US3857737A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sequential catalyzation of fuel cell supported platinum catalyst
Assignee: RTX Corp
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Filing: 1973-09-18
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Granted: 1974-12-31
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Expires: 1993-09-18
Abstract
Abstract A fuel cell electrode catalyst, adapted for application to a carbon fiber support mat substrate to form a fuel cell electrode, comprising small crystals of noble metal fuel cell catalyst specie, such as platinum, deposited on discrete particles of an inert carrier or support such as carbon powder, is formed by the repetitive process of: mixing the powder with a dilute solution of the salt so as to form a slurry, the slurry then being concentrated and dried followed by the decomposition of the salt to form a partial product which is then used in place of the carrier powder in a repetition of the process until the desired concentration of catalyst is achieved. Usage of a low concentration of catalyst salt results in a smaller crystallite, which yields a higher surface area of catalyst, for a more active electrode that provides an improved current/voltage performance characteristic at a lower cost.
Inventors
- 👤 F Kemp
- 👤 M George
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 14:08
CPC Classifications
H; H01; H01M; H01M4/00; H01M4/86; H01M4/90; H01M4/92; B; B01; B01J; B01J23/00; B01J23/38; B01J23/40; B01J37/00; B01J37/02; B01J37/0201; B01J37/0203; H01M4/925; H01M4/926; H01M2004/8678; H01M2004/8684; H01M2004/8689; H01M2300/00; H01M2300/0002; H01M2300/0005; H01M2300/0008; H01M2300/0014; Y; Y02; Y02E; Y02E60/00; Y02E60/30; Y02E60/50
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
320 words
IN THE PREPARATION OF FUEL CELL ELECTRODE SUPPORTED CATALYTIC POWDERS COMPRISING A PREDETERMINED FIXED AMOUNT OF PLATINUM DISPOSED IN A DESIRED CONCENTRATION ON CARBON SUPPORT POWDERS BY THE FORMATION OF THE PLATINUM FROM PLATINUM DIAMINO DINITRITE, THE STEPS OF: A. MIXING ON THE ORDER OF 10 GRAMS OF GRAPHITIZED CARBON POWDER, HAVING A PARTICULAR SIZE ON THE ORDER OF 1-5 MICRONS IN DIAMETER AND A SURFACE AREA OF ON THE ORDER OF 75 TO 200 SQUARE METERS PER GRAM, IN A DILUTE SOLUTION COMPRISING ON THE ORDER OF 1 GRAM OF PLATINUM DIAMINO DINITRITE DISSOLVED IN NITRIC ACID, THE CONCENTRATION OF THE SOLUTION BEING SUCH THAT THE EFFECTIVE AMOUNT OF THE DINITRITE THEREIN IS LESS THAN THAT REQUIRED FOR THE FORMATION OF THE ENTIRE PREDETERMINED FIXED AMOUNT OF THE PLATINUM ON THE CARBON SUPPORT POWDERS; B. SLOWLY CONCENTRATING THE -DINITRITE SOLUTION IN THE SLURRY UNTIL A NEARLY DRY PASTE IS FORMED, AND REMOVING ALL OF SAID SOLVENT FROM SAID SOLUTION, FORMING SUBSTANTIALLY A POWDER; C. HEATING THE POWDER AT A TEMPERATURE IN EXCESS OF THE DECOMPOSITION TEMPERATURE OF THE -DINITRITE, PROVIDING AN INTERMEDIATE PRODUCT COMPRISING CARBON POWDERS HAVING LESS THAN THE PREDETERMINED FIXED AMOUNT OF THE PLATINUM ABSORBED ON THE SURFACE THEREOF; D. IMMERSING THE INTERMEDIATE PRODUCT IN A DILUTE SOLUTION OF PLATINUM DIAMINO DINITRITE DISSOLVED IN A SOLVENT, THE CONCENTRATION OF THE -DINITRITE THEREIN NOT EXCEEDING THAT REQUIRED TO PROVIDE BY FORMATION ON THE INTERMEDIATE PRODUCT AN ADDITIONAL AMOUNT OF THE PLATINUM NOT EXCEEDING THE AMOUNT REQUIRED TO FORM THE PREDETERMINED FIXED AMOUNT OF PLATINUM ON THE CARBON POWDERS; E. REPEATING STEP (B); F. HEATING THE POWDER AT A TEMPERATURE IN EXCESS OF THE DECOMPOSITION TEMPERATURE OF THE -DINITRITE, PROVIDING POWDERS HAVING NOT MORE THAN THE PREDETERMINED FIXED AMOUNT OF PLATINUM ON THE SURFACE THEREOF; G. AND, IF THE CONCENTRATION OF PLATINUM IS LESS THAN THE PREDETERMINED FIXED AMOUNT, REPEATING STEPS (D) THROUGH (F) UNTIL SUCH AMOUNT IS PROVIDED.
