EP2961527A1 - Method for synthesizing bimetal catalyst particles made of platinum and of another metal and use thereof in an electrochemical hydrogen production method - Google Patents

Method for synthesizing bimetal catalyst particles made of platinum and of another metal and use thereof in an electrochemical hydrogen production method

Info

Publication number
EP2961527A1
EP2961527A1 EP14706561.9A EP14706561A EP2961527A1 EP 2961527 A1 EP2961527 A1 EP 2961527A1 EP 14706561 A EP14706561 A EP 14706561A EP 2961527 A1 EP2961527 A1 EP 2961527A1
Authority
EP
European Patent Office
Prior art keywords
catalyst particles
metal
platinum
bimetallic catalyst
synthesizing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP14706561.9A
Other languages
German (de)
French (fr)
Inventor
Nicolas Guillet
Joseph NGAMENI JIEMBOU
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Original Assignee
Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Commissariat a lEnergie Atomique et aux Energies Alternatives CEA filed Critical Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Publication of EP2961527A1 publication Critical patent/EP2961527A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
    • C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
    • C25B11/091—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds
    • C25B11/093—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds at least one noble metal or noble metal oxide and at least one non-noble metal oxide
    • 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
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/03—Precipitation; Co-precipitation
    • B01J37/031—Precipitation
    • B01J37/035—Precipitation on carriers
    • 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
    • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
    • B01J21/18—Carbon
    • 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
    • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/56—Platinum group metals
    • B01J23/62—Platinum group metals with gallium, indium, thallium, germanium, tin or lead
    • B01J23/622—Platinum group metals with gallium, indium, thallium, germanium, tin or lead with germanium, tin or lead
    • B01J23/626—Platinum group metals with gallium, indium, thallium, germanium, tin or lead with germanium, tin or lead with tin
    • B01J35/23—
    • B01J35/393—
    • 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
    • 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
    • B01J37/34—Irradiation by, or application of, electric, magnetic or wave energy, e.g. ultrasonic waves ; Ionic sputtering; Flame or plasma spraying; Particle radiation
    • B01J37/341—Irradiation by, or application of, electric, magnetic or wave energy, e.g. ultrasonic waves ; Ionic sputtering; Flame or plasma spraying; Particle radiation making use of electric or magnetic fields, wave energy or particle radiation
    • B01J37/344—Irradiation by, or application of, electric, magnetic or wave energy, e.g. ultrasonic waves ; Ionic sputtering; Flame or plasma spraying; Particle radiation making use of electric or magnetic fields, wave energy or particle radiation of electromagnetic wave energy
    • B01J37/345—Irradiation by, or application of, electric, magnetic or wave energy, e.g. ultrasonic waves ; Ionic sputtering; Flame or plasma spraying; Particle radiation making use of electric or magnetic fields, wave energy or particle radiation of electromagnetic wave energy of ultraviolet wave energy
    • 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
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/02—Hydrogen or oxygen
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures
    • 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
    • C01B2203/02—Processes for making hydrogen or synthesis gas
    • C01B2203/0205—Processes for making hydrogen or synthesis gas containing a reforming step
    • C01B2203/0227—Processes for making hydrogen or synthesis gas containing a reforming step containing a catalytic reforming step
    • C01B2203/0238—Processes for making hydrogen or synthesis gas containing a reforming step containing a catalytic reforming step the reforming step being a carbon dioxide reforming step
    • 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
    • C01B2203/1064—Platinum group metal catalysts
    • C01B2203/107—Platinum 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
    • C01B2203/12—Feeding the process for making hydrogen or synthesis gas
    • C01B2203/1205—Composition of the feed
    • C01B2203/1211—Organic compounds or organic mixtures used in the process for making hydrogen or synthesis gas
    • C01B2203/1235—Hydrocarbons
    • C01B2203/1241—Natural gas or methane
    • 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
    • Y02P20/141—Feedstock
    • 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

