WO2008152638A2 - Materials, their preparation, and their uses in electrodes for fuel cells - Google Patents
Materials, their preparation, and their uses in electrodes for fuel cells Download PDFInfo
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- WO2008152638A2 WO2008152638A2 PCT/IL2008/000801 IL2008000801W WO2008152638A2 WO 2008152638 A2 WO2008152638 A2 WO 2008152638A2 IL 2008000801 W IL2008000801 W IL 2008000801W WO 2008152638 A2 WO2008152638 A2 WO 2008152638A2
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/90—Selection of catalytic material
- H01M4/92—Metals of platinum group
- H01M4/921—Alloys or mixtures with metallic elements
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- 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
- H01M4/8605—Porous electrodes
- H01M4/8621—Porous electrodes containing only metallic or ceramic material, e.g. made by sintering or sputtering
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- 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
- H01M4/8647—Inert electrodes with catalytic activity, e.g. for fuel cells consisting of more than one material, e.g. consisting of composites
- H01M4/8652—Inert electrodes with catalytic activity, e.g. for fuel cells consisting of more than one material, e.g. consisting of composites as mixture
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/88—Processes of manufacture
- H01M4/8878—Treatment steps after deposition of the catalytic active composition or after shaping of the electrode being free-standing body
- H01M4/8882—Heat treatment, e.g. drying, baking
- H01M4/8885—Sintering or firing
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/90—Selection of catalytic material
- H01M4/92—Metals of platinum group
- H01M4/925—Metals of platinum group supported on carriers, e.g. powder carriers
- H01M4/926—Metals of platinum group supported on carriers, e.g. powder carriers on carbon or graphite
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- 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
Definitions
- the present invention relates to a catalyst comprising Pt-Sn and at least one oxide selected from Ti ⁇ 2, Zr ⁇ 2 and Ce ⁇ 2.
- a method for making the catalyst by microwave and sonochemical means is also provided, as well as uses of the catalyst in electrodes for fuel cells.
- PtRu/C-Au/Ti ⁇ 2 have been prepared by surface sol-gel methods and tested as methanol oxidation catalysts [Y. Han, Haksoo; S, Yong-Gun. Journal of Power Sources, 159(1), 484-490 (2006)], PtRu/TiO2 [M. Hepel, I. Kumarihamy, C. J. Zhong, Electrochemistry Communications, 8(9), 1439- 1444 (2006)]. It is believed that TiO 2 provides better dispersion of the catalysts and promotes CO oxidation through orbital overlap with the surface bonded catalyst.
- a typical DMFC anode is coated with a layer of polymer-bonded catalyst on one side of the electrode.
- the particles directly within the electrode structure, providing good adherence to the conductive porous structure serving as support and electrode. This process is carried out in a continuous manner using microwave and sono-chemical methods, to simultaneously prepare the material and deposit it on the electrode.
- the obtained anode does not require additional polymer to provide the adherence to the surface and therefore provides better catalysts utilization and improve the methanol mass transport to the active particles.
- the invention provides a catalyst having formula Pt x -Sn y -(M) Z; wherein 0 ⁇ x,y,z ⁇ l, and wherein M is selected from among Ti ⁇ 2, Zr ⁇ 2 and Ce ⁇ 2.
- a catalyst according to the invention may have a formula selected, for example, from Pt 1 -Sn 1 -(TiO 2 )I, Pt 1 -Sm-(TiO 2 )CS, Pto.75-Sno. 2 5-(TiO 2 )i, and Pto.25-Sno.75- (TiO 2 )i.
- Said catalyst may further comprise Ru.
- said catalyst has a formula selected from Pt 1 -Sn 1 -Ru 1 -(TiO 2 )I, Pt1-Sno.5-Ruo.25- (TiO 2 )i, Pti-Sno. 2 5-Rui-(TiO 2 )i, Pt 1 -SnO 15 -RuCs-(TiO 2 )O-S, and Pto.5-Sno.5-Ruo.5- (TiO 2 )i.
- other ratios may be advantageous.
- the invention proved a method for manufacturing a catalyst as defined above, comprising carrying out the synthesis in the consecutive steps of microwaving and sonicating of a reaction mixture containing reagents - -
- the method of the invention further comprises adding Ru during the MW (microwave) and/or SC (sonochemical) synthesis steps, to form Pt-Sn-Ru-Ti ⁇ 2.
