WO2014025049A1

WO2014025049A1 - Solid carrier-supported iron group solid solution-type alloy composite and catalyst using same

Info

Publication number: WO2014025049A1
Application number: PCT/JP2013/071735
Authority: WO
Inventors: 山内　美穂
Original assignee: 国立大学法人九州大学
Priority date: 2012-08-10
Filing date: 2013-08-09
Publication date: 2014-02-13
Also published as: JP6230126B2; JPWO2014025049A1

Abstract

The present invention relates to a solid carrier and a composite including iron group metal-based alloy particles which are supported with the solid carrier. The iron group metal-based alloy particles are, for example, iron group metal-based alloy particles comprising two or three iron group metals selected from the group consisting of iron group metals (a)Fe, Co and Ni (where the two or three iron-group metals are solid solution-type alloys), or iron group metal-based alloy particles comprising one or two or three iron group metals selected from the group consisting of iron group metals (c)Fe, Co and Ni and one or two or more transition metals selected from the group consisting of transition metals Cr, Mn, Cu, Mo, Ru, Rh, Pd, Ag, Ir, Pt and Au (where the one or two or three iron group metals and one or two or more transition metals are solid solution-type alloys). The present invention provides a catalyst with improved catalyst characteristics as a catalyst for electrodes of a fuel cell and a catalyst with improved CO conversion rate, carbon number and olefin selectivity as a catalyst for a Fischer-Tropsch reaction.

Description

Solid support-supported iron group solid solution type alloy composite and catalyst using the same

The present invention relates to a solid support-supported iron group solid solution type alloy composite and a catalyst using the same.

A fuel cell directly converts chemical energy into electrical energy by supplying fuel and an oxidant (mainly oxygen) to two electrically connected electrodes and electrochemically oxidizing the fuel. Therefore, the fuel cell exhibits high energy conversion efficiency. A fuel cell generally has a basic structure of a membrane / electrode assembly in which an electrolyte membrane is sandwiched between a pair of electrodes. There are alkaline fuel cells using an anion conductive solid polymer electrolyte membrane as an electrolyte membrane and proton fuel cells using a proton conductive solid polymer electrolyte membrane.

In the alkaline fuel cell, when hydrogen is used as the fuel, the reaction of the formula (1) proceeds at the fuel electrode (anode), and the reaction of the formula (2) proceeds at the oxygen electrode (cathode). The total reaction is shown by formula (3).
Fuel electrode: H ₂ + 2OH ⁻ → 2H ₂ O + 2e ⁻ (1)
Oxygen electrode: (1/2) O ₂ + H ₂ O + 2e ⁻ → 2OH ⁻ (2)
Total reaction: H ₂ + (1/2) O ₂ → H ₂ O (3)

Electrons generated in Equation (1) reach the oxygen electrode after working with an external load via an external circuit. The hydroxide ions generated in the formula (2) move from the oxygen electrode side to the fuel electrode side in the solid polymer electrolyte membrane. The water produced by the formula (1) mainly passes through the gas diffusion layer and is discharged to the outside, or permeates the solid polymer electrolyte membrane from the fuel electrode to the oxygen electrode, and the formula (2 ).

Fuel cells that use organic compounds other than hydrogen, for example, alcohols as fuel, are also known. A direct methanol fuel cell is a typical example. As its name suggests, direct methanol fuel cells react methanol directly at the fuel electrode without producing hydrogen from methanol in the fuel reformer. The cell reaction of a direct methanol fuel cell is shown.
_{_{Anode: CH 3 OH + H 2 O}} → CO 2 + 6H + + 6e -
Oxygen _{^{electrode: 3 / 2O 2 + 6H +}} + 6e - → 3H 2 O
Total reaction: CH ₃ OH + 3 / 2O ₂ → CO ₂ + 2H ₂ O
In a direct methanol fuel cell, methanol is directly oxidized at the fuel electrode, and carbon dioxide is produced at the fuel electrode and water is produced at the oxygen electrode as reaction products.

As described above, the electrode reaction in the fuel cell uses a catalyst for promoting the reaction in both the fuel electrode and the oxygen electrode. As a catalyst for electrode reaction of a fuel cell, a noble metal such as platinum is mainly used. However, noble metal catalysts represented by platinum have limited reserves and are relatively expensive.

In order to further promote the use of fuel cells, it is essential to provide a new catalyst that replaces the precious metal catalyst. A candidate for a new catalyst material that can replace the noble metal catalyst is an iron group metal. For example, a fuel cell catalyst containing platinum as a main component and further containing nickel and iron is known (Patent Document 1).

Incidentally, a catalyst using an iron group metal is known as a catalyst other than a catalyst for an electrode of a fuel cell. A catalyst for Fischer-Tropsch reaction for the production of soft olefins (Patent Document 2)

Special table 2007-504624 JP 2006-297286 A

Regarding a fuel cell electrode catalyst, there is no known fuel cell catalyst composed of only an iron group metal and having a catalytic performance at a practical level. An iron group metal is inexpensive, but a catalyst made only of an iron group metal or a catalyst mainly composed of an iron group metal has lower performance than a noble metal catalyst. Accordingly, a first object of the present invention is to provide a catalyst made of only an iron group metal or a catalyst containing an iron group metal as a main component, which has improved catalyst characteristics as a catalyst for an electrode of a fuel cell.

Regarding the catalyst using an iron group metal for Fischer-Tropsch reaction, there is a problem that the conversion rate of CO (carbon monoxide) is low in the conventional catalyst. Accordingly, a second object of the present invention is to provide a catalyst composed of only an iron group metal or a catalyst mainly composed of an iron group metal, which has an improved CO (carbon monoxide) conversion rate as a Fischer-Tropsch reaction catalyst. That is.

In order to achieve the above object of the present invention, the present inventors considered as follows. In order to control the properties of the metal catalyst, it is important to optimize the adsorption properties with the substrate. One method for improving the chemical reactivity of the base metal is to form an alloy. When different metals interact chemically, a new energy (band) state and Fermi energy (chemical potential) are formed. In the case of transition metals, it is thought that the catalytic properties change greatly depending on the position of the center of gravity of the d-band (d-band center). By adapting the position of the d-band to the target reaction, a highly active catalyst can be obtained. May be obtained. In addition, it is important for the component metals to be solid-dissolved uniformly in order to efficiently promote chemical interaction between the metals.

In the present invention, from the above viewpoint, a technique capable of producing an iron group alloy in which component metals are dissolved at an atomic level is developed, and the obtained alloy is used as a fuel cell electrode catalyst and a Fischer-Tropsch reaction catalyst. The present invention was completed by finding that the catalytic reaction activity and reaction selectivity were improved.

[1]
A composite comprising a solid support and any one of the following iron group metal-based alloy particles supported on the solid support (a) to (d).
(a) Iron group metal alloy particles composed of two or three kinds of iron group metals selected from the iron group metal group consisting of Fe, Co and Ni, provided that the iron group metal alloys are the above-described two or three A kind of iron group metal is a solid solution type alloy,
(b) Iron group metal alloy particles containing two or three kinds of iron group metals selected from the group consisting of iron group metals consisting of Fe, Co and Ni, provided that the iron group metal alloys are at least the two kinds Or three kinds of iron group metals are solid solution type alloys,
(c) One, two or three iron group metals selected from the iron group metal group consisting of Fe, Co and Ni, and Cr, Mn, Cu, Mo, Ru, Rh, Pd, Ag, Ir, Pt And an iron group metal alloy particle composed of one or more transition metals selected from the group of transition metals consisting of Au, wherein the iron group metal alloy is the one, two or three iron groups The metal and one or more transition metals are solid solution type alloys,
(d) One, two or three types of iron group metals selected from the group of iron group metals consisting of Fe, Co and Ni, and Cr, Mn, Cu, Mo, Ru, Rh, Pd, Ag, Ir, Pt And an iron group metal alloy particle containing one or more transition metals selected from the group of transition metals consisting of Au, wherein the iron group metal alloy is at least one of the above-mentioned one, two or three kinds The iron group metal and one or more transition metals are solid solution type alloys,
[2]
The iron group metal-based alloy particle has at least one iron group metal atom bonded to a different metal atom in a volume of 16.7 nm ^{3 of} one alloy particle, provided that the different metal atom is the iron group metal atom. The complex according to [1], which is a different iron group metal atom, the transition metal atom, or an iron group metal atom different from the iron group metal atom and a metal atom other than the transition metal atom .
[3]
The composite according to [1] or [2], wherein the iron group metal-based alloy particle is an alloy particle having a volume of one particle of 16.7 nm ³ or more and 10,466.7 nm ³ or less.
[4]
The composite according to any one of [1] to [3], wherein the solid support is a carbon-based material or an inorganic material, and contains particles having a diameter in the range of 1 nm to 10 μm.
[5]
[1] A catalyst for a solid oxide alkaline fuel cell, comprising the composite according to any one of [4].
[6]
The solid oxide alkaline fuel cell catalyst according to [5], wherein the solid support is made of a conductive material.
[7]
The catalyst for a solid oxide alkaline fuel cell according to [6], wherein the conductive material is a carbon-based material, and the carbon-based material is activated carbon, carbon black, carbon nanotube, or a porous carbon material.
[8]
[1] to [4] A Fischer comprising the composite according to any one of the above (except for the composite in which the iron group metal alloy particles are iron group metal alloy particles composed of Fe and Co).・ Tropsch reaction catalyst.
[9]
Iron group metal-containing compounds (where the iron group metal is selected from the group of iron group metals consisting of Fe, Co and Ni) and transition metal-containing compounds (where the transition metals are Cr, Mn, Cu, Mo, Ru, Rh, A step of preparing a mixture by mixing at least two metal-containing compounds selected from the group consisting of Pd, Ag, Ir, Pt and Au (selected from the group of transition metals consisting of Au), a protective polymer, a solvent and a solid support (1 ),
By adding a reducing agent for metal ions contained in the metal-containing compound to the obtained mixture, precursor particles containing at least two kinds of metals selected from the group consisting of iron group metals and transition metals and a solid support are obtained. Step (2) of preparing, and heating the precursor particles in a hydrogen-containing atmosphere to reduce the precursor particles, so that at least two metal alloy particles selected from the group consisting of iron group metals and transition metals A production method comprising a step (3) of obtaining a composite supported on a solid support.
[10]
The at least two compounds used in step (1) are two or three iron group metal-containing compounds, or one or more iron group metal-containing compounds and one or more transition metals. The production method according to [9], which is a contained compound.
[11]
The production according to [9] or [10], wherein the step (3) is performed under the condition that the obtained iron group nanoalloy particles have a crystallite size having a volume of 16.7 nm ³ or more and 10466.7 nm ³ or less. Method.
[12]
The production method according to any one of [9] to [11], wherein the hydrogen content in the hydrogen-containing atmosphere in the step (3) is in the range of more than 10 vol% and not more than 100 vol%.
[13]
The method according to any one of [9] to [12], wherein the heating in the step (3) is in the range of 200 ° C to 1,000 ° C.
[14]
The precursor particles containing the iron group metal obtained in the step (2) are particles containing at least one of iron oxide, cobalt oxide and nickel oxide. 2. The production method according to item 1.
[15]
Any one of [9] to [14], wherein a protective polymer having the same solubility as that of the iron group metal-containing compound and the transition metal-containing compound in water and a solvent and interacting with the metal complex raw material and sometimes accompanied by complex formation is used. The production method according to item.
[16]
The reduction in step (2) is performed in the range of 0 to 200 ° C. The production method according to any one of [9] to [15], wherein the redox potential of the reducing agent is lower than that of the component metal.

ADVANTAGE OF THE INVENTION According to this invention, the composite which can provide the catalyst which consists of an iron group metal only, or the catalyst which has an iron group metal as a main component with improved catalyst characteristics as an electrode catalyst of a fuel cell, and this composite The alkaline fuel cell catalyst to be used can be provided. Furthermore, according to the present invention, as a catalyst for the Fischer-Tropsch reaction, a catalyst composed of only an iron group metal or an iron group metal having improved CO (carbon monoxide) conversion rate and selectivity to an olefin is a main component. A composite capable of providing a catalyst and a catalyst for a Fischer-Tropsch reaction using the composite can be provided.

According to (a) the conventional (impregnation) method (after 900 ° C. heat treatment) prepared in Reference Example 1, and (b) the present invention (after 900 ° C. heat treatment) obtained in Example 1-1. The TEM image of the prepared Fe-based alloy nanoalloy supported catalyst is shown. 3 shows powder XRD patterns of FexCoyNi (1-x-y) / C obtained in Examples 1-1 to 4. Shows a STEM-EDS (elemental map) image of Fe _₅₀ Co ₅₀ / C precursor obtained in Example 1-2 (a) and the nano-alloy catalyst (b). 1 shows a TEM image (Test Example 4) of a binary nano-alloy (RT to 1000 ° C., 10 K / min, 10 min Keep, N ₂ ). 3 shows a TEM image (Test Example 4) of metal nanoparticles. The direct glycol inorganic alkaline battery power generation characteristics (Test Example 5) using FexCoyNi (100-xy) / C / as an anode catalyst are shown. The powder XRD pattern (overall image) of Fe33Co33Ni33 / C. Co50Ni50 / C, Fe50Co50 / C, and Fe50Ni50 / C produced in Example 2-1 is shown. The element mapping by STEM-HAADF and EDS of Fe33Co33Ni33 / C of Table 1 produced in Example 2-1 and the result of the one-dimensional analysis are shown. (There are twins and stacking faults in the particles. The particles are covered with an oxide film. Each element is homogeneously dissolved in the nanoparticles and no phase separation is observed.) The element mapping by STEM-HAADF and EDS of Co50Ni50 / C of Table 1 produced in Example 2-1 and the result of the one-dimensional analysis are shown. The element mapping by STEM-HAADF and EDS of Fe50Co50 / C of Table 1 produced in Example 2-1 and the result of the one-dimensional analysis are shown. The element mapping by STEM-HAADF and EDS of Fe50Ni50 / C of Table 1 produced in Example 2-1 and the result of the one-dimensional analysis are shown. The experimental result of the electrochemical oxidation of ethylene glycol obtained in Example 2-7 is shown. The experimental result regarding the direct glycol alkaline fuel cell characteristic obtained in Example 2-8 is shown. 2 shows an ASF distribution (an ASF model in an FT reaction) that probabilistically predicts the product distribution obtained by the FT reaction used in Example 3. The product distribution in the FT reaction after 16 hours on Fe50Co50 / Al2O3 obtained in Example 3 is shown. The olefin and paraffin selectivity in the C3-C5 compound in the FT reaction on Fe50Co50 / Al2O3 obtained in Example 3 is shown.

[Composite containing iron group metal alloy particles]
The present invention relates to a composite comprising a solid support and any one of the following iron group metal alloy particles (a) to (d) supported on the solid support.

(a) Iron group metal alloy particles (a) The iron group metal alloy particles of (a) are iron group metals composed of two or three kinds of iron group metals selected from the group consisting of Fe, Co and Ni. Based alloy particles. However, the iron group metal alloy is a solid solution type alloy of the two or three kinds of iron group metals. In the present specification, the iron group metal group means a group consisting of Fe, Co and Ni. Fe, Co, and Ni are expressed in atomic% (in the present specification, unless otherwise specified,% with respect to the alloy composition means atomic%) and are contained in the range of 0 to 99%. However, the total of Fe, Co, and Ni is 100 atomic%, and at least two of Fe, Co, and Ni have a content exceeding 0.1 atomic%. Fe, C and Ni are expressed in atomic%, preferably each in the range of 0.01 to 99.99%, more preferably in the range of 1 to 99%, still more preferably in the range of 5 to 95%, and still more preferably each. It is contained in the range of 10 to 90%, still more preferably in the range of 20 to 80%, and still more preferably in the range of 30 to 70%.

More specifically, the iron group metal alloy particles (a) are composed of four types of alloy particles of Fe—Co, Fe—Ni, Co—Ni, and Fe—Co—Ni.

In Fe-Co, the Fe: Co atomic% ratio ranges from 0.1 to 99.9: 99.9 to 0.1, preferably from 1 to 99:99 to 1, more preferably from 10 to 90:90 to 10, and Preferably in the range of 20-80: 80-20, more preferably in the range of 30-70: 70-30, even more preferably in the range of 40-60: 60-40, even more preferably 45-55: 55-45. Range. However, when used as an electrode catalyst for a fuel cell, the Fe: Co atomic% ratio can be appropriately determined in consideration of product distribution, power density, and current efficiency.

In Fe-Ni, the Fe: Ni atomic% ratio ranges from 0.1 to 99.9: 99.9 to 0.1, preferably from 1 to 99:99 to 1, more preferably from 10 to 90:90 to 10, and Preferably in the range of 20-80: 80-20, more preferably in the range of 30-70: 70-30, even more preferably in the range of 40-60: 60-40, even more preferably 45-55: 55-45. Range. However, when used as an electrode catalyst for a fuel cell, the Fe: Ni atomic% ratio can be appropriately determined in consideration of product distribution, power density, current efficiency, and life. When used as a Fischer-Tropsch reaction catalyst, the Fe: Ni atomic% ratio can be appropriately determined in consideration of the conversion rate of raw materials, the selectivity of products, and the yield.

In Co-Ni, the Co: Ni atomic% ratio is in the range of 0.1 to 99.9: 99.9 to 0.1, preferably in the range of 1 to 99:99 to 1, more preferably in the range of 10 to 90:90 to 10, and Preferably in the range of 20-80: 80-20, more preferably in the range of 30-70: 70-30, even more preferably in the range of 40-60: 60-40, even more preferably 45-55: 55-45. Range. However, when used as a catalyst for an electrode of a fuel cell, the Co: Ni atomic% ratio can be appropriately determined in consideration of product distribution, power density, current efficiency, and lifetime. When used as a Fischer-Tropsch reaction catalyst, the Co: Ni atomic% ratio can be appropriately determined in consideration of the conversion rate of raw materials, the selectivity of products, and the yield.

In Fe-Co-Ni, the Fe: Co: Ni atomic% ratio can be in the range of 0.01 to 999 when Fe is 1, and Ni can be in the range of 0.01 to 999. . However, the total of the three elements is 100 atomic%. For example, when Co is 0.5 and Ni is 0.5 when Fe is 1, the Fe: Co: Ni atomic% ratio is 50:25:25. When Fe is 1, Co is preferably in the range of 0.05 to 99.95, more preferably in the range of 0.1 to 99.9, and still more preferably in the range of 0.5 to 99.5. When Fe is 1, Ni can be preferably in the range of 0.05 to 99.95, more preferably in the range of 0.1 to 99.9, and still more preferably in the range of 0.5 to 99.9. However, when used as an electrode catalyst for a fuel cell, the Fe: Co: Ni atomic% ratio can be appropriately determined in consideration of product distribution, power density, current efficiency, and lifetime. When used as a Fischer-Tropsch reaction catalyst, the Fe: Co: Ni atomic% ratio can be appropriately determined in consideration of the conversion rate of raw materials, the selectivity of products, and the yield.

(b) Iron group metal alloy particles (b) The iron group metal alloy particles of (b) contain two or three iron group metals selected from the iron group metal group consisting of Fe, Co and Ni. Metal alloy particles. However, the iron group metal-based alloy is a solid solution type alloy in which at least the two or three kinds of iron group metals are used.
In addition to containing two or three types of iron group metals selected from the iron group metal group consisting of Fe, Co, and Ni, the iron group metal-based alloy particles of (b) are described later (c) and ( Additional components other than the transition metal contained in the iron group metal alloy particles of d) may be contained within a range that does not affect the catalyst performance of the iron group metal alloy particles of (b). Examples of such additional components include Al, Zn, V, W, Ta, Y, Re, and Bi. However, the content of the additional component is not particularly limited, but considering that it does not affect the catalytic performance of the iron group metal alloy particles of (b), it is less than 1%, preferably 0.5%. It is suitable that it is less than. In addition, about the part which consists of 2 or 3 types of iron group metals chosen from the iron group metal group which consists of Fe, Co, and Ni, it is the same as that of the iron group metal alloy of the iron group metal alloy particle of (a). .

(c) Iron group metal alloy particles (c) The iron group metal alloy particles of (c) are one, two or three kinds of iron group metals selected from the group of iron group metals consisting of Fe, Co and Ni, and These are iron group metal alloy particles composed of one or more transition metals selected from the group of transition metals composed of Cr, Mn, Cu, Mo, Ru, Rh, Pd, Ag, Ir, Pt and Au. In the present specification, the transition metal group means a group consisting of Cr, Mn, Cu, Mo, Ru, Rh, Pd, Ag, Ir, Pt and Au. However, the said iron group metal-type alloy is a solid solution type alloy in which the said 1 type, 2 type, or 3 type iron group metal and 1 type, or 2 or more types of transition metal are.

The iron group metal alloy particles (c) are iron group metal alloy particles composed of one, two or three kinds of iron group metals and one or more kinds of transition metals. For example, any one of iron group metals Fe, Co, and Ni and iron group metal alloy particles composed of one or more transition metals, Fe and Co, Fe and Ni, or Co and Ni and 1 These are iron group metal alloy particles composed of seeds or two or more transition metals, and iron group metal alloy particles composed of Fe, Co, and Ni and one or more transition metals. The contents of iron group metals and transition metals are each in the range of 0.1 to 99.9%. However, the total of iron group metals and transition metals is 100 atomic%. The content of iron group metal and transition metal, expressed in atomic%, is preferably in the range of 1 to 99%, more preferably in the range of 5 to 95%, and still more preferably in the range of 10 to 90%. More preferably, each is in the range of 20 to 80%, still more preferably in the range of 30 to 70%, and still more preferably in the range of 40 to 60%. However, depending on the type of iron group metal and transition metal, when used as a catalyst for fuel cell electrodes, the atoms of the iron group metal and transition metal are considered in consideration of product distribution, power density, current efficiency and life. The% ratio can be determined as appropriate. Similarly, when used as a Fischer-Tropsch reaction catalyst, the atomic% ratio of the iron group metal and the transition metal can be appropriately determined in consideration of the conversion rate of the raw material, the selectivity of the product, and the yield.

When the iron group metal alloy particles (c) contain two or three kinds of iron group metals, the combination and content ratio of the iron group metals in the iron group metal alloy particles (a) can be referred to. When two or more transition metals are contained, the transition metal combination and content ratio can be appropriately determined in consideration of the crystal structure and solid solution state of the alloy and its catalytic properties.

(d) Iron group metal alloy particles (d) The iron group metal alloy particles of (d) are one, two or three types of iron group metals selected from the group of iron group metals consisting of Fe, Co and Ni, and These are iron group metal alloy particles containing one or more transition metals selected from the group of transition metals consisting of Cr, Mn, Cu, Mo, Ru, Rh, Pd, Ag, Ir, Pt and Au. However, the iron group metal alloy is a solid solution type alloy in which at least one, two or three kinds of iron group metals and one or more kinds of transition metals are used.
The iron group metal alloy particles of (d) contain one or more transition metals selected from the two or three types of iron group metals selected from the iron group metal group and the transition metal group. In addition, an additional component other than the iron group metal and the transition metal can be contained in a range that does not affect the catalyst performance of the iron group metal alloy particles of (d). Examples of such additional components include Al, Zn, V, W, Ta, Y, Re, Bi, and the like. However, the content of the additional component is not particularly limited, but considering that it does not affect the catalytic performance of the iron group metal alloy particles of (d), it is less than 1%, preferably 0.5%. It is suitable that it is less than. In addition, about the part which consists of 2 or 3 types of iron group metals chosen from an iron group metal group, and 1 type or 2 or more types of transition metals chosen from a transition metal group, the iron group metal alloy particle of (c) This is the same as the iron group metal alloy.

<Solid solution type alloy>
In the iron group metal alloy particles (a), two or three iron group metals are solid solution type alloys. In the iron group metal alloy particles of (b), at least two or three kinds of iron group metals are solid solution type alloys, and may be a solid solution type alloy together with the iron group metals including additional components. In the iron group metal alloy particles (c), one, two or three iron group metals and one or more transition metals are solid solution type alloys. In the iron group metal alloy particles of (d), at least one, two or three kinds of iron group metals and one or more kinds of transition metals are solid solution type alloys, and iron groups including additional components are included. It can be a solid solution type alloy together with a metal.

In the present invention, the solid solution type alloy means that the metal atoms constituting the alloy are present uniformly in the alloy particles. Furthermore, the iron group alloy catalyst in which the component metals of the present invention are dissolved at the atomic level is made to be an iron group alloy particle having a small particle size at the nano level, thereby further improving the catalytic reaction activity and reaction selectivity. Also based on. Here, the atomic level means that at least one iron group metal atom bonded to a different metal atom exists in a volume of 16.7 nm ^{3 of} one alloy particle.

However, the different metal atom is an iron group metal atom different from the iron group metal atom, the transition metal atom, or an iron group metal atom different from the iron group metal atom and the transition metal atom. Is an additional component metal atom. That is, in the iron group metal-based alloy particle (a), the different metal atom is an iron group metal atom different from the iron group metal atom. In the iron group metal alloy particles of (b), the different metal atom is an iron group metal atom different from the iron group metal atom or an additional component metal atom. In the iron group metal alloy particles of (c), the different metal atom is an iron group metal atom or a transition metal atom different from the iron group metal atom. In the iron group metal alloy particles of (d), the different metal atom is an iron group metal atom or transition metal atom different from the iron group metal atom, or is an additional component metal atom.

In the solid solution type alloy particles, it is desirable that the number of iron group metal atoms bonded to different metal atoms present in a volume of 16.7 nm ^{3 of} one alloy particle is in proportion to the alloy composition.

The iron group metal alloy particles are preferably alloy particles having a particle volume of 16.7 nm ³ or more and 10,466.7 nm ³ or less from the viewpoint that they can be used as a highly active catalyst. Viewpoint volume one particle is preferably 20 nm ³ or more 5,000 nm ³ or less, more preferably 50 nm ³ or more 1,000 nm ³ or less, still more preferably used as a catalyst is highly active is at 50 nm ³ or more 1,000 nm ³ or less To preferred. In the composite of the present invention, any alloy particles containing at least 10% by mass or more of alloy particles having a volume within the above range may be supported on a solid support. The loading amount of the alloy particles having a volume within the above range on the solid support is preferably 30% by mass or more, more preferably 50% by mass or more, further preferably 70% by mass or more, and more preferably 90% by mass or more. It is.

Solid Support The composite of the present invention comprises a solid support and any one of iron group metal alloy particles (a) to (d) supported on the solid support. The solid carrier can be appropriately selected from materials that can exhibit suitable activity and durability when the composite of the present invention is used as various catalysts. The solid support used in the composite of the present invention is preferably at least partially made of a porous material, and it is appropriate that iron group metal alloy particles are supported on the surface of the porous material. Therefore, it is appropriate for the solid support used in the composite of the present invention that at least the surface of the portion on which the iron group metal alloy particles are supported is made of a porous material, and the entire solid support is made of a porous material. Alternatively, the surface of a support made of a non-porous material may be coated with a porous material. The support may be made of another porous material.

The solid support used in the composite of the present invention can be at least partially made of, for example, a carbon-based material or an inorganic material. Examples of the carbon-based material include activated carbon and carbon nanotubes. An inorganic oxide material can be mentioned as an inorganic material. Examples of the inorganic oxide material include silica, alumina, silica-alumina, zeolite, titania, zirconia and the like. The solid support preferably has a large surface area, for example, a specific surface area of 500 to 2000 m ² / g is preferred.

The shape and form of the solid carrier are not particularly limited, and can be, for example, powder, particle, granule, pellet, honeycomb or the like. The carrier in the form of powder, particles, granules, or pellets can be composed of, for example, only the above-mentioned porous material carrier material. On the other hand, the carrier having a honeycomb structure may be a non-porous material, for example, a surface of a support made of cordierite or the like and coated with the porous material carrier material. Further, as described above, the support may be made of another porous material.

When the shape of the solid carrier is, for example, powder, particle or granule, the solid carrier suitably contains particles having a diameter in the range of 1 nm to 10 μm, and the diameter is in the range of 10 nm to 10 μm. It is preferable to contain particles, and it is more preferable to contain particles having a diameter in the range of 10 nm to 500 μm. The particle size of the solid support can be appropriately selected according to the use of the composite of the present invention.

The amount of iron group metal alloy particles supported on the solid support can be appropriately determined in consideration of the type of iron group metal alloy particles, the type of solid support, the use of the composite, and the like. For example, the supported amount of iron group metal-based alloy particles can be in the range of 0.01 to 50 with respect to the solid support 100 in terms of mass ratio. From the viewpoint of high activity per unit mass of the composite and high activity per unit mass of the iron group metal alloy particles, the amount of iron group metal alloy particles supported on the solid support 100 is 0.1. It is preferably in the range of ˜30, more preferably in the range of 0.5-15, and even more preferably in the range of 1-10. However, it is not intended to be limited to this range.

[Production method of composite]
The composite of the present invention can be produced by a method including steps (1) to (3).
In the present invention, in order to control the particle size of the alloy particles, a solution in which a water-soluble polymer is mixed as an inhibitor of the aggregation of iron group metal ions and / or transition metal ions and particles is used. It is expected that the iron group metal ions and / or transition metal ions interact with the polymer to suppress aggregation between the same type of metals. A reducing agent was added to this mixed solution to reduce it to a metal once, and it was re-oxidized as it was, thereby mixing the iron group metal and its oxide and / or transition metal or transition metal oxide with a water-soluble polymer. A nanoalloy precursor is prepared. Even in the precursor, solid solution (mixing) of metal ions at the atomic level is maintained. Furthermore, by heating the precursor in a hydrogen atmosphere, it becomes possible to simultaneously reduce the constituent metal ions, the component metal is dissolved at the atomic level, and the nano-alloy catalyst whose particle size is controlled (for example, 1-50 nm) can be produced.

Process (1)
Step (1) is a step of preparing a mixture by mixing at least two metal-containing compounds selected from the group consisting of an iron group metal-containing compound and a transition metal-containing compound, a protective polymer, a solvent, and a solid support. However, the iron group metal is selected from the iron group metal group consisting of Fe, Co and Ni, and the transition metal group is composed of Cr, Mn, Cu, Mo, Ru, Rh, Pd, Ag, Ir, Pt and Au. Chosen from. The at least two compounds used in step (1) are two or three iron group metal-containing compounds, or one or more iron group metal-containing compounds and one or more transition metals. Containing compounds.

The iron group metal-containing compound is not particularly limited as long as it is a compound containing an iron group metal. Appropriate solubility in the solvent used in step (1) is appropriate. Examples of such compounds include inorganic iron group metal-containing compounds such as iron group metal chlorides, sulfates, nitrates, and hydrates thereof, and complexes containing iron group metals. When the iron group metal is iron, examples thereof include inorganic iron-containing compounds such as iron chloride, iron sulfate, iron nitrate, and hydrates thereof, and also complexes containing iron. Examples of the complex containing iron include iron acetate, iron acetylacetonate, tetraethylammonium tetrachloroiron (II), tetraethylammonium tetrachloroiron (III), bis (sulfide) tetranitrosyl and iron (2-) sodium. Octahydrate, tris (sulfide) heptanitrosyltetraferrate (1-) ammonium monohydrate, hexaammineiron (II) bromide, tetrakis (thiophenolato) iron (II) acid tetraphenylphosphonium, tetrakis (2,3 , 5,6-tetramethylphenolato) tetraethylammonium iron (III), potassium hexacyanoferrate (II), potassium hexacyanoferrate (III), pentacyanoammineferrate sodium trihydrate, pentacyano Sodium ammine iron (III) trihydrate, sodium pentacyanonitrosyl iron (III) dihydrate, pentacyanonitroiron (II) Examples include potassium acid monohydrate, sodium tetracyano (ethylenediamine) iron (II) acid trihydrate, and the like. However, these compounds are illustrative and are not intended to be limiting.

When the iron group metal is nickel, for example, inorganic nickel-containing compounds such as nickel chloride, nickel nitrate and hydrates thereof, and further complexes containing nickel can be given. Examples of the complex containing nickel include nickel acetate, nickel acetylacetonate, tetraethylammonium tetrachloronickel (II), tetraethylammonium tetrabromonickel (II), hexaamminenickel (II) chloride, dinitrotetraamminenickel ( II), potassium tetracyanonickel (II) monohydrate, potassium barium hexanitronickel (II), tris (ethylenediamine) nickel (II) sulfate, bis (ethylenediamine) diaquanickel nitrate, ethylenediaminetetraaquanickel (II) Sulfate monohydrate, dinitro (ethylenediamine) nickel (II), bis (N, N-dimethylethylenediamine) nickel (II) perchloric acid, bis (2,3-dimethyl-2,3-diaminobutane ) Nickel (II) iodide, bis (perchlorato) tetrapyridine nickel ( II), acetylacetonato (nitrato) (N, N, N ′, N′-tetramethylethylenediamine) nickel (II) and the like. However, these compounds are illustrative and are not intended to be limiting.

When the iron group metal is cobalt, examples thereof include inorganic cobalt-containing compounds such as cobalt chloride, cobalt sulfate, cobalt nitrate and hydrates thereof, and further complexes containing cobalt. Examples of the complex containing cobalt include cobalt acetate (II) tetrahydrate, cobalt acetylacetonate, potassium hexacyanocobalt (III), calcium (ethylenediaminetetraacetato) cobalt (III), pentachlorohydrate (chloro ( Ethylenediaminetetraacetato) cobalt (III) potassium, dichlorobis (ethylenediamine) cobalt (III) chloride, carbonatotetraamminecobalt (III) chloride, tris (ethylenediamine) cobalt (III) chloride trihydrate, ethylenediaminetetra Nitrocobalt (III) potassium, diamminebis (oxalato) cobalt (III) potassium, cobalt thiocyanate (II) trihydrate, hexaammine cobalt (II) chloride, pentaammine nitrocobalt (III) chloride, Cobalt (II) perchlorate Mention may be made of a hydrate and the like. However, these compounds are illustrative and are not intended to be limiting.

The transition metal-containing compound is not particularly limited as long as it is a compound containing a transition metal. Appropriate solubility in the solvent used in step (1) is appropriate. Examples of such compounds include inorganic transition metal-containing compounds such as transition metal chlorides, sulfates, nitrates, and hydrates thereof, and complexes containing transition metals. Examples of the complex containing a transition metal include chromium (III) acetate monohydrate, chromium (III) oxalate hexahydrate, hexaammine chromium (III) chloride, and chromium (III) ammonium dodecahydrate. , Ammonium tetrachloromanganese (II) dihydrate, potassium pentachloromanganese (II), potassium hexacyanomanganese (III), copper acetate (II) monohydrate, potassium pentanitrocopper (II), Ammonium tetrachlorocopper (II), potassium dimolybdate, ammonium pentachlorooxomolybdate (V), sodium trimolybdate heptahydrate, tris (acetylacetonato) ruthenium (III), hexacyanoruthenium (II) acid Potassium trihydrate, potassium tris (oxalato) ruthenium (III), potassium hexacyanorhodium (III), Oxaammine rhodium (III) chloride, potassium tris (oxalato) rhodium (III), sodium tetrachloropalladium (IV), potassium hexachloropalladium (IV), tetraamminepalladium (II) chloride monohydrate, diammine Silver (I) sulfate, silver acetate (I), potassium dicyanosilver (I), potassium hexachloroiridium (IV), hexaammineiridium (III) chloride, potassium iridium sulfate (III) dodecahydrate, Tetraammineplatinum (II) chloride monohydrate, ammonium tetrachloroplatinum (II), ammonium hexachloroplatinum (IV), potassium tetrachlorogold (III) dihydrate, potassium dicyanogold (I), Examples include potassium tetracyanoaurate (III). However, these compounds are illustrative and are not intended to be limiting.

The protective polymer exhibits affinity for the iron group metal-containing compound and / or transition metal-containing compound, and further exhibits solubility in a solvent, such as the iron group metal-containing compound and / or transition metal-containing compound. A polymer having a functional group moiety having an affinity for the metal-containing compound, for example, a polymer having a polar functional group, is suitable, and a water-soluble polymer is preferred. Examples of the protective polymer include polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polyethylene glycol (PEG), polyvinyl ether, polyacrylate, poly (mercaptomethylenethrylene-N-vinyl-2-pyrrolidone), polyacrylonitrile. And so on. Furthermore, a polymer having a cyclic amide structure such as PVP is preferable. The protective polymer has a solubility in water and a solvent that is equivalent to that of the iron group metal-containing compound and the transition metal-containing compound, and may be a substance that interacts with the metal complex raw material and may be complexed.

The role of the protective polymer is mainly to prevent aggregation between the precursor particles and / or alloy particles produced in the steps (2) and (3), and to reduce the size of the precursor particles and / or alloy particles produced. Is to control. The average particle diameter of the precursor particles and / or alloy nanoparticles is, for example, 1 to 200000 nm, desirably 1 to 5000 nm, preferably 1 to 1000 nm, more preferably 1 to 200 nm, and still more preferably. 1-100 nm, even more preferably 1-50 nm, even more preferably 1-20 nm, even more preferably 1-10 nm, and most preferably the average particle size is in the range of 1-4 nm. It is. Therefore, in order to maintain this particle diameter, it is preferable to use a means for protecting each nanoparticle from aggregation or the like, and a protective polymer is used as a means therefor. Furthermore, the particle size of the alloy can be controlled by adjusting the ratio of metal to protective polymer. For example, when the amount of the protective polymer in the solvent is relatively increased, the particle size of the precipitated precursor particles and / or alloy particles is reduced. By utilizing this phenomenon, the particle size of the precursor particles and / or alloy particles can be controlled. In addition, the particle size of the alloy particle to precipitate can be adjusted also by adjusting the density | concentration of an iron group metal containing compound and / or a transition metal containing compound.

The solvent is a solvent capable of dissolving the iron group metal-containing compound and / or the transition metal-containing compound and the protective polymer. Here, dissolution is a state in which the iron group metal-containing compound and / or the transition metal-containing compound and the protective polymer are dissolved in a solvent, and the solution is preferably transparent. As the solvent, water and / or an organic solvent or a mixed solvent thereof can be used. The organic solvent is preferably an organic solvent having an affinity for water or an organic solvent having a polar site from the viewpoint of excellent solubility in an iron group metal-containing compound and / or transition metal-containing compound and a protective polymer. The solvent can also be a mixed solvent of water and an organic solvent having an affinity for water. The organic solvent may be appropriately selected according to the type of the iron group metal-containing compound and / or transition metal-containing compound and the protective polymer. For example, polyhydric alcohols such as ethanol, propanol, ethylene glycol, triethylene glycol, and glycerin are used. Can be used. Even when using a mixed solvent of water and an organic solvent, considering the solubility of the iron group metal-containing compound and / or transition metal-containing compound and the protective polymer, the type of organic solvent and the mixing ratio of the organic solvent and water Can be adjusted as appropriate.

The presence state of the iron group metal-containing compound and / or transition metal-containing compound and the protective polymer in the solvent is not particularly limited, and may be in a dispersed and / or dissolved state. The dispersed state is a dispersion, and the dissolved state is a solution. Note that the solid carrier is dispersed in a solvent. The mixture can also be heated during dissolution. This includes cases where dispersion and dissolution coexist. Whether the iron group metal-containing compound and / or the transition metal-containing compound and the protective polymer are in a dispersed state, a dissolved state, or a coexistence state of both, the iron group metal-containing compound and / or the transition metal is contained. It varies depending on the type of the compound and the protective polymer, the solvent, and the concentration of the iron group metal-containing compound and / or transition metal-containing compound and the protective polymer in the solvent. The concentrations of the iron group metal-containing compound and / or transition metal-containing compound and the protective polymer in the solvent are determined in consideration of the composition of the precursor, the particle diameter, and the like. The concentration of the protective polymer, the concentration of the iron group metal ion and / or the concentration of the transition metal ion in the dispersion or solution is, for example, in the range of 1 × 10 ⁻⁷ to 10 mol / L for the protective polymer, 1 × 10 ^-10 ~ 10mol / L range, and transition metal ions can be in the range of ^{1 × 10 -10 ~ 10mol / L} .

The dispersion or solution can be prepared by adding a protective polymer and an iron group metal-containing compound and / or a transition metal-containing compound to the solvent and dissolving or dispersing it. There is no restriction | limiting in the addition order of a protective polymer and an iron group metal containing compound and / or a transition metal containing compound. It can also be prepared by appropriately mixing a solution in which the protective polymer is dispersed or dissolved, a solution in which the iron group metal-containing compound is dissolved, and a solution in which the transition metal-containing compound is dissolved. The solid carrier can be added to and mixed with the dispersion or solution thus obtained to prepare a mixture, and when the protective polymer and the iron group metal-containing compound and / or transition metal-containing compound are added to the solvent. In addition, a mixture can be prepared by adding a solid carrier.

The operation of dispersing or dissolving the iron group metal-containing compound, transition metal-containing compound and protective polymer in a solvent can be carried out at room temperature or under heating or cooling. Furthermore, the operation of dispersion or dissolution in the solvent may be performed in a stationary state or in a stirred state. Furthermore, the mixture can be prepared by adding a solid carrier at room temperature or under heating or cooling.

Process (2)
In step (2), a reducing agent for the metal ions contained in the metal-containing compound is added to the mixture obtained in step (1), so that the supported precursor containing iron group metal or iron group metal and transition metal is added. This is a process for preparing body particles.

The reducing agent is selected from substances whose oxidation-reduction potential is lower than the oxidation-reduction potential of the metal to be reduced. Specifically, as the reducing agent, it is appropriate to use a compound whose standard reduction potential is more negative than hydrogen (0 eV) at room temperature from the viewpoint of strong ability to reduce iron group metal ions to metals. Examples of such a reducing agent include MBH ₄ , MEt ₃ BH (M = Na, K), sodium cyanoborohydride NaBH ₃ CN, lithium borohydride LiBH ₄ , lithium triethylborohydride LiBHEt ₃ , and borane complex. BH ₃ · L (L is a ligand, such as THF (tetrahydrofuran), SMe ₂ (dimethyl sulfide)), triethylsilane Et ₃ SiH, sodium bis (2-methoxyethoxy) aluminum hydride (Sodium Bis (2-methoxyethoxy ) Alminium Hydride; Red-Al). However, some of these reducing agents are dangerous because they react explosively with water and cannot be used in an aqueous solution. In that case, it is appropriate to use a solvent other than water (for example, an aprotic polar solvent such as tetrahydrofuran, N, N-dimethylformamide, dimethylsulfoxide) as the solvent.

The amount of reducing agent used is appropriately determined in consideration of the amount of iron group metal and / or transition metal contained in the metal raw material, for example, the total amount of iron group metal and / or transition metal ions to be reduced. It can be in the range of equivalent to 200 times equivalent or less. Preferably, it is in the range of the equivalent of the total amount of iron group metal and / or transition metal ion to 50 times equivalent or less

The method for adding the reducing agent is not particularly limited, but for example, a powdery or granular reducing agent can be added to the mixture. Alternatively, for example, a powdery or granular reducing agent may be dissolved and / or dispersed in the solvent used in the step (1), and the dissolved and / or dispersed liquid may be added to the mixture. The solvent used is preferably inert to the reducing agent from the viewpoint of reduction efficiency.

The precursor particles are prepared by reducing the iron group metal and / or transition metal ions with the above reducing agent. The reduction temperature with the reducing agent is determined in consideration of the crystal structure of the alloy to be prepared by reduction, and is suitably in the range of 0 to 200 ° C., for example. The range of 25 to 160 ° C. is preferable.

In the step (2), the obtained precursor particles containing an iron group metal and / or transition metal are particles containing an iron group metal oxide and / or a transition metal oxide, or an iron group metal alloy. Alternatively, it is a particle containing an iron group metal and a transition metal alloy, and an iron group metal oxide or an iron group metal oxide and a transition metal oxide. When the amount of the reducing agent is excessive, the iron group metal and / or the transition metal ion may be reduced to the metal (alloy) correspondingly by the reduction during the preparation of the precursor particles. However, the precursor particles containing metal are oxidized by being exposed to an atmosphere containing oxygen. Therefore, the precursor particles immediately after the synthesis have a relatively high metal (alloy) content, and the amount thereof decreases with time. The ratio of iron group metal alloy or iron group metal and transition metal alloy, and iron group metal oxide or iron group metal oxide and transition metal oxide (alloy: oxide) varies depending on the reduction conditions. The range can be: 0.1 to 100: 0.1 to 100. However, it is not intended to be limited to this range.

The ratio of the iron group metal or the ratio of the iron group metal and the transition metal in the precursor particles can be appropriately determined by adjusting the composition ratio of the raw materials according to the composition of the target alloy particles. The precursor particles containing the iron group metal obtained in the step (2) can be, for example, particles containing at least one of iron oxide, cobalt oxide, and nickel oxide.

The reaction product in the step (2) can be appropriately washed with an organic solvent or the like after completion of the reaction and before being subjected to the step (3). For example, a mixed solution of acetone and diethyl ether is used as an organic solvent, and this solution is added to the solid phase and the liquid phase until separation occurs, and then centrifuged to recover the solid phase. Next, the recovered solid phase is dispersed in water, and acetone is added to the dispersion to separate the solid phase and the liquid phase again, followed by centrifugation to obtain a washed sample. By this operation, the complex composed of the metal supported on the solid support can be separated from impurities such as Na and boric acid.

Process (3)
In step (3), the precursor particles are heated in a hydrogen-containing atmosphere to reduce the precursor particles, and alloy particles having a volume of 16.7 nm ³ or more and 10466.7 nm ³ or less are supported on a solid support. This is a step of obtaining a complex.

The heat treatment in the hydrogen atmosphere can be performed at a predetermined temperature and hydrogen pressure after removing the solvent from the precursor particles obtained in the step (2) or together with the solvent. The temperature can be, for example, in the range of 200 ° C. to 1000 ° C., and the hydrogen pressure can be in the range of 0.01 Pa to 100 MPa. The conditions for the heat treatment in the hydrogen atmosphere are preferably in the range of 300 to 950 ° C. and the hydrogen pressure in the range of 0.01 MPa to 5 MPa. The conditions of the heat treatment in the hydrogen atmosphere are more preferably in the range of 400 to 900 ° C. and the hydrogen pressure in the range of 0.1 MPa to 3 MPa. The heating temperature is more preferably in the range of 500 to 900 ° C. The treatment time can be appropriately set according to the temperature and pressure, and can be, for example, in the range of 0.05 to 10 hours. However, it is not intended to be limited to this range. The hydrogen content of the hydrogen-containing atmosphere can be, for example, in the range of more than 1 vol% and not more than 100 vol%, and can contain an inert gas such as argon or nitrogen in addition to hydrogen.

The hydrogen atmosphere heat treatment in the step (3) is preferably performed under the condition that the obtained iron group nanoalloy particles have a crystallite size having a volume of 16.7 nm ³ or more and 10466.7 nm ³ or less. By selecting conditions from a temperature in the range of 200 ° C. to 1000 ° C. and a hydrogen pressure in the range of 0.01 Pa to 100 MPa, alloy particles having a crystallite size having the above volume range can be obtained.

[Alkaline fuel cell catalyst]
The composite of the present invention can be used as a catalyst for a solid oxide alkaline fuel cell. The alkaline fuel cell can be, for example, a fuel cell that uses hydrogen as a fuel as described above. Furthermore, the alkaline fuel cell can be, for example, a fuel cell using a glycol as a fuel (an alkaline direct ethylene glycol fuel cell). In a cycle using glycol as a fuel, a selective oxidation catalyst that generates oxalic acid from glycol and does not oxidize to carbon dioxide is preferable, and the complex of the present invention includes a catalyst exhibiting such selective oxidation activity. Yes.

[Anode for fuel cell]
The present invention includes an anode for a fuel cell having a layer comprising an anode composition containing the composite of the present invention and an anion conductive material on a substrate surface.

The ion-conducting material used for the anode composition has a function as an ion-conducting medium for conducting hydroxide ions generated by an electrochemical reaction to the solid polymer electrolyte at the cathode. It has a function as a binder that binds the catalyst particles made of the composite to the conductive porous substrate as an electrode catalyst layer. As this ion conductive material, a material made of the same material as the solid polymer electrolyte or the solid oxide electrolyte can be used, for example, known as Flemillon (Asahi Glass). Not only is the catalyst particles excellent in binding properties but also ion conductivity. However, the ion conductive material that can be used in the present invention is not limited to the solid polymer electrolyte.

According to the present invention, in the electrode catalyst layer, the ratio of the mass of the catalyst particles to the mass of the ion conductive material (hereinafter sometimes referred to as “catalyst particle / polymer mass ratio”) is, for example, 3/1 to 20 / 1 and preferably in the range of 4/1 to 18/1.

In the present invention, the electrode catalyst layer may contain a small amount of other resin as a binder for the catalyst particles in addition to the ion conductive material. Examples of the other resin include a fluorine resin having no proton conductivity, and more specifically, for example, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, polytetrafluoroethylene. Mention may be made of ethylene fluoride. The proportion of the resin in the binder is preferably 30% by weight or less, and particularly preferably 10% by weight or less in the binder.

In addition, examples of the conductive porous substrate include paper, nonwoven fabric, woven fabric, knitted fabric, and conductive porous membrane made of fibers such as porous carbon powder and conductive polymer.

[Membrane electrode assembly for fuel cells]
The present invention further includes a membrane electrode assembly for a fuel cell in which the anode and the cathode of the present invention are laminated with a polymer electrolyte membrane interposed therebetween.

In the present invention, the cathode is formed by binding and supporting an electrode catalyst together with a binder as an electrode catalyst layer on a conductive porous substrate, and its configuration is not particularly limited. The electrode catalyst layer is, for example, a carbon black powder carrying platinum fine particles, a carbon black powder as a conductive auxiliary agent, a binder for bringing them together, and an ion conductor that becomes a conductor of ions generated by an electrochemical reaction. Suitably contains a functional material or the like.

For example, the cathode may be a paste using, for example, carbon black powder supporting platinum fine particles and, if necessary, carbon black as a conductive aid using a suitable binder, and this is described above. It can obtain by apply | coating to such an electroconductive porous base material, heating and drying.

In addition, each conductive porous substrate constituting the cathode and the anode can have a conductive water repellent layer on the side on which the electrode catalyst is supported in order to prevent so-called flooding.

〔Fuel cell〕
Furthermore, the present invention includes a fuel cell including the fuel cell membrane electrode assembly of the present invention.

The operating temperature of the fuel cell according to the present invention is usually 0 ° C. or higher, preferably in the range of 15 to 200 ° C., more preferably in the range of 30 to 100 ° C. When the operating temperature is too high, the material used may be deteriorated or peeled off.

In an alkaline direct ethylene glycol fuel cell, the composite of the present invention can be used as a catalyst for the fuel electrode (anode). However, since it is used as a catalyst for electrodes, the solid support is preferably a conductive material, for example, a carbon-based material (for example, activated carbon, carbon black, carbon nanotube, porous carbon material, etc.). As shown in the Examples, the complex of the present invention exhibits ethylene glycol oxidation reaction (EOR) activity. The reaction in this fuel cell is as follows.
Fuel _{_{electrode: HOCH 2 CH 2 OH + 8}} OH - → (COOH) 2 + 6 H 2 O + 8 e -
Oxygen _{_{electrode: 2 O 2 + 4 H 2}} O + 8 e - → 8 OH -
Total reaction: HOCH ₂ CH ₂ OH + 2 O ₂ → (COOH) ₂ + 2 H ₂ O

An alkaline direct ethylene glycol fuel cell can be constructed by using the composite of the present invention as a catalyst for a fuel electrode (anode). Furthermore, by reducing oxalic acid, which is an emission from a fuel cell that uses ethylene glycol as a fuel, to ethylene glycol using, for example, a photocatalyst, a fuel cell capable of reusing the fuel can be provided.

[Fischer-Tropsch reaction catalyst]
The composite of the present invention can be used as a catalyst for a Fischer-Tropsch (FT) reaction. However, regarding the FT reaction catalyst, the composite in which the iron group metal alloy particles are iron group metal alloy particles made of Fe and Co are excluded from the composite of the present invention.

The FT reaction is a method of synthesizing hydrocarbons from synthesis gas (a mixed gas containing carbon monoxide and hydrogen as main components). Examples of the FT reaction include a reaction in which a linear saturated or unsaturated hydrocarbon is produced from synthesis gas (CO + H ₂ ) using the complex of the present invention as a catalyst. The reaction formula at this time is as follows.
nCO + (2n + 1) H ₂ → C _n H _{2n + 2} + nH ₂ O
nCO + 2nH ₂ → C _n H _2n + nH ₂ O

The catalyst for FT reaction comprising the composite of the present invention has a high CO conversion rate and efficiency when used for the production of light olefins having 2 to 4 carbon atoms such as ethylene, propylene and butene by FT reaction. It can be obtained well. The FT reaction catalyst comprising the composite of the present invention is particularly suitable for the production of propylene. The pressure in the FT reaction can be, for example, in the range of normal pressure to 10 MPa, preferably in the range of 0.5 to 5 MPa, and the temperature is in the range of 200 to 450 ° C., preferably in the range of 200 to 350 ° C. be able to.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not intended to be limited to the scope described in the examples.

[Example 1-1] Fe ₃₃ Co ₃₃ Ni ₃₃ / C50wt%
0.0747 g of iron (II) acetate, 0.0706 g of cobalt (II) acetate, 0.0996 g of nickel (II) acetate tetrahydrate, 0.0515 g of polyethylene glycol (hereinafter referred to as PEG) and 0.0692 g of vulcan (registered) (Trademark) was mixed with 200 ml of triethylene glycol (hereinafter referred to as TEG). The mixed solution was heated to 80 ° C., 0.75 g of NaBH ₄ was added, and the mixture was stirred for 5 minutes and then allowed to cool. A mixed solution of acetone: diethyl ether = 2: 1 was added to the reaction mixture until separation occurred between the black layer and the colorless and transparent solution layer, and then centrifuged to obtain a black sample. The resulting black precipitate was dispersed in water. Acetone was added to this mixture to separate the black sample from the colorless and transparent solution, and the operation of centrifuging was repeated three times to obtain a black sample.

This sample is called a catalyst precursor. The catalyst precursor was dried in a vacuum desiccator. The dried catalyst precursor was pulverized into a powder. 500 mg of the precursor powder was transferred to a quartz boat, and a catalyst was prepared by raising the temperature to 700 ° C. while 5% H ₂ —Ar gas was circulated.

TEM measurement revealed that the particle size of Fe-Co-Ni nanoparticles supported on Vulcan (registered trademark) was 35.6 nm. From the powder XRD measurement, it was found that the nanoparticles in the prepared catalyst had a bcc structure. From the ICP-AES measurement, the catalyst contained 49 wt% of metal, Fe: Co: Ni = 34: 34: 32 It was clear that there was.

[Example 1-2] Fe ₅₀ Co ₅₀ / C50wt%
0.5611 g of iron (II) acetate, 0.5333 g of cobalt (II) acetate, 2.6337 g of PEG and 0.3460 g of Vulcan® were mixed in 200 ml of TEG. After heating the mixed solution to 80 ° C., 2.2895 g of NaBH 4 was added and stirred for 8 minutes, and then allowed to cool. A mixed solution of acetone: diethyl ether = 2: 1 was added to the reaction mixture until separation occurred between the black layer and the colorless and transparent solution layer, and then centrifuged to obtain a black sample. The resulting black precipitate was dispersed in water. Acetone was added to this mixture to separate the black sample from the colorless and transparent solution, and the operation of centrifuging was repeated three times to obtain a black sample. This sample is called a catalyst precursor. The catalyst precursor was dried in a vacuum desiccator.

The dried catalyst precursor was pulverized into a powder. 500 mg of the precursor powder was transferred to a quartz boat, and a catalyst was prepared by raising the temperature to 700 ° C. while 5% H ₂ —Ar gas was circulated.

TEM measurement revealed that the particle size of Fe-Co nanoparticles supported on Vulcan (registered trademark) was 24 nm. From the powder XRD ナノ measurement, it was found that the nanoparticles in the prepared catalyst had a bcc structure. From the ICP-AES measurement, it was clear that the catalyst contained 47 wt% of metal and Fe: Co = 51: 49. I did.

[Example 1-3] Co ₅₀ Ni ₅₀ / C50wt%
0.5335 g cobalt (II) acetate, 0.7471 g nickel (II) acetate tetrahydrate, 2.6378 g PEG and 0.3458 g Vulcan® were mixed in 200 ml TEG. The mixed solution was heated to 80 ° C., 2.31 g of NaBH ₄ was added, and the mixture was stirred for 10 minutes and then allowed to cool. A mixed solution of acetone: diethyl ether = 2: 1 was added to the reaction mixture until separation occurred between the black layer and the colorless and transparent solution layer, and then centrifuged to obtain a black sample. The resulting black precipitate was dispersed in water. Acetone was added to this mixture to separate the black sample from the colorless and transparent solution, and the operation of centrifuging was repeated three times to obtain a black sample. This sample is called a catalyst precursor. The catalyst precursor was dried in a vacuum desiccator.

TEM measurement revealed that the particle size of Co-Ni nanoparticles supported on Vulcan (registered trademark) was 13 nm. From the powder XRD ナノ measurement, it was found that the nanoparticles in the prepared catalyst had a bcc structure. From the ICP-AES measurement, it was clear that the catalyst contained 42 wt% of metal and Co: Ni = 48: 52. I did.

[Example 1-4] Fe50Ni50 / C50wt%
0.5612 g of iron (II) acetate, 0.7471 g of nickel (II) acetate tetrahydrate, 2.6368 g of PEG and 0.71 g of Vulcan® were mixed into 200 ml of TEG. After heating the mixed solution to 80 ° C., 2.4037 g of NaBH ₄ was added and stirred for 7 minutes, and then allowed to cool. A mixed solution of acetone: diethyl ether = 2: 1 was added to the reaction mixture until separation occurred between the black layer and the colorless and transparent solution layer, and then centrifuged to obtain a black sample. The resulting black precipitate was dispersed in water. Acetone was added to this mixture to separate the black sample from the colorless and transparent solution, and the operation of centrifuging was repeated three times to obtain a black sample. This sample is called a catalyst precursor. The catalyst precursor was dried in a vacuum desiccator.

TEM measurement revealed that the particle size of Fe-Ni nanoparticles supported on Vulcan (registered trademark) was 22 nm. From the powder XRD ナノ measurement, it was found that the nanoparticles in the prepared catalyst had a bcc structure. From the ICP-AES measurement, it was clear that the catalyst contained 44 wt% of metal and Fe: Ni = 50: 50. I did.

[Example 1-5]
Fe ₂₅ Co ₇₅ / C20wt%
0.135 g of iron (II) acetate, 0.4 g of cobalt (II) acetate, 1.33 g of polyethylene glycol (hereinafter referred to as PEG) and 0.71 g of Vulcan (registered trademark) in 200 ml of triethylene glycol (hereinafter referred to as TEG) Mixed). After heating the mixed solution to 120 ° C., 1.1 g of NaBH ₄ was added and stirred for 5 minutes, and then allowed to cool. A mixed solution of acetone: diethyl ether = 2: 1 was added to the reaction mixture until separation occurred between the black layer and the colorless and transparent solution layer, and then centrifuged to obtain a black sample. The resulting black precipitate was dispersed in water. Acetone was added to this mixture to separate the black sample from the colorless and transparent solution, and the operation of centrifuging was repeated three times to obtain a black sample. This sample is called a catalyst precursor. The catalyst precursor was dried in a vacuum desiccator.

TEM measurement revealed that the particle size of Fe-Co nanoparticles supported on Vulcan (registered trademark) was 17 ± 8 nm. From the powder XRD measurement, it was found that the nanoparticles in the prepared catalyst had a bcc structure. From the ICP-AES measurement, the catalyst contained 14.1 wt% of metal, and Fe: Co = 22: 78. It was clear.

[Example 1-6] Fe ₆₀ Co ₄₀ / C20wt%
0.26 g iron (III) acetylacetonate, 0.27 g cobalt (II) acetate, 1.33 g PEG and 0.71 g Vulcan® were mixed in 200 ml TEG. The mixed solution was heated to 80 ° C., 1.1 g of NaBH ₄ was added, and the mixture was stirred for 5 minutes and then allowed to cool. A mixed solution of acetone: diethyl ether = 2: 1 was added to the reaction mixture until separation occurred between the black layer and the colorless and transparent solution layer, and then centrifuged to obtain a black sample. The resulting black precipitate was dispersed in water. Acetone was added to this mixture to separate the black sample from the colorless and transparent solution, and the operation of centrifuging was repeated three times to obtain a black sample. This sample is called a catalyst precursor. The catalyst precursor was dried in a vacuum desiccator.

The dried catalyst precursor was pulverized into a powder. 500 mg of precursor powder was transferred to a quartz boat, and a catalyst was prepared by raising the temperature to 700 ° C. in a state where 5% H2-Ar soot gas was circulated.

TEM measurement revealed that the particle size of Fe-Co nanoparticles supported on Vulcan (registered trademark) was 24 ± 14 nm. From the powder XRD measurement, it was found that the nanoparticles in the prepared catalyst had a bcc structure. From the ICP-AES measurement, the catalyst contained 12.7 wt% of metal and Fe: Co = 55: 45%. It was clear.

[Example 1-7] Fe ₇₅ Co ₂₅ / C20 wt%
0.39 g of iron (II) acetate, 0.13 g of cobalt (II) acetate, 1.33 g of PEG and 0.71 g of Vulcan® were mixed into 200 ml of TEG. After heating the mixed solution to 120 ° C., 1.1 g of NaBH ₄ was added and stirred for 5 minutes, and then allowed to cool. A mixed solution of acetone: diethyl ether = 2: 1 was added to the reaction mixture until separation occurred between the black layer and the colorless and transparent solution layer, and then centrifuged to obtain a black sample. The resulting black precipitate was dispersed in water. Acetone was added to this mixture to separate the black sample from the colorless and transparent solution, and the operation of centrifuging was repeated three times to obtain a black sample.

TEM measurement revealed that the nanoparticles supported on Vulcan (registered trademark) had a particle size of 18 ± 9 nm. From powder XRD measurement, Fe nanoparticles in the prepared catalyst have a bcc structure, and from ICP-AES measurement, it was clear that the catalyst contained 22 wt% of metal and Fe: Co = 72: 28%. .

[Reference Example 1] Co / C50wt%
1.06 g of cobalt (II) acetate, 1.33 g of PEG and 0.71 g of Vulcan® were mixed into 200 ml of TEG. After heating the mixed solution to 120 ° C., 1.1 g of NaBH ₄ was added and stirred for 5 minutes, and then allowed to cool. A mixed solution of acetone: diethyl ether = 2: 1 was added to the reaction mixture until separation occurred between the black layer and the colorless and transparent solution layer, and then centrifuged to obtain a black sample. The resulting black precipitate was dispersed in water. Acetone was added to this mixture to separate the black sample from the colorless and transparent solution, and the operation of centrifuging was repeated three times to obtain a black sample. This sample is called a catalyst precursor. The catalyst precursor was dried in a vacuum desiccator.

The dried catalyst precursor was pulverized into a powder. 500 mg of the precursor powder was transferred to a quartz boat and heated to 800 ° C. in a state where 5% H ₂ —Ar gas was circulated to prepare a catalyst.

From the TEM measurement, it was found that the particle diameter of the Co nanoparticles supported on Vulcan (registered trademark) was 39.5 nm. From the powder XRD measurement, it was found that the nanoparticles in the prepared catalyst had an fcc structure. From the ICP-AES measurement, it was found that Co8.2 was contained in the catalyst.

[Reference Example 2] Fe / C35wt%
0.14 g of iron (II) acetate and 0.35 g of PEG were mixed in 200 ml of TEG. After heating the mixed solution to 80 ° C., 0.08 g of Vulcan (registered trademark) was mixed and stirred. After adding 0.3 g of NaBH ₄ and stirring for 5 minutes, the mixture was allowed to cool. To the reaction mixture, a mixed solution of acetone: diethyl ether = 1: 0 was added to the black layer and the colorless and transparent solution layer until separation occurred, followed by centrifugation to obtain a black sample. The resulting black precipitate was dispersed in water. Acetone was added to this mixture to separate the black sample from the colorless and transparent solution, and the operation of centrifuging was repeated three times to obtain a black sample. This sample is called a catalyst precursor. The catalyst precursor was dried in a vacuum desiccator.

From the TEM measurement, it was found that the particle size of the Fe nanoparticles supported on Vulcan (registered trademark) was 28.1 ± 12.3 nm. From the powder XRD measurement, the Fe nanoparticles in the prepared catalyst have a bcc structure and an fcc structure, and from the ICP-AES measurement, it is clear that the catalyst contains 28.5 wt% Fe.

[Reference Example 3] Ni / C50wt%
3.9 g of nickel (II) acetate tetrahydrate, 7 g of PEG were mixed into 200 ml of TEG. After heating the mixed solution to 80 ° C., 0.9 g of Vulcan (registered trademark) was mixed and stirred. 6 g of NaBH ₄ was added and stirred for 5 minutes, and then allowed to cool. A mixed solution of acetone: diethyl ether = 1: 0 was added to the reaction mixture until separation occurred between the black layer and the colorless and transparent solution layer, followed by centrifugation to obtain a black sample. The resulting black precipitate was dispersed in water. Acetone was added to this mixture to separate the black sample from the colorless and transparent solution, and the operation of centrifuging was repeated three times to obtain a black sample. This sample is called a catalyst precursor. The catalyst precursor was dried in a vacuum desiccator.

TEM measurement revealed that the Ni nanoparticles supported on Vulcan (registered trademark) had a particle size of 37.0 ± 11.5 nm. From the powder XRD measurement, it was found that the Ni particles in the prepared catalyst had an fcc structure, and from the ICP-AES measurement, the catalyst contained 46.3 wt% of Ni.

[Test Example 1]
Fig. 1 (a) shows the conventional (impregnation) method (after 900 ° C heat treatment) preparation obtained in Reference Example 1, and (b) shows the present invention obtained in Example 1-1 (900 ° C heat treatment). The TEM image of the Fe-based alloy nanoalloy-supported catalyst prepared in the latter step is shown.

[Test Example 2]
FIG. 2 shows the powder XRD patterns of FexCoyNi (1-xy) / C obtained in Examples 1-1 to 4.

[Test Example 3]
FIG. 3 shows an STEM-EDS (element map) image of the Fe ₅₀ Co ₅₀ / C precursor (a) and the nanoalloy catalyst (b) obtained in Example 1-2. It can be seen that iron and cobalt are dispersed within 16.7 nm ³ .

[Test Example 4]
TEM image of FexCoyNi (100-xy) / C and metal composition analysis result by TEM-EDS Fig. 4 shows a TEM image of the binary nano-alloy (RT-1000 ° C, 10 K / min, 10 min Keep, N ₂ ). FIG. 5 shows a TEM image of the metal nanoparticles.

[Test Example 5]
FIG. 6 shows the power generation characteristics of a direct glycol inorganic alkaline battery using FexCoyNi (100-xy) / C as an anode catalyst. The output characteristics change depending on the composition.

[Example 2-1] Preparation of Fe-Co-Ni nanoalloy catalyst (1) A weight / g of (2) metal salt raw material A, (3) B weight / g of (4) metal salt raw material B, ( 5) C weight / g (6) Metal salt raw material C, (7) D weight / g (8) Protective agent D and (9) E weight / g (10) Carrier E (11) F capacity / Mixed with ml (12) Solvent F.
The mixed solution was heated to (13) temperature / ° C., (14) weight / g NaBH ₄ was added, and the mixture was stirred for (15) hours and then allowed to cool. A mixed solution of acetone: diethyl ether = composition (16): (17) was added to the reaction mixture until separation occurred between the black layer and the colorless and transparent solution layer, followed by centrifugation to obtain a black sample. The resulting black precipitate was dispersed in water. Acetone and diethyl ether were added to the mixture to again separate the black sample from the colorless and transparent solution, and centrifuged to obtain a black sample. This sample is called a catalyst precursor. The catalyst precursor was dried in a vacuum desiccator.
The dried catalyst precursor was pulverized into a powder. (18) Transfer the weight / g of precursor powder to a quartz boat and sinter the precursor at (19) temperature / ° C for (20) hours / minute with 5% H ₂ -Ar gas flowing. Produced.
From the TEM measurement, it was found that the particle size of the supported nanoparticles was (21) diameter / nm. From the ICP-AES measurement, it was found that the metal contained (22) metal loading / wt% in the catalyst, and Fe: Co: Ni = composition (23) :( 24) :( 25). Each description of (1) to (25) is shown in Table 1. A composite using γ-Al2O3 as a support material other than activated carbon (Vulcan) was also synthesized.

[Example 2-2] Preparation of Fe-Co-Cr nanoalloy catalyst An Fe-Co-Cr nanoalloy catalyst was prepared in the same manner as in Example 2-1. Each explanation of (1) to (25) is shown in Table 2.

[Example 2-3] Preparation of Fe-Cr nanoalloy catalyst An Fe-Cr nanoalloy catalyst was prepared in the same manner as in Example 2-1. However, (1) to (4) in Example 2-1 correspond to (1) to (4) in Table 3, and (7) to (25) correspond to (5) to (22) in Table 3. To do.

[Example 2-4] Preparation of Fe-Mn nanoalloy catalyst An Fe-Mn nanoalloy catalyst was prepared in the same manner as in Example 2-1. However, (1) to (4) in Example 2-1 correspond to (1) to (4) in Table 4, and (7) to (25) correspond to (5) to (22) in Table 4. To do.

[Example 2-5] Fe-Co-Ni / C powder XRD pattern Fe33Co33Ni33 / C (= FeCoNi / C) and Co50Ni50 of Table 1 prepared in Example 2-1 by Cu Kα rays using D8ADVANCE manufactured by BRUKER Powder XRD patterns of / C (= CoNi / C), Fe50Co50 / C (= FeCo / C), and Fe50Ni50 / C (= FeNi / C) were measured (FIG. 7). Co / C, Fe / C, and Ni / C are samples obtained in Reference Examples 1 to 3. An overall image of the XRD pattern is shown in FIG. For all nanoalloy catalysts, diffraction patterns from a single crystalline phase were obtained, suggesting that all samples had a solid solution structure.

[Example 2-6] Element mapping measurement by STEM-EDS and its one-dimensional analysis Fe33Co33Ni33 / C of Table 1 prepared in Example 2-1 using JEM-ARM 200F and CEOS Cs corrector at an acceleration voltage of 120 kV Element mapping and one-dimensional analysis of (= FeCoNi / C), Co50Ni50 / C (= CoNi / C), Fe50Co50 / C (= FeCo / C), Fe50Ni50 / C (= FeNi / C) by STEM-HAADF and EDS I did. The distance between each point of element mapping is 0.773 nm in both the x-axis and y-axis directions, and the distance between each point of line analysis is around 0.2-0.5 nm. The results are shown in FIGS. From the obtained TEM photograph, the constituent elements of the nano-alloy in the range of resolution measured any nano alloys are uniformly distributed throughout the particle, that constituent molecules is present in the volume of 16.7 nm ³ Show. Further, when the characteristic X-ray counts from the elements were measured on a straight line plotted on the BF STEM image, it was found that the same was true for all constituent elements at any position. This revealed that the constituent elements were uniformly distributed in the nanoalloy.

[Example 2-7] Electrochemical oxidation of ethylene glycol on Fe-Co-Ni / C Fe33Co33Ni33 / C (= FeCoNi / C) and Co50Ni50 / C (= About 700 mg of ethylene glycol was added to 50 mg of a catalyst of CoNi / C), Fe50Co50 / C (= FeCo / C), or Fe50Ni50 / C (= FeNi / C) to prepare a black suspension. The black suspension was soaked in carbon felt to prepare an electrode catalyst.
Subsequently, about 50 mL of KOH (20 wt%) aqueous solution containing 30 wt% ethylene glycol and 30 wt% ethylene glycol was added to one of the reaction cells sandwiched with the Nafion membrane as a partition, and the previously prepared electrode catalyst was held with a stainless steel clip. The prepared electrode was used as a working electrode and introduced into the solution together with the Hg / HgO reference electrode. About 50 mL of KOH (20 wt%) aqueous solution was added to the other cell, and the Pt line was used as a counter electrode. The reaction solution was bubbled with N _{2 for} about 1 hour to replace the system with N ₂ . The gas phase components in the cell in the initial state before the start of the reaction were analyzed by gas chromatography analysis after N ₂ bubbling. Further, about 50 mL of the cell solution on the working electrode and counter electrode side is collected, and the sample diluted with 450 mL of deionized water is analyzed with a liquid chromatograph (LC-20AD) manufactured by Shimadzu Corporation. analyzed. Subsequently, electrode oxidation was performed at a constant potential for about 125 minutes while applying a voltage of 1.0 V vs. RHE. After applying the voltage, the gas phase component in the reaction solution on the working electrode side was analyzed by GC analysis. In addition, 50 mL of the reaction solution after voltage application was analyzed with the LC-20AD described above, the solution components were analyzed, and the amounts of various components generated with voltage application were calculated from the difference from the initial state.
The results of the examination are shown in FIG. It was found that the product was different on the Fe-Co-Ni / C catalyst due to its metal composition. Furthermore, it became clear that they depended greatly on the applied voltage. In addition, when FeCoNi / C was used, it was confirmed that oxalic acid had the highest selectivity (ca. 16%). Co / C, Fe / C, and Ni / C are the results for the samples obtained in Reference Examples 1 to 3.

[Example 2-8] Direct glycol alkaline fuel cell characteristics using Fe-Co-Ni / C Fe33Co33Ni33 / C (= FeCoNi / C), Co50Ni50 / C (= CoNi / C), Fe50Co50 / C (= FeCo / C) or Fe50Ni50 / C (= FeNi / C) catalyst and Na _x CoO ₂ electrolyte powder were mixed and heated at 400 ° C. for 1 hour in a state in which He gas was circulated to produce a sintered body. Thereafter, the sintered body and Na _x CoO ₂ pressure-molded pellets were simultaneously heated at 300 ° C. for 30 minutes under a flow of wet H ₂ gas to produce anode electrodes and Na _x CoO ₂ electrolyte pellets. As the cathode electrode, P50T carbon paper coated with 9.44 mg / cm ^{2 of} a powder obtained by mixing Na _x CoO ₂ electrolyte powder and Vulcan XC-72R carbon powder in a weight ratio of 2: 1 was used. Anode and cathode electrodes each having a diameter of 5 mmφ were used. The prepared anode electrode catalyst, electrolyte pellet, and cathode electrode were installed in a fuel cell evaluation cell manufactured by ElectroChem, and the fuel cell characteristics were evaluated. The anode electrode side was filled with an aqueous solution containing 10 wt% ethylene glycol and 10 wt% potassium hydroxide, 70 ° C wet O ₂ gas was circulated at 200 ml / min on the cathode electrode side, and the evaluation cell was 70 ° C Held on. The current-voltage characteristics were measured with a Solartron Electrochemical Test System 1280C. As a result of open circuit voltage measurement, an electromotive force of 0.6-0.7 (V) was confirmed. The result of the current-voltage characteristic measurement is shown in FIG. It was confirmed that the power density showed a maximum of 46.0 (mW / cm ² ) on Fe50Co50 / C. Co / C, Fe / C, and Ni / C are the results for the samples obtained in Reference Examples 1 to 3.

[Example 3]
FT reaction was performed using Fe50Co50 / Al2O3 prepared in Example 2-1.
The reaction device used was BEL-REA manufactured by Nippon Bell. A reaction tube having a diameter of 1.0 cm was filled with 0.5 g of an Al ₂ O ₃ supported FeCo catalyst. Pretreatment was performed for 5 hours under conditions of H ₂ at 400 ° C, 0.1 MPa, 50 sccm. Subsequently, H ₂ / CO (= 1) was treated at 260 ° C, 1.0 MPa, 37 sccm for 16 hours, and then H ₂ / CO (= 1) was treated at 300 ° C, 0.1 MPa, 50 sccm. The treatment was performed for 5 hours. After that, FT reaction was performed for 16 hours under the conditions of H ₂ / CO (= 1) at 300 ° C, 1.0 MPa, 37 sccm. CO conversion and lower hydrocarbon selectivity were determined using a gas chromatograph connected to BEL-REA. For the selectivity of long-chain hydrocarbons, a toluene trap was placed after the reaction tube, and after completion of the reaction, the product was assigned by gas chromatography.

The reaction results are shown in Table 5. Under these reaction conditions, the CO conversion rate is not so high at 15%, but the selectivity to propylene is 24%, and the formation of C3 compounds in the ASF distribution (Fig. 14) that probabilistically predicts the product distribution obtained by the FT reaction. The probability is very large compared with 18%. Further, as shown in Table 5, FIG. 15 and FIG. 16, it was found that the olefin selectivity in the product was high. The FT reaction activity in the catalyst in which Fe and Co are dissolved at the atomic level is considered to be different from that of a normal catalyst.

The present invention is useful in fields related to metal alloy composites useful for fuel cell electrode catalysts and Fischer-Tropsch reaction catalysts.

Claims

A composite comprising a solid support and any one of the following iron group metal-based alloy particles supported on the solid support (a) to (d).
(a) Iron group metal alloy particles composed of two or three kinds of iron group metals selected from the iron group metal group consisting of Fe, Co and Ni, provided that the iron group metal alloys are the above-described two or three A kind of iron group metal is a solid solution type alloy,
(b) Iron group metal alloy particles containing two or three kinds of iron group metals selected from the group consisting of iron group metals consisting of Fe, Co and Ni, provided that the iron group metal alloys are at least the two kinds Or three kinds of iron group metals are solid solution type alloys,
(c) One, two or three iron group metals selected from the iron group metal group consisting of Fe, Co and Ni, and Cr, Mn, Cu, Mo, Ru, Rh, Pd, Ag, Ir, Pt And an iron group metal alloy particle composed of one or more transition metals selected from the group of transition metals consisting of Au, wherein the iron group metal alloy is the one, two or three iron groups The metal and one or more transition metals are solid solution type alloys,
(d) One, two or three types of iron group metals selected from the group of iron group metals consisting of Fe, Co and Ni, and Cr, Mn, Cu, Mo, Ru, Rh, Pd, Ag, Ir, Pt And an iron group metal alloy particle containing one or more transition metals selected from the group of transition metals consisting of Au, wherein the iron group metal alloy is at least one of the above-mentioned one, two or three kinds The iron group metal and one or more transition metals are solid solution type alloys,
The iron group metal-based alloy particle has at least one iron group metal atom bonded to a different metal atom in a volume of 16.7 nm 3 of one alloy particle, provided that the different metal atom is the iron group metal atom. The composite according to claim 1, which is a different iron group metal atom, the transition metal atom, or an iron group metal atom different from the iron group metal atom and a metal atom other than the transition metal atom. .
The composite according to claim 1, wherein the iron group metal-based alloy particles are alloy particles having a volume of one particle of 16.7 nm 3 or more and 10,466.7 nm 3 or less.
The composite according to any one of claims 1 to 3, wherein the solid support is a carbon-based material or an inorganic material, and contains particles having a diameter in the range of 1 nm to 10 µm.
A catalyst for a solid oxide alkaline fuel cell comprising the composite according to any one of claims 1 to 4.
The catalyst for a solid oxide alkaline fuel cell according to claim 5, wherein the solid support is made of a conductive material.
The catalyst for a solid oxide alkaline fuel cell according to claim 6, wherein the conductive material is a carbon-based material, and the carbon-based material is activated carbon, carbon black, carbon nanotube, or a porous carbon material.
A Fischer-Tropsch containing the composite according to any one of claims 1 to 4, except that the iron group metal alloy particles are iron group metal alloy particles composed of Fe and Co. Reaction catalyst.
Iron group metal-containing compounds (where the iron group metal is selected from the group of iron group metals consisting of Fe, Co and Ni) and transition metal-containing compounds (where the transition metals are Cr, Mn, Cu, Mo, Ru, Rh, A step of preparing a mixture by mixing at least two metal-containing compounds selected from the group consisting of Pd, Ag, Ir, Pt and Au (selected from the group of transition metals consisting of Au), a protective polymer, a solvent and a solid support (1 ),
By adding a reducing agent for metal ions contained in the metal-containing compound to the obtained mixture, precursor particles containing at least two kinds of metals selected from the group consisting of iron group metals and transition metals and a solid support are obtained. Step (2) of preparing, and heating the precursor particles in a hydrogen-containing atmosphere to reduce the precursor particles, so that at least two metal alloy particles selected from the group consisting of iron group metals and transition metals A production method comprising a step (3) of obtaining a composite supported on a solid support.
The at least two compounds used in step (1) are two or three iron group metal-containing compounds, or one or more iron group metal-containing compounds and one or more transition metals. The manufacturing method of Claim 9 which is a containing compound.
The method according to claim 9 or 10, wherein the step (3) is performed under a condition that the obtained iron group nanoalloy particles have a crystallite size having a volume of 16.7 nm 3 or more and 10466.7 nm 3 or less.
The production method according to any one of claims 9 to 11, wherein the hydrogen content of the hydrogen-containing atmosphere in the step (3) is in the range of more than 10 vol% and not more than 100 vol%.
The production method according to any one of claims 9 to 12, wherein the heating in the step (3) is in the range of 200 ° C to 1,000 ° C.
The precursor particles containing an iron group metal obtained in the step (2) are particles containing at least one of iron oxide, cobalt oxide, and nickel oxide. The manufacturing method as described in.
The protective polymer is a substance having a solubility in water and a solvent equivalent to that of the iron group metal-containing compound and the transition metal-containing compound, and may be complexed by interacting with the metal complex raw material. The manufacturing method of any one of Claims.
The reduction in step (2) is performed in the range of 0 to 200 ° C. The production method according to any one of claims 9 to 15, wherein the redox potential of the reducing agent is lower than that of the component metal.