Definitions

  • the field of the invention is that of H 2 / O 2 fuel cells.
  • pressurized hydrogen tanks gas storage
  • metal hydrides storage in solid form
  • biofuels and gaseous hydrocarbons such as natural gas or liquids such as alcohol, gasoline or gas oil are potentially sources of hydrogen and an electrochemical cell connected to a low-power power supply.
  • an electrochemical cell connected to a low-power power supply.
  • Platinum is very often used as a reaction catalyst in electrochemical systems, but its use for a purification application as anode material is problematic although it is the best material used at low temperature for the reaction of electro-oxidation of hydrogen (H 2 -> 2H + + 2e " ).
  • Pt platinum
  • Pt platinum
  • This poisoning is done by adsorption of CO on the surface of the Pt irreversibly by blocking the available adsorption sites, thus preventing the adsorption of hydrogen, and its oxidation.
  • Pt-Ru platinum-ruthenium
  • Pt-Sn platinum-tin
  • Pt-Mo platinum-molybdenum
  • Pt-Co platinum-cobalt
  • the present invention relates to a method based on the optimization of the operating conditions of synthesis in order to limit the growth phase of the nanoparticles and to favor that of germination making it possible to increase the number of germs.
  • the limitation of the growth phase makes it possible to obtain nanoparticles of small sizes, typically of the order of 2 to 5 nm and a larger number of particles.
  • the subject of the present invention is a process for synthesizing particles of bimetallic catalyst based on platinum and at least one second metal, characterized in that it comprises the chemical reduction of a first salt or complex based on platinum and at least one second salt or complex based on said second metal, said chemical reduction comprising the following steps:
  • the reducing agent is formic acid, the temperature of said chemical reduction being carried out at a temperature of between approximately 0 ° C. and 8 ° C., advantageously being of the order of 4 ° C. vs.
  • the reducing agent is hydrazine, the temperature of said reduction being carried out at a temperature between 0 ° C. and 2 ° C.
  • the reducing agent is formaldehyde, the temperature of said reduction being carried out at a temperature of between -19 ° C. and 0 ° C.
  • the process comprises the mixture of salt or platinum complex and salt or complex of said second metal, in the presence of particles of carbon black or metal oxide or metal nitride or carbide metallic.
  • the amount of reducing agent is greater than or equal to the amount necessary to carry out the chemical reduction of all platinum salts and complexes and those of the second metal.
  • the reaction is carried out in the presence of an additional source of energy to accelerate the chemical reduction operation without promoting the growth of nanoparticles.
  • the additional energy source is a source of ultraviolet radiation.
  • the source of ultraviolet radiation emits in a wavelength range of between about 200 nm and 300 nm.
  • the second metal is tin, or ruthenium, or molybdenum, or cobalt.
  • the bimetallic catalyst particles are based on platinum and tin and their size distribution has a median value of 4 nm with a low dispersion: the standard deviation is of the order of 1 , 1.
  • the subject of the invention is also the use of the process for synthesizing bimetallic catalyst particles according to the invention, for a method of electrochemical hydrogen production comprising a catalytic reforming reaction in the presence of said catalyst particles and a mixture gas comprising hydrocarbon compounds.
  • the metal particles obtained by the synthesis method of the invention appear in fact less sensitive to pollution by the hydrocarbon compounds present in the gas mixture than the particles obtained according to the methods described in the state of the art.
  • the gaseous mixture comprises carbon monoxide, carbon dioxide and methane.
  • FIG. 1 illustrates the UV absorption spectra of the PtCl 6 2 - ions
  • FIG. 2 illustrates the particle size distribution of the Pt 3 Sn / C catalysts synthesized at room temperature and at 4 ° C., according to the process of the invention
  • FIG. 3 illustrates the cyclic voltammogram obtained on Pt 3 Sn / C synthesized at room temperature in an aqueous solution of H 2 SO 4 at a concentration of 0.5 M at 25 ° C .;
  • FIG. 4 illustrates the cyclic voltammogram obtained on Pt 3 Sn / C synthesized at 4 ° C. in an aqueous solution of H 2 SO 4 at a concentration of 0.5 M at 25 ° C .;
  • FIG. 5 illustrates the evolution of the electro-oxidation current of H 2 on Pt 3 Sn / C synthesized at ambient temperature and at 4 ° C. in an aqueous solution of H 2 SO 4 of concentration 0.5 M after having subjected the catalyst to a mixture of compound gas 50 ppm CO in H 2 and 0.24 V vs. ERH and reaches a quasi stationary state of evolution of the oxidation current of hydrogen over time.
  • Pt-M platinum-metal alloy
  • Applicant uses the method FAM (Formic Acid Method) as described in the article E.l. Santiago et al. "CO tolerance on PtMo / C electrocatalysts prepared by the formic acid method" Electrochimica Acta 48 (2003) 3527-3534.
  • solutions of salts or complexes of Pt and a metal alloy as precursors of Pt-M catalysts supported or not on carbon black with a high specific surface area, a metal oxide (TiO 2 2 , ZrO 2 , Al 2 O 3 , ...) or metal nitrides (TiN, TaN, BN), metal carbides (TiC, WC, W 2 C, Mo 2 C, etc.).
  • the solutions of salts or complexes of Pt and the alloy metal element M are mixed with the carbon support and the whole is shaken vigorously with ultrasound for at least half an hour , time necessary to obtain a homogeneous mixture.
  • the volume of the solutions is determined from the concentration of the solutions and so as to obtain the atomic composition of the desired metal alloy.
  • the support mass of metal nanoparticles useful for the synthesis is determined so that it represents 50% of the mass of the synthesized catalyst.
  • Formic acid is used as a reducing agent and is added to the previously described mixture.
  • the volume of the formic acid must be in excess so that the chemical reduction of the salts or metal complexes is completed.
  • the whole mixture is then brought to a temperature between the freezing temperature of water and that of formic acid. After 12 to 72 hours, the chemical reduction is complete and a metal powder is obtained representing the catalyst.
  • the lowering of the temperature favors the decrease of the growth rate of the nanoparticles and consequently lengthens the duration of chemical reduction of the metal salts. To overcome this lengthening of duration, it is appropriate to accelerate the chemical reduction reaction without increasing the rate of growth.
  • the vial containing the mixture may advantageously be exposed to a source of energy, for example ultraviolet (UV) rays which make it possible, thanks to this energy supply, to accelerate the reaction (the germination of the particles), thus favoring the multiplicity of seeds. in the nanoparticular state without promoting their growth.
  • a source of energy for example ultraviolet (UV) rays which make it possible, thanks to this energy supply, to accelerate the reaction (the germination of the particles), thus favoring the multiplicity of seeds. in the nanoparticular state without promoting their growth.
  • UV rays which make it possible, thanks to this energy supply, to accelerate the reaction (the germination of the particles), thus favoring the multiplicity of seeds. in the nanoparticular state without promoting their growth.
  • the wavelength of the UV rays is preferably chosen between 200 and 300 nm, corresponding to the absorption zone of the complex platinum of Pt, as shown in FIG.
  • Embodiment Pt-Sn / C catalysts of 3: 1 molar composition were synthesized by chemical reduction with formic acid.
  • Aqueous solutions of platinum and tin salts of 0.01 M concentration were mixed in the presence of carbon black and vigorously shaken with ultrasound for a period of about one hour.
  • the volumes of K 2 PtCl 6 , 6H 2 0 and SnCl 2 , 2H 2 0 solutions mixed are respectively 15 ml and 5 ml so as to obtain an atomic ratio of 3: 1.
  • a large amount of formic acid HCOOH (ACS reagent, greater than or equal to 98% Sigma-Aldrich) with a molar ratio of the order of 1000: 1, between formic acid and metal salts, used as a reducing agent is added to the mixture to allow a simultaneous reduction of the platinum and tin salts.
  • the objective of carrying out the synthesis at this temperature is to reduce during the synthesis, the growth rate of the nanoparticles which has a growth dependence with temperature.
  • the electro-active surface corresponds more precisely to the electro-chemically active surface for the reactions considered, which one seeks to increase.
  • Figure 2 illustrates particle size distributions of Pt 3 Sn / C catalysts synthesized at room temperature (25 ° C) and at 4 ° C and demonstrates the high percentage of small particles, typically 3 to 4 nm. with the synthesis method of the invention.
  • EDS Energy Dispersive X-ray Spectrometry
  • the electroactive surface of the catalyst prepared at 4 ° C. is thus much larger than that of the same catalyst synthesized at 25 ° C.
  • the Applicant has carried out the cyclic voltammograms in an electrochemical half-cell at 25 ° C. with a scanning speed of 10 mV / s, relative to the various catalysts prepared.
  • cyclic voltammetry is a method of electrochemical analysis based on the measurement of the current flow resulting from the reduction or oxidation of the compounds which come into contact with a working electrode (the sample studied) under effect of a controlled variation of the potential difference with a fixed potential electrode, called the reference electrode. It helps identify and measure quantitatively a large number of compounds and also to study the chemical reactions including these compounds.
  • the high absorption power can be characterized by the absence of oxidation peaks (positive current) on the voltammogram having the measured current density as a function of the applied potential E to the working electrode.
  • the absence of these peaks on the voltammogram reflects the blocking of adsorption sites of the catalyst by another species.
  • Figure 3 relates to the results obtained with Pt 3 Sn / C particles prepared at 25 ° C.
  • Curve 3a is relative to the voltammetric curve (under N 2 , in 0.5 MH 2 SO 4 at 25 ° C. and 10 mV.s.sup.- 1 ) carried out after pollution of the catalyst by adsorption of CO.
  • Figure 4 relates to the results obtained with Pt 3 Sn / C particles prepared at 4 ° C.
  • curve 4a the same cyclic voltammetric curve after pollution of the catalyst by CO adsorption shows that the pollution of the catalyst is not complete: the hydrogen desorption peaks are still observed.
  • curve 4a between 0.1 and 0.4 V vs. ERH and oxidation of CO starts at an electrode potential of 0.3 V vs. ERH.
  • the gain, in terms of energy, for the oxidation of hydrogen in the presence of traces of polluting gases is nearly 30% (0.72 kWh / Nm 3 H 2 with the catalyst synthesized at 4 ° C, against 0, 96 kWi // Nm 3 H 2 with the catalyst synthesized at 25 ° C).
  • the Applicant has also followed the evolution of the electro-oxidation current of H 2 on Pt 3 Sn / C synthesized at room temperature and at 4 ° C. in an electrochemical half-cell device, when the electrode is fed with a mixture gas composed of 50 ppm CO in H 2 and subjected to a potential of 0.24 V vs. ERH.
  • FIG. 5 shows via the curves 5a and 5b the difference in behavior with a catalyst produced according to the present invention at a temperature of 4 ° C., compared to a catalyst produced at ambient temperature.

Abstract

The invention relates to a method for synthesizing bimetal catalyst particles made of platinum and of at least one second metal, characterized in that said method includes the chemical reduction of a first salt or complex made of platinum and of at least one second salt or complex made of said second metal, said chemical reduction comprising the following steps: producing a mixture including said first salt or complex made of platinum, and of said second salt or complex made of said second metal, in the presence of a pure reducing agent in liquid form under ambient conditions of temperature and pressure (CATP), said conditions being defined as equal at 25°C and 100kPa, respectively; and heating said mixture to a temperature between approximately the freezing temperature of water and the freezing temperature of the reducing agent.