- Said M being an oxide selected from Ti ⁇ 2 or Zr ⁇ 2 or Ce ⁇ 2, is added during the SC synthesis step, using a templating agent selected from dodecylamine, octadecylamine, and sodium dodecylsulfate.
- the templating agent serves as a part of the template for constructing the particle around it, rendering a specific shape and structure to the particle.
- the method according to the invention comprises a) precipitating Pt and Sn on a surface located in a reaction zone saturated with (chloroplatinic acid) and SnCl2 and comprising an oxide selected from Ti ⁇ 2, Zr ⁇ 2 and Ce ⁇ 2; and b) synthesizing said catalyst, as the reactants are pumped into said reaction zone; wherein said reaction zone is exposed to MW or SC.
- the synthesis may be carried out in a continuous manner.
- particles are synthesized by means of MW, followed by plating said surface with them while applying ultrasound (US).
- the method of catalyst synthesis comprises sonicating the reaction mixture consisting of H2PtCl6, SnCb, a metal oxide, and a substrate, wherein said oxide is selected from the group consisting of Ti ⁇ 2, Zr ⁇ 2 and Ce ⁇ 2, and said substrate is selected from the group consisting of carbon, woven and non woven metallic substrate, composite polymer, conductive particles, and a combination thereof, thereby providing a catalyst within a porous substrate.
- Said carbon may comprise graphite
- said substrate may comprise, for example, stainless steel, titanium nickel, expended metal, metal foam, etc.
- Said conductive particles may comprise carbon, gold, titanium, or silver.
- Said catalyst with said substrate, processed according to the method of the invention provide a porous body with excellent performance as an electrode part.
- Said SC step may comprise electromagnetic radiation in the range GHz-THz. In one - -
- the method according to the invention comprises the generation of plasma.
- the invention relates to the use of a catalyst having formula Pt x -Sn y -(M) Z , wherein 0 ⁇ x,y,z ⁇ l, and wherein M is selected from among Ti ⁇ 2, Zr ⁇ 2 and Ce ⁇ 2 in the oxidation of fuels, including methanol, ethanol, formic acid, formaldehyde, and glucose in fuel cells.
- Said fuel cell may comprise DMFC, or other fuel cell, such as a fuel cell selected from phosphoric acid fuel cell, polymer electrolyte fuel cell, and alkaline fuel cell.
- Fig. 1. is a schematic description of preparation method of DMFC anode by directly deposit the catalysts using sono-chemical and microwave methods;
- Fig. 2. is a potentiodynamic measurement (20mv/sec) comparing FCV anode with Pto . i 6 -Sno . i6-(TiO2)i and JM (Jonson Matthy Co.) commercial PtRu black catalysts in 0.5M H 2 SO 4 +1M CH 3 OH, 25 0 C. Identical counter Pt black (JM) electrode and reference electrodes Ag/AgCl are used for these experiments; and
- Fig. 3. is the comparison between electrodes comprising i) a PtSn/Ti ⁇ 2 catalyst synthesized according to one embodiment of the invention (lower curve), and ii) a commercial PtRu catalyst (upper curve).
- Pt x -Sn y -(Ti ⁇ 2) z catalysts (wherein 0 ⁇ x,y,z ⁇ l), either as free standing catalysts or on a conductive substrate such as carbon particles or electrode.
- the invention provides a Pt x -Sn y -(M) Z catalyst, wherein 0 ⁇ x,y,z ⁇ l, and wherein M is selected from among Ti ⁇ 2, Zr ⁇ 2 and Ce ⁇ 2.
- the invention also relates to a method for manufacturing a Pt x -Sn y -( Ti ⁇ 2)z catalyst wherein 0 ⁇ x,y,z ⁇ l, comprising carrying out the synthesis in the consecutive steps of microwaving and sonicating, Ru may be further added, in the MW (microwave) and/or SC (sonochemical) synthesis steps, to form Pt-Sn-Ru- Ti ⁇ 2.
- a broad frequency range of electromagnetic radiation may be employed, when preparing the catalyst and electrodes comprising it.
- the invention also provides a process for preparing an electrode on porous substrate, comprising sonicating the reaction mixture on a substrate of a material selected from carbon, graphite, woven and non woven or metallic substrate, such as stainless steel, titanium nickel (woven, non woven, expended metal and metal foam), or on composite polymer and conductive particles (carbon, gold, titanium, silver).
