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US4484992A
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Process for the production of hydrogen by means of heterogeneous photoredox catalysis
Assignee: Novartis Corp
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Filing: 1982-01-25
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Granted: 1984-11-27
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Expires: 2002-01-25
Abstract
Abstract A process is described for the selective production of hydrogen by means of heterogeneous photoredox catalysis, in which mixtures of water and alkali metal sulfites or sulfides, alkaline earth metal sulfites or sulfides or ammonium sulfites or sulfides are reacted under the action of light in a suspension of a cadmium sulfide, cadmium sulfoselenide or titanium dioxide/semiconductor powder which is at least partially coated with Cu, Cr, Ni, Co or a noble metal or mixtures thereof. The catalysts which can be employed in this process (coated semiconductor powders) are in some cases novel.
Inventors
- 👤 Niklaus Buhler
- 👤 Jean F. Reber
- 👤 Kurt Meier
- 👤 Milos Rusek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:44
CPC Classifications
C; C01; C01B; C01B3/00; C01B3/02; C01B3/04; C01B3/042; B; B01; B01J; B01J27/00; B01J27/02; B01J27/04; B01J27/057; B01J27/0573; C01B3/046; Y; Y02; Y02E; Y02E60/00; Y02E60/30; Y02E60/36
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
73 words
A process for the selective production of hydrogen by means of heterogeneous photoredox catalysts, which comprises reacting mixtures of water and alkali metal sulfites or sulfides, alkaline earth metal sulfites or sulfides or ammonium sulfites or sulfides under the action of light in a suspension of a cadmium sulfide, cadmium sulfoselenide or titanium dioxide/semiconductor powder which is at least partially coated with Cu, Cr, Ni, Co or a noble metal or mixtures thereof.
Claim 2
Dependent Claim
73 words
A process for the selective production of hydrogen by means of heterogeneous photoredox catalysts, which comprises reacting mixtures of water and alkali metal sulfites or sulfides, alkaline earth metal sulfites or sulfides or ammonium sulfites or sulfides under the action of light in a suspension of a cadmium sulfide, cadmium sulfoselenide or titanium dioxide/semiconductor powder which is at least partially coated with Cu, Cr, Ni, Co or a noble metal or mixtures thereof.
Claim 3
Dependent Claim
14 words
A process according to claim 1, wherein water is used as the suspending agent.
Claim 4
Dependent Claim
20 words
A process according to claim 1, wherein an alkali metal sulfite or sulfide or ammonium sulfite or sulfide is used.
Claim 5
Dependent Claim
14 words
A process according to claim 1, wherein sodium sulfite or ammonium sulfite is used.
Claim 6
Dependent Claim
26 words
A process according to claim 1, wherein the reaction is carried out a temperature between 20° C. and the boiling point of the suspending agent used.
Claim 7
Dependent Claim
39 words
A process according to claim 1, wherein the semiconductor powders, of the type defined, which have been coated with the metals, are employed in an amount of 0.05 to 8% by weight, relative to the volume of the reaction.
Claim 8
Dependent Claim
37 words
A process according to claim 1, wherein cadmium sulfoselenide/semiconductor or titanium dioxide (anatase modification)/semiconductor powders or, cadmium sulfide/semiconductor powders which are at least partially coated with rhodium, nickel, osmium, ruthenium or nickel/rhodium or silver/platinum mixtures, are used.
Claim 9
Dependent Claim
28 words
A process according to claim 1, wherein a cadmium sulfide/semiconductor, cadmium sulfoselenide/semiconductor or titanium dioxide (anatase modification)/semiconductor powder which is at least partially coated with platinum, is used.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-11-27 | 1988-05-28 | 1988-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-27 | 1992-05-28 | 1992-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-11-27 | 1996-05-28 | 1996-11-27 | $7700.00 | Window Closed / Lapsed |