Description

PROCEDE DE SYNTHESE DE PARTICULES DE CATALYSEUR  PROCESS FOR SYNTHESIZING CATALYST PARTICLES
BIMETALLIQUE A BASE DE PLATINE ET D'UN AUTRE METAL ET LEUR UTILISATION DANS UNE MÉTHODE DE PRODUCTION ELECTROCHIMIQUE D'HYDROGENE  BIMETALLIUM BASED ON PLATINUM AND ANOTHER METAL AND THEIR USE IN A METHOD OF ELECTROCHEMICALLY PRODUCING HYDROGEN
Le domaine de l'invention est celui des piles à combustible H2/02. L'utilisation de ce type de pile à combustible dans l'industrie automobile en lieu et place des moteurs à combustion interne rencontre toujours des problèmes liés au stockage de l'hydrogène : les réservoirs d'hydrogène sous pression (stockage gazeux) sont potentiellement dangereux et les hydrures métalliques (stockage sous forme solide) sont inappropriés en raison de leur densité énergétique faible comme décrit dans l'article de : Schlapbach L. Z ittel A. Hydrogen-storage materials for mobile applications. Nature 2001 ; 414 :353-8. The field of the invention is that of H 2 / O 2 fuel cells. The use of this type of fuel cell in the automotive industry in place of internal combustion engines still faces problems related to the storage of hydrogen: pressurized hydrogen tanks (gas storage) are potentially dangerous and metal hydrides (storage in solid form) are unsuitable because of their low energy density as described in the article by: Schlapbach L. Z. A. Hydrogen-storage materials for mobile applications. Nature 2001; 414: 353-8.
La production d'hydrogène à bord du véhicule par reformage catalytique offre une solution alternative au stockage direct d'hydrogène comme décrit dans l'article de : Basile A, Galluci F, Paturzo L. « Hydrogen production from methanol by oxidative steam reforming carried out in a membrane reactor », Catalysis today 2005 ; 104:251 -9, mais une étape de purification est nécessaire pour alimenter la pile à combustible.  The production of hydrogen on board the vehicle by catalytic reforming offers an alternative solution to the direct storage of hydrogen as described in the article by: Basil A, Galluci F, Paturzo L. "Hydrogen production from methanol by oxidative steam reforming carried out in a membrane reactor ", Catalysis today 2005; 104: 251-9, but a purification step is necessary to feed the fuel cell.
Pour ce type d'application, les biocarburants et des hydrocarbures gazeux comme le gaz naturel ou liquides tels que l'alcool, l'essence ou le gasoil sont potentiellement des sources d'hydrogène et une cellule électrochimique connectée à une alimentation électrique de faible puissance peut être utilisée pour extraire à basse température l'hydrogène du mélange gazeux contenant le monoxyde de carbone (CO), dioxyde de carbone (C02), méthane (CH4) et d'autres gaz. For this type of application, biofuels and gaseous hydrocarbons such as natural gas or liquids such as alcohol, gasoline or gas oil are potentially sources of hydrogen and an electrochemical cell connected to a low-power power supply. can be used to extract hydrogen at low temperature from the gaseous mixture containing carbon monoxide (CO), carbon dioxide (CO 2 ), methane (CH 4 ) and other gases.
En appliquant une tension électrique suffisante aux bornes de la cellule, l'électro-oxydation de l'hydrogène et du monoxyde de carbone ont lieu à l'anode :  By applying a sufficient electrical voltage across the cell, the electro-oxidation of hydrogen and carbon monoxide takes place at the anode:
H2 → 2ΗΓ + 2e" (E° (H7H2)=0 vs. ESH, potentiel standard d'équilibre électrochimique, ESH étant le potentiel de l'électrode standard à hydrogène) H 2 → 2ΗΓ + 2e " (E ° (H7H 2 ) = 0 vs. ESH, standard electrochemical equilibrium potential, ESH being the potential of the standard hydrogen electrode)
COadS + H20 C02 + 2H+ + 2e" CO a d S + H 2 0 C0 2 + 2H + + 2e "
comme décrit dans l'article de : M. Ciureanu et al., "Electrochemical Impédance Study of Electrode-Membrane Assemblies in PEM Fuel Cells I. Electro-oxidation of H2 and H2/CO Mixtures on Pt-Based Gas-Diffusion Electrodes" Journal of the Electrochemical Society 1999, 146, 4031 ^1040. as described in the article by: M. Ciureanu et al., "Electrochemical Impedance Study of Electrode-Membrane Assemblies in PEM Fuel Cells I. Electrooxidation of H 2 and H 2 / CO Mixtures on Pt-Based Gas-Diffusion Electrodes "Journal of the Electrochemical Society 1999, 146, 4031-1040.
Le platine est très souvent utilisé en tant que catalyseur de réaction, dans les systèmes électrochimiques, mais son utilisation pour une application de purification comme matériau d'anode pose problème bien qu'il soit le meilleur matériau utilisé à basse température pour la réaction d'électro-oxydation d'hydrogène (H2 -> 2H+ + 2e"). Platinum is very often used as a reaction catalyst in electrochemical systems, but its use for a purification application as anode material is problematic although it is the best material used at low temperature for the reaction of electro-oxidation of hydrogen (H 2 -> 2H + + 2e " ).
En effet, le platine (Pt) est onéreux, rare et moins performant à bas potentiel à cause de la facilité qu'a le monoxyde de carbone (contenu dans l'hydrogène reformé) à l'empoisonner. Cet empoisonnement se fait par adsorption du CO à la surface du Pt de façon irréversible en bloquant les sites d'adsorption disponibles, empêchant ainsi l'adsorption de l'hydrogène, et son oxydation.  Indeed, platinum (Pt) is expensive, rare and less powerful at low potential because of the ease of carbon monoxide (contained in the reformed hydrogen) to poison it. This poisoning is done by adsorption of CO on the surface of the Pt irreversibly by blocking the available adsorption sites, thus preventing the adsorption of hydrogen, and its oxidation.
Or, l'électro-oxydation du CO à la surface du Pt supporté sur du carbone, c'est-à-dire du CO en CO2 (CO + H2O -> CO2 + 2H+ + 2e") se fait à des potentiels relativement élevés se situant autour de 0,7 à 0,8 V vs. ESH, ce qui nécessite un apport d'énergie non négligeable. However, the electro-oxidation of CO on the surface of Pt supported on carbon, that is to say of the CO to CO 2 (CO + H 2 O -> CO 2 + 2H + + 2e ") is at relatively high potentials ranging from 0.7 to 0.8 V vs. ESH, which requires a significant energy input.
Pour pallier aux difficultés rencontrées avec le platine Pt liées essentiellement à sa mauvaise tolérance au monoxyde de carbone CO, de nouveaux catalyseurs d'anode sont recherchés.  To overcome the difficulties encountered with platinum Pt mainly related to its poor tolerance to carbon monoxide CO, new anode catalysts are sought.
Pour aboutir à ces nouveaux types de catalyseurs, l'élaboration d'un alliage de Pt avec un métal de transition peut être envisagée ou l'association du Pt fortement divisé à une phase du type oxyde métallique. Plusieurs alliages de platine tels que le platine-ruthénium (Pt-Ru), le platine- étain (Pt-Sn), le platine-molybdène (Pt-Mo), le platine-cobalt (Pt-Co) supportés sur du noir de carbone de grande surface spécifique font l'objet d'études dans le but de trouver le meilleur alliage à base de platine qui possède une bonne tolérance au monoxyde de carbone CO et qui permette d'autre part d'oxyder ledit monoxyde de carbone CO à bas potentiel.  To achieve these new types of catalysts, the development of a Pt alloy with a transition metal can be envisaged or the combination of highly divided Pt with a metal oxide phase. Several platinum alloys such as platinum-ruthenium (Pt-Ru), platinum-tin (Pt-Sn), platinum-molybdenum (Pt-Mo), platinum-cobalt (Pt-Co) supported on black high surface area carbon are being studied in order to find the best platinum-based alloy that has a good tolerance to carbon monoxide CO and that on the other hand oxidizes said carbon monoxide CO to low potential.
II est par ailleurs connu que les performances de ces catalyseurs anodiques vis-à-vis de l'électro-oxydation de H2/CO dépendent de leur structure, de leur composition chimique, de la taille nanométrique des particules et de la nature de leur support. La maîtrise de la technique d'élaboration et de la méthode de préparation des catalyseurs permet de contrôler les propriétés physico-chimiques. Les nanoparticules métalliques sont généralement synthétisées par réduction chimique de sels ou complexes métalliques en présence d'un agent réducteur. Lors de la synthèse, le mécanisme de développement des nanoparticules se fait par germination et croissance. Cette étape est importante car elle détermine la taille des particules et impacte par conséquent, la surface électroactive du catalyseur. It is moreover known that the performances of these anodic catalysts with respect to the electro-oxidation of H 2 / CO depend on their structure, their chemical composition, the nanometric size of the particles and the nature of their composition. support. The mastery of the preparation technique and the method of preparation of the catalysts makes it possible to control the physicochemical properties. Metallic nanoparticles are generally synthesized by chemical reduction of salts or metal complexes in the presence of a reducing agent. During the synthesis, the mechanism of development of the nanoparticles is by germination and growth. This step is important because it determines the particle size and therefore impacts the electroactive surface of the catalyst.
L'obtention des nanoparticules de catalyseur par réduction chimique de sels ou complexes métalliques en présence d'un agent réducteur est une méthode simple à mettre en œuvre mais la maîtrise et le contrôle des phases de germination et croissance des nanoparticules restent un enjeu majeur.  Obtaining the catalyst nanoparticles by chemical reduction of salts or metal complexes in the presence of a reducing agent is a simple method to implement but the control and control of the germination and growth phases of the nanoparticles remain a major issue.