- a material selected from carbon, graphite, woven and non woven or metallic substrate such as stainless steel, titanium nickel (woven, non woven, expended metal and metal foam), or on composite polymer and conductive particles (carbon, gold, titanium, silver).
- a material selected from carbon, graphite, woven and non woven or metallic substrate such as stainless steel, titanium nickel (woven, non woven, expended metal and metal foam), or on composite polymer and conductive particles (carbon, gold, titanium, silver).
- Fig. 1 One embodiment is schematically illuminated in Fig. 1.
- the invention enables advantageous uses of Pt ⁇ -Sn r (M)z catalysts
- the materials described above, as well as the electrode preparation methods described above are utilized in manufacturing other types of fuel cells, including phosphoric acid fuel cells, polymer electrolyte fuel cells, and alkaline fuel cells.
- the invention also relates to the use of the plasma generated in a microwave process in the preparation of catalysts and electrodes.
- S11CI2 (Strem) is dissolved in 50 gr. Ethylene glycol by vigorous stirring. A stoichiometric amount of 77.85 mg (Strem) is added and the solution is bubbled with pure Ar for 10 minutes. Than the solution is irradiated by microwave for 10 minutes under Ar atmosphere. After cooling, the powder product is washed 3 times with ethanol and dried. In some occasions, carbon black (Vulcan XC72R) or mesoporous Ti ⁇ 2 support in 5-1:1 PtSn : support ratio is added during synthesis.
- Carbonized porous materials (e.g. Toray) were used as a substrate for direct deposition of the catalysts.
- the electrodes were placed in a flow cell glass reactor connected to a glass condenser to avoid solvent evaporation.
- Reactants solution (described above) is streams through the cell using a peristaltic pump at flow rate of less than lml/min while exposing it to microwave radiation 2.4GHz at 900watts (see Fig. 1). After cooling, the electrode containing the product catalysts, strongly bonded to the inner pour walls, is rinsed with ethanol and dried.
- the typical voltammorams obtained with commercial (JM) shown in Fig. 2 demonstrate the higher activity of Pt x -Sn r (Ti ⁇ 2)z catalyst prepared by microwave method compare to the state of the art commercial PtRu black powder catalyst (form JM).
- the current density obtained from the microwave synthesized material is 50-100% higher than the best commercial catalysts known today.
- Fig. 3 shows the comparison between PtSn/TiO2 microwave synthesized nano-catalyst on Torray60 sheet electrode (1.7mg PtSn/TiO2 /cm2), and JM commercial PtRu catalyst on Torray ⁇ O sheet electrode (5mg PtRu/cm2).
- the cathodes used in both cells were commercial E-TEK Pt electrodes(5mg Pt/cm2).
- the cells were operated with IM MeOH water solution and 02 (10 ml/min) at 60°C. The results are normalized per lmg Pt. It can be seen that the electrode according to one embodiment of the invention provides superior performance.
Abstract
Provided are a catalyst and a method for manufacturing it, wherein the catalyst contains at least Pt, Sn, and one of TiO2, ZrO2, and CeO2. The catalyst is advantageously formulated with a porous matrix and is used in preparing anode for fuel cells of various types.
Description
MATERIALS, THEIR PREPARATION. AND THEIR USES IN ELECTRODES FOR FUEL CELLS
Field of the Invention
The present invention relates to a catalyst comprising Pt-Sn and at least one oxide selected from Tiθ2, Zrθ2 and Ceθ2. A method for making the catalyst by microwave and sonochemical means is also provided, as well as uses of the catalyst in electrodes for fuel cells.
Background of the Invention
Materials and electrodes have been developed for use in oxidation of alcohol (e.g. methanol) fuel in fuel cells. These types of fuel cells are comprised of two electrodes, one for fuel oxidation and the counter as the oxygen reduction, to produce electrical power, water and CO2 as products. Alcohol electro- oxidation reaction occurs on metal catalyst particles in the anode. The activity of these materials is determined by their structure and atomic composition, which is strongly influenced by the preparation methods.
While this field is evolving continuously, there is still a need for efficient methods to prepare electrodes of the above-discussed type, as well as for improved electrodes.
The conventional synthesis of PtSn-based catalyst have been reported [G. Ertl ,M. Newmann and K.M.Streit, Surf. Sci. 64, 393 (1977); P.N. Ross, in "Electrocatalysis", J. Lipkowaski and P.N. Ross (eds), John Wiley & Sons - VCH, New York, pp 43-74(1998), E. Gr antcharova- Anderson and A.B. Anderson, Electrochem. Acta, 44, 4543 (1999)] suggesting a bi-functional Langmuir-Hinshelhood mechanism, in addition to a weakly bonded CO attributed to electronic properties of PtSn alloy. The preparation of PtRu catalysts by similar methods has been described before, but the preparation of PtSn-based catalysts in these routes has not been attempted before.
PtRu/C-Au/Tiθ2, have been prepared by surface sol-gel methods and tested as methanol oxidation catalysts [Y. Han, Haksoo; S, Yong-Gun. Journal of Power Sources, 159(1), 484-490 (2006)], PtRu/TiO2 [M. Hepel, I. Kumarihamy, C. J. Zhong, Electrochemistry Communications, 8(9), 1439- 1444 (2006)]. It is believed that TiO2 provides better dispersion of the catalysts and promotes CO oxidation through orbital overlap with the surface bonded catalyst.
A typical DMFC anode is coated with a layer of polymer-bonded catalyst on one side of the electrode. According to the invention to be described below, it has now been made possible to deposit the particles directly within the electrode structure, providing good adherence to the conductive porous structure serving as support and electrode. This process is carried out in a continuous manner using microwave and sono-chemical methods, to simultaneously prepare the material and deposit it on the electrode. Thus, the obtained anode does not require additional polymer to provide the adherence to the surface and therefore provides better catalysts utilization and improve the methanol mass transport to the active particles.
Summary of the Invention
The invention provides a catalyst having formula Ptx-Sny-(M)Z; wherein 0<x,y,z<l, and wherein M is selected from among Tiθ2, Zrθ2 and Ceθ2. A catalyst according to the invention may have a formula selected, for example, from Pt1-Sn1-(TiO2)I, Pt1-Sm-(TiO2)CS, Pto.75-Sno.25-(TiO2)i, and Pto.25-Sno.75- (TiO2)i. Said catalyst may further comprise Ru. In some embodiments, said catalyst has a formula selected from Pt1-Sn1-Ru1-(TiO2)I, Pt1-Sno.5-Ruo.25- (TiO2)i, Pti-Sno.25-Rui-(TiO2)i, Pt1-SnO15-RuCs-(TiO2)O-S, and Pto.5-Sno.5-Ruo.5- (TiO2)i. In other embodiments, other ratios may be advantageous. The invention proved a method for manufacturing a catalyst as defined above, comprising carrying out the synthesis in the consecutive steps of microwaving and sonicating of a reaction mixture containing reagents
- -
providing Pt, Sn, and the required metal oxides, for example selected from EbPtCIe, SnCb, RuCb, Tiθ2, Zrθ2, and Ceθ2, at various stoichiometric ratios, preferably in ethylene glycol. Said catalyst has in one embodiment formula Ptχ-S%-( Tiθ2)z. In a preferred embodiment, the method of the invention further comprises adding Ru during the MW (microwave) and/or SC (sonochemical) synthesis steps, to form Pt-Sn-Ru-Tiθ2. Said M, being an oxide selected from Tiθ2 or Zrθ2 or Ceθ2, is added during the SC synthesis step, using a templating agent selected from dodecylamine, octadecylamine, and sodium dodecylsulfate. The templating agent serves as a part of the template for constructing the particle around it, rendering a specific shape and structure to the particle. In a preferred embodiment, the method according to the invention comprises a) precipitating Pt and Sn on a surface located in a reaction zone saturated with
(chloroplatinic acid) and SnCl2 and comprising an oxide selected from Tiθ2, Zrθ2 and Ceθ2; and b) synthesizing said catalyst, as the reactants are pumped into said reaction zone; wherein said reaction zone is exposed to MW or SC. The synthesis may be carried out in a continuous manner. In one embodiment, particles are synthesized by means of MW, followed by plating said surface with them while applying ultrasound (US). In an important aspect of the invention, the method of catalyst synthesis comprises sonicating the reaction mixture consisting of H2PtCl6, SnCb, a metal oxide, and a substrate, wherein said oxide is selected from the group consisting of Tiθ2, Zrθ2 and Ceθ2, and said substrate is selected from the group consisting of carbon, woven and non woven metallic substrate, composite polymer, conductive particles, and a combination thereof, thereby providing a catalyst within a porous substrate. Such form is useful in constructing electrodes for fuel cells. Said carbon may comprise graphite, said substrate may comprise, for example, stainless steel, titanium nickel, expended metal, metal foam, etc. Said conductive particles may comprise carbon, gold, titanium, or silver. Said catalyst with said substrate, processed according to the method of the invention, provide a porous body with excellent performance as an electrode part. Said SC step may comprise electromagnetic radiation in the range GHz-THz. In one
- -
embodiment, the method according to the invention, utilizing the microwave step, comprises the generation of plasma.
