US4045315A
Expired / Lapsed
US
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Solar photolysis of water
Assignee: National Aeronautics and Space Administration
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Filing: 1976-02-13
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Granted: 1977-08-30
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Expires: 1996-02-13
Abstract
Abstract Hydrogen is produced by the solar photolysis of water in a first photo-oxidation vessel with a transparent wall in the presence of a water soluble photo-oxidizable reagent and an insoluble hydrogen recombination catalyst. Simultaneously oxygen is produced in a second photo-reduction reactor with a transparent wall in the presence of an insoluble photo-reduction reagent catalyst. When spent, the solution from the first reactor is fed into the second reactor. A reaction occurs in the dark in which the redox reagents are regenerated, and the regenerated photo-oxidation reagent solution is recycled to the first reactor. The photo-oxidation reagent is preferably a europium salt, and the first reactor also contains a hydrogen recombination catalyst such as platinum supported on glass beads. The photo-reduction catalyst is a bifunctional reagent catalyst including a transition metal salt such as a manganese oxychloride salt covalently bonded to the surface of a high area support such as glass fibers, together with a hydroxyl or chlorohydroxyl decomposition catalyst of high area.
Inventors
- 👤 with respect to an invention of Fletcher James C. Administrator of the National Aeronautics and Space Administration
- 👤 Porter R. Ryason
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:09
CPC Classifications
C; C01; C01B; C01B3/00; C01B3/02; C01B3/06; C01B3/061; B; B01; B01J; B01J19/00; B01J19/08; B01J19/12; B01J19/122; B01J19/127; C01B3/04; C01B3/042; C01B3/08; C01B3/10; Y; Y02; Y02E; Y02E60/00; Y02E60/30; Y02E60/36; Y02P; Y02P20/00; Y02P20/10; Y02P20/133; Y10; Y10S; Y10S204/00; Y10S204/902; Y10S204/903; Y10S204/904; Y10S204/905
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
104 words
A method of photolyzing water comprising the steps of: applying solar radiation to a first vessel containing an aqueous solution of a water soluble photo-oxidizable reagent and generating hydrogen gas therefrom while forming a spent solution containing oxidized, spent reagent; applying solar radiation to a second vessel containing water and a water insoluble photoreducible reagent catalyst and generating oxygen gas therefrom while forming spent, reduced photoreducible reagent catalyst; combining the spent solution containing oxidized photo-oxidizable reagent with the spent reduced photo-reducible reagent catalyst and regenerating said reagents in the dark to form a solution of regenerated photo-oxidizable reagent containing water-insoluble, regenerated photo-reducible reagent catalyst.
Claim 2
Independent Claim
104 words
A method of photolyzing water comprising the steps of: applying solar radiation to a first vessel containing an aqueous solution of a water soluble photo-oxidizable reagent and generating hydrogen gas therefrom while forming a spent solution containing oxidized, spent reagent; applying solar radiation to a second vessel containing water and a water insoluble photoreducible reagent catalyst and generating oxygen gas therefrom while forming spent, reduced photoreducible reagent catalyst; combining the spent solution containing oxidized photo-oxidizable reagent with the spent reduced photo-reducible reagent catalyst and regenerating said reagents in the dark to form a solution of regenerated photo-oxidizable reagent containing water-insoluble, regenerated photo-reducible reagent catalyst.
Claim 3
Dependent Claim
40 words
A method according to claim 1 in which the soluble photo-oxidizable reagent is a material which absorbs strongly in the solar range at ground level and is capable of photolyzing water to produce hydrogen with a quantum efficiency exceeding 0.1%.
Claim 4
Dependent Claim
39 words
A method according to claim 2 in which the reagent is a transition metal cation selected from Eu ++ , Cr ++ , V ++ and Ti ++ and the pH of the solution is no more than 5.
Claim 5
Dependent Claim
27 words
A method according to claim 3 in which the solution further contains 0.5 to 5M of Cl - , SO 4 = or PO 4 = .
Claim 6
Dependent Claim
83 words
A method according to claim 1 in which the photo-oxidation reaction is conducted in a first vessel, having one wall transparent to sea level solar radiation and the other walls opaque to said radiation, the photo-reduction reaction is carried out in a second vessel having one wall transparent to sea level solar radiation and the other walls opaque to said radiation, and further including the step of transferring the spent solution from the first vessel to the second vessel for regenerating said reagents.
Claim 7
Dependent Claim
22 words
A method according to claim 5 further including the step of returning the solution containing regenerated photo-oxidizable reagent to the first vessel.
Claim 8
Dependent Claim
25 words
A method according to claim 5 further including the step of placing an opaque cover over the transparent wall of the second vessel during regeneration.
Claim 9
Dependent Claim
22 words
A method according to claim 5 in which the first vessel further contains an insoluble, hydrogen recombination catalyst immobilized on a support.
Claim 10
Dependent Claim
21 words
A method according to claim 8 in which the recombination catalyst is selected from Pt, Rh, Pd, Ir, Os and Ni.