C'est pourquoi et dans ce contexte, la présente invention, a pour objet une méthode basée sur l'optimisation des conditions opératoires de synthèse afin de limiter la phase de croissance des nanoparticules et favoriser celle de la germination permettant d'accroître le nombre de germes.  This is why, and in this context, the present invention relates to a method based on the optimization of the operating conditions of synthesis in order to limit the growth phase of the nanoparticles and to favor that of germination making it possible to increase the number of germs.
En comparaison avec une évolution spontanée lors de la synthèse de particules par réduction chimique (sans modification des paramètres opératoires), la limitation de la phase de croissance permet d'obtenir des nanoparticules de petites tailles typiquement de l'ordre de 2 à 5 nm et un nombre de particules plus important.  In comparison with a spontaneous evolution during the synthesis of particles by chemical reduction (without modification of the operating parameters), the limitation of the growth phase makes it possible to obtain nanoparticles of small sizes, typically of the order of 2 to 5 nm and a larger number of particles.
La conjugaison de ces deux aspects offre une configuration microstructurale dans laquelle la surface électroactive du catalyseur est optimale.  The combination of these two aspects provides a microstructural configuration in which the electroactive surface of the catalyst is optimal.
La modification de la température à laquelle la réduction chimique des sels et complexes métalliques a lieu, représente le moyen le plus efficace pour réduire la vitesse de croissance des particules car les deux paramètres évoluent dans le même sens.  The modification of the temperature at which the chemical reduction of salts and metal complexes takes place represents the most effective means of reducing the growth rate of the particles, since the two parameters evolve in the same direction.
Plus précisément, la présente invention a pour objet un procédé de synthèse de particules de catalyseur bimétallique à base de platine et d'au moins un second métal caractérisé en ce qu'il comprend la réduction chimique d'un premier sel ou complexe à base de platine et d'au moins un second sel ou complexe à base dudit second métal, ladite réduction chimique comportant les étapes suivantes :  More specifically, the subject of the present invention is a process for synthesizing particles of bimetallic catalyst based on platinum and at least one second metal, characterized in that it comprises the chemical reduction of a first salt or complex based on platinum and at least one second salt or complex based on said second metal, said chemical reduction comprising the following steps:
- la réalisation d'un mélange comprenant ledit premier sel ou complexe à base de platine et ledit second sel ou complexe à base dudit second métal, en présence d'un agent réducteur pur sous forme liquide dans les conditions ambiantes de température et de pression (CATP), lesdites conditions étant définies à 25° C et 100 kPa ; the production of a mixture comprising said first salt or platinum-based complex and said second salt or complex to base of said second metal, in the presence of a pure reducing agent in liquid form under ambient temperature and pressure (CATP) conditions, said conditions being defined at 25 ° C and 100 kPa;
- la mise en température comprise entre environ la température de congélation de l'eau et la température de congélation de l'agent réducteur, dudit mélange.  - Warming up between about the freezing temperature of the water and the freezing temperature of the reducing agent, said mixture.
Selon une variante de l'invention, l'agent réducteur est l'acide formique, la température de ladite réduction chimique étant effectuée à une température comprise entre environ 0°C et 8°C, pouiant avantageusement être de l'ordre de 4° C.  According to a variant of the invention, the reducing agent is formic acid, the temperature of said chemical reduction being carried out at a temperature of between approximately 0 ° C. and 8 ° C., advantageously being of the order of 4 ° C. vs.
Selon une variante de l'invention, l'agent réducteur est l'hydrazine, la température de ladite réduction étant effectuée à une température comprise entre 0° C et 2°C.  According to a variant of the invention, the reducing agent is hydrazine, the temperature of said reduction being carried out at a temperature between 0 ° C. and 2 ° C.
Selon une variante de l'invention, l'agent réducteur est le formaldéhyde, la température de ladite réduction étant effectuée à une température comprise entre -19°C et 0°C.  According to a variant of the invention, the reducing agent is formaldehyde, the temperature of said reduction being carried out at a temperature of between -19 ° C. and 0 ° C.
Selon une variante de l'invention, le procédé comprend le mélange de sel ou de complexe de platine et de sel ou de complexe dudit second métal, en présence de particules de noir de carbone ou d'oxyde métallique ou de nitrure métallique ou de carbure métallique.  According to a variant of the invention, the process comprises the mixture of salt or platinum complex and salt or complex of said second metal, in the presence of particles of carbon black or metal oxide or metal nitride or carbide metallic.
Selon une variante de l'invention, la quantité d'agent réducteur est supérieure ou égale à la quantité nécessaire pour procéder à la réduction chimique de l'ensemble des sels ou complexes du platine et de ceux du second métal.  According to a variant of the invention, the amount of reducing agent is greater than or equal to the amount necessary to carry out the chemical reduction of all platinum salts and complexes and those of the second metal.
Selon une variante de l'invention, la réaction est effectuée en présence d'une source d'énergie additionnelle permettant d'accélérer l'opération de réduction chimique sans favoriser la croissance de nanoparticules.  According to a variant of the invention, the reaction is carried out in the presence of an additional source of energy to accelerate the chemical reduction operation without promoting the growth of nanoparticles.
Selon une variante de l'invention, la source d'énergie additionnelle est une source de rayonnements ultra-violets.  According to a variant of the invention, the additional energy source is a source of ultraviolet radiation.
Selon une variante de l'invention, la source de rayonnements ultra-violets émet dans une gamme de longueurs d'onde comprises entre environ 200 nm et 300 nm. Selon une variante de l'invention, le second métal est de l'étain, ou du ruthénium, ou du molybdène, ou du cobalt. According to a variant of the invention, the source of ultraviolet radiation emits in a wavelength range of between about 200 nm and 300 nm. According to a variant of the invention, the second metal is tin, or ruthenium, or molybdenum, or cobalt.
Selon une variante de l'invention, les particules de catalyseur bimétallique sont à base de platine et d'étain et leur distribution en taille présente une valeur médiane de 4 nm avec une faible dispersion : l'écart type est de l'ordre de 1 ,1 .  According to a variant of the invention, the bimetallic catalyst particles are based on platinum and tin and their size distribution has a median value of 4 nm with a low dispersion: the standard deviation is of the order of 1 , 1.
L'invention a aussi pour objet l'utilisation du procédé de synthèse de particules de catalyseur bimétallique selon l'invention, pour une méthode de production électrochimique d'hydrogène comprenant une réaction de reformage catalytique en présence desdites particules de catalyseur et d'un mélange gazeux comprenant des composés hydrocarbonés. Les particules métalliques obtenues par la méthode de synthèse de l'invention apparaissent en effet moins sensibles à la pollution par les composés hydrocarbonés présents dans le mélange gazeux que les particules obtenues selon les méthodes décrites dans l'état de l'art.  The subject of the invention is also the use of the process for synthesizing bimetallic catalyst particles according to the invention, for a method of electrochemical hydrogen production comprising a catalytic reforming reaction in the presence of said catalyst particles and a mixture gas comprising hydrocarbon compounds. The metal particles obtained by the synthesis method of the invention appear in fact less sensitive to pollution by the hydrocarbon compounds present in the gas mixture than the particles obtained according to the methods described in the state of the art.
Selon une variante, le mélange gazeux comprend du monoxyde de carbone, du dioxyde de carbone et du méthane.  According to one variant, the gaseous mixture comprises carbon monoxide, carbon dioxide and methane.
L'invention sera mieux comprise et d'autres avantages apparaîtront à la lecture de la description qui va suivre donnée à titre non limitatif et grâce aux figures annexées parmi lesquelles : The invention will be better understood and other advantages will become apparent on reading the description which follows given by way of non-limiting example and by virtue of the appended figures among which:
- la figure 1 illustre les spectres d'absorption UV des ions PtCI6 2" ;FIG. 1 illustrates the UV absorption spectra of the PtCl 6 2 - ions;
- la figure 2 illustre la distribution de la taille de particules des catalyseurs Pt3Sn/C synthétisés à température ambiante et à 4°C, selon le procédé de l'invention ; FIG. 2 illustrates the particle size distribution of the Pt 3 Sn / C catalysts synthesized at room temperature and at 4 ° C., according to the process of the invention;
- la figure 3 illustre le voltampérogramme cyclique obtenu sur Pt3Sn/C synthétisé à température ambiante dans une solution aqueuse de H2S04 de concentration 0,5 M à 25 °C ;FIG. 3 illustrates the cyclic voltammogram obtained on Pt 3 Sn / C synthesized at room temperature in an aqueous solution of H 2 SO 4 at a concentration of 0.5 M at 25 ° C .;