The invention relates to the use of a catalyst having formula Ptx-Sny-(M)Z, wherein 0<x,y,z<l, and wherein M is selected from among Tiθ2, Zrθ2 and Ceθ2 in the oxidation of fuels, including methanol, ethanol, formic acid, formaldehyde, and glucose in fuel cells. Said fuel cell may comprise DMFC, or other fuel cell, such as a fuel cell selected from phosphoric acid fuel cell, polymer electrolyte fuel cell, and alkaline fuel cell.
Brief Description of the Drawings
The above and other characteristics and advantages of the invention will be more readily apparent through the following examples, and with reference to the appended drawings, wherein:
Fig. 1. is a schematic description of preparation method of DMFC anode by directly deposit the catalysts using sono-chemical and microwave methods;
Fig. 2. is a potentiodynamic measurement (20mv/sec) comparing FCV anode with Pto.i6-Sno.i6-(TiO2)i and JM (Jonson Matthy Co.) commercial PtRu black catalysts in 0.5M H2SO4 +1M CH3OH, 250C. Identical counter Pt black (JM) electrode and reference electrodes Ag/AgCl are used for these experiments; and
Fig. 3. is the comparison between electrodes comprising i) a PtSn/Tiθ2 catalyst synthesized according to one embodiment of the invention (lower curve), and ii) a commercial PtRu catalyst (upper curve).
Detailed Description of the Preferred Embodiments
It has now been surprisingly found that it is possible to use microwave irradiation and sono-chemical methods, to prepare Ptx-Sny-(Tiθ2)z catalysts (wherein 0<x,y,z<l), either as free standing catalysts or on a conductive substrate such as carbon particles or electrode.
The invention provides a Ptx-Sny-(M)Z catalyst, wherein 0<x,y,z<l, and wherein M is selected from among Tiθ2, Zrθ2 and Ceθ2. The invention also relates to a method for manufacturing a Ptx-Sny-( Tiθ2)z catalyst wherein 0<x,y,z<l, comprising carrying out the synthesis in the consecutive steps of microwaving and sonicating, Ru may be further added, in the MW (microwave) and/or SC (sonochemical) synthesis steps, to form Pt-Sn-Ru- Tiθ2. A broad frequency range of electromagnetic radiation may be employed, when preparing the catalyst and electrodes comprising it. Thus the invention also provides a process for preparing an electrode on porous substrate, comprising sonicating the reaction mixture on a substrate of a material selected from carbon, graphite, woven and non woven or metallic substrate, such as stainless steel, titanium nickel (woven, non woven, expended metal and metal foam), or on composite polymer and conductive particles (carbon, gold, titanium, silver). One embodiment is schematically illuminated in Fig. 1. As a skilled person will appreciate, the invention enables advantageous uses of Ptχ-Snr(M)z catalysts for the oxidation of fuels, such as, without being limited to them, methanol, ethanol, formic acid, formaldehyde, and glucose. In an important aspect of the invention, the materials described above, as well as the electrode preparation methods described above, are utilized in manufacturing other types of fuel cells, including phosphoric acid fuel cells, polymer electrolyte fuel cells, and alkaline fuel cells. The invention also relates to the use of the plasma generated in a microwave process in the preparation of catalysts and electrodes.
Experimental Procedures
Synthetic procedure for PtSn powders/electrodes:
The materials were synthesized by using microwave or ultrasound irradiation. Typical synthetic conditions are listed as follows:
- -
Microwave:
30.14 mg S11CI2 (Strem) is dissolved in 50 gr. Ethylene glycol by vigorous stirring. A stoichiometric amount of 77.85 mg
(Strem) is added and the solution is bubbled with pure Ar for 10 minutes. Than the solution is irradiated by microwave for 10 minutes under Ar atmosphere. After cooling, the powder product is washed 3 times with ethanol and dried. In some occasions, carbon black (Vulcan XC72R) or mesoporous Tiθ2 support in 5-1:1 PtSn : support ratio is added during synthesis.
