US20060144189A1 - Method for preparing colloidal solution and carrier having colloidal particles fixed on surface thereof, fuel cell cathode, fuel cell anode and method for preparing the same and fuel cell using the same, and low temperature oxidation catalyst, method for preparing the same and fuel cell fuel modifying device using the same - Google Patents

Method for preparing colloidal solution and carrier having colloidal particles fixed on surface thereof, fuel cell cathode, fuel cell anode and method for preparing the same and fuel cell using the same, and low temperature oxidation catalyst, method for preparing the same and fuel cell fuel modifying device using the same Download PDF

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US20060144189A1
US20060144189A1 US10/521,567 US52156705A US2006144189A1 US 20060144189 A1 US20060144189 A1 US 20060144189A1 US 52156705 A US52156705 A US 52156705A US 2006144189 A1 US2006144189 A1 US 2006144189A1
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fuel cell
metal salt
colloidal particles
solution
reducing agent
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Inventor
Kiyoshi Miyashita
Akihiro Hishinuma
Tsutomu Sakai
Toyo Okubo
Hiroshi Shingu
Yohei Iseki
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Nippon Sheet Glass Co Ltd
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Nippon Sheet Glass Co Ltd
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Priority claimed from JP2002351839A external-priority patent/JP2004181365A/ja
Priority claimed from JP2002351838A external-priority patent/JP2004185995A/ja
Priority claimed from JP2002351837A external-priority patent/JP2004185994A/ja
Application filed by Nippon Sheet Glass Co Ltd filed Critical Nippon Sheet Glass Co Ltd
Assigned to NIPPON SHEET GLASS CO., LTD. reassignment NIPPON SHEET GLASS CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ISEKI, YOHEI, OKUBO, TOYO, SAKAI, TSUTOMU, SHINGU, HIROSHI, MIYASHITA, KIYOSHI, HISHINUMA, AKIHIRO
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
    • B01J13/0004—Preparation of sols
    • B01J13/0008—Sols of inorganic materials in water
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
    • B01J13/0004—Preparation of sols
    • B01J13/0043—Preparation of sols containing elemental metal
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/20—Catalysts, in general, characterised by their form or physical properties characterised by their non-solid state
    • B01J35/23—Catalysts, in general, characterised by their form or physical properties characterised by their non-solid state in a colloidal state
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/16—Reducing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/05—Metallic powder characterised by the size or surface area of the particles
    • B22F1/054—Nanosized particles
    • B22F1/0545—Dispersions or suspensions of nanosized particles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00—Making metallic powder or suspensions thereof
    • B22F9/16—Making metallic powder or suspensions thereof using chemical processes
    • B22F9/18—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds
    • B22F9/24—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds starting from liquid metal compounds, e.g. solutions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/88—Processes of manufacture
    • H01M4/8825—Methods for deposition of the catalytic active composition
    • H01M4/8846—Impregnation
    • H01M4/885—Impregnation followed by reduction of the catalyst salt precursor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/88—Processes of manufacture
    • H01M4/8878—Treatment steps after deposition of the catalytic active composition or after shaping of the electrode being free-standing body
    • H01M4/8882—Heat treatment, e.g. drying, baking
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/90—Selection of catalytic material
    • H01M4/92—Metals of platinum group
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/90—Selection of catalytic material
    • H01M4/92—Metals of platinum group
    • H01M4/925—Metals of platinum group supported on carriers, e.g. powder carriers
    • H01M4/926—Metals of platinum group supported on carriers, e.g. powder carriers on carbon or graphite
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/06—Combination of fuel cells with means for production of reactants or for treatment of residues
    • H01M8/0662—Treatment of gaseous reactants or gaseous residues, e.g. cleaning
    • H01M8/0668—Removal of carbon monoxide or carbon dioxide
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M2004/8678—Inert electrodes with catalytic activity, e.g. for fuel cells characterised by the polarity
    • H01M2004/8689—Positive electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12014—All metal or with adjacent metals having metal particles
    • Y10T428/12028—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, etc.]
    • Y10T428/12063—Nonparticulate metal component
    • Y10T428/12097—Nonparticulate component encloses particles

Definitions

  • the present invention relates to a method for paring a colloidal solution containing colloidal particles that can exert catalytic functions and the like; and to a carrier wherein the colloidal particles are fixed on various substrates.
  • the present invention also relates to a fuel cell cathode that promotes oxygen reduction reaction; a method for the manufacture thereof, and a fuel cell using the same.
  • the present invention also relates to a fuel cell anode that promotes hydrogen oxidation reaction; a method for the manufacture thereof; and a fuel cell using the same.
  • the present invention relates to a low temperature oxidation catalyst the exhibits excellent catalytic activity under a service temperature of 300° C. or below, a method for the manufacture thereof and a fuel modifying device for a fuel cell using the low-temperature oxidation catalyst.
  • fine particles of a metal such as platinum, fictions as a catalyst.
  • the fine metal particles are nominally fixed on the surfaces of substrates, such as fibers, woven fabrics, non-woven fabrics, films and powdered bodies.
  • substrates such as fibers, woven fabrics, non-woven fabrics, films and powdered bodies.
  • a dispersion method wherein bulk metal is pulverized using a pulverizer, such as a colloid mill, and the pulverized fine particles are dispersed in a solvent.
  • fine metal particles obtained using a dispersion method have large average particle diameters, and are relatively difficult to fix on the surface of a substrate.
  • the average pore diameter of the formed pores in the order of 1 to 10 nm; therefore, fine metal particles cannot enter into the pores, and cannot be well fixed on the surface of the glass river.