- la figure 4 illustre le voltampérogramme cyclique obtenu sur Pt3Sn/C synthétisé à 4° C dans une solution aqueuse de H2S04 de concentration 0,5 M à 25 °C ; FIG. 4 illustrates the cyclic voltammogram obtained on Pt 3 Sn / C synthesized at 4 ° C. in an aqueous solution of H 2 SO 4 at a concentration of 0.5 M at 25 ° C .;
- la figure 5 illustre l'évolution du courant d'électro-oxydation de H2 sur Pt3Sn/C synthétisés à température ambiante et à 4°C dans une solution aqueuse de H2S04 de concentration 0,5 M après avoir soumis le catalyseur à un mélange de gaz composé de 50 ppm de CO dans H2 et à 0,24 V vs. ERH et atteint un état quasi stationnaire de l'évolution du courant d'oxydation de l'hydrogène au cours du temps. Pour la synthèse d'un catalyseur d'alliage platine-métal (Pt-M), leFIG. 5 illustrates the evolution of the electro-oxidation current of H 2 on Pt 3 Sn / C synthesized at ambient temperature and at 4 ° C. in an aqueous solution of H 2 SO 4 of concentration 0.5 M after having subjected the catalyst to a mixture of compound gas 50 ppm CO in H 2 and 0.24 V vs. ERH and reaches a quasi stationary state of evolution of the oxidation current of hydrogen over time. For the synthesis of a platinum-metal alloy (Pt-M) catalyst, the
Demandeur utilise la méthode FAM (Formic Acid Method) telle que décrite dans l'article E.l. Santiago et al. « CO tolérance on PtMo/C electrocatalysts prepared by the formic acid Method » Electrochimica Acta 48 (2003) 3527- 3534. Applicant uses the method FAM (Formic Acid Method) as described in the article E.l. Santiago et al. "CO tolerance on PtMo / C electrocatalysts prepared by the formic acid method" Electrochimica Acta 48 (2003) 3527-3534.
Selon la présente invention, il est proposé d'utiliser des solutions de sels ou complexes de Pt et d'un allié métallique comme précurseurs de catalyseurs Pt-M supportés ou non sur du noir de carbone de grande surface spécifique, un oxyde métallique (TiO2, ZrO2, AI2O3, ...) ou des nitrures métalliques (TiN, TaN, BN), des carbures métalliques (TiC, WC, W2C, Mo2C,...). According to the present invention, it is proposed to use solutions of salts or complexes of Pt and a metal alloy as precursors of Pt-M catalysts supported or not on carbon black with a high specific surface area, a metal oxide (TiO 2 2 , ZrO 2 , Al 2 O 3 , ...) or metal nitrides (TiN, TaN, BN), metal carbides (TiC, WC, W 2 C, Mo 2 C, etc.).
Dans le cas d'un support de carbone, les solutions de sels ou complexes de Pt et de l'élément métallique allié M sont mélangés au support de carbone et l'ensemble est agité vigoureusement aux ultra-sons pendant au moins une demi-heure, temps nécessaire pour obtenir un mélange homogène.  In the case of a carbon support, the solutions of salts or complexes of Pt and the alloy metal element M are mixed with the carbon support and the whole is shaken vigorously with ultrasound for at least half an hour , time necessary to obtain a homogeneous mixture.
Le volume des solutions est déterminé à partir de la concentration des solutions et de manière à obtenir la composition atomique de l'alliage métallique souhaitée. La masse de support de nanoparticules métalliques utile pour la synthèse est déterminée de façon à ce qu'elle représente 50% de la masse du catalyseur synthétisé. L'acide formique est utilisé comme agent réducteur et est rajouté au mélange précédemment décrit.  The volume of the solutions is determined from the concentration of the solutions and so as to obtain the atomic composition of the desired metal alloy. The support mass of metal nanoparticles useful for the synthesis is determined so that it represents 50% of the mass of the synthesized catalyst. Formic acid is used as a reducing agent and is added to the previously described mixture.
Le volume de l'acide formique doit être en excès pour que la réduction chimique des sels ou complexes métalliques soit achevée.  The volume of the formic acid must be in excess so that the chemical reduction of the salts or metal complexes is completed.
L'ensemble du mélange est par la suite porté à une température comprise entre la température de congélation de l'eau et celle de l'acide formique. Au bout de 12 à 72 heures, la réduction chimique est achevée et on obtient une poudre métallique représentant le catalyseur.  The whole mixture is then brought to a temperature between the freezing temperature of water and that of formic acid. After 12 to 72 hours, the chemical reduction is complete and a metal powder is obtained representing the catalyst.
L'abaissement de la température favorise la diminution de la vitesse de croissance des nanoparticules et allonge par conséquent la durée de réduction chimique des sels métalliques. Pour pallier cet allongement de durée, il convient d'accélérer la réaction de réduction chimique sans pour autant augmenter la vitesse de croissance. The lowering of the temperature favors the decrease of the growth rate of the nanoparticles and consequently lengthens the duration of chemical reduction of the metal salts. To overcome this lengthening of duration, it is appropriate to accelerate the chemical reduction reaction without increasing the rate of growth.
Le flacon contenant le mélange peut avantageusement être exposé à une source d'énergie par exemple de rayons ultraviolets (UV) qui permettent grâce à cet apport d'énergie d'accélérer la réaction (la germination des particules), favorisant ainsi la multiplicité de germes à l'état nanoparticulaire sans pour autant favoriser leur croissance. La longueur d'onde des rayons UV est choisie de préférence entre 200 et 300 nm, correspondant à la zone d'absorption du platine complexe de Pt, comme montré sur la figure 1 .  The vial containing the mixture may advantageously be exposed to a source of energy, for example ultraviolet (UV) rays which make it possible, thanks to this energy supply, to accelerate the reaction (the germination of the particles), thus favoring the multiplicity of seeds. in the nanoparticular state without promoting their growth. The wavelength of the UV rays is preferably chosen between 200 and 300 nm, corresponding to the absorption zone of the complex platinum of Pt, as shown in FIG.
Exemple de réalisation Des catalyseurs de Pt-Sn/C de composition molaire 3 :1 ont été synthétisés par réduction chimique à l'acide formique. Embodiment Pt-Sn / C catalysts of 3: 1 molar composition were synthesized by chemical reduction with formic acid.
Les solutions de K2PtCI6, 6H20 et SnCI2, 2H20 de chez Sigma- Aldrich ont été utilisées comme précurseurs des catalyseurs de Pt-Sn supportés sur du noir de carbone de grande surface spécifique (Vulcan XC- 72R, Cabot Corp., 250 m2/g). The solutions of K 2 PtCl 6 , 6H 2 O and SnCl 2 , 2H 2 0 from Sigma-Aldrich were used as precursors of Pt-Sn catalysts supported on carbon black with a high specific surface area (Vulcan XC-72R, Cabot Corp., 250 m 2 / g).
Les solutions aqueuses de sels de platine et d'étain de concentration 0,01 M ont été mélangées en présence du noir de carbone et agitées vigoureusement aux ultra-sons pendant une durée d'environ une heure. Les volumes des solutions K2PtCI6, 6H20 et SnCI2, 2H20 mélangées sont respectivement de 15 ml et 5 ml de façon à obtenir un rapport atomique de 3 : 1 . Aqueous solutions of platinum and tin salts of 0.01 M concentration were mixed in the presence of carbon black and vigorously shaken with ultrasound for a period of about one hour. The volumes of K 2 PtCl 6 , 6H 2 0 and SnCl 2 , 2H 2 0 solutions mixed are respectively 15 ml and 5 ml so as to obtain an atomic ratio of 3: 1.
Une grande quantité d'acide formique HCOOH (ACS reagent, supérieure ou égale à 98% Sigma-AIdrich) d'un rapport molaire de l'ordre de 1000 : 1 , entre l'acide formique et les sels métalliques, utilisé comme agent réducteur, est ajoutée au mélange pour permettre une réduction simultanée des sels de platine et d'étain.  A large amount of formic acid HCOOH (ACS reagent, greater than or equal to 98% Sigma-Aldrich) with a molar ratio of the order of 1000: 1, between formic acid and metal salts, used as a reducing agent is added to the mixture to allow a simultaneous reduction of the platinum and tin salts.
Deux exemples de conditions opératoires de synthèse ont été réalisés :  Two examples of synthetic operating conditions were carried out:
- un premier exemple à température ambiante pendant 24 heures ; - un second exemple à 4°C pendant 72 heures. Au bout de la durée précisée précédemment, une poudre métallique a été obtenue. La masse de Pt+Sn représente 50% en masse du catalyseur. La température de 4° C a été choisie de manière à ce qu'elle soit comprise entre 0 et 8°C. a first example at room temperature for 24 hours; a second example at 4 ° C. for 72 hours. At the end of the period specified above, a metal powder was obtained. The mass of Pt + Sn represents 50% by weight of the catalyst. The temperature of 4 ° C was chosen so that it was between 0 and 8 ° C.
L'objectif de réaliser la synthèse à cette température est de réduire lors de la synthèse, la vitesse de croissance des nanoparticules qui a une dépendance croissance avec la température.  The objective of carrying out the synthesis at this temperature is to reduce during the synthesis, the growth rate of the nanoparticles which has a growth dependence with temperature.
Les résultats obtenus sont répertoriés dans le Tableau ci-après et concernent les propriétés physico-chimiques des catalyseurs de Pt3Sn/C synthétisés à température ambiante et à 4°C. The results obtained are listed in the Table below and relate to the physico-chemical properties of Pt 3 Sn / C catalysts synthesized at room temperature and at 4 ° C.