Carbonized porous materials (e.g. Toray) were used as a substrate for direct deposition of the catalysts. The electrodes were placed in a flow cell glass reactor connected to a glass condenser to avoid solvent evaporation. Reactants solution (described above) is streams through the cell using a peristaltic pump at flow rate of less than lml/min while exposing it to microwave radiation 2.4GHz at 900watts (see Fig. 1). After cooling, the electrode containing the product catalysts, strongly bonded to the inner pour walls, is rinsed with ethanol and dried.
Ultrasound:
The same amounts of reactants are dissolved in 100 ml Ethylene glycol. The solution is bubbled with pure Ar for 30 minutes. Than the solution is sonicated at ambient temperature for 1 hour by a high intensity ultrasonic probe (Sonics, 1.13 mm Ti horn, 20 kHz, lOOW/cm2). After cooling, the powder product is washed 3 times with ethanol and dried. In some occasions, carbon black (Vulcan XC72R) or mesoporous Tiθ2 support in 5-1:1 PtSn : support ratio is added during synthesis.
In order to deposit the product on an electronically conducting substrate, a 19mm disc of the substrate is placed in a tube shaped cell containing a solution of 13.7 mg SnCb and 35.4 mg ^PtCl6 in 13 ml Ethylene glycol. The solution is sonicated for 1 hour after which the prepared electrode is washed with ethanol and dried.
Results:
The typical voltammorams obtained with commercial (JM) shown in Fig. 2 demonstrate the higher activity of Ptx-Snr(Tiθ2)z catalyst prepared by microwave method compare to the state of the art commercial PtRu black powder catalyst (form JM). The current density obtained from the microwave synthesized material is 50-100% higher than the best commercial catalysts known today.
Fig. 3 shows the comparison between PtSn/TiO2 microwave synthesized nano-catalyst on Torray60 sheet electrode (1.7mg PtSn/TiO2 /cm2), and JM commercial PtRu catalyst on TorrayβO sheet electrode (5mg PtRu/cm2). The cathodes used in both cells were commercial E-TEK Pt electrodes(5mg Pt/cm2). The cells were operated with IM MeOH water solution and 02 (10 ml/min) at 60°C. The results are normalized per lmg Pt. It can be seen that the electrode according to one embodiment of the invention provides superior performance.
While this invention has been described in terms of some specific examples, many modifications and variations are possible. It is therefore understood that within the scope of the appended claims, the invention may be realized otherwise than as specifically described.
Claims
1. A catalyst having formula Ptx-Sny-(M)Z, wherein 0<x,y,z<l, and wherein M is selected from among TiO2, ZrO2 and Ceθ2.
2. A catalyst according to claim 2, having a formula selected from the group consisting Of Pt1-Sn1-(TiO2)I, Pt1-Sn1-(TiO2)O-S, Pto.7β-Sno.25-(Tiθ2)i, and Pto.26-Sno.7β-(TiO.Oi.
3. A catalyst according to claim 1, further comprising Ru.
4. A catalyst according to claim 3, having a formula selected from the group consisting of Pt1-Sn1-Ru1-(TiO2)I, Pt1-SnO1S-RUc2S-(TiO2)I, Pt1- 
Pti-Sno.5-Ruo.5-(TiOa)o.5, and 
5. A method of manufacturing a catalyst having formula Ptχ-Sny-(M)Z, wherein 0<x,y,z<l, and wherein M is selected from among TiO2, ZrO2 and CeO2, comprising carrying out the synthesis in the consecutive steps of microwaving and sonicating of a reaction mixture comprising chloroplatinic acid, an Sn salt, and an oxide selected from TiO2, ZrO2 and CeO2.
6. A method according to claim 5, wherein said catalyst has formula Ptx- 
7. A method according to claim 5, further comprising adding Ru during the MW (microwave) and/or SC (sonochemical) synthesis steps, to form Pt- Sn-Ru-TiO2.
8. A method according to claim 5, wherein said M, being TiO2 or ZrO2 or CeO2, is added during the SC synthesis step, using a templating agent selected from dodecylamine, octadecylamine, and sodium dodecylsulfate.
9. A method according to claim 5, comprising a) precipitating Pt and Sn on a surface located in a reaction zone saturated with EkPtClβ and SnCl2, and comprising an oxide selected from TiO2, ZrO2 and CeO2,; and b) synthesizing said catalyst, as the reactants are pumped into said reaction zone; wherein said reaction zone is exposed to MW or SC.
