Classifications

• • 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
• • 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
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
  • B01J23/48—Silver or gold
  • B01J23/52—Gold
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
  • C01B3/02—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen
  • C01B3/32—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air
  • C01B3/34—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents
  • C01B3/38—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents using catalysts
  • C01B3/40—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents using catalysts characterised by the catalyst
• • 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
  • H01M8/0606—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants
  • H01M8/0612—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants from carbon-containing material
• • 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
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
  • C01B2203/10—Catalysts for performing the hydrogen forming reactions
  • C01B2203/1041—Composition of the catalyst
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
  • C01B2203/10—Catalysts for performing the hydrogen forming reactions
  • C01B2203/1041—Composition of the catalyst
  • C01B2203/1047—Group VIII metal catalysts
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
  • C01B2203/10—Catalysts for performing the hydrogen forming reactions
  • C01B2203/1041—Composition of the catalyst
  • C01B2203/1076—Copper or zinc-based catalysts
• • 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
  • H01M2004/8684—Negative electrodes
• • 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
  • H01M8/10—Fuel cells with solid electrolytes
  • H01M8/1009—Fuel cells with solid electrolytes with one of the reactants being liquid, solid or liquid-charged
• • 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
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/50—Improvements relating to the production of bulk chemicals
  • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts
• • 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