La surface électro-active correspond plus précisément à la surface électro-chimiquement active pour les réactions considérées, que l'on cherche à augmenter. La figure 2 illustre les distributions de taille de particules de catalyseurs Pt3Sn/C synthétisées à température ambiante (25 °C) et à 4° C et met en évidence le pourcentage élevé de particules de faible taille, typiquement de 3 à 4 nm, avec le procédé de synthèse de l'invention. The electro-active surface corresponds more precisely to the electro-chemically active surface for the reactions considered, which one seeks to increase. Figure 2 illustrates particle size distributions of Pt 3 Sn / C catalysts synthesized at room temperature (25 ° C) and at 4 ° C and demonstrates the high percentage of small particles, typically 3 to 4 nm. with the synthesis method of the invention.
Plus précisément on obtient les paramètres de tailles répertoriés dans le tableau ci-après : Pt3Sn/C (25 °C) Pt3Sn/C (4°C) More precisely, we obtain the size parameters listed in the table below: Pt3Sn / C (25 ° C) Pt3Sn / C (4 ° C)
Taille moyenne 5,89 3,92  Average size 5.89 3.92
Taille médiane 6,00 4,00  Median size 6.00 4.00
Ecart type 1 ,45 1 ,10  Standard deviation 1, 45 1, 10
Des mesures effectuées par analyse dispersive en énergie (EDS pour Energy Dispersive X-ray Spectrometry) fournissent également les résultats ci-après : Measurements performed by Energy Dispersive X-ray Spectrometry (EDS) also provide the following results:
La surface électroactive du catalyseur préparé à 4°C est ainsi bien plus grande que celle du même catalyseur synthétisé à 25 °C. The electroactive surface of the catalyst prepared at 4 ° C. is thus much larger than that of the same catalyst synthesized at 25 ° C.
Cela signifie que la quantité de catalyseur nécessaire par exemple au bon fonctionnement d'un système de production électrochimique d'hydrogène comprenant une réaction de reformage catalytique en présence de particules de catalyseur obtenu selon le procédé de l'invention et d'un mélange gazeux comprenant des composés hydrocarbonés peut ainsi avantageusement être inférieure à celle utilisée avec un catalyseur obtenu avec un procédé de l'art antérieur.  This means that the amount of catalyst necessary, for example, for the proper functioning of an electrochemical hydrogen production system comprising a catalytic reforming reaction in the presence of catalyst particles obtained according to the process of the invention and a gaseous mixture comprising hydrocarbon compounds can thus advantageously be lower than that used with a catalyst obtained with a method of the prior art.
Le Demandeur a réalisé les voltampérogrammes cycliques en demi-cellule électrochimique à 25 °C avec une vitesse de balayage de 10 mV/s, relatifs aux différents catalyseurs préparés. The Applicant has carried out the cyclic voltammograms in an electrochemical half-cell at 25 ° C. with a scanning speed of 10 mV / s, relative to the various catalysts prepared.
II est rappelé que la voltampérométrie cyclique est une méthode d'analyse électrochimique basée sur la mesure du flux de courant résultant de la réduction ou de l'oxydation des composés qui entrent en contact avec une électrode de travail (l'échantillon étudié) sous l'effet d'une variation contrôlée de la différence de potentiel avec une électrode au potentiel fixe, appelée électrode de référence. Elle permet d'identifier et de mesurer quantitativement un grand nombre de composés et également d'étudier les réactions chimiques incluant ces composés. It is recalled that cyclic voltammetry is a method of electrochemical analysis based on the measurement of the current flow resulting from the reduction or oxidation of the compounds which come into contact with a working electrode (the sample studied) under effect of a controlled variation of the potential difference with a fixed potential electrode, called the reference electrode. It helps identify and measure quantitatively a large number of compounds and also to study the chemical reactions including these compounds.
Le fort pouvoir d'absorption peut être caractérisé par l'absence de pics d'oxydation (courant positifs) sur le voltampérogramme présentant la densité de courant mesuré en fonction du potentiel appliqué E à l'électrode de travail. L'absence de ces pics sur le voltampérogramme traduit le blocage des sites d'adsorption du catalyseur par une autre espèce.  The high absorption power can be characterized by the absence of oxidation peaks (positive current) on the voltammogram having the measured current density as a function of the applied potential E to the working electrode. The absence of these peaks on the voltammogram reflects the blocking of adsorption sites of the catalyst by another species.
La figure 3 concerne les résultats obtenus avec les particules de Pt3Sn/C préparées à 25 °C. La courbe 3a est relative à la courbe de voltampérométrie (sous N2, dans 0,5 M H2S04 à 25°C et 10 mV.s1) réalisée après pollution du catalyseur par adsorption du CO. Figure 3 relates to the results obtained with Pt 3 Sn / C particles prepared at 25 ° C. Curve 3a is relative to the voltammetric curve (under N 2 , in 0.5 MH 2 SO 4 at 25 ° C. and 10 mV.s.sup.- 1 ) carried out after pollution of the catalyst by adsorption of CO.
On peut établir la comparaison avec la courbe 3b réalisée après désorption du CO (cycle de voltampérométrie : CV)  The comparison with the curve 3b carried out after CO desorption (voltammetry cycle: CV) can be compared
La pollution du catalyseur est complète : aucun courant d'oxydation n'est observé sur la courbe 3a dans la gamme de potentiel correspondant à la désorption de l'hydrogène électro-adsorbé (Hupd : underpotentially deposited H) : entre 0,1 et 0,4 V vs. ERH. L'oxydation du CO débute lorsque le potentiel de l'électrode dépasse 0,4 V vs. ERH.  The pollution of the catalyst is complete: no oxidation current is observed on curve 3a in the potential range corresponding to the desorption of electro-adsorbed hydrogen (Hupd: underpotentially deposited H): between 0.1 and 0 , 4 V vs. ERH. Oxidation of CO starts when the electrode potential exceeds 0.4 V vs. ERH.
La figure 4 concerne les résultats obtenus avec les particules de Pt3Sn/C préparées à 4°C. Pour le catalyseur préparé à4°C, la même courbe de voltampérométrie cyclique après pollution du catalyseur par adsorption du CO (courbe 4a), montre que la pollution du catalyseur n'est pas totale : les pics de désorption de l'hydrogène sont encore observés sur la courbe 4a entre 0,1 et 0,4 V vs. ERH et l'oxydation du CO débute à un potentiel de l'électrode de 0,3 V vs. ERH. Figure 4 relates to the results obtained with Pt 3 Sn / C particles prepared at 4 ° C. For the catalyst prepared at 4 ° C., the same cyclic voltammetric curve after pollution of the catalyst by CO adsorption (curve 4a) shows that the pollution of the catalyst is not complete: the hydrogen desorption peaks are still observed. on curve 4a between 0.1 and 0.4 V vs. ERH and oxidation of CO starts at an electrode potential of 0.3 V vs. ERH.
On peut établir la comparaison avec la courbe 4b réalisée après désorption du CO (cycle de voltampérométrie : CV).  The comparison with curve 4b carried out after desorption of CO (voltammetric cycle: CV) can be established.
Le gain, en terme énergétique, pour l'oxydation de l'hydrogène en présence de traces de gaz polluants est de près de 30% (0,72 kWh/Nm3 H2 avec le catalyseur synthétisé à 4°C, contre 0,96 kWi//Nm3 H2 avec le catalyseur synthétisé à 25 °C). Le Demandeur a également suivi l'évolution du courant d'électro- oxydation de H2 sur Pt3Sn/C synthétisés à température ambiante et à 4°C dans un dispositif de demi cellule électrochimique, lorsque l'électrode est alimentée par un mélange de gaz composé de 50 ppm de CO dans H2 et soumise à un potentiel de 0,24 V vs. ERH. The gain, in terms of energy, for the oxidation of hydrogen in the presence of traces of polluting gases is nearly 30% (0.72 kWh / Nm 3 H 2 with the catalyst synthesized at 4 ° C, against 0, 96 kWi // Nm 3 H 2 with the catalyst synthesized at 25 ° C). The Applicant has also followed the evolution of the electro-oxidation current of H 2 on Pt 3 Sn / C synthesized at room temperature and at 4 ° C. in an electrochemical half-cell device, when the electrode is fed with a mixture gas composed of 50 ppm CO in H 2 and subjected to a potential of 0.24 V vs. ERH.
La figure 5 montre via les courbes 5a et 5b la différence de comportement avec un catalyseur réalisé selon la présente invention à une température de 4° C, comparativement à un catalyseur réalisé à température ambiante.  FIG. 5 shows via the curves 5a and 5b the difference in behavior with a catalyst produced according to the present invention at a temperature of 4 ° C., compared to a catalyst produced at ambient temperature.
La densité de courant mesurée au cours du temps (j) est rapportée à celle mesurée lorsque l'échantillon est alimenté en hydrogène pur (jmax). Initialement, le catalyseur n'est pas pollué donc j = jmax et j/jmax=1■ The current density measured over time (j) is related to that measured when the sample is supplied with pure hydrogen (jmax). Initially, the catalyst is not polluted so j = j max and j / j ma x = 1 ■
Dans le cas du catalyseur synthétisé à 25 ° C (courbe 5a), la densité de courant mesurée au cours du temps diminue rapidement pour atteindre 71 % du courant initial après 1 heure d'empoisonnement au CO. Pour le catalyseur synthétisé à 4°C, le courant mesuré après 1 heure d'empoisonnement est de 93% du courant initial. Le catalyseur synthétisé à 4°C est donc beaucoup plus tolérant au CO que celui synthétisé à 25° C (figure 5b).  In the case of the catalyst synthesized at 25 ° C (curve 5a), the current density measured over time decreases rapidly to 71% of the initial current after 1 hour of CO poisoning. For the catalyst synthesized at 4 ° C., the current measured after 1 hour of poisoning is 93% of the initial current. The catalyst synthesized at 4 ° C is therefore much more tolerant to CO than that synthesized at 25 ° C (Figure 5b).