  • the width of the particle size distribution of fine metal particles is large, it is difficult to evenly fix fine metal particles on the surface of the substrate.
  • a 2-L round bottom flask with a condenser is used, and 960 ml of distilled water is poured therein and well boiled using a mantle heat.
  • an aqueous solution of chloroplatinic acid (1 g-Pt/L) is added, the solution is brought to boiling again, 120 ml of an aqueous solution of sodium citrate (1% by weight) is added, and boiling is continued.
  • the solution is initially light yellow in color due to the presence of chloroplatinic acid, it is gradually darkened, and becomes dark brown in 30 minutes after the addition of sodium citrate.
  • the reason of vigorous boiling during reaction is because oxygen in the air interferes with the reaction.
  • the platinum colloid must be eared in the state wherein dissolved oxygen is removed, and if the colloid is prepared in the state wherein the solution is not vigorously boiled, reproducible results cannot be obtained because a long time is consumed for the synthesis, or aggregation occurs.
  • an inert gas such as nitrogen gas
  • the platinum colloid can be prepared at a temperature as low as 70° C.
  • Chloroplatinic acid and sodium citrate that have not reacted can be removed by passing the solution through a column packed with the ion-exchange resin, Amberlite MB-1. Although the degree of removal can be defined by measuring the electrical conductivity of the solution, 6 ml of the ion-exchange resin is sufficient for 100 ml of the colloidal solution. At tis time, the quantity of the platinum colloid adsorbed on the ion-exchange resin is extremely small.”
  • this publication describes that in the above-described means, the average particle diameter of the platinum colloid increases with increase in the refluxing time (reaction time) of the reacting solution, and when the reaction time is about 5 hours, the average particle diameter reaches about 32 angstroms and thereat it is kept constant.
  • reaction time refluxing time
  • Japanese Patent Application Laid-Open No. 07-256112 describes a method for fixing metal platinum on zeolite, wherein zeolite is fed in an aqueous solution of divalent platinum ammine salt suction-filtered, washed with water and heat-dried, heated to 500° C. and maintained at this temperature, exposed to oxygen for a predetermined time, and then exposed to hydrogen to fix metal platinum on zeolite.
  • fine platinum particles are fixed in the pores of zeolite of an average diameter of 0.4 to 2 nm, and a catalyst carrier that can adsorb and oxidize bipolar molecules, such as carbon monoxide can be obtained.
  • Japanese Patent Application Laid-Open No. 2002-222655 describes a method for preparing a cathode catalyst, wherein a commercially available carbon powder is added in a carrier solution prepared by adding an aqueous solution of ruthenium nitrate to a solution of a platinum ethoxide complex, and dried and further exposed to hydrogen while heating in an electric furnace to form a platinum-ruthenium alloy on above-described carbon powder.
  • Japanese Patent Application Laid-Open No. 2002-222655 describes a method for preparing a cathode catalyst, wherein a commercially available carbon powder is added in a carrier solution prepared by adding an aqueous solution of ruthenium nitrate to a solution of a platinum ethoxide complex, and dried and further exposed to hydrogen while heating in an electric furnace to form a platinum-ruthenium alloy on above-described carbon powder.
  • 2001-357857 describes a method for manufacturing a fuel cell anode wherein carbon black fired at a high temperature is immersed in a solution containing chloroplatinic acid and formalin and cooled to ⁇ 10° C., and then sodium hydroxide is dropped to fix ultra-fine platinum particles to the carbon black.
  • This method for preparing a colloidal solution can be said to be an excellent method, because the uniformity of the particle diameters of the colloidal particles is high, and the metal recovery rate is as relatively high as 70 to 80%. However, if the average particle diameter of the colloidal particles can be closer to 16 angstroms, the catalytic activity can be further elevated, because the specific surface area of the colloidal particles can be increased that much. The room for the improvement of the metal recovery rate is also left.
  • an object of the present invention is to provide a method for easily preparing a colloidal solution that can prepare colloidal particles having smaller particle diameters while elevating the metal recovery rate.
  • Another object of the present invention is to provide a carrier that exhibits functions, such as catalyzing efficiently by fixing the colloidal particles on a substrate.
  • Another object of the present invention is to provide a fuel cell cathode that can efficiently perform an oxygen reduction reaction, even if the adhesion quantity of the colloidal particles, which is a catalyst, is small. Also another object of the present invention is to provide a method for easily manufacturing the fuel cell cathode. A further object of the present invention is to provide a fuel cell having power generation efficiency using the fuel cell cathode.
  • Another object of the present invention is to provide a fuel cell anode that can efficiently perform a hydrogen oxidation reaction, even if the adhesion quantity of the colloidal particles, which is a catalyst, is small. Also another object of the present invention is to provide a method for easily manufacture the fuel cell anode. A further object of the present invention is to provide a fuel cell having power generation efficiency using the fuel cell anode.
  • Another object of the present invention is to provide a low-temperature oxidation catalyst that exhibits a high catalytic activity, even if the adhesion quantity of the colloidal particles, which is a catalyst is small. Also another object of the present invention is to provide a method for easily manufacturing the low-temperature oxidation catalyst. A further object of the present invention is to provide a fuel modifying device for a fuel cell that causes a CO shifting reaction even if the service temperate is 300° C. or below, particularly 200° C. or below, using the low-temperature oxidation catalyst having a big catalytic activity.
  • the present invention is characterized, in a method for preparing a colloidal solution described in the above described publications, in that the parameters of the concentration of a metal salt, the ratio of equivalent concentration of a reducing agent to the equivalent concentration of the metal salt, and the reaction time are sophisticatedly combined and adjusted. Specifically, the optimal conditions for preparing in the method for preparing a colloidal solution are provided.