10. A method according to claim 9, wherein the synthesis is carried out in a continuous manner.
11. A method according to claim 9, comprising synthesizing particles by means of MW, and further plating said surface with said particles by applying SC.
12. A method according to claim 5, comprising sonicating the reaction mixture consisting of KkPtCIe, SnCb, a metal oxide, and a substrate, wherein said oxide is selected from the group consisting of Tiθ2, Zrθ2 and Ceθ2, and said substrate is selected from the group consisting of carbon, woven and non woven metallic substrate, composite polymer, conductive particles, and a combination thereof, thereby providing a catalyst within a porous substrate.
13. A method according to claim 12, wherein said carbon comprises graphite.
14. A method according to claim 12, wherein said substrate comprises stainless steel, titanium nickel, expended metal, and metal foam.
15. A method according to claim 12, wherein said conductive particles comprise carbon, gold, titanium, or silver. _ _
16. A method according to claim 12, wherein said catalyst is a part of an electrode.
17. A method according to claim 5, comprising electromagnetic radiation in the range GHz-THz.
18. A method according to claim 5, wherein said microwave process comprises the generation of plasma.
19. Use of a catalyst according to claim 1, for the oxidation of fuels, including methanol, ethanol, formic acid, formaldehyde, and glucose in fuel cells.
20. Use of a catalyst according to claim 1 in a fuel cell selected from methanol fuel cell, phosphoric acid fuel cell, polymer electrolyte fuel cell, and alkaline fuel cell.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IL183967A IL183967A0 (en) | 2007-06-14 | 2007-06-14 | Preparation methods and novel materials for direct methanol fuel cell (dmfc) anodes |
| IL183967 | 2007-06-14 |
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| Publication Number | Publication Date |
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| WO2008152638A2 true WO2008152638A2 (en) | 2008-12-18 |
| WO2008152638A3 WO2008152638A3 (en) | 2010-02-25 |
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| PCT/IL2008/000801 WO2008152638A2 (en) | 2007-06-14 | 2008-06-12 | Materials, their preparation, and their uses in electrodes for fuel cells |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102780011A (en) * | 2012-06-29 | 2012-11-14 | 青岛科技大学 | Direct methanol fuel cell anode catalyst and preparation method of direct methanol fuel cell anode catalyst |
| CN107029645A (en) * | 2017-05-12 | 2017-08-11 | 武汉喜玛拉雅光电科技股份有限公司 | A kind of continuous microwave synthesizer and the method that platinum carbon catalyst is prepared with it |
| CN114551904A (en) * | 2022-02-25 | 2022-05-27 | 内蒙古科技大学 | Composite rare earth catalyst and preparation method and application thereof |
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| US6833019B1 (en) * | 2003-01-31 | 2004-12-21 | The United States Of America As Represented By The Secretary Of The Navy | Microwave assisted continuous synthesis of nanocrystalline powders and coatings using the polyol process |
| US7138159B2 (en) * | 1998-02-24 | 2006-11-21 | Cabot Corporation | Method for the deposition of an electrocatalyst layer |
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| US6156211A (en) * | 1997-01-31 | 2000-12-05 | Lynntech, Inc. | Enhanced photocatalytic conversion of methane to methanol using a porous semiconductor membrane |
| US7138159B2 (en) * | 1998-02-24 | 2006-11-21 | Cabot Corporation | Method for the deposition of an electrocatalyst layer |
| US6833019B1 (en) * | 2003-01-31 | 2004-12-21 | The United States Of America As Represented By The Secretary Of The Navy | Microwave assisted continuous synthesis of nanocrystalline powders and coatings using the polyol process |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102780011A (en) * | 2012-06-29 | 2012-11-14 | 青岛科技大学 | Direct methanol fuel cell anode catalyst and preparation method of direct methanol fuel cell anode catalyst |
| CN107029645A (en) * | 2017-05-12 | 2017-08-11 | 武汉喜玛拉雅光电科技股份有限公司 | A kind of continuous microwave synthesizer and the method that platinum carbon catalyst is prepared with it |
| CN114551904A (en) * | 2022-02-25 | 2022-05-27 | 内蒙古科技大学 | Composite rare earth catalyst and preparation method and application thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2008152638A3 (en) | 2010-02-25 |
| IL183967A0 (en) | 2007-10-31 |
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