Claims

REVENDICATIONS
1 . Procédé de synthèse de particules de catalyseur bimétallique à base de platine et d'au moins un second métal caractérisé en ce qu'il comprend la réduction chimique d'un premier sel ou complexe à base de platine et d'au moins un second sel ou complexe à base dudit second métal, ladite réduction chimique comportant les étapes suivantes : 1. Process for the synthesis of platinum-based bimetallic catalyst particles and of at least one second metal, characterized in that it comprises the chemical reduction of a first salt or platinum-based complex and at least one second salt or complex based on said second metal, said chemical reduction comprising the following steps:
- la réalisation d'un mélange comprenant ledit premier sel ou complexe à base de platine et ledit second sel ou complexe à base dudit second métal en présence d'un agent réducteur pur sous forme liquide dans les conditions ambiantes de température et de pression (CATP), lesdites conditions étant respectivement définies comme égales à 25°C et 100kPa ; - la mise en température comprise entre environ la température de congélation de l'eau et la température de congélation de l'agent réducteur, dudit mélange.  the production of a mixture comprising said first platinum-based salt or complex and said second salt or complex based on said second metal in the presence of a pure reducing agent in liquid form under ambient temperature and pressure conditions (CATP) ), said conditions being respectively defined as equal to 25 ° C and 100kPa; - Warming up between about the freezing temperature of the water and the freezing temperature of the reducing agent, said mixture.
2. Procédé de synthèse de particules de catalyseur bimétallique selon la revendication 1 , caractérisé en ce que l'agent réducteur est l'acide formique, la mise en température étant effectuée entre environ 0°C et 8°C 2. Bimetallic catalyst particles synthesis process according to claim 1, characterized in that the reducing agent is formic acid, the temperature setting being carried out between about 0 ° C and 8 ° C
3. Procédé de synthèse de particules de catalyseur bimétallique selon la revendication 1 , caractérisé en ce que l'agent réducteur est l'hydrazine (N2H4), la mise en température étant effectuée entre environ 0° C et 2° G 3. Process for synthesizing bimetallic catalyst particles according to claim 1, characterized in that the reducing agent is hydrazine (N 2 H 4 ), the heating being carried out between approximately 0 ° C and 2 ° G.
4. Procédé de synthèse de particules de catalyseur bimétallique selon l'une des revendications 1 à 3, caractérisé en ce qu'il comprend le mélange de sel ou de complexe de platine et de sel ou de complexe dudit second métal en présence de particules de noir de carbone ou d'oxyde métallique ou de nitrure métallique ou de carbure métallique. 4. Process for synthesizing bimetallic catalyst particles according to one of claims 1 to 3, characterized in that it comprises the mixture of salt or platinum complex and salt or complex of said second metal in the presence of particles of black carbon or metal oxide or metal nitride or metal carbide.
5. Procédé de synthèse de particules de catalyseur bimétallique selon l'une des revendications 1 à 4, caractérisé en ce que la quantité d'agent réducteur est supérieure ou égale à la quantité nécessaire pour procéder à la réduction chimique de l'ensemble des sels ou complexes du platine et de ceux du second métal. 5. Process for synthesizing bimetallic catalyst particles according to one of claims 1 to 4, characterized in that the quantity of reducing agent is greater than or equal to the amount necessary to carry out the chemical reduction of all the salts or complexes of platinum and those of the second metal.
6. Procédé de synthèse de particules de catalyseur bimétallique selon l'une des revendications 1 à 5, caractérisé en ce que la réaction est effectuée en présence d'une source d'énergie additionnelle permettant d'accélérer l'opération de réduction chimique sans favoriser la croissance de nanoparticules. 6. Process for synthesizing bimetallic catalyst particles according to one of claims 1 to 5, characterized in that the reaction is carried out in the presence of an additional source of energy to accelerate the chemical reduction operation without favoring the growth of nanoparticles.
7. Procédé de synthèse de particules de catalyseur bimétallique selon la revendication 6, caractérisé en ce que la source d'énergie additionnelle est une source de rayonnement ultra-violets. 7. Process for synthesizing bimetallic catalyst particles according to claim 6, characterized in that the additional energy source is a source of ultraviolet radiation.
8. Procédé de synthèse de particules de catalyseur bimétallique selon la revendication 7, caractérisé en ce que la source de rayonnement ultra-violets émet dans une gamme de longueurs d'onde comprises entre environ 200 nm et 300 nm. The process for synthesizing bimetallic catalyst particles according to claim 7, characterized in that the ultraviolet radiation source emits in a wavelength range between about 200 nm and 300 nm.
9. Procédé de synthèse de particules de catalyseur bimétallique selon l'une des revendications 1 à 8, caractérisé en ce que le second métal est de l'étain ou du ruthénium, ou du molybdène ou du cobalt. 9. Process for synthesizing bimetallic catalyst particles according to one of claims 1 to 8, characterized in that the second metal is tin or ruthenium, or molybdenum or cobalt.
10. Procédé de synthèse de particules de catalyseur bimétallique selon la revendication 9, caractérisé en ce que la distribution en taille desdites particules présente une taille médiane de 4 nm et un écart type de 1 ,1 . 10. Process for synthesizing bimetallic catalyst particles according to claim 9, characterized in that the size distribution of said particles has a median size of 4 nm and a standard deviation of 1.1.
1 1 . Utilisation du procédé de synthèse de particules de catalyseur bimétallique selon l'une des revendications 1 à 10, pour une méthode de production électrochimique d'hydrogène comprenant une réaction de reformage catalytique en présence desdites particules de catalyseur et d'un mélange gazeux comprenant des composés hydrocarbonés. 1 1. Use of the method for synthesizing bimetallic catalyst particles according to one of claims 1 to 10, for an electrochemical hydrogen production method comprising a catalytic reforming reaction in the presence of said catalyst particles and a gaseous mixture comprising compounds hydrocarbon.
12. Utilisation du procédé de synthèse de particules de catalyseur bimétallique selon la revendication 1 1 , caractérisée en ce que le mélange gazeux comprend du monoxyde de carbone, du dioxyde de carbone et du méthane. 12. Use of the method of synthesis of bimetallic catalyst particles according to claim 1 1, characterized in that the gaseous mixture comprises carbon monoxide, carbon dioxide and methane.
EP14706561.9A 2013-02-26 2014-02-24 Method for synthesizing bimetal catalyst particles made of platinum and of another metal and use thereof in an electrochemical hydrogen production method Withdrawn EP2961527A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR1351679A FR3002464A1 (en) 2013-02-26 2013-02-26 PROCESS FOR THE SYNTHESIS OF BIMETALLIC CATALYST PARTICLES BASED ON PLATINUM AND ANOTHER METAL AND METHOD FOR THE ELECTROCHEMICAL PRODUCTION OF HYDROGEN USING THE SYNTHESIS METHOD
PCT/EP2014/053535 WO2014131724A1 (en) 2013-02-26 2014-02-24 Method for synthesizing bimetal catalyst particles made of platinum and of another metal and use thereof in an electrochemical hydrogen production method

