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US4460443A
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Electrolytic photodissociation of chemical compounds by iron oxide electrodes
Assignee: University of California
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Filing: 1982-09-09
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Granted: 1984-07-17
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Expires: 2002-09-09
Abstract
Abstract Chemical compounds can be dissociated by contacting the same with a p/n type semi-conductor diode having visible light as its sole source of energy. The diode consists of low cost, readily available materials, specifically polycrystalline iron oxide doped with silicon in the case of the n-type semi-conductor electrode, and polycrystalline iron oxide doped with magnesium in the case of the p-type electrode. So long as the light source has an energy greater than 2.2 electron volts, no added energy source is needed to achieve dissociation.
Inventors
- 👤 Gabor A. Somorjai
- 👤 Christofer H. Leygraf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 15:11
CPC Classifications
C; C25; C25B; C25B1/00; C25B1/50; C25B1/55; Y; Y02; Y02E; Y02E60/00; Y02E60/30; Y02E60/36
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
110 words
A process for the photocatalytic dissociation of chemical compounds comprising ionizing said chemical compounds in aqueous solution into respective cations and anions, contacting the aqueous solution with a first electrode comprised of an n-type iron oxide semi-conductor material, and with a second electrode comprised of a p-type iron oxide semi-conductor material, providing an electrical connection between said first and second electrodes and insulated from said aqueous solution, shining light energy in the visible region onto both said electrodes to induce an electrical potential therebetween and through said aqueous solution, and neutralizing and liberating the cations at the p-type iron oxide electrode and the anions at the n-type iron oxide electrode.
Claim 2
Dependent Claim
110 words
A process for the photocatalytic dissociation of chemical compounds comprising ionizing said chemical compounds in aqueous solution into respective cations and anions, contacting the aqueous solution with a first electrode comprised of an n-type iron oxide semi-conductor material, and with a second electrode comprised of a p-type iron oxide semi-conductor material, providing an electrical connection between said first and second electrodes and insulated from said aqueous solution, shining light energy in the visible region onto both said electrodes to induce an electrical potential therebetween and through said aqueous solution, and neutralizing and liberating the cations at the p-type iron oxide electrode and the anions at the n-type iron oxide electrode.
Claim 3
Dependent Claim
18 words
The process of claim 1 wherein the visible light has an energy of at least 2.2 electron volts.
Claim 4
Dependent Claim
15 words
The process of claim 1 wherein the n-type iron oxide material is doped with silicon.
Claim 5
Dependent Claim
18 words
The process of claim 3 wherein the silicon is present in from about 1 to 10 atom %.
Claim 6
Dependent Claim
15 words
The process of claim 1 wherein the p-type iron oxide material is doped with magnesium.
Claim 7
Dependent Claim
18 words
The process of claim 5 wherein the magnesium is present in from about 1 to 20 atom %.
Claim 8
Dependent Claim
20 words
The method of claim 5 wherein the aqueous solution is maintained at a pH of from about 6 to 14.
Claim 9
Dependent Claim
12 words
The process of claim 1 wherein the ionized chemical compound is water.
Claim 10
Independent Claim
106 words
A method for dissociating water into its elements utilizing visible light as the sole energy source comprising providing a p/n type semi-conductor diode where said diode consists of a p-type iron oxide semi-conductor electrode doped with magnesium in electrical contact with an n-type iron oxide semi-conductor electrode doped with silicon, contacting said diode with water maintained at a pH of from about 6 to 14, exposing said diode to visible light having an energy of at least 2.2 electron volts to generate an electrical potential between said electrodes to thereby dissociate the water and evolve hydrogen at the p-type electrode and oxygen at the n-type electrode.
Claim 11
Independent Claim
106 words
A method for dissociating water into its elements utilizing visible light as the sole energy source comprising providing a p/n type semi-conductor diode where said diode consists of a p-type iron oxide semi-conductor electrode doped with magnesium in electrical contact with an n-type iron oxide semi-conductor electrode doped with silicon, contacting said diode with water maintained at a pH of from about 6 to 14, exposing said diode to visible light having an energy of at least 2.2 electron volts to generate an electrical potential between said electrodes to thereby dissociate the water and evolve hydrogen at the p-type electrode and oxygen at the n-type electrode.
References Cited (Backward Citations)
US4259418A
Cited
US4263111A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-07-17 | 1988-01-16 | 1988-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-07-17 | 1992-01-16 | 1992-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-07-17 | 1996-01-16 | 1996-07-17 | $7700.00 | Window Closed / Lapsed |