  • the colloidal particles prepared using the method of the present invention have particle diameters of the 10-nm order, and have extremely high uniformity, they can be easily and strongly fixed only be applying the colloidal solution onto porous glass fibers or the like using means well known to the art. Therefore, according to the present invention, a carrier having extremely high catalytic activity and durability can be easily manufactured.
  • the methods for manufacturing a fuel cell cathode, fuel cell anode, and a low-temperature oxidation catalyst according to the present invention are characterized in that colloidal particles are fixed on a substrate, using a colloidal solution pared in a state wherein a solution containing a metal salt and a reducing agent is boiled to remove dissolved oxygen.
  • colloidal solution having extremely high stability even without containing a stabilizer or the like is applied onto a substrate, no heating or firing of the substrate for forming the colloidal particles are required, the colloidal particles can be easily fixed on the substrate, and there is no lowering of the catalytic activity due to the formation of residue.
  • the above described colloidal solution can be prepared from an inexpensive metal salt as a starting material using a simple process, the paring costs are extremely low. Also since the above described colloidal solution has a uniform particle diameter, and Is difficult to aggregate even in high concentration, no stabilizers for preventing precipitation are required, and the colloidal particles can be evenly fixed on the substrate.
  • the oxygen reducing reaction can be efficiently started even if the quantity of adhered colloidal particles is small. Furthermore, according to a fuel cell according to the present invention, the efficiency of power generation can be improved.
  • a fuel cell anode according to the present invention he hydrogen oxidizing reaction can be efficiently started even if the quantity of adhered colloidal particles is small. Furthermore, according to a fuel cell according to the present invention, the efficiency of power generation can be improved.
  • a high catalytic activity can be exhibited even if the fixing rate of the catalyst is low.
  • the CO shifting reaction can be started at a high efficiency even at a low temperature of 300° C. or below, in particular, 150 to 200° C. Therefore, since this device can contribute to the improvement of the power generating efficiency of fuel cells, and enables the use of members having not so high heat resistance, the option of member selection is widened.
  • FIG. 1 is a diagram showing the results of measuring CO conversion rates of the Examples.
  • the reducing agent is not specifically limited as long as it dissolves in water, and alcohols, citric acids, marboxylic acids, ketones, ethers, aldehydes or esters can be exemplified. The combination of two or more of these can also be used As alcohols, methanol, ethanol, 1-propanol, 2-propanol, ethylene glycol or glycerin can be exemplified.
  • citric acids, citric acid, and citrate such as sodium acetate, potassium cite and ammonium citrate cam be exemplified
  • carboxylic acids formic acid, acetic acid, fumaric acid, malic acid, succinic acid, aspartic acid or carboxylates thereof can be exemplified.
  • ketones acetone or methylethyl ketone can be can be exemplified.
  • ethers diethyl ether cam be exemplified.
  • aldehydes formalin or acetaldehyde can be exemplified.
  • esters methyl formate, methyl acetate or ethyl acetate can be exemplified.
  • citric acids are preferable for forming stable colloidal particles of a metal having a particle diameter of 1 to 5 nm.
  • the particle diameter thereof is preferably 1.6 nm or more.
  • the solvent composing the reaction solution is not specifically limited as long as it can dissolve the reducing agent and the metal salt, and water, alcohols, ketones or ethers can be exemplified. The combination of two or more of these can also be used.
  • alcohols methanol, ethanol, 1-propanol or 2-propanol can be exemplified.
  • ketones methyl formate, methyl acetate or ethyl acetate can be exemplified.
  • ethers methyl ethyl ether or diethyl ether can be exemplified. From point of view of completely dissolving the metal salts, the solvent is preferably water or alcohols.
  • the metal salt is not specifically limited as long as it is dissolved in the solvent and reduced by a reducing agent,
  • a reducing agent For example, chlorides, nitrates, sulfites or metal complex compounds of platinum (Pt), ruthenium (Ru), gold (Au), lead (Pb), rhodium (Rh), iridium (Ir), cobalt (Co), iron (Fe), nickel (Ni), copper (Cu) or tin (Sn) can be listed.
  • the combination of two or more of these can also be used.
  • the colloidal particles of an alloy can be prepared When a platinum salt is used as the metal salt, the particle diameter of colloidal particles becomes particularly small, and stable colloidal particles of 1 to 5 nm can be obtained.
  • Boiling a reaction solution containing a metal salt and a reducing agent accelerates the reducing reaction of metal ions while elating dissolved oxygen.
  • the metal ions in the reaction solution are concurrently reduced to form an innumerable number or meal atoms are formed, and these drift in the reaction solution. This can be estimated from the fact that although the colloidal solution 30 minutes after the start of tie reaction exhibit little catalytic activity in Example 1 described below, the platinum concentration thereof (the concentration of the residual metal after removing metal ions, that is, the concentration of colloidal particles) becomes relatively high.
  • metal atoms and the clusters thereof that cannot exhibit catalytic activity are present because the particle diameter has not reached 1.6 nm, although the metal ions are reduced and no longer present as ions, and are not caught by ion-exchange resin. It is considered that since these meal atoms attract metal ions and cause the reducing reaction to occur, or metal atoms and clusters aggregate, the colloidal particles grow gradually to catalytic activity.
  • the reaction time is 60 minutes or more and 300 minutes or less when the concentration of the metal salt in the reaction solution is 1 ⁇ 10 ⁇ 4 mol/L or more and less than 4 ⁇ 10 ⁇ 4 mol/L, and the equivalent concentration of the reducing agent is four times or more and 20 times or less the equivalent concentration of the metal salt.