Publications (1)

Publication Number Publication Date
EP2961527A1 true EP2961527A1 (en) 2016-01-06

Family

ID=48140086

Family Applications (1)

Application Number Title Priority Date Filing Date
EP14706561.9A Withdrawn EP2961527A1 (en) 2013-02-26 2014-02-24 Method for synthesizing bimetal catalyst particles made of platinum and of another metal and use thereof in an electrochemical hydrogen production method

Country Status (5)

Country Link
US (1) US20160010229A1 (en)
EP (1) EP2961527A1 (en)
JP (1) JP2016513013A (en)
FR (1) FR3002464A1 (en)
WO (1) WO2014131724A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2775979C1 (en) * 2022-01-31 2022-07-12 Кирилл Олегович Паперж Method for production of platinum-containing catalysts for fuel cells and electrolyzers

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108161021A (en) * 2017-11-29 2018-06-15 清华大学 A kind of ice is mutually sustained the method for preparing atom level dispersion
CN109014238A (en) * 2018-05-24 2018-12-18 清华大学 A kind of method of low temperature liquid phase synthesized high-performance metal material

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL8201396A (en) * 1982-04-01 1983-11-01 Dow Chemical Nederland SILVER CATALYST AND A METHOD FOR THE PREPARATION THEREOF.
JP3912377B2 (en) * 2003-12-25 2007-05-09 日産自動車株式会社 Method for producing exhaust gas purification catalyst powder

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2775979C1 (en) * 2022-01-31 2022-07-12 Кирилл Олегович Паперж Method for production of platinum-containing catalysts for fuel cells and electrolyzers

Also Published As

Publication number Publication date
US20160010229A1 (en) 2016-01-14
FR3002464A1 (en) 2014-08-29
WO2014131724A1 (en) 2014-09-04
JP2016513013A (en) 2016-05-12

Similar Documents

Publication Publication Date Title
Guo et al. New understandings of ethanol oxidation reaction mechanism on Pd/C and Pd2Ru/C catalysts in alkaline direct ethanol fuel cells
JP4541458B2 (en) Solid polymer fuel cell
Cai et al. Bi-modified Pd/C catalyst via irreversible adsorption and its catalytic activity for ethanol oxidation in alkaline medium
Bergamaski et al. Ethanol oxidation on carbon supported platinum-rhodium bimetallic catalysts
US10446852B2 (en) Fuel-cell system and method of generating energy from crude fuel
Suzuki et al. Fundamental studies on direct ammonia fuel cell employing anion exchange membrane
Puthiyapura et al. Biobutanol as Fuel for Direct Alcohol Fuel Cells Investigation of Sn-Modified Pt Catalyst for Butanol Electro-oxidation
Parreira et al. PtSnNi/C nanoparticle electrocatalysts for the ethanol oxidation reaction: Ni stability study
Mukherjee et al. Improved carbonate formation from ethanol oxidation on nickel supported Pt–Rh electrode in alkaline medium at room temperature
EP3347937A1 (en) P/metal-n-c hybrid catalyst
Kormanyos et al. Influence of fuels and pH on the dissolution stability of bifunctional PtRu/C alloy electrocatalysts
Souza et al. Niobium increasing the electrocatalytic activity of palladium for alkaline direct ethanol fuel cell
US5786026A (en) Method for producing composite catalytic molding
Katayama et al. Enhancement of ammonia oxidation activity over Y2O3-modified platinum surface: Promotion of NH2, ad dimerization process
Rodríguez-Gómez et al. Influence of the GDL and assembly mode of a PEM cell on the ethanol revalorization into chemicals
Souza et al. Niobium enhances electrocatalytic Pd activity in alkaline direct glycerol fuel cells
Dresch et al. Advancing direct ethanol fuel cell operation at intermediate temperature by combining Nafion-hybrid electrolyte and well-alloyed PtSn/C electrocatalyst
Mahajan et al. Kinetic parameters of anodic oxidation of methanol in alkali: Effect of diameter of Pd nano-catalyst, composition of electrode and solution and mechanism of the reaction
EP2961527A1 (en) Method for synthesizing bimetal catalyst particles made of platinum and of another metal and use thereof in an electrochemical hydrogen production method
WO2020109063A1 (en) Method for preparing a catalytic material for electrochemical reduction reactions, containing a group vi metal and a group viii metal, obtained by chemical reduction
Papaioannou et al. Pt–Ir binary electrodes for direct oxidation of methanol in low-temperature fuel cells (DMFCs)
EP2344870B1 (en) Device for determining carbon monoxide concentration and related method
Benipal et al. Direct fast pyrolysis bio-oil fuel cell
Belenov et al. PtCu/C materials doped with different amounts of gold as the catalysts of oxygen electroreduction and methanol electrooxidation
EP1479121A2 (en) Full cell electrocatalyst of pt-ni-mn/fe

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20150805

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

AX Request for extension of the european patent

Extension state: BA ME

RIN1 Information on inventor provided before grant (corrected)

Inventor name: NGAMENI JIEMBOU, JOSEPH

Inventor name: GUILLET, NICOLAS

DAX Request for extension of the european patent (deleted)
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20170901