Claim 11
Dependent Claim
17 words
A method according to claim 9 in which the support is non porous glass beads or fibers.
Claim 12
Dependent Claim
21 words
A method according to claim 10 in which the metal concentration of the recombination catalyst is 0.5 to 0.005% by weight.
Claim 13
Dependent Claim
24 words
A method according to claim 10 in which the surface of the glass support contains a deposited layer of a silica or alumina hydrogel.
Claim 14
Dependent Claim
21 words
A method according to claim 12 in which the recombination catalyst comprises Pt deposited on an alumina hydrogel coated glass bead.
Claim 15
Dependent Claim
38 words
A method according to claim 5 in which the insoluble photo-reducible reagent catalyst contains a first component capable of decomposing OH. or ClOH. - radicals and a second component comprising a regenerable reductant for the soluble photo-oxidizable reagent.
Claim 16
Dependent Claim
23 words
A method according to claim 14 in which the first component comprises Pt, MnO 2 , PbO, Fe 3 O 4 or ZnO.
Claim 17
Dependent Claim
31 words
A method according to claim 14 in which the second component comprises a water stable oxychloride of a metal selected from Mn, Ti, V, Cu, Ni, Cd, Sb, Pb or Fe.
Claim 18
Dependent Claim
17 words
A method according to claim 16 in which both components are supported on a high area support.
Claim 19
Dependent Claim
46 words
A method according to claim 17 in which the first component is present on the support in an amount from 0.01 to 0.5% and the second component is provided on the support in an amount from 1/5 to 1/20 of the amount of the first component.
Claim 20
Dependent Claim
19 words
A method according to claim 17 in which the second component is covalently bonded to a fibrous glass support.
Claim 21
Dependent Claim
20 words
A method according to claim 19 in which the glass support contains a photochromic additive to increase the photoactive range.
Claim 22
Dependent Claim
18 words
A method according to claim 20 in which the additive is selected from silver, copper or iron halides.
Claim 23
Independent Claim
127 words
An apparatus for the photolysis of water comprising in combination: a first vessel for receiving an aqueous solution of photo-oxidizable reagent and having at least one wall portion transparent to solar radiation, said first vessel containing an immobilized, insoluble hydrogen recombination catalyst, and having a hydrogen gas outlet; a second vessel having at least one wall portion transparent to solar radiation and containing an immobilized photo-reduction reagent-catalyst, and having an oxygen gas outlet; photo-reagent regenerating means including means for transferring solution containing oxidized, photo-oxidizable reagent from the first vessel to the second vessel, for conducting a reaction in the dark in which the oxidized, photo-oxidizable reagent is reduced and the immobilized, reduced photo-reduction reagent-catalyst is oxidized and including means for recycling the solution to the first vessel.
Claim 24
Independent Claim
127 words
An apparatus for the photolysis of water comprising in combination: a first vessel for receiving an aqueous solution of photo-oxidizable reagent and having at least one wall portion transparent to solar radiation, said first vessel containing an immobilized, insoluble hydrogen recombination catalyst, and having a hydrogen gas outlet; a second vessel having at least one wall portion transparent to solar radiation and containing an immobilized photo-reduction reagent-catalyst, and having an oxygen gas outlet; photo-reagent regenerating means including means for transferring solution containing oxidized, photo-oxidizable reagent from the first vessel to the second vessel, for conducting a reaction in the dark in which the oxidized, photo-oxidizable reagent is reduced and the immobilized, reduced photo-reduction reagent-catalyst is oxidized and including means for recycling the solution to the first vessel.
Claim 25
Dependent Claim
30 words
An apparatus according to claim 22 in which the immobilized hydrogen recombination catalyst is selected from Pt, Rh, Pd, Ir, Os or Ni deposited on non-porous glass beads or fibers.
Claim 26
Dependent Claim
46 words
An apparatus according to claim 23 in which the immobilized photo-reduction reagent-catalyst comprises two components deposited on a high area support, the first component being capable of decomposing OH. or ClOH. - radicals and the second component comprising a regenerable reductant for the soluble photo-oxidizable reagent.
Claim 27
Dependent Claim
53 words
An apparatus according to claim 24 in which the first component is selected from Pt, MnO 2 , Fe 3 O 4 or ZnO and the second component is covalently bonded to the support and is selected from a water stable oxychloride of Mn, Ti, V, Cu, Ni, Cd, Sb, Pb or Fe.
Claim 28
Dependent Claim
30 words
An apparatus according to claim 22 in which the photo-reagent regenerating means further includes opaque cover means for covering the transparent wall portion of the second vessel during reagent regeneration.
References Cited (Backward Citations)
US3925212A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-08-29 | 1981-02-28 | 1981-08-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-29 | 1985-02-28 | 1985-08-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-29 | 1989-02-28 | 1989-08-30 | $7700.00 | Window Closed / Lapsed |