  • the meal recovery rate can be 80 to 100%, and the average particle diameter of metal colloidal particles can be 2.3 nm or smaller.
  • the reaction time is 30 minutes or more and 150 minutes or less when the concentration of the metal salt in the reaction solution is 4 ⁇ 10 ⁇ 4 mol/L or more and less tan 6 ⁇ 10 ⁇ 4 mol/L, and the equivalent concentration of the reducing agent is four times or more and 20 times or less the equivalent concentration of the metal salt
  • the average particle diameter of metal colloidal particles can be 2 nm or smaller without precipitating the metal colloidal particles.
  • the reaction time is 30 minutes or more and 90 minutes or less when the concentration of the metal salt in the reaction solution is 6 ⁇ 10 ⁇ 4 mol/L or more and 15 ⁇ 10 ⁇ 4 mol/L or less, and the equivalent concentration of the reducing agent is four times or more and 20 times or less the equivalent concentration of the metal salt
  • the average particle diameter of metal colloidal particles can be reduced without precipitating the metal colloidal particles.
  • the reaction time is 60 minutes or more and 120 minutes or less when the concentration of the metal salt in the reaction solution is 4 ⁇ 10 ⁇ 4 mol/L or more and less than 6 ⁇ 10 ⁇ 4 mol/L, and the equivalent concentration of the reducing agent is twice or more and less than four times the equivalent concentration of the metal salt.
  • the average particle diameter of metal colloidal particles can be 23 nm or smaller without precipitating the metal colloidal particles.
  • the reaction time is 30 minutes or more and 240 minutes or less when the concentration of the metal salt in the reaction solution is 6 ⁇ 10 ⁇ 4 mol/L or more and 15 ⁇ 10 ⁇ 4 mol/L or less, and the equivalent concentration of the reducing agent is twice or more and less than four times the equivalent concentration of the metal salt
  • the average particle diameter of metal colloidal particles can be 1.8 nm or smaller without precipitating the metal colloidal particles.
  • the reaction time is 60 minutes or more and 120 minutes or less when the concentration of the metal salt in the reaction solution is 4 ⁇ 10 ⁇ 4 mol/L or more and less than 6 ⁇ 10 ⁇ 4 mol/L, and the equivalent concentration of the reducing agent is equal to one or more and less than twice the equivalent concentration of the metal salt
  • the average particle diameter of metal colloidal particles can be 2.3 nm or smaller without precipitating the metal colloidal particles.
  • the reaction time is 30 minutes or more and 120 minutes or less when the concentration of the metal salt in the reaction solution is 6 ⁇ 10 ⁇ 4 mol/L or more and 15 ⁇ 10-4 mol/L or less, and the equivalent concentration of the reducing agent is equal to one or more and less than twice the equivalent concentration of the metal salt
  • the average particle diameter of metal colloidal particles can be 1.8 nm or smaller without precipitating the metal colloidal particles.
  • the concentration of the metal salt is less than 1 ⁇ 10 ⁇ 4 mol/L, the reaction solution is unsuitable for industrial applications, because the reducing reaction of metal ions is difficult to occur, and a long time is required until the colloidal particles grow to a predetermined particle diameter.
  • concentration of the metal salt exceeds 15 ⁇ 10 ⁇ 4 mol/L, colloidal particles are easily aggregated, and precipitation occurs in the early stage aft the start of reaction.
  • the equivalent concentration of the reducing agent in the reaction solution is less than the equivalent concentration of the metal salt, some of the metal salt cannot be reduced and the metal recovery rate lowers naturally.
  • the equivalent concentration of the reducing agent exceeds 20 times the equivalent concentration of the metal salt, since the reducing agent itself aggregates and precipitates, the metal salt is also entangled in the precipitation, and the metal recovery rate lowers.
  • the colloidal solution prepared under the conditions of the above embodiments can be applied to various substrates using means well known to the art such as a dip method and a spray method.
  • the kind of the substrate is not specifically limited as long as colloidal particles can be fixed.
  • carbons, inorganic ceramics or organic polymers can be used. Two or more of these substrates can also be used in combination.
  • carbons activated charcoal, charcoal and carbon fibers can be exemplified.
  • inorganic ceramics alumina, titania, magnesia, silica or zeolite can be exemplified.
  • organic polymers polyethylene, polypropylene, polystyrene, polyimide, polysulfone, polysilicone, Nafion or polycellulose can be exemplified.
  • glass fibers and scale-shaped glass are suited.
  • chemical treatment is performed using an acid or alkali solution, the surface of glass fibers and scale-shaped glass become porous easily. Since the average diameter of pores in these porous bodies is normally in the order of 1 to 10 nm, the colloidal particles of a metal prepared under the above conditions of the embodiments can well enter in the pores of the porous body, and can be strongly fixed there.
  • a carrier using porous gas fiber or scale-shaped glass as the substrate has a large specific surface area of the substrate, the carrier can exhibit highly efficient catalytic activity, and excels in durability.
  • This carrier is processed into textiles, non-woven fabrics, and utilized, for example, as an exhaust-gas cleaning filter in an engine muffler.
  • the invention of a method for preparing a colloidal solution, and a carrier having colloidal particles fixed on the guru thereof will be more specifically described below, using examples, a reference example and comparative examples.
  • a colloidal solution was prepared according to the description of the above-described publication. Referring to the colloidal solution of Reference Example 1, examples, the reference example and comparative examples will be sequentially described.
  • a 1,500-ml flask, a 100-ml conical flask a 200-ml conical fask a reflux condenser and a stirrer were immersed in aqua regia for a day and night, and the apparatuses were well cleaned using pure water ion-exchanged and ultra-filtered
  • the reflux condenser is installed on the flask and the pure water was heated to a temperature of 100° C.
  • the aqueous solution of tetratachloroplanic acid was charged from the 100-ml conical flask to the 1,500-ml flask, and heated to 100° C. again. Furthermore, in order to remove dissolved oxygen, boiling was performed for 30 minutes. Then, the aqueous solution of sodium citrate slowly added from the 200-ml flask so that the boiling state could be maintained.
  • the ratio of the mol concentration of sodium citrate to the mol concentration of platinum is 13.2. Since sodium citrate function as monatomic donor, the equivalent concentration of sodium citrate to the equivalent concentration of platinum is 3.3.
  • the concentration of the colloidal particles in the colloidal solution was measured using plasma emission speetometry, and an adequate amount of the colloidal particles were further sampled to determine the state of the catalytic activity thereof, that is, the particle diameter of the colloidal particles utilizing the hydrogen peroxide decomposing reaction.
  • the results of these measurements are shown in Table 1 below together with the concentration of the reaction solution and the like.
  • the average particle diameter of the colloidal particles of platinum in the reaction solution rapidly cooled to room temperature 120 minutes aft the start of the reaction was measured using a transmission electron microscope.
  • the average particle diameter of the colloidal particles was 3.5 nm, and it was confirmed to agree with the result of measurement utilizing the hydrogen peroxide decomposing reaction.
  • the recovery rate of platinum can be obtained by dividing the platinum concentration in the product (colloidal particles) column in Table 1 by the platinum concentration and converting the quotient to percentage.
  • Example 1 is the example according to the first embodiment, that is, claim 1 , and the Example 2 and the examples that follow are examples corresponding to the number of each claim.
  • a colloidal solution of platinum was prepared in the same manner as in Reference Example 1 except that the ratio of the equivalent concentration of sodium citrate to the equivalent concentration of platinum in the reaction solution is 33 times. As a result the occurrence of precipitation started in the reaction solution before 60 elapsed after the start of the reaction.
  • the colloidal particles prepared using the above described method have particle diameters in the order of 1 nm, have extremely high uniformity, requires no stabilizers even in a high-concentration state and causes little aggregation. Therefore, by using me well known to the art such as immersing the substrates in the colloidal solution, the colloidal particles can be easily and strongly fixed on the substrate. Also by using the colloidal solution, no heating or firing together with the substrate for forming colloidal particles is required, and not only the preparing process can be simplified, but also the formation of residues and impurities byproducts) due to above described formation can be avoided. As a result, according to the method of the preset invention, a fuel cell cathode, a fuel cell anode with extremely nigh catalytic activity and durability, and a low-temperature oxidation catalyst can be easily and conveniently obtained
  • Means for applying the colloidal solution prepared to the substrate is not specifically limited, but means well known to the art, such as a dip method and a spray method, can be exemplified.
  • the kind of the substrate is not specifically limited as long as colloidal particles can be fixed, and the substrate has required functions as a file cell cathode and a fuel cell anode, such as electric conductivity and heat resistance.
  • a fuel cell anode such as electric conductivity and heat resistance.
  • graphite or carbon black can be used.
  • the form and shape of the substrate are also not specifically limited, but rod shape, fiber shape, plate shape, woven fabrics or bulk (aggregated body) can be exemplified.
  • the kind of the substrate for a low-temperature oxidation catalyst is not specifically limited as long as the substrate can fix colloidal particles, and has required functions as the carrier of the low-temperature oxidation catalyst such as oxidation resistance and beat resistance.
  • carbon inorganic ceramics or organic polymers can be use& Two or more kinds can also be used in combination.
  • carbon activated charcoal, charcoal, carbon fibers and carbon black can be exemplified.
  • inorganic ceramics alumina, titania, magnesia, silica or zeolite can be exemplified.
  • organic polymers polyethylene, polypropylene, polystyrene, polyimide, polysulfone, polysilicone, Nafion or polycellulose can be exemplified.
  • the form and shape of the substrate are also not specifically limited, but fibers, woven fabrics, non-woven fabrics, films or powders can be exemplified.
  • glass fibers and scale-shaped glass are suited. When chemical treatment is performed using an acid or alkali solution, the surfaces of glass fibers and scale-shaped glass become porous easily. Since the average diameter of pores in these porous bodies is normally in the order of 1 to 10 nm, the colloidal particles of a metal prepared under the above embodiments can well enter in the pores of the porous body, and can be strongly fixed there.
  • the reducing agent is not specifically limited as long as it dissolves in water, and alcohols, citric acids, carboxylic acids, ketones, ethers, aldehydes or esters can be exemplified. The combination of two or more of these can also be used.
  • alcohols methanol, ethanol, 1-propanol, 2-propanol, ethylene glycol or glycerin can be exemplified.
  • citric acids citric acid, and citrates, such as sodium citrate, potassium citrate and ammonium citrate can be exemplified.
  • carboxylic acids formic acid, acetic acid, fumaric acid, malic acid, succinte acid, aspic acid or carboxylates thereof can be exemplified.
  • ketones acetone or methylethyl ketone can be can be exemplified.
  • ethers diethyl ether can be exemplified.
  • aldehydes formalin or acetaldehyde can be-exemplified.
  • esters methyl formate, methyl acetate or ethyl acetate can be exemplified.
  • sodium citrate is particularly preferable because of its high reducibility and easy handing.
