, the catalyst that has been reduced until then is It will be oxidized. It is recognized that not only the catalyst itself is damaged by the heat of oxidation, but the catalyst itself is damaged, and in some cases, the runaway reaction may cause the honeycomb carrier to melt. did.

  Thus, the object of the present invention is to exhibit high decomposition performance in the ammonia decomposition reaction by the autothermal reforming method, and to suppress the heat of oxidation generated even in an oxidative atmosphere state, to the catalyst itself. It is to provide a catalyst form for suppressing damage and runaway reaction.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found the following configuration and have reached the present invention.

  A first invention is a catalyst for producing hydrogen by decomposing ammonia formed by supporting a catalyst component on a honeycomb formed body, the catalyst component containing a catalytically active component and a heat-resistant oxide, The catalyst is characterized in that the catalytically active component is at least one element selected from iron, cobalt and nickel, and the supported amount of the catalytically active component is 20 to 80 g per liter of honeycomb formed body. . The shape of the catalyst is not preferable for pellets, particles, or powdered catalysts because the pressure loss of the reactor filled with the catalyst increases when the reaction conditions become high, and a honeycomb catalyst is suitable. .

Further, the oxygen consumption rate of the catalyst component after reduction under air circulation is preferably 1.0 × 10 ^{−7 to} 1.0 × 10 ⁻⁵ mol per gram of catalyst component at 100 ° C./second. .

  In addition to the heat-resistant oxide contained in the catalyst component in the honeycomb molded body, 10 to 100 g of the heat-resistant oxide per liter of the honeycomb molded body may be loaded, and then the catalyst component may be loaded. preferable. The heat-resistant oxide is preferably at least one oxide selected from alumina, silica, zirconia and ceria.

  A second invention is a method for producing hydrogen, wherein ammonia is decomposed to produce hydrogen using the catalyst.

  According to the present invention, due to the solution of the above problem, in the ammonia decomposition reaction by the autothermal reforming method, high decomposition performance is exhibited, and even if the supply of ammonia is interrupted due to abnormal operation or the like, By reducing the oxidation heat, damage to the catalyst itself or runaway reaction can be suppressed.

  Hereinafter, the hydrogen production catalyst and the hydrogen production method using the catalyst according to the present invention will be described in detail. However, the scope of the present invention is not limited to these explanations, and the present invention is not limited to the following examples. It can change suitably and implement in the range which does not impair the meaning.

  A catalyst for producing hydrogen according to the present invention is a catalyst in which a catalyst component is supported on a honeycomb formed body, the catalyst component contains a catalytic active component and a heat-resistant oxide, and the catalytic active component is iron, It is at least one element selected from cobalt and nickel, and the amount of the catalytically active component supported is 20 to 80 g per liter of honeycomb formed body, and is a catalyst for producing hydrogen by decomposing ammonia.

1. Catalyst The hydrogen production catalyst in the present invention contains a catalytically active component and a heat-resistant oxide as catalyst components, and the catalytically active component may be at least one element selected from iron, cobalt and nickel. That's fine. The supported amount of the catalytically active component may be 20 to 80 g per liter of the honeycomb formed body, preferably 25 to 70 g, more preferably 30 to 60 g, and further preferably 30 to 50 g. If the amount of the catalytically active component supported is less than 20 g per liter of honeycomb formed body, sufficient catalytic activity cannot be obtained, and if it exceeds 80 g, the oxidation heat when the catalyst is exposed to oxidizing conditions becomes too high. .

  On the other hand, as the heat-resistant oxide contained in the catalyst component, a porous oxide generally used for a catalyst carrier or the like can be used. Specifically, at least one oxide selected from alumina, silica, zirconia, ceria, titania, zeolite, silica-alumina, silica-titania, titania-zirconia, zirconia-ceria, and the like can be used. Among these, at least one oxide selected from alumina, silica, zirconia and ceria is preferable. The amount of these heat-resistant oxides in the catalyst component is preferably 5 to 80% by mass, more preferably 10 to 70% by mass. If the content of the heat-resistant oxide in the catalyst component is less than 5%, the catalyst activity is remarkably lowered due to aggregation of the catalyst active component, which is not preferable, and if it exceeds 80%, the catalyst active component in the catalyst component is relatively small. This is not preferable because sufficient catalytic activity cannot be obtained.

The oxygen consumption rate in the air circulation of the catalyst component after reduction is preferably 1.0 × 10 ^{−7 to} 1.0 × 10 ⁻⁵ mol per gram / second of the catalyst component at 100 ° C., more preferably. Is 2.5 × 10 ^{−7 to} 7.5 × 10 ⁻⁶ mol, more preferably 5.0 × 10 ^{−7 to} 5.0 × 10 ⁻⁶ mol. When the oxygen consumption rate of the catalyst component after the reduction under air flow is less than 1.0 × 10 ⁻⁷ mol per gram of catalyst component at 100 ° ^C./second , the catalytically active component is hardly reduced even in a high-temperature reducing atmosphere. In many cases, the catalyst is a catalyst, and such a difficult-to-reduced catalyst is not preferred because of its low ammonia decomposition activity. When the oxygen consumption rate in the air flow of the catalyst component after reduction is greater than 1.0 × 10 ⁻⁵ mol per gram of catalyst component at 100 ° C. per second, the activity against oxygen is too high and the honeycomb due to the heat of metal oxidation This is not preferable because overheating of the film is remarkably accelerated. Usually, the oxygen consumption rate in the air circulation of the reduced catalyst component can be measured by temperature-programmed oxidation measurement.

  The supported amount as the catalyst component is preferably 25 to 250 g per liter of the honeycomb formed body. If the amount of the catalyst component supported is less than 25 g per liter of the honeycomb formed body, the catalyst activity is low because it is not preferable. Absent.

  In addition, the catalyst in the present invention is preferably a catalyst in which a heat-resistant oxide is previously supported on a honeycomb formed body and then a catalyst component is supported. That is, a catalyst having a heat-resistant oxide layer between the honeycomb formed body and the catalyst component is preferable. The reason for this is that by having a heat-resistant oxide layer, uneven distribution of the catalyst component in the corners of the cells of the honeycomb formed body can be suppressed, and the contained catalyst active component can be used efficiently. It is thought that it is possible to reduce damage to the catalyst component by releasing the oxidation heat due to the oxidation reaction to the layer side, and to contribute to the suppression of oxidation heat runaway.

  The amount of the heat-resistant oxide previously supported on the honeycomb formed body may be 10 to 100 g, preferably 20 to 100 g, and more preferably 30 to 100 g per liter of the honeycomb formed body.

  As the heat-resistant oxide previously supported on the honeycomb formed body, a porous oxide similar to the heat-resistant oxide contained in the catalyst component can be used. Specifically, at least one oxide selected from alumina, silica, zirconia, ceria, titania, zeolite, silica-alumina, silica-titania, titania-zirconia, zirconia-ceria, and the like can be used. Among these, at least one oxide selected from alumina, silica, zirconia and ceria is preferable.

2. Honeycomb formed body The honeycomb formed body used in the present invention may be a honeycomb formed body having polygonal cells. For example, the cells are preferably triangular, quadrangular, or hexagonal, and these sides are preferably straight, but may be somewhat bent or deformed for the convenience of forming a honeycomb formed body. The number of cells of the honeycomb formed body is not particularly limited, but is 30 to 160, preferably 60 to 140, per 1 cm ² . The wall thickness is 25 to 130 μm, preferably 50 to 110 μm.

  The material of these honeycomb formed bodies is not particularly limited, and any of various ceramics and metals can be used. However, since ammonia is a substance having metal corrosiveness, a corrosion-resistant material is preferable. It is preferable to use ceramics such as cordierite and silicon carbide.

  The equivalent diameter of the honeycomb formed body is 1 to 15 cm, preferably 1 to 11 cm, and the length is 1 to 20 cm, preferably 1 to 15 cm.

3. Catalyst Production Method As a method for obtaining the above-described catalyst, a method generally used for preparing this type of catalyst can be used. For example, (1) a method of preparing a catalyst by immersing the honeycomb in a slurry obtained by wet pulverization of a catalyst component, removing excess slurry, drying and firing, and (2) wet pulverizing a heat-resistant oxide. (3) a heat-resistant oxide precursor, wherein the honeycomb is immersed in the resulting slurry, the excess slurry is removed, dried or fired, then immersed in an aqueous liquid of the catalytically active component, the excess liquid is removed and dried or fired. This is a method of preparing a catalyst by immersing the honeycomb in a sol-like material, or a liquid material containing an aqueous liquid of a catalytically active component, and removing excess liquid material, followed by drying and firing. The drying temperature is preferably 50 to 300 ° C and the firing temperature is preferably 300 to 700 ° C.

  When the catalyst component is supported on the honeycomb molded body by the above procedure, the amount of the catalyst component to be supported varies depending on the composition, viscosity, and solid component concentration (solid component concentration with respect to the liquid amount) of the slurry. It is preferable to confirm that the target loading amount is obtained. If the catalyst component is less than the target loading amount in a single operation, the target loading amount can be achieved by repeating the above preparation method a plurality of times.

  When the slurry viscosity is high, the slurry can be supported on the honeycomb molded body after being adjusted to a slurry suitable for supporting by adding a surfactant and adjusting the pH.

4). Hydrogen production method Ammonia decomposition reaction, which is an endothermic reaction by partially burning ammonia with oxygen in the raw material gas to produce hydrogen by decomposing ammonia by autothermal reforming method using the catalyst The hydrogen can be efficiently obtained by performing the heat of combustion. As source gas, ammonia and air, or oxygen-containing gas can be used.

The space velocity of the source gas is 1,000 to 100,000 h ⁻¹ , preferably 10,000 to 100,000 h ⁻¹ , and the reaction temperature is 400 to 1000 ° C., preferably 500 to 800 ° C. When air is used as the raw material gas, the flow rate ratio of air to ammonia (Air / NH ₃ ) in the raw material gas is 0.4 to 1.2, preferably 0.6 to 1.0. When an oxygen-containing gas is used as the source gas, the flow ratio of oxygen to ammonia in the source gas is 0.08 to 0.25, preferably 0.12 to 0.21.

[Example]
Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited to the following examples, and may be implemented with appropriate modifications within a range that can meet the gist of the present invention. These are all included in the technical scope of the present invention.

(Catalyst production example 1)
Weigh 128.1 g of cobalt nitrate hexahydrate, 13.6 g of cerium nitrate hexahydrate, 13.6 g of lanthanum nitrate hexahydrate, and 151.2 g of zirconium oxynitrate dihydrate and dissolve in 1 L of pure water. Then, a metal nitrate aqueous solution was prepared. 343.7 g of potassium hydroxide was dissolved in 2 L of pure water to prepare an aqueous potassium hydroxide solution. While stirring the potassium hydroxide aqueous solution, the metal nitrate aqueous solution was added dropwise. After completion of dropping, the obtained suspension was subjected to suction filtration, and washed with pure water 5 times to obtain a precipitate. The obtained precipitate was dried overnight at 120 ° C. and then calcined at 650 ° C. for 1 hour in an air atmosphere to obtain a catalyst component. After roughly pulverizing the catalyst component in an alumina mortar, 100 g of the catalyst component powder, 100 g of pure water, and 10 g of colloidal silica sol were mixed, and wet pulverized with a ball mill for 12 hours. A hexagonal cell cordierite honeycomb molded body (melting point: 1450 ° C., wall thickness: 76.2 μm) having 93 cells per 1 cm ² is coated with the catalyst component slurry by the wash coat method, and excess slurry is air blown. The step of blowing and drying at 120 ° C. was repeated 4 times. The obtained honeycomb catalyst after drying was fired at 500 ° C. for 1 hour to obtain a honeycomb catalyst coated with a catalyst component (Catalyst 1). The amount of the catalyst active component supported on the obtained catalyst 1 was 60 g per liter of the honeycomb formed body. Further, after reducing the catalyst component used in the catalyst 1, the oxygen consumption rate under air flow was measured and found to be 9.48 × 10 ⁻⁷ mol per gram / second of the catalyst component at 100 ° C.

(Catalyst production example 2)
In the coating by the wash coating method of Catalyst Production Example 1, the same operation as in Example 1 was performed except that the number of steps was changed to 2 to obtain a honeycomb catalyst coated with a catalyst component (Catalyst 2). The amount of the catalyst active component supported on the obtained catalyst 2 was 30 g per liter of the honeycomb formed body.

(Catalyst production example 3)
291.0 g of cobalt nitrate hexahydrate, 43.4 g of cerium nitrate hexahydrate, and 49.3 g of zirconia sol (containing 25% by mass in terms of ZrO ₂ ) were weighed and dissolved in 1 L (liter) of pure water. A nitrate aqueous solution was prepared. 147.6 g of potassium hydroxide was dissolved in 2 L of pure water to prepare an aqueous potassium hydroxide solution. While stirring the potassium hydroxide aqueous solution, the metal nitrate aqueous solution was added dropwise. After completion of dropping, the obtained suspension was subjected to suction filtration, and washed with pure water 5 times to obtain a precipitate. The obtained precipitate was dried overnight with a 120 ° C. dryer, and then calcined at 800 ° C. for 3 hours in an air atmosphere to obtain a catalyst component. After roughly pulverizing the catalyst component in an alumina mortar, 100 g of catalyst component powder, 100 g of pure water and 10 g of colloidal silica sol were mixed, and wet pulverized with a ball mill for 6 hours. The same hexagonal cell cordierite honeycomb formed body as in Catalyst Preparation Example 1 was coated with the obtained catalyst component slurry by the wash coat method, and the excess slurry was blown off by air blow and dried at 120 ° C. only once. . The obtained honeycomb catalyst after drying was fired at 500 ° C. for 1 hour to obtain a honeycomb catalyst coated with a catalyst component (Catalyst 3). The amount of the catalyst active component supported in the obtained catalyst 3 was 37 g per liter of the honeycomb formed body. Further, after reducing the catalyst component used in the catalyst 3, the oxygen consumption rate under air flow was measured and found to be 1.66 × 10 ⁻⁶ mol per gram of catalyst / second at 100 ° C.

(Catalyst production example 4)
In the wash coating method of Catalyst Production Example 1, a slurry obtained by wet-pulverizing 100 g of α-alumina powder, 100 g of pure water and 10 g of colloidal silica sol was coated once by the wash coating method, and then the catalyst component-containing slurry described in Catalyst Preparation Example 1 Was repeated four times to obtain a honeycomb catalyst coated with a heat-resistant oxide and a catalyst component (Catalyst 4). The amount of the catalyst active component supported on the obtained catalyst 4 was 58 g per liter of the honeycomb molded body. It was. Further, the amount of the heat-resistant oxide layer supported was 50 g per liter of the honeycomb formed body.

(Catalyst production example 5)
In the washcoat method of Catalyst Production Example 1, the same operation as in Example 1 was performed except that the number of steps was changed to 6 to obtain a honeycomb catalyst coated with a catalyst component (Catalyst 5). The amount of the catalyst active component supported on the obtained catalyst 5 was 90 g per liter of the honeycomb formed body.

(Catalyst Production Example 6)
In the washcoat method of Catalyst Production Example 1, except that the number of steps was changed to one, the same operation as in Example 1 was performed to obtain a honeycomb catalyst coated with a catalyst component (Catalyst 6). The amount of the catalyst active component supported on the obtained catalyst 6 was 15 g per liter of the honeycomb formed body.

(Catalyst Production Example 7)
In the washcoat method of Catalyst Production Example 3, the same operation as in Example 1 was performed except that the number of steps was changed to 3 to obtain a honeycomb catalyst coated with a catalyst component (Catalyst 7). The amount of the catalyst active component supported on the obtained catalyst 7 was 110 g per liter of the honeycomb formed body.

(Examples 1-7)
[Catalyst activity evaluation]
Activity evaluation of the honeycomb catalysts 1 to 7 obtained above was performed. Specifically, a K-type thermocouple for measuring the temperature in the honeycomb was inserted into a honeycomb catalyst hollowed out into a cylindrical shape having an outer diameter of 25 mm and a length of 40 mm, and mounted in a tubular reactor. An adiabatic reaction was carried out while circulating ammonia as a raw material gas at 6.55 L / min and air at 4.91 L / min from the reactor inlet side. The reaction temperature was 400 to 600 ° C. due to the combustion heat of ammonia, and the reactor outlet gas was obtained by trapping unreacted NH ₃ with dilute sulfuric acid and then measuring the outlet gas flow rate with a positive displacement flow meter. The obtained results are shown in Table 1.

[How to find the ammonia conversion rate]
The ammonia conversion rate was determined by the following formula (1).
NH ₃ conversion (%) =
Outlet gas flow rate after reaction (mL / min) × 0.00764-13.95 (1)
In Formula (1), the conversion rate of ammonia (NH ₃ ) in the raw material gas to hydrogen (H ₂ ) can be calculated based on the outlet gas flow rate after the reaction. As a premise of the formula (1), it can be used when other gas concentrations such as NH ₃ concentration, air concentration, dilution gas introduced into the raw material gas are set constant, and the formula (1) is used to evaluate the catalytic activity. It is an expression that is valid under conditions.

  As the reaction of ammonia, there are an ammonia combustion reaction in which ammonia and oxygen in the air react to generate nitrogen and water, and an ammonia decomposition reaction in which ammonia decomposes to generate hydrogen and nitrogen.

  Since the ammonia combustion reaction is normally a reaction that is almost 100% complete at about 300 ° C., it is considered that 100% combustion occurs under the above-described catalytic activity evaluation conditions. Therefore, 1 mol of ammonia and 3/4 mol of oxygen are consumed in the raw material gas, and 1/2 mol of nitrogen and 3/2 mol of water are generated after the reaction. The amount of gas of 1/3 mol of the exit gas after the reaction is increased with respect to 1 mol of oxygen in the raw material gas.

  On the other hand, in the ammonia decomposition reaction, when 1 mol of ammonia is decomposed, 3/2 mol of hydrogen and 1/2 mol of nitrogen are produced. The amount of 1 mole of the exit gas after the reaction is increased with respect to 1 mole of ammonia in the raw material gas.

  Here, 0.00764 and 13.95 in the equation (1) are numerical values obtained from the linear relationship between the post-reaction outlet gas amount and the ammonia conversion rate under the catalytic activity evaluation conditions (the slope and the intercept respectively). Equivalent).

  Therefore, the ammonia conversion rate can be calculated simply by measuring the post-reaction outlet gas amount.

[Oxidation heat evaluation]
At the time of catalyst activity evaluation, only the supply of ammonia as a source gas was stopped, and the temperature change of the K-type thermocouple when only air was circulated for 10 seconds was measured. Then, after the measurement, the honeycomb catalyst was taken out and it was confirmed whether or not the appearance was changed. Further, the catalytic activity was evaluated again after the evaluation of heat of oxidation, and changes in the catalytic activity were also confirmed. The obtained results are shown in Table 1.

[Oxygen consumption rate evaluation]
The evaluation of the oxygen consumption rate in the air of the catalyst component after the reduction can be performed by the temperature rising oxidation measurement. A catalyst analyzer (catalyst analyzer BEL-CAT-A manufactured by Nippon Bell Co., Ltd.) was used for the temperature rising oxidation measurement. 10 mg of the catalyst component was weighed and filled into a sample tube. As pretreatment, reduction treatment was performed for 1 hour at a reduction temperature of 600 ° C. while 5% H ₂ / Ar gas was passed at a flow rate of 50 mL / min. Next, the temperature was lowered to about 60 ° C. while flowing helium gas at a flow rate of 50 mL / min, and hydrogen purge was performed with helium gas for 20 minutes after the temperature was lowered. Thereafter, 5% O ₂ / He gas was allowed to flow at a flow rate of 50 mL / min and stabilized for 20 minutes, and then the temperature was raised to 500 ° C. at a temperature rising rate of 5 K / min, and temperature-raising oxidation measurement was performed. By calibrating with 5% O ₂ / He gas, the oxygen consumption rate of the catalyst component was obtained from the TCD signal obtained by the temperature-programmed oxidation measurement. Here, the sensitivity of the TCD signal during measurement was Hi.

Table 1

* Thermocouple measurement upper limit (1000 ° C) or higher In Examples 1 and 4 and Comparative Examples 1 and 3, the temperature rise due to oxidation heat exceeded the thermocouple measurement upper limit (1000 ° C), so accurate temperature can be measured. There wasn't. However, in Examples 1 and 4, although the appearance of the catalyst was not changed although it was exposed to high heat, the ammonia conversion rate showed a slight decrease in the ammonia decomposition reaction again, but showed a high ammonia conversion rate. It was. Similarly, in Example 2 and Example 3, no change in appearance was observed, and a high ammonia conversion rate was exhibited in the ammonia decomposition reaction again.

  On the other hand, in Comparative Example 1 and Comparative Example 3, the honeycomb was dissolved by the oxidation heat, and as a result, the cells were clogged and the ammonia decomposition reaction could not be performed again.

  Moreover, in Comparative Example 2 with a small amount of catalytically active component, although the heat of oxidation was suppressed, the ammonia conversion rate itself was low.

  INDUSTRIAL APPLICABILITY The present invention can be used for a technique for obtaining hydrogen by decomposing ammonia by an autothermal reforming method, and can be used for a hydrogen source for a fuel cell or the like, or used for a hydrogen source for general chemical reaction. Can do.

Claims (5)

A catalyst for producing hydrogen by decomposing ammonia by an autothermal reforming method in which a catalyst component is supported on a honeycomb formed body, the catalyst component containing a catalytically active component and a heat-resistant oxide, A catalyst characterized in that the catalytically active component is at least one element selected from iron, cobalt and nickel, and the amount of the catalytically active component supported is 20 to 80 g per liter of honeycomb formed body. The oxygen consumption rate in the air circulation of the catalyst component after reduction is 1.0 × 10 ^{−7 to} 1.0 × 10 ⁻⁵ mol per gram / second of the catalyst component at 100 ° C. The catalyst according to claim 1.   2. The honeycomb formed body, in addition to the heat-resistant oxide contained in the catalyst component, 10 to 100 g of a heat-resistant oxide per liter of the honeycomb formed body is supported, and then the catalyst component is supported. Or the catalyst according to 2.   The catalyst according to any one of claims 1 to 3, wherein the heat-resistant oxide is at least one oxide selected from alumina, silica, zirconia and ceria. A method for producing hydrogen, comprising decomposing ammonia by an autothermal reforming method to produce hydrogen using the catalyst according to any one of claims 1 to 4.