Claim 2
Dependent Claim
320 words
IN THE PREPARATION OF FUEL CELL ELECTRODE SUPPORTED CATALYTIC POWDERS COMPRISING A PREDETERMINED FIXED AMOUNT OF PLATINUM DISPOSED IN A DESIRED CONCENTRATION ON CARBON SUPPORT POWDERS BY THE FORMATION OF THE PLATINUM FROM PLATINUM DIAMINO DINITRITE, THE STEPS OF: A. MIXING ON THE ORDER OF 10 GRAMS OF GRAPHITIZED CARBON POWDER, HAVING A PARTICULAR SIZE ON THE ORDER OF 1-5 MICRONS IN DIAMETER AND A SURFACE AREA OF ON THE ORDER OF 75 TO 200 SQUARE METERS PER GRAM, IN A DILUTE SOLUTION COMPRISING ON THE ORDER OF 1 GRAM OF PLATINUM DIAMINO DINITRITE DISSOLVED IN NITRIC ACID, THE CONCENTRATION OF THE SOLUTION BEING SUCH THAT THE EFFECTIVE AMOUNT OF THE DINITRITE THEREIN IS LESS THAN THAT REQUIRED FOR THE FORMATION OF THE ENTIRE PREDETERMINED FIXED AMOUNT OF THE PLATINUM ON THE CARBON SUPPORT POWDERS; B. SLOWLY CONCENTRATING THE -DINITRITE SOLUTION IN THE SLURRY UNTIL A NEARLY DRY PASTE IS FORMED, AND REMOVING ALL OF SAID SOLVENT FROM SAID SOLUTION, FORMING SUBSTANTIALLY A POWDER; C. HEATING THE POWDER AT A TEMPERATURE IN EXCESS OF THE DECOMPOSITION TEMPERATURE OF THE -DINITRITE, PROVIDING AN INTERMEDIATE PRODUCT COMPRISING CARBON POWDERS HAVING LESS THAN THE PREDETERMINED FIXED AMOUNT OF THE PLATINUM ABSORBED ON THE SURFACE THEREOF; D. IMMERSING THE INTERMEDIATE PRODUCT IN A DILUTE SOLUTION OF PLATINUM DIAMINO DINITRITE DISSOLVED IN A SOLVENT, THE CONCENTRATION OF THE -DINITRITE THEREIN NOT EXCEEDING THAT REQUIRED TO PROVIDE BY FORMATION ON THE INTERMEDIATE PRODUCT AN ADDITIONAL AMOUNT OF THE PLATINUM NOT EXCEEDING THE AMOUNT REQUIRED TO FORM THE PREDETERMINED FIXED AMOUNT OF PLATINUM ON THE CARBON POWDERS; E. REPEATING STEP (B); F. HEATING THE POWDER AT A TEMPERATURE IN EXCESS OF THE DECOMPOSITION TEMPERATURE OF THE -DINITRITE, PROVIDING POWDERS HAVING NOT MORE THAN THE PREDETERMINED FIXED AMOUNT OF PLATINUM ON THE SURFACE THEREOF; G. AND, IF THE CONCENTRATION OF PLATINUM IS LESS THAN THE PREDETERMINED FIXED AMOUNT, REPEATING STEPS (D) THROUGH (F) UNTIL SUCH AMOUNT IS PROVIDED.