  • citric acids or carboxylic acids are pebble as the reducing agent.
  • citric acids are preferable for forming stable colloidal particles of a meal having a particle diameter of 1 to 5 nm.
  • the catalytic activity of colloidal particles at a low temperature e.g., at 100° C. or below
  • the particle diameter thereof is preferably 1.6 nm or more.
  • the solvent composing the reaction solution is not specifically limited as long as it can dissolve the reducing agent and the metal salt, and water, alcohols, ketones or ethers can be exemplified. The combination of two or more of these can also be used.
  • alcohols meal, ethanol, 1-propanol or 2-propanol can be exemplified.
  • ketones methyl formate, methyl acetate or ethyl acetate can be exemplified.
  • ethers methyl ethyl ether or diethyl ether can be exemplified. From point of view of completely dissolving the metal salts, the solvent is preferably water or alcohols.
  • the meal salt is not specifically limited as long as it is dissolved in the solvent, is reduced by a reducing agent, and can function as a catalyst when it becomes colloidal particles.
  • a reducing agent for example, chlorides, nitrates, sulfates or metal complex compounds of platinum (Pt), ruthenium (Ru), gold (Au), lead (Pb), rhodium (Rh), iridium (Ir), cobalt (Co), iron (Fe), nickel (Ni), copper (Cu) or tin (Sn) can be listed. The combination of two or more of these can also be used. If the combination of two or more of metal salts is used, the colloidal particles of an alloy can be prepared.
  • the particle diameter of colloidal particles becomes particularly small, and stable colloidal particles of 1 to 5 nm can be obtained.
  • the particle diameter of the colloidal particles becomes more uniformed.
  • a fuel cell cathode and a fuel cell anode can be obtained only by processing them using means well known to the art. Since colloidal particles are not coated with impurities or residues in the fuel cell cathode, the catalytic activity, that is, oxygen-reducing reactivity thereof is extremely high. Therefore, since the oxygen-reducing reaction occurs at high efficiency in the fuel cell using the cathode according to the present invention, the power-generation efficiency thereof is improved. Also since colloidal particles are not coated with impurities or residues in the fuel cell anode, the catalytic activity, that is, hydrogen-oxidizing reactivity thereof is extremely high. Therefore, since the hydrogen-oxidizing reaction occurs at high efficiency in the fuel cell using the anode according to the present invention, the power generation efficiency thereof is improved.
  • the method for manufacturing the fuel cell is not specifically limited, but means well known to the art can be used as it is.
  • a “low-temperature oxidation catalyst” means an oxidation catalyst that is used at 300° C. or below, especially in the temperature region between 100 and 300° C. Since colloidal particles are not coated with impurities or residues in the low-temperature oxidation catalyst, the catalytic activity is extremely high. Especially in the low-temperature region between 150 and 200° C., the catalytic activity is two to three times the catalytic activity of the catalyst using colloidal particles prepared by existing methods, specifically by heating or firing on the surface of a carrier, such as zeolite. This aspect will be described later in examples.
  • the low-temperature oxidation catalyst is utilized in a fuel modifying device for a fuel cell
  • the CO-shifting reaction (CO+H 2 O ⁇ CO 2 +H 2 ) can be efficiently caused at 300° C. or below, especially in the low-temperature region between 150 and 200° C. Therefore, since conventional manufacturing methods and members can be used without modification in the fuel modifying device for a fuel cell according to the present invention, the power-generation efficiency of a fuel cell can be easily and conveniently improved at low costs.
  • the method for manufacturing the fuel modifying device for a fuel cell is not specifically limited, but means well known to the art can be used as it is.
  • the invention of a fuel cell cathode, a fuel cell anode; a method for preparing the same, and a fuel cell will be specifically described below using examples and comparative examples.
  • a 1,500-ml flask, a 100-ml conical flask, a 200-ml conical flask, a reflux condenser and a stirrer were immersed in aqua regia for a day and night, and the apparatuses were well cleaned using pure water ion-exchanged and ultra-filtered.
  • the reflux condenser is installed on the flask, and the pure water was heated to a temperature of 100° C. In order to remove dissolved oxygen, the pure water was boiled as it was for one hour.
  • tetratachloroplanic acid hexahydrate (50 mg as platinum) was weighed and charged into the 100 ml conical and pure water ion-exchanged and ultra-fitted was added to make 50 ml.
  • One grain of sodium citrate was weighed and charged in the 200 ml conical flask, and pure water ion-exchanged and ultra-filtered was added to make 100 ml.
  • the aqueous solution of tetratachloroplanic acid was charged from the 100-ml conical flask to the 1,500-ml flask, and heated to 100° C. again.
  • the concentration of the colloidal particles in the colloidal solution was measured using plasma emission spectrometry, and an adequate amount of the colloidal particles were further sampled to determine the state of the catalytic activity thereof, tat is, the particle diameter of the colloidal particles using the hydrogen peroxide decomposing reaction.
  • tat is, the particle diameter of the colloidal particles using the hydrogen peroxide decomposing reaction.
  • the concentration of the colloidal particles of platinum was 31.25 mg/L, and tee catalytic activity was 0.79 mol-O 2 mg-Pt/min
  • the average particle diameter of the colloidal particles of platinum was measured using a transmission electron microscope. As a result, the average particle diameter of the colloidal particles was 3.5 nm, and it was confined to agree with the result of measurement utilizing the hydrogen peroxide decomposing reaction.
  • a colloidal solution and a fuel cell cathode were prepared in the same manner as in Example 8, except that the time from the start of the reaction to the stop of the reaction in the state wherein the aqueous solution of sodium citrate had been completely added in the 1,500 ml flask, and the reducing reaction was continued in the boiling state.
  • the average particle diameter of the colloidal particles of platinum in the colloidal solution measured using a transmission electron microscope was known to be 1.1 nm.
  • the quantity of the colloidal particles of platinum fixed on the surface of the graphite electrode was 10 ⁇ g-Pt/cm 2 same as in Example 8.
  • the means for fixing the colloidal particles of platinum on a graphite electrode in Example 8 was changed as follows: A graphite electrode was immersed in a solution containing bisacetyl acetonate platonic acid, pulled up after allowing to stand for a while, and heated and fired in the presence of hydrogen to form the colloidal particles of platinum on the graphite electrode.
  • the quantity of the colloidal particles of platinum fixed on the surface of the graphite electrode was 10 ⁇ l-P/cm 2 same as in Example 8.
  • a 1,500 ml flask, a 100-ml conical fask, a 200-ml conical fask, a reflux condenser and a stirrer were immersed in aqua regia for a day and night, and the apparatuses were well cleaned using pure water ion-exchanged and ultra-filtered.
  • the reflux condenser is installed on the fask and the pure water was heated to a temperature of 100° C. In order to remove dissolved oxygen, the pure water was boiled as it was for one hour.
  • tetachloroplatinic acid hexahydrate (50 mg as platinum) was weighed and charged into the 100-ml conical flask, and pure water ion-exchanged and ultra-filtered was added to make 50 ml.
  • One gram of sodium citrate was weighed and charged in the 200 ml conical flask, and pure water ion-exchanged and ultra-filtered was added to make 100 ml.
  • the aqueous solution of to tetachloroplatinic acid was charged from the 100 nm conical flask to the 1,500-ml flask, and heated to 100° C. again.
  • the reducing reaction was continued in the boiling state, and reaction was stopped 120 minutes after the start of reaction, and each reaction solution was rapidly cooled to roam temperature.
  • the cooled reaction solution was passed through a column packed with ion-exchange resin Amberlite MB-1 (manufactured by Organo Corporation), and metal ions and the reducing agent left in the reaction solution were removed to obtain a stable colloidal solution.
  • the concentration of the colloidal particles in the colloidal solution was measured plasma emission spectrometry, and an adequate amount of the colloidal particles were fierier sampled to determine the state of the catalytic activity thereof that is, the particle diameter of the colloidal particles utilizing the hydrogen peroxide decomposing reaction.
  • the concentration of the colloidal particles of platinum was 31.25 mg/L, and the catalytic activity was 0.79 mol-O 2 /mg-Pt/mm.
  • the average particle diameter of the colloidal particles of platinum was measured using a transmission electron microscope. As a result the average particle diameter of the colloidal particles was 3.5 nm, and it was confirmed to agree with the result of measurement utilizing the hydrogen peroxide decomposing reaction.
  • the means for fixing the colloidal particles of platinum on a graphite electrode in Example 10 was changed as follows: A graphite electrode was immersed in a solution containing bisacetyl acetate platonic acid, pulled up after allowing to stand for a while, and heated and fired in the presence of hydrogen to form the colloidal particles of platinum on the graphite electrode.
  • the quantity of the colloidal particles of platinum fixed on the sulfite of the graphite electrode was 10 ⁇ g-Pt/cm 2 same as in Example 10.
  • the reflux condenser is installed on the flask, and the pure water was heated to a temperature of 100° C. In order to remove dissolved oxygen, the pure water was boiled as it was for one hour.
  • tetachloroplatinic acid hexahydrate (50 mg as platinum) was weighed and charged into the 100-ml conical flask, and pure water ion-exchanged and ultra-filtered was added to make 50 ml.
  • One gram of sodium citrate was weighed and charged in the 200-ml conical flask and pure water ion-exchanged and ultra-filtered was added to make 100 ml.
  • the aqueous solution of tetrachloroplatinic acid was charged from the 100-ml conical flask to the 1,500-ml flask, and heated to 100° C. again.
  • the cooled reaction of the colloidal particles in the colloidal solution was measured using plasma emission spectrometry, and an adequate amount of the colloidal particles were further sampled to determine the state of the catalytic activity thereof, that is, the particle diameter of the colloidal particles utilizing the hydrogen peroxide decomposing reaction
  • the concentration of the colloidal particles of platinum was 31.25 mg/L
  • the catalytic activity was 0.79 mol-O 2 /mg-Pt/min.
  • the average particle diameter of the colloidal particles of platinum was measured using a transmission electron microscope. As a result the average particle diameter of the colloidal particles was 3.5 nm, and it was confirmed to agree with the result of measurement utilizing the hydrogen peroxide decomposing reaction.
  • the fine alumina particles After adding the fine alumina particles in the colloidal solution prepared using the above-described means and immersing for a predetermined time, the fine particles were pulled up and naturally died. Thereafter, the fine alumina particles were stored in a desiccator for several days to completely remove the solvent of the colloidal solution Thereafter, the fixation rate of the colloidal particles of platinum in the fine alumina particles was measured (calculated from the mass difference between before and after the fixation of the colloidal particles of platinum). The fixation rats of the colloidal particles of platinum was 0.27% by mass.
  • a colloidal solution and a low temperature oxidation catalyst were prepared in the same manner as in Example 11, except that tie time from the start of the reaction to the stop of the reaction was shorten in the state wherein the aqueous solution of sodium citrate had been completely added in the 1,500 ml flask, and the reducing reaction was continued in the boiling state.
