US3900342A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Silver catalyst and a method of its manufacture
Assignee: Siemens AG
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Filing: 1972-04-28
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Granted: 1975-08-19
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Expires: 1992-04-28
Abstract
Abstract A silver-containing catalyst, adapted for employment in fuel cell electrodes, comprising metallic silver chemically reduced and precipitated on a metal hydroxide gel, such as a plurality of hydroxides of bismuth, cobalt, iron, nickel and/or titanium. The total metal of the hydroxide comprises about 0.5 to 5 weight %, based on the total silver, in the finished catalyst. The amount of hydroxides employed is only that required as carrier in the finished catalyst. The catalyst is prepared by slowly adding a silver salt solution and reducing agent to an alkaline solution of the hydroxides, preferably with stirring and at a low (e.g. 0*-15*C) temperature. Thereafter, the supernatant liquid is separated and the solid dried.
Inventors
- 👤 Karl Hohne
- 👤 Renate Bogusch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 07:13
CPC Classifications
B; B01; B01J; B01J23/00; B01J23/38; B01J23/54; B01J23/66; B01J23/70; B01J23/89
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
47 words
A SILVER CATALYST SUITABLE FOR USE AS A FUEL CELL ELECTRODE MATERIAL COMPRISING AN UNLEACHED COMPOSITE OF PREDOMINANTLY METALLIC SILVER DISPOSED ON TWO OR MORE COMMINGLED HYDROXIDES OF BISMUHT, COBALT, IRON, NICKEL AND TITANIUM, IN WHICH THE TOTAL METAL CONTENT OF SAID HYDROXIDES IS IN THE RANGE
Claim 2
Dependent Claim
47 words
A SILVER CATALYST SUITABLE FOR USE AS A FUEL CELL ELECTRODE MATERIAL COMPRISING AN UNLEACHED COMPOSITE OF PREDOMINANTLY METALLIC SILVER DISPOSED ON TWO OR MORE COMMINGLED HYDROXIDES OF BISMUHT, COBALT, IRON, NICKEL AND TITANIUM, IN WHICH THE TOTAL METAL CONTENT OF SAID HYDROXIDES IS IN THE RANGE
Claim 3
Dependent Claim
9 words
The catalyst of claim 1 which comprises bismuth hydroxide.
Claim 4
Dependent Claim
13 words
The catalyst of claim 1 which comprises hydroxides of bismuth, cobalt and nickel.
Claim 5
Dependent Claim
13 words
The catalyst of claim 1 which comprises hydroxides of bismuth, nickel and titanium.
Claim 6
Dependent Claim
14 words
The catalyst of claim 1 which comprises hydroxides of bismuth, iron, nickel and titanium.
Claim 7
Dependent Claim
104 words
In the process of manufacture of a silver catalyst by chemical reduction in an alkaline aqueous medium of a dissolved silver salt and precipitation of metallic silver on a metal hydroxide gel contained in said medium, the improvement which comprises employing a commingled mixture of at least two metal hydroxides in gel form, said hydroxides being present in the reaction zone in essentially the same amount thereof as required in the finished catalyst, and said hydroxides having a total metal content in the range of from about 0.5 to about 5 weight % based on the amount of silver present in the finished catalyst.
Claim 8
Dependent Claim
104 words
In the process of manufacture of a silver catalyst by chemical reduction in an alkaline aqueous medium of a dissolved silver salt and precipitation of metallic silver on a metal hydroxide gel contained in said medium, the improvement which comprises employing a commingled mixture of at least two metal hydroxides in gel form, said hydroxides being present in the reaction zone in essentially the same amount thereof as required in the finished catalyst, and said hydroxides having a total metal content in the range of from about 0.5 to about 5 weight % based on the amount of silver present in the finished catalyst.
Claim 9
Dependent Claim
18 words
In the process of claim 6, the further improvement of employing bismuth hydroxide as one of the hydroxides.
Claim 10
Dependent Claim
20 words
In the method of claim 6, the further improvement of employing a mixture of hydroxides of bismuth, nickel and titanium.
Claim 11
Dependent Claim
12 words
In the method of claim 8, the improvement of including iron hydroxide.
Claim 12
Dependent Claim
20 words
In the process of claim 6, the further improvement of employing a mixture of hydroxides of bismuth, cobalt and nickel.
References Cited (Backward Citations)
US3201223A
Cited
US3369886A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-18 | 1979-02-17 | 1979-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-18 | 1983-02-17 | 1983-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-18 | 1987-02-17 | 1987-08-19 | $7700.00 | Window Closed / Lapsed |