Claim 3
Dependent Claim
27 words
A process according to claim 1 wherein said desired concentration is within the range of 1% to 50% of catalyst on 99% to 50% inert support powder.
Claim 4
Dependent Claim
27 words
A process according to claim 2 wherein said desired concentration is within the range of 5% to 20% of catalyst on 95% to 80% inert support powder.
Claim 5
Dependent Claim
19 words
A process according to claim 1 wherein said steps (d) through (f) are repeated between 3 and 10 times.
Claim 6
Dependent Claim
19 words
A process according to claim 4 wherein said steps (d) through (f) are repeated between 3 and 6 times.
Claim 7
Dependent Claim
63 words
A process according to claim 1 wherein said step (b) comprises stirring said slurry at a moderately elevated temperature below the boiling point of said solvent so as to slowly concentrate the salt solution in the slurry until a nearly dry paste is formed, and drying the paste by heating at a temperature somewhat in excess of the boiling point of said solvent.
Claim 8
Dependent Claim
289 words
In the preparation of fuel cell electrode supported catalytic powders comprising a predetermined fixed amount of platinum catalyst disposed in a desired concentration of between 5% and 20% platinum on between 95% and 80% inert support powders by the formation of the platinum crystals from platinum diammino dinitrite, the steps of: a. immersing graphitized carbon powders in a dilute solution of platinum diamino dinitrite in a solvent, the concentration of the solution being such that the effective amount of the -dinitrite therein is less than that required for the formation of the entire predetermined fixed amount of the platinum on the carbon support powders; b. slowly concentrating the -dinitrite solution in the slurry until a nearly dry paste is formed, and removing all of said solvent from said solution, forming substantially a powder; c. heating the powder at a temperature in excess of the decomposition temperature of the -dinitrite, providing an intermediate product comprising carbon powders having less than the predetermined fixed amount of the platinum absorbed on the surface thereof; d. immersing the intermediate product in a dilute solution of platinum diammino dinitrite dissolved in a solvent, the concentration of the -dinitrite therein not exceeding that required to provide by formation on the intermediate product an additional amount of the platinum not exceeding the amount required to form the predetermined fixed amount of platinum on the carbon powders; e. repeating step (b); f. heating the powder at a temperature in excess of the decomposition temperature of the -dinitrite, providing powders having not more than the predetermined fixed amount of platinum on the surface thereof; g. and, if the concentration of platinum is less than the predetermined fixed amount, repeating steps (d) through (f) until such amount is provided.
Claim 9
Dependent Claim
289 words
In the preparation of fuel cell electrode supported catalytic powders comprising a predetermined fixed amount of platinum catalyst disposed in a desired concentration of between 5% and 20% platinum on between 95% and 80% inert support powders by the formation of the platinum crystals from platinum diammino dinitrite, the steps of: a. immersing graphitized carbon powders in a dilute solution of platinum diamino dinitrite in a solvent, the concentration of the solution being such that the effective amount of the -dinitrite therein is less than that required for the formation of the entire predetermined fixed amount of the platinum on the carbon support powders; b. slowly concentrating the -dinitrite solution in the slurry until a nearly dry paste is formed, and removing all of said solvent from said solution, forming substantially a powder; c. heating the powder at a temperature in excess of the decomposition temperature of the -dinitrite, providing an intermediate product comprising carbon powders having less than the predetermined fixed amount of the platinum absorbed on the surface thereof; d. immersing the intermediate product in a dilute solution of platinum diammino dinitrite dissolved in a solvent, the concentration of the -dinitrite therein not exceeding that required to provide by formation on the intermediate product an additional amount of the platinum not exceeding the amount required to form the predetermined fixed amount of platinum on the carbon powders; e. repeating step (b); f. heating the powder at a temperature in excess of the decomposition temperature of the -dinitrite, providing powders having not more than the predetermined fixed amount of platinum on the surface thereof; g. and, if the concentration of platinum is less than the predetermined fixed amount, repeating steps (d) through (f) until such amount is provided.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-30 | 1978-07-01 | 1978-12-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-30 | 1982-07-01 | 1982-12-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-30 | 1986-07-01 | 1986-12-31 | $7700.00 | Window Closed / Lapsed |