US4414080A
Expired / Lapsed
US
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Photoelectrochemical electrodes
Assignee: CAIFORNIA INSTITUTE OF TECHNOLOGY 1201 EAST CALIFORNIA BLVD PASADENA CA 91125 A CORP OF
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Filing: 1982-05-10
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Granted: 1983-11-08
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Expires: 2002-05-10
Abstract
Abstract The surface (20) of a moderate band gap semiconductor (12) such as p-type molybdenum sulfide is modified to contain an adherent film (24) of charge mediating ionene polymer containing an electroactive unit such as bipyridinium. Electron transport between the electrode (12) and the mediator film (24) is favorable and photocorrosion and recombination processes are suppressed. Incorporation of particles (26) of catalyst such as platinum within the film (24) provides a reduction in overvoltage. The polymer film is readily deposited on the electrode surface and can be rendered stable by ionic or addition cross-linking. Catalyst can be predispersed in the polymer film or a salt can be impregnated into the film and reduced therein.
Inventors
- 👤 Roger M. Williams
- 👤 Alan Rembaum
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 01:34
CPC Classifications
H; H01; H01G; H01G9/00; H01G9/20; H01G9/2004; C; C25; C25B; C25B11/00; C25B11/04; C25B11/051; C25B11/073; C25B11/091; C25B11/095; C25B1/00; C25B1/50; C25B1/55; H01G9/2027; H01G9/2031; H01G9/2054; H01M; H01M14/00; H01M14/005; H01M4/00; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02E10/542; Y02P; Y02P20/00; Y02P20/10; Y02P20/133; Y10; Y10S; Y10S204/00; Y10S204/03
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
39 words
An electrode for an electrochemical cell comprising: a conductive substrate; and a film of stable, electrolyte-permeable, charge-mediating, conductive, polymer containing quaternized bipyridyl groups and cross-links between unsaturated groups on different polymer chains deposited on a surface of the substrate.
Claim 2
Dependent Claim
39 words
An electrode for an electrochemical cell comprising: a conductive substrate; and a film of stable, electrolyte-permeable, charge-mediating, conductive, polymer containing quaternized bipyridyl groups and cross-links between unsaturated groups on different polymer chains deposited on a surface of the substrate.
Claim 3
Dependent Claim
19 words
An electrode according to claim 1 in which the film has a thickness from 100 Angstroms to 10 microns.
Claim 4
Dependent Claim
20 words
An electrode according to claim 2 in which the thickness of the film is from 500 Angstroms to 5,000 Angstroms.
Claim 5
Dependent Claim
24 words
An electrode according to claim 2 in which the electrode further contains an effective amount of a catalyst capable of promoting an electrochemical reaction.
Claim 6
Dependent Claim
24 words
An electrode according to claim 4 in which the reaction is the photolysis of water and the catalyst promotes the generation of hydrogen gas.
Claim 7
Dependent Claim
22 words
An electrode according to claim 5 in which the catalyst is a dispersion of fine particles of noble metal within the film.
Claim 8
Dependent Claim
27 words
An electrode according to claim 6 in which the catalyst is platinum and is present in an amount from 1 to 50% by weight of the film.
Claim 9
Dependent Claim
21 words
An electrode according to claim 2 in which the polymer has a molecular weight from 10 3 to 10 6 .
Claim 10
Dependent Claim
63 words
An electrode according to claim 2 in which the polymer is selected from polymers of the formula: ##STR8## where n is an integer from 10 to 1,000 and R is aliphatic or aromatic groups selected from ##STR9## where m is an integer from 1 to 20, p is an integer from 1 to 3 and q is an integer from 1 to 5.
Claim 11
Dependent Claim
25 words
An electrode according to claim 9 in which R includes alkylene of 2 to 12 carbon atoms and alkenylene of 4 to 8 carbon atoms.
Claim 12
Dependent Claim
21 words
An electrode according to claim 2 in which the polymer is the cross-linked product of the prepolymer of the formula: ##STR10##
Claim 13
Dependent Claim
29 words
An electrode according to claim 1 for use in a photoelectrochemical cell in which the substