US4305794A
Expired / Lapsed
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Photochemical electrode
Assignee: National Research Development Corp UK
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Filing: 1979-12-19
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Granted: 1981-12-15
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Expires: 1999-12-19
Abstract
Abstract Photochemical electrode can decompose water when irradiated with visible light and consists of red mercuric sulphide blackened by iodide treatment as a coating on a platinum mesh.
Inventors
- 👤 Robert S. Davidson
- 👤 Charles J. Willsher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:50
CPC Classifications
C; C25; C25B; C25B1/00; C25B1/50; C25B1/55; H; H01; H01G; H01G9/00; H01G9/20; H01M; H01M14/00; H01M14/005; Y; Y10; Y10S; Y10S204/00; Y10S204/03
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
50 words
A photochemical electrode for use in an electrochemical cell, comprising: a conductive member in contact with photochemically active, blackened mercuric sulfide, said mercuric sulfide initially applied to said conductive member as red mercuric sulfide and being converted to said black form upon contact of said electrode with a reducing electrolyte.
Claim 2
Dependent Claim
50 words
A photochemical electrode for use in an electrochemical cell, comprising: a conductive member in contact with photochemically active, blackened mercuric sulfide, said mercuric sulfide initially applied to said conductive member as red mercuric sulfide and being converted to said black form upon contact of said electrode with a reducing electrolyte.
Claim 3
Dependent Claim
12 words
The electrode of claim 1, wherein said conductive member is a mesh.
Claim 4
Dependent Claim
18 words
The electrode of claim 2, wherein said conductive member is a mesh of metal or of carbon fibers.
Claim 5
Dependent Claim
16 words
The electrode of claim 1, wherein said mercuric sulfide forms a coating on said conductive member.
Claim 6
Dependent Claim
30 words
The electrode of claim 1, wherein said mercuric sulfide is applied to said conductive member in the form of a slurry, suspension or fluidised bed of initially red mercuric sulfide.
Claim 7
Dependent Claim
20 words
The electrode of claim 1, wherein said reducing electrolyte contains a halide ion or thiocyanate ion as a reducing agent.
Claim 8
Dependent Claim
22 words
The electrode of claim 1 or 6, wherein the atomic percent of mercury in said blackened mercuric sulfide is at least 48.9%.
Claim 9
Dependent Claim
27 words
The electrode of claim 6, wherein said mercuric sulfide is blackened in said reducing electrolyte at a potential of within 0.2 V of the standard calomel electrode.
Claim 10
Dependent Claim
20 words
The electrode of claim 6 or 8, wherein said mercuric sulfide is blackened over a period of from 30-240 minutes.
Claim 11
Independent Claim
88 words
A method for converting light into electricity in a photochemical cell, comprising; subjecting a photochemical electrode to light in said photochemical cell additionally containing an inert counterelectrode and an electrolyte in which said electrodes are immersed, thus generating an electrical current within said cell said photochemical electrode comprising a conductive member in contact with photochemically active, blackened mercuric sulfide, said mercuric sulfide initially applied to said conductive member as red mercuric sulfide and being converted to said black form upon contact of said electrode with a reducing electrolyte.
Claim 12
Independent Claim
88 words
A method for converting light into electricity in a photochemical cell, comprising; subjecting a photochemical electrode to light in said photochemical cell additionally containing an inert counterelectrode and an electrolyte in which said electrodes are immersed, thus generating an electrical current within said cell said photochemical electrode comprising a conductive member in contact with photochemically active, blackened mercuric sulfide, said mercuric sulfide initially applied to said conductive member as red mercuric sulfide and being converted to said black form upon contact of said electrode with a reducing electrolyte.
Claim 13
Independent Claim
112 words
A method of electrolysing water in a photochemical cell, comprising; subjecting a photochemical electrode 13 to light in said photochemical cell additionally containing an inert counterelectrode and an aqueous electrolyte in which said electrodes are immersed, thereby generating an electrical current within said cell which results in the generation of hydrogen at one of said electrodes and oxygen at the other electrode; and collecting the products of electrolysis said photochemical electrode comprising a conductive member in contact with photochemically active, blackened mercuric sulfide, said mercuric sulfide initially applied to said conductive member as red mercuric sulfide and being converted to said black form upon contact of said electrode with a reducing electrolyte.
Claim 14
Independent Claim
112 words
A method of electrolysing water in a photochemical cell, comprising; subjecting a photochemical electrode 13 to light in said photochemical cell additionally containing an inert counterelectrode and an aqueous electrolyte in which said electrodes are immersed, thereby generating an electrical current within said cell which results in the generation of hydrogen at one of said electrodes and oxygen at the other electrode; and collecting the products of electrolysis said photochemical electrode comprising a conductive member in contact with photochemically active, blackened mercuric sulfide, said mercuric sulfide initially applied to said conductive member as red mercuric sulfide and being converted to said black form upon contact of said electrode with a reducing electrolyte.
Claim 15
Dependent Claim
25 words
The method of claim 11, wherein a biasing potential of a potential less than the thermodynamic potential for electrolysing water is applied across said electrodes.
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) | 1984-12-14 | 1985-06-15 | 1985-12-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-12-14 | 1989-06-15 | 1989-12-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-12-14 | 1993-06-15 | 1993-12-15 | $7700.00 | Window Closed / Lapsed |