Definitions

• the invention relates to a gold catalyst for oxidation of hydrocarbon and thus suitable for the fuel cell industry.
• Fuel cells are attractive alternative to the internal combustion engine technology, since they offer zero emission, higher effiency and reliability.
• the direct methanol fuel cell has been considerate as the ideal fuel cell system since it produces electric power by the direct conversion of methanol at the fuel cell anode.
• the DMFC is more attractive than the conventional hydrogen fuel cells especially for transportation, where at present bulky gas bottles with compressed hydrogen are carried.
• commercialisation of DMFC has been impeded, major limitation being the anode performance which requires highly efficient and cost effective oxidation catalyst which at present is still not available.
• Gold has always been regarded as far less active than the platinum group methals (PGM's). Recent publications, however, have shown that gold, when highly dispersed on reducible oxides, is very active for carbon monoxide oxidation at low temperature.
• German patent DE 3914294 describes a gold catalyst dispersed on a support containing iron oxide and alumine oxide and/or aluminosilicate. This catalyst, however, has unsatisfactory conversion of carbon monoxide at higher space velocity and is poisoned by moisture and sulphur dioxide.
• Bulgarian patent No. 101,490 describes gold catalyst for oxidation of carbon monoxide and hydrocarbons, reduction of nitrogen oxides and decomposition of ozone.
• the catalyst is suitable for removing toxic exhaust gases from the combustion engine, for decomposition of ozone at low temperatures, etc. Summary of the invention
• a catalyst for direct electrochemical oxidation of methanol, hydrocarbons and methane comprises a complex of gold and reducible oxide of a transition metal on a porous support of oxides selected from ceria, titanium and zirconia.
• the transition metal could be chromium, copper, cobalt, manganese, iron or a combination of those metals.
• the concentration of the gold is from 0.1 % to 2.5%, but preferably less than 1.3% and the total concentration of the metals in the active composition should not exceed 6% from the total mass of the catalyst.
• the support of mixed oxides has large surface area typically 80 m 2 /g to 400 m 2 /g, with ceria oxide concentration from 30% to 70 %, titania oxide 5% to 25% and zirconia oxide from 5% to 25%.
• the gold-transition metal oxide particles are deposited on the support by the methods of the known art: impregnation, precipitation, co-precipitation, wet incipient dryness or a combination of these techniques.
• the particles of the active component are finely and evenly dispersed through the support and should be of a size less than 40 nm, preferably less than 20 nm.
• the calcination of the catalyst is maintained in oxidising atmosphere at temperature from 100° to 500°C.
• the working temperature of the catalyst is from 0 o to 650°C.
• the catalyst could have applications in the following areas of the fuel cell technology:
• Fuel cells are electrochemical energy converters. They consist of two electrodes containing electrocatalysts and an electrolyte. Gas fuel is fed to the anode and is absorbed on the catalitically active surface, where an oxidation reaction occurs.
• the ionized fuel passes through the electrolite and on the surface of the cathode absorbs electrons and combines with oxygen thus forming water. This process could take place at temperature below 100°C.
• the force behind the process of ion migration is the concentration gradient between the two interfaces, electrode and electrolyte.
• the oxidation of methane could generate hydrogen, required for the electrochemical oxidation at the anode of the fuel cell: CH 4 + 0 2 - C0 2 + 2H 2 (3)
• the direct methanol fuel cell has been considerate as the ideal fuel cell since it provides electric power by the direct conversion of methanol at the fuel cell anode.
• the DMFC is more attractive than conventional hydrogen fuelled cells particulary for transportation applications.
• the gold catalyst may be used for direct electrochemical oxidation and of hydrocarbons at low temperatures, below their termal decomposition.
• the catalyst of the invention oxidises methanol at temperature below 100°C.
• the catalyst could be suitable for direct conversion of methane.
• the gold catalyst is highly efficient oxidation catalyst: total oxidation of methane to carbon dioxide occurs even under partial oxidation conditions. • The complete oxidation of methane occurs below 550°C.
• the catalyst were tested in reaction gas mixture containing 0.25% CH 4 balance air and 2.5% CH 4 , balance air at a gas hourly space velocity (GHSV) of
• Samples 1, 2, 3 were tested in the gas mixture at temperature from ambient up to 500°C.
• the temperature range for samples 4, 5, 6 was increased to 600°C.
• the space velocity was 12 000 h "1 .
• sample 6 was cooled in air from 600°C to room temperature and re-tested in the gas mixture again to 600°C.
• the total methane conversion and selectivity of products to C0 2 and CO was determine as a function of temperature.
• test mixture (a) After testing to 600°C, the catalyst was cooled in air to room temperature and the reaction repeated in order to establish catalyst stability and reproducibility.
• the results in test mixture (a) are given in Figure 3 and the results in test mixture (b) are given in Figure 4. In both figures the repeat test are shown in Run 2.
• Tests for methanol oxidation were carried out with samples 2 and 5. The experiments were performed by pumping liquid methanol into a vaporiser. The gas mixture was 6.5% CH 3 OH, balance air and gas hourly space velocity 20 000 h "1 . The results are given in Table 1 and show that Sample 5, which contains higher concentration of gold and titanium oxide, is superior in respect to the methanol oxidation.
• the gold catalyst of the invention shows exceptional capacity for oxidation of carbon monoxide at ambient temperature. This could be utilised for the removal of impurities, mainly CO, from the anodic fuel. Comparison between the gold catalyst and platinum catalyst shows the superiority of the catalyst of the invention. The test was carried with a gas mixture containing 1% CO, balance air at gas hourly space velocity 60 OOOh "1 .

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Electrochemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Sustainable Development (AREA)
• Manufacturing & Machinery (AREA)
• Life Sciences & Earth Sciences (AREA)
• Sustainable Energy (AREA)
• Materials Engineering (AREA)
• Health & Medical Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Combustion & Propulsion (AREA)
• Inorganic Chemistry (AREA)
• Catalysts (AREA)
• Industrial Gases (AREA)
• Inert Electrodes (AREA)
• Liquid Carbonaceous Fuels (AREA)

Applications Claiming Priority (3)

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• 1997
  • 1997-09-29 BG BG101931A patent/BG62723B1/bg unknown
• 1998
  • 1998-09-29 JP JP2000513671A patent/JP2001522122A/ja active Pending
  • 1998-09-29 EP EP98943591A patent/EP1027152A1/en not_active Withdrawn
  • 1998-09-29 WO PCT/BG1998/000016 patent/WO1999016546A1/en not_active Application Discontinuation
  • 1998-09-29 AU AU91479/98A patent/AU9147998A/en not_active Abandoned

Non-Patent Citations (1)

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