  • the average particle diameter of the colloidal particles of platinum in the colloidal solution measured using a transmission electron microscope was known to be 1.1 nm.
  • the fixing rate of the colloidal particles of platinum in the low-temperature oxidation catalyst fine alumina particles having the colloidal particles of platinum fixed thereon was 0.20% by mass.
  • Example 11 the low-temperature oxidation catalyst was not prepared, but commercially available fine alumna particles having the colloidal particles of platinum fixed hereon (N-220, manufactured by Sud-Chemie Catalysts Japan, Inc.) were used.
  • the fixing rate of the colloidal particles of platinum in the fine alumina particles was 0.20% by mass, and since the measured specific surface area of the colloidal particles of platinum was about 160 m 2 /g, the average particle diameter thereof is considered to be about 1 nm, substantially equal to the colloidal particles of platinum prepared in Example 12. Further, the CO conversion rate was measured under the same conditions as in Example 11. The results are shown in FIG. 1 .
  • the low-temperature oxidation catalyst according to the present invention has higher catalytic activity tan the catalyst prepared by existing methods.
  • the catalytic activity is as high as two to three times the catalyst prepared by existing methods.
  • Example 11 By comparing Example 11 and Example 12, it is known that the larger the average particle diameter of the colloidal particles of platinum, the lower temperature region the catalytic activity starts elevating. However, since the larger the average particle diameter, the easier the colloidal particles of platinum precipitate, it is preferable that the average particle diameter is 5 nm or less. Specifically, the preferable average particle diameter of the colloidal particles of platinum is 3.5 to 5 nm.
  • the present invention Since the present invention is constituted as described above, it exerts the following effects.
  • a method for forming the colloidal particles of a metal by boiling a solution containing a metal salt and a reducing agent the average particle diameter of the colloidal particles can be further reduced and uniformize, and various properties thereof, such as catalytic activity, can be improved by combining and adjusting three preparing conditions (parameters) directly affecting the formation, association and aggregation of the colloidal particles.
  • the metal recovery rate of the metal salt can also be improved.
  • a carrier having a high catalytic activity, as well as durability can be obtained.
  • the present invention since the present invention is constituted as described above, it exerts the following effects. According to the methods for preparing a cathode, a fuel cell anode, and a low-temperature oxidation catalyst of the present invention, since an extremely stable colloidal solution contains no impurities, such as a stabilizer, is applied onto the substrate, no beating or firing of the substrate for obtaining the colloidal particles becomes required, and concurrently, the lowering of the catalytic activity due to the occurrence of residues or the like can be avoided. Also since the colloidal solution can be prepared in a simple process using an inexpensive metal salt as the starting material, the preparation costs can be suppressed. Also since the colloidal solution has a uniform particle diameter, and hardly aggregates even in a high concentration, no stabilizers for preventing precipitation are required.
  • a fuel cell cathode of the present invention water can be efficiently formed from hydrogen ions and oxygen. Furthermore, according to a fuel cell of the present invention, power-generating efficiency can be improved. In addition, according to a fuel cell anode of the present invention, hydrogen ions can be efficiently formed. Furthermore, according to a fuel cell of the present invention, power-generating efficiency can be improved.
  • a low-temperature oxidation catalyst of the present invention catalytic functions can be exerted at a high efficiency in an environment of 300° C. or below, particularly 150 to 200° C.
  • fuel modifying device for a fuel cell of the present invention the CO shifting reaction can be efficiently caused even at low temperatures. Therefore, the device can contribute to the improvement of the power-generating efficiency of the fuel cell, and by utilizing members having not so high heat resistance, the manufacturing costs can be reduced.

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US10/521,567 2002-07-16 2003-06-16 Method for preparing colloidal solution and carrier having colloidal particles fixed on surface thereof, fuel cell cathode, fuel cell anode and method for preparing the same and fuel cell using the same, and low temperature oxidation catalyst, method for preparing the same and fuel cell fuel modifying device using the same Abandoned US20060144189A1 (en)

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JP2002351839A JP2004181365A (ja) 2002-12-03 2002-12-03 低温酸化触媒、その製造方法およびそれを用いた燃料電池用燃料改質装置
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US20080295499A1 (en) * 2007-05-31 2008-12-04 James Joshua Driscoll Exhaust system utilizing a low-temperature oxidation catalyst
US20090215615A1 (en) * 2006-07-11 2009-08-27 3M Innovative Properties Company Method of forming supported nanoparticle catalysts
RU2508179C1 (ru) * 2012-07-10 2014-02-27 Федеральное государственное бюджетное учреждение "Национальный исследовательский центр "Курчатовский институт" Способ получения коллоидов металлов
US8951931B2 (en) 2010-03-02 2015-02-10 Nippon Sheet Glass Company, Limited Noble metal fine particle supported catalyst and method for producing the catalyst, and purifying catalyst

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JP4853498B2 (ja) * 2008-06-17 2012-01-11 トヨタ自動車株式会社 燃料電池用金微粒子担持担体触媒の製造方法及び該方法で製造された金微粒子を含む固体高分子型燃料電池用触媒

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US20080295499A1 (en) * 2007-05-31 2008-12-04 James Joshua Driscoll Exhaust system utilizing a low-temperature oxidation catalyst
US8951931B2 (en) 2010-03-02 2015-02-10 Nippon Sheet Glass Company, Limited Noble metal fine particle supported catalyst and method for producing the catalyst, and purifying catalyst
RU2508179C1 (ru) * 2012-07-10 2014-02-27 Федеральное государственное бюджетное учреждение "Национальный исследовательский центр "Курчатовский институт" Способ получения коллоидов металлов

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