JP2005103468A - Metal particle-carrying composite oxide, its preparing method and hydrocarbon based fuel reformer using the oxide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal particle-carrying composite oxide in which metal particles are uniformly deposited on the surface of a composite oxide, as a base material, with high number density. <P>SOLUTION: The metal particle-carrying composite oxide is provided with the base material comprising a composite oxide of a hardly reducible metal oxide and an easily reducible metal oxide, and active metal particles deposited on the surface of the metal particle carrying composite oxide. The above composite oxide contains at least one kind of an additive metal selected from the group consisting of Sc, Cr, B, Fe, Ga, In, Lu, Nb and Si with the amount of 0.01 mol% or more and 0.25 mol% or less in terms of an element. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a metal particle-supported composite oxide, a method for producing the same, and a hydrocarbon fuel reformer using the same.

  In fuel cells, particulate reforming catalysts in which metal catalyst fine particles are supported on oxide ceramics have been used. Such a catalyst is required to be improved because the catalyst utilization rate is low, and the activity decreases with long-term use. When applied to a fuel reformer, the catalyst particles are generally supported on a porous pellet-shaped ceramic and used by being filled in a reaction vessel. Since pressure loss increases due to the filling of the pellets, in some cases, the fuel gas must be pressurized and supplied.

  Recently, there has been proposed a method for producing a metal / ceramic composite material having excellent mechanical properties by reducing a composite oxide sintered body to precipitate some metal particles (see, for example, Non-Patent Document 1). . The deposited metal particles are fine and have good dispersibility, and also have excellent adhesion with the composite oxide as a substrate. However, many metal particles are precipitated inside the base material mainly composed of grain boundaries, which is inefficient for use as a catalyst, and there is a risk of deterioration from internal grain boundaries when used for a long time. .

As the catalyst, it is preferable that the metal particles are present only on the very surface portion of the composite oxide, and in terms of catalytic activity, the number density of metal particles (the number of catalyst particles per unit area) is high, Those having a large specific metal surface area advantageous for catalytic reaction are preferred. By adopting the reduction precipitation method as described above, it is possible to produce the catalyst / support as an integrated one. For example, if a porous support is used, a catalyst that is easy to handle and a compact catalyst can be obtained. It is done. However, with the current materials, the amount of catalyst on the surface part that contributes to the reaction is not sufficient, and a volume is required to ensure an appropriate amount of catalyst. For this reason, it has not been possible to sufficiently reduce the size and size of the fuel reformer.
J. Am. Ceram. Soc., Vol. 80, No. 5, 1139 (1997)

  An object of the present invention is to provide a metal particle-supporting composite oxide in which metal particles are uniformly deposited at a high number density on the surface of the composite oxide as a substrate, and a method for producing the same.

  Another object of the present invention is to provide a small and compact hydrocarbon fuel reformer.

  A metal particle-supported composite oxide according to an embodiment of the present invention includes a base material composed of a composite oxide of a hardly reducible metal oxide and a readily reducible metal oxide, and deposited on the surface of the composite oxide base material. The composite oxide comprises at least one additive metal selected from the group consisting of Sc, Cr, B, Fe, Ga, In, Lu, Nb and Si in an element amount of 0. It is contained in the amount of 0.01 mol% or more and 0.25 mol% or less.

A method for producing a metal particle-supported composite oxide according to an embodiment of the present invention includes a nonreducible metal oxide powder, an easily reducible metal oxide powder, and Sc, Cr, B, Fe, Ga, In Mixing a powder containing at least one additive metal selected from the group consisting of Lu, Nb and Si to obtain a mixed powder;
Molding the mixed powder to obtain a molded body,
Sintering the molded body to obtain a sintered body made of a composite oxide of the hardly-reducible metal oxide and the easily-reducible metal oxide; and reducing the sintered body to make the easily-reduced Comprising a step of precipitating conductive metal particles on the surface of the composite oxide,
The mixed powder contains the additive metal in an amount of 0.01 mol% or more and 0.25 mol% or less.

A hydrocarbon fuel reformer according to an embodiment of the present invention includes a fuel tank that contains a hydrocarbon fuel,
A modifier tank containing a modifier for reforming the hydrocarbon fuel;
A preheating device for vaporizing the hydrocarbon fuel and the modifier,
A mixer for mixing the vaporized hydrocarbon fuel and the reformer,
A reformer having a catalyst layer containing a reforming catalyst for reacting a gas mixed by the mixer and reforming it into a fuel containing hydrogen as a main component; and a heating device for heating the reformer. And
A metal particle-supporting composite oxide according to an embodiment of the present invention is used for the reforming catalyst.

  According to one aspect of the present invention, a metal particle-supporting composite oxide in which metal particles are uniformly deposited at a high number density on the surface of the composite oxide as a substrate, and a method for producing the same are provided. According to another aspect of the present invention, a small and compact hydrocarbon fuel reformer is provided.

  Embodiments of the present invention will be described below.

  The metal particle carrying | support complex oxide concerning embodiment of this invention contains the base material which consists of complex oxide of an easily reducible metal oxide and a hardly reducible metal oxide.

  An easily reducible oxide refers to a metal oxide that can be reduced to a metal in a hydrogen atmosphere at room temperature to 1500 ° C. or under plasma conditions, or in an inert atmosphere using a carbon jig. Specific examples include oxides such as Cu, Co, Fe, Ni, Zn, Sn, Cd, Pd, Hg, and Ag. When used as a catalyst for gas reforming or gas synthesis, nickel oxide, cobalt oxide, and iron oxide are preferable, and nickel oxide is most preferable because of high catalyst efficiency. Such easily reducible oxides may be used alone or in combination of two or more.

  On the other hand, a non-reducible oxide refers to an oxide that is not reduced to a metal in a reducing atmosphere such as hydrogen at room temperature to 1500 ° C. Specific examples include oxides such as Al, Mg, Si, Zr, Ti, Hf, and Ce. The hardly reducible metal oxides may be used alone or in combination of two or more. Among these hardly-reducible metal oxides, magnesium oxide, zirconium oxide, and cerium oxide are preferable from the viewpoint of forming a stable solid solution, and magnesium oxide is most preferable.

The composite oxide in the embodiment of the present invention is composed of the solid solution of the reducible metal oxide and the hardly reducible metal oxide as described above. As the solid solution, for example, a complete solid solution of oxides such as NiO—MgO, CoO—MgO, FeO—MgO, and NiO—CoO—MgO is preferable. Alternatively, a system in which the solid solubility limit of the easily reducible metal oxide to the hardly reducible metal oxide is 1 atomic% or more at the hydrogen reduction temperature, such as ZrO ₂ —NiO, MgO—CuO, MgO—CuO—ZnO. It may be.

  As a result of intensive studies on the relationship between the characteristics of the precipitated metal by reduction and the reforming performance, the present inventors have found that when a predetermined amount of a specific metal element is contained, It has been found that sometimes significant metal particle precipitation occurs. Examples of the metal element having such an action include Sc, Cr, B, Fe, Ga, In, Lu, Nb, and Si, and Cr and Sc are particularly preferable. These metals are preferably added in the form of oxides because they are readily available and can be added by simple methods such as mixing and firing. It may be added in any manner.

  The metal particle-supporting composite oxide according to the embodiment of the present invention can be produced by preparing a mixed powder, solid solution / firing, and subjecting it to a reduction treatment.

  In preparing the mixed powder, first, at least one additive metal selected from a non-reducing oxide, a non-reducing oxide, and Sc, Cr, B, Fe, Ga, In, Lu, Nb and Si. Are uniformly mixed with a ball mill or the like. At this time, it is desirable to use a material made of nylon or the like for the balls and pots so that no mixing occurs. Although it may mix by any method of a wet type and a dry type, wet mixing is preferable in order to perform more uniform mixing, and binders, such as PVA (polyvinyl alcohol), may be added.

  For example, it is preferable to mix MgO powder, which is a nonreducible oxide, and NiO powder or CoO powder, which is an easily reducible oxide, in a molar ratio of 2: 1. By mixing the hardly-reducible oxide and the easily-reducible oxide at a ratio of 2: 1, the amount of deposited metal by hydrogen reduction can be suppressed to an appropriate amount, and coalescence and particle growth between metal particles can be suppressed. . As an application of such a complex oxide, a ternary system such as a NiO-MgO-CuO system may be considered. When this composite oxide sintered body is reduced, Ni and Cu are precipitated, and Ni—Cu alloy particles can be formed on the oxide surface.

On the other hand, the aforementioned metal element is preferably added in the form of an oxide such as Sc ₂ O ₃ . The amount of the metal element component such as Sc is defined as 0.01 mol% or more and 0.25 mol% or less with respect to the entire mixed powder. When the amount of added metal is less than 0.01 mol%, a sufficient amount of easily reducible metal particles cannot be deposited on the surface of the composite oxide. On the other hand, if it exceeds 0.25 mol%, the added compound itself remains at the grain boundary of the solid solution, impairing the sinterability of the composite oxide, and causing a decrease in strength. Further, precipitation due to reduction becomes excessive, and metal particles aggregate and coalesce, resulting in a decrease in catalyst performance.

  The optimum amount to be added varies depending on the metal particles to be precipitated, the reduction conditions, and the like, but if the reduction temperature is too high or the reduction time is too long, the precipitated particles grow large. In this case, since the catalytic activity is lowered, it is desirable to perform the reduction treatment at an appropriate temperature and time.

  The obtained mixed powder is molded into a predetermined shape to obtain a molded body. For example, it can be formed into a honeycomb shape, a foam shape, or a sheet shape with a groove serving as a fluid flow path. A composite oxide (solid solution sintered body) is produced by sintering this molded body to a solid solution by sintering in the range of 1000 ° C. to 1400 ° C. For example, a metal particle-supported composite oxide formed into a honeycomb shape and subjected to a reduction treatment as will be described later to deposit Ni particles on the surface can be suitably used as a reforming catalyst for hydrocarbon fuel.

  The obtained solid solution sintered body is subjected to a reduction treatment in an atmosphere of hydrogen gas or the like, thereby depositing metal particles on the surface of the composite oxide and the grain boundary interface. For example, in the case of NiO—MgO, a part of the solid solution, Ni particles that are easily reduced, are reduced and deposited on the surface of the composite oxide. The Ni particles are excellent in dispersibility, and have high adhesion to the base material because they are formed by precipitation from the inside of the complex oxide as the base material.

  The temperature and time of the reduction treatment can be appropriately selected according to the material used. For example, in the case of a NiO—MgO system, it is preferable to perform a reduction treatment for about 10 minutes at a temperature of 500 to 1000 ° C. If the reduction temperature is too high, the growth of metal particles may proceed more than necessary, causing aggregation and destruction at the grain boundary, or reducing the catalyst performance. On the other hand, if the temperature is too low, it takes a long time for the heat treatment, which is not industrially preferable.

  The metal particle carrying | support composite oxide concerning embodiment of this invention is obtained by the above process.

  The metal particle-supported composite oxide thus produced can be suitably used as a hydrocarbon-based fuel reforming catalyst. The configuration of a hydrocarbon fuel reformer according to an embodiment of the present invention is schematically shown in FIG.

In the illustrated hydrocarbon fuel reformer, a hydrocarbon fuel storage tank 10 contains gaseous fuel such as CH ₄ or liquid fuel such as CH ₃ OH or C ₂ H ₅ OH. Water or carbon dioxide gas for reforming is stored in the modifier tank 20. The fuel and the reformer are vaporized in the preheating devices 30 and 40, respectively, and introduced into the mixer 50. The mixed gas reacts in the reforming catalyst layer 80 to be reformed into a fuel mainly composed of hydrogen.

  When the obtained reformed gas is used as a fuel for a fuel cell, it is supplied to a carbon monoxide converter (not shown) to reduce the CO concentration in the reformed gas, and then the solid polymer membrane type What is necessary is just to supply to the fuel electrode of fuel cells etc. (not shown).

  In the illustrated example, the burner 70 is used to uniformly heat the reforming catalyst layer 80, but combustion heating by a catalyst may be employed.

  The reforming catalyst layer 80 can be loaded with, for example, a metal particle-supporting composite oxide 110 produced in a honeycomb shape as shown in FIG. In the embodiment of the present invention, the metal particles 90 are precipitated from the composite oxide 100 by reduction. Therefore, as schematically shown in FIG. 3, the metal particles 90 are formed on the inner wall surface of the honeycomb serving as a gas flow path. be able to. Further, by using such a honeycomb-shaped catalyst, handling becomes easy and pressure loss with respect to the flow of fuel or reformed gas can be remarkably reduced.

  Embodiments of the present invention will be described in more detail with specific examples below, but the present invention is not limited to these.

(Examples 1-2, Comparative Examples 1-3)
NiO powder (average particle size of about 1 μm) as an easily reducible metal oxide and MgO powder (average particle size of about 1 μm) as a hardly reducible metal oxide are in a molar ratio of NiO: MgO = 1: 2. Weighed so that As the additive compound, high-purity Sc ₂ O ₃ was prepared and added so as to be 0.015 mol% and 0.2 mol% in terms of Sc element. This was uniformly mixed in a wet manner using a nylon ball for 20 hours to obtain a mixed powder.

The mixed powder was pressure-molded with a die press at a pressure of 1 ton / cm ² , and then the compact was sintered in air at 1300 ° C. for 5 hours to prepare a composite oxide sintered body. Next, while flowing hydrogen gas with a purity of 99.9% at a flow rate of 500 cc / min, the temperature was raised at a rate of 15 ° C./min, and a reduction treatment was performed at 1000 ° C. for 10 minutes to precipitate Ni particles. Was done. The sample used for the weight loss measurement was prepared by pulverizing the sintered body with a mortar until the size became about several μm. Further, the microstructure was observed with a scanning electron microscope (SEM), and the active metal specific surface area by hydrogen adsorption was measured with a chemical adsorption measuring device.

  The density, reduction in weight loss, and active metal specific surface area are summarized in Table 1 below together with the composite oxide composition, added oxide and added metal amount.

Further, three kinds of mixed powders were prepared in the same manner as described above except that the addition amount of Sc ₂ O ₃ was changed to 0 mol%, 0.008 mol% and 0.3 mol% in terms of Sc element. did. Metal particle composite oxides of Comparative Examples 1 to 3 were prepared in the same manner as described above except that the mixed powder thus obtained was used. The properties of the obtained metal particle composite oxide were evaluated in the same manner as described above, and the results are summarized in Table 1 below.

(Examples 3 to 10)
The additive compound was changed to Cr ₂ O ₃ , In ₂ O ₃ , Lu ₂ O ₃ , Ga ₂ O ₃ , B ₂ O ₃ , Fe ₂ O ₃ , Nb ₂ O ₃ , and SiO ₂ , each of which was a metal element Eight kinds of mixed powders were obtained in the same manner as described above except that about 0.15 mol% was added in an amount.

  Except for using such a mixed powder, metal particle composite oxides of Examples 3 to 10 were produced in the same manner as described above. The properties of the obtained metal particle composite oxide were evaluated in the same manner as described above, and the results are summarized in Table 1 below.

(Example 11, Comparative Example 4)
CuO powder (average particle diameter 1 μm) was further used as a raw material powder as an easily reducible metal oxide, and weighed so that the mixed composition was MgO: NiO: CuO = 2: 1: 0.1 (mol ratio). As an additive compound, high-purity Sc ₂ O ₃ was prepared and added so as to be 0.15 mol% in terms of Sc element to obtain a mixed powder.

  A metal particle composite oxide of Example 11 was produced in the same manner as described above except that such a mixed powder was used. In the obtained metal particle composite oxide, Ni—Cu alloy particles were precipitated on the surface. Further, a metal particle composite oxide of Comparative Example 4 was produced in the same manner except that no additive compound was blended.

  The properties of the obtained metal particle composite oxide were evaluated in the same manner as described above, and the results are summarized in Table 1 below.

(Example 12, Comparative Example 5)
The same as described above, except that the easily reducible metal oxide was changed to CoO powder (average particle size 1 μm), and Sc ₂ O ₃ powder as an additive compound was added so that the amount of Sc element was 0.15 mol%. Thus, a metal particle composite oxide of Example 12 was produced. Further, a metal particle composite oxide of Comparative Example 5 was produced in the same manner except that no additive compound was blended.

The properties of the obtained metal particle composite oxide were evaluated in the same manner as described above, and the results are summarized in Table 1 below.

  From the comparison between Example 1 and Comparative Example 1, it can be seen that the reduction in weight loss and the active metal specific surface area are increased by containing 0.015 mol% of the added metal. The result of Example 2 shows that when the metal addition amount is 0.20 mol%, the reduction loss is increased to 10.1%, and the active metal specific surface area is increased 10 times as much as the case of no addition. Has been.

  On the other hand, as shown in Comparative Example 2, when the metal addition amount is less than 0.01 mol%, the characteristics are almost the same as those of the additive-free material (Comparative Example 1), and the effect is hardly seen. . In addition, when the amount of metal added exceeds 0.25 mol% (Comparative Example 3), it was confirmed from observation of the structure that the coarsening and aggregation of the precipitated particles became remarkable, and it was not preferable as a catalyst. This tendency was the same when a compound containing another metal element was used.

Further, as shown in the results of Examples 3 to 10, Cr ₂ O ₃ , In ₂ O ₃ , Lu ₂ O ₃ , Ga ₂ O ₃ , B ₂ O ₃ , Fe ₂ O ₃ , Nb ₂ O ₃ , When either of the compounds of SiO ₂ and SiO ₂ is added, the weight loss during reduction increases, and the active metal specific surface area increases accordingly.

  Furthermore, more excellent characteristics can be obtained when the composition of the composite oxide is MgO—NiO—CuO (Example 11) and MgO—CoO (Example 12).

  Thus, it has been clarified that the addition of a trace amount of elements promotes the precipitation of metallic Ni particles (or Ni—Cu particles, Co particles) on the surface of the composite oxide. Compared with the material of the comparative example that does not contain the additive metal, the metal particle-supporting composite oxide according to the embodiment of the present invention has high number density (number of precipitated metal particles per unit area) in any case, It had a structure formed uniformly on the surface without agglomeration and coalescence. The density varied depending on the metal element to be added. In general, the density tends to decrease as the amount of the metal element added increases. This is probably because most of the added oxide remains in the grain boundary and inhibits the sinterability. In order to avoid deterioration of the mechanical properties, it is necessary to keep the addition amount of the metal element at a maximum of 0.25 mol%.

(Example 13, Comparative Example 6)
NiO powder (average particle size of about 1 μm) as an easily reducible metal oxide and MgO (average particle size of about 1 μm) as a hardly reducible metal oxide have a molar ratio of NiO: MgO = 1: 2. Weighed as follows. As the additive compound, high-purity Sc ₂ O ₃ was prepared and added so as to be 0.05 mol% in terms of Sc element. This was uniformly mixed by wet using a nylon ball for 20 hours to obtain a mixed powder.

After mixing, an organic solvent-based binder was added and kneaded, and the kneaded product was extruded to form a honeycomb formed body. The obtained molded body was introduced into a degreasing furnace, heated to 500 ° C. over 8 hours, and degreased at 500 ° C. for 5 hours. After degreasing, sintering was performed at 1300 ° C. for 5 hours to obtain a porous honeycomb body having a cell number of 300 cells / in ² , a wall thickness of 0.5 mm, and φ20 mm × 15 mm.

  This sintered body was reduced in a hydrogen stream of 500 cc / min at 900 ° C. for 10 minutes to precipitate Ni particles, and the Ni particle-supporting honeycomb of Example 13 in which the catalyst and the porous body as the support were integrated. A mold catalyst was prepared. In the obtained honeycomb type catalyst, as shown in FIG. 3, Ni particles as the metal particles 90 were uniformly dispersed on the surface of the MgO—NiO-based composite oxide substrate 100.

Further, a honeycomb type catalyst of Comparative Example 6 was produced in the same manner except that Sc ₂ O ₃ as an additive compound was not added.

  The honeycomb-type catalyst produced in this way was filled in the catalyst packed bed in the reformer shown in FIG. 1, and the conversion rate was evaluated.

CH ₄ gas and CO ₂ gas were accommodated in the fuel tank 10 and the reformer tank 20, respectively, and introduced into the reformer 60 through the preheating devices 30 and 40 at a flow rate of 50 cc / min. The reformer 60 was heated to 800 ° C. to generate hydrogen gas. The gas reformed through the honeycomb catalyst was quantitatively analyzed with a gas analyzer.

As a result, when the honeycomb type catalyst of Comparative Example 6 was used, the conversion rate of CH ₄ to H ₂ and CO was as low as 70% at 800 ° C., whereas the honeycomb type catalyst of Example 13 was used. When used, the conversion was over 95%. In addition, production of about 1.8 moles of hydrogen per 1 mole of CH ₄ was observed.

(Example 14, comparative example 7)
CuO powder (average particle diameter 1 μm) was further used as a raw material powder as an easily reducible metal oxide, and weighed so that the mixed composition was MgO: NiO: CuO = 2: 1: 0.1 (mol ratio). As the additive compound, high-purity Sc ₂ O ₃ was prepared and added so as to be 0.1 mol% in terms of Sc element to obtain a mixed powder. This was wet mixed uniformly for 20 hours by a nylon ball mill to obtain a mixed powder.

After mixing, an organic solvent-based binder was added and kneaded, and the kneaded product was extruded to form a honeycomb formed body. The obtained molded body was introduced into a degreasing furnace, heated to 500 ° C. over 8 hours, and degreased at 500 ° C. for 5 hours. After degreasing, sintering was performed at 1300 ° C. for 5 hours to obtain a porous honeycomb body having a cell number of 300 cells / in ² , a wall thickness of 0.5 mm, and φ20 mm × 15 mm.

  This sintered body was reduced in a hydrogen stream of 500 cc / min at 900 ° C. for 10 minutes to precipitate Ni and Cu particles, whereby a metal particle-supporting honeycomb type catalyst of Example 14 was produced. In the obtained honeycomb type catalyst, as shown in FIG. 3, Ni—Cu particles as metal particles 90 were uniformly dispersed on the surface of the MgO—NiO—CuO-based composite oxide substrate 100.

Further, a honeycomb type catalyst of Comparative Example 7 was produced in the same manner except that Sc ₂ O ₃ as an additive compound was not added.

  The honeycomb-type catalyst produced in this way was filled in the catalyst packed bed in the reformer shown in FIG. 1, and the conversion rate was evaluated.

As the fuel gas, CH ₃ OH and H ₂ O were vaporized by the preheating devices 30 and 40 and introduced. The mixing ratio of CH ₃ OH and H ₂ O was 1: 4 in terms of molar ratio, the methanol gas flow rate was 30 cc / min, and the water vapor flow rate was 120 cc / min. The reformed gas that passed through the honeycomb catalyst was quantitatively analyzed by a gas analyzer.

When the honeycomb type catalyst of Comparative Example 7 was used, the weight reduction was only about 0.4% by hydrogen reduction at 900 ° C. × 10 minutes. This is presumably because the densification during sintering progressed due to the presence of CuO, and the overall surface area decreased. As a result, although the conversion rate of CH ₃ OH to other gases exceeded 90% at 400 ° C., the amount of hydrogen produced was 1.7 mol with respect to 1 mol of CH ₃ OH.

In contrast, the honeycomb type catalyst of Example 14 had a weight loss of about 3%, and the CH ₃ OH conversion was 95% at 350 ° C. and 100% at 400 ° C. Approximately 2.4 moles of hydrogen could be produced per mole of CH ₃ OH.

  The present invention can be suitably used as a catalyst / catalyst support for hydrocarbon fuel reforming, gas synthesis, fuel cell electrodes, or as a catalyst material for carbon nanotube fiber synthesis.

1 is a schematic diagram showing a hydrocarbon fuel reformer according to an embodiment of the present invention. The perspective view showing a honeycomb-shaped metal particle carrying | support complex oxide. Schematic showing the cross-sectional structure of a honeycomb-shaped metal particle carrying | support complex oxide.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Hydrocarbon fuel tank; 20 ... Reformer tank; 30 ... Preheating apparatus 40 ... Preheating apparatus; 50 ... Mixer; 60 ... Reformer; 70 ... Burner 80 ... Reforming catalyst layer; Metal catalyst particles 100 ... Composite oxide substrate; 110 ... Metal particle-supported composite oxide.

Claims (3)

  A substrate comprising a complex oxide of a hardly-reducible metal oxide and an easily-reducible metal oxide; and active metal particles deposited on the surface of the complex oxide substrate, wherein the complex oxide is Sc And at least one additive metal selected from the group consisting of Cr, B, Fe, Ga, In, Lu, Nb, and Si in an amount of 0.01 mol% to 0.25 mol% in terms of element amount A metal oxide-supported composite oxide. At least one additional metal selected from the group consisting of oxide powders of non-reducible metals, oxide powders of easily reducible metals, and Sc, Cr, B, Fe, Ga, In, Lu, Nb, and Si A step of mixing a powder containing
Molding the mixed powder to obtain a molded body,
Sintering the molded body to obtain a sintered body made of a composite oxide of the hardly-reducible metal oxide and the easily-reducible metal oxide, and reducing the sintered body to make the easily-reduced Comprising a step of precipitating conductive metal particles on the surface of the composite oxide,
The mixed powder contains the additive metal in an amount of 0.01 mol% or more and 0.25 mol% or less. A fuel tank for containing hydrocarbon fuel,
A modifier tank containing a modifier for reforming the hydrocarbon fuel;
A preheating device for vaporizing the hydrocarbon fuel and the modifier,
A mixer for mixing the vaporized hydrocarbon fuel and the reformer,
A reformer having a catalyst layer containing a reforming catalyst for reacting a gas mixed by the mixer and reforming it into a fuel containing hydrogen as a main component; and a heating device for heating the reformer. And
A hydrocarbon-based fuel reformer using the metal particle-supported composite oxide according to claim 1 as the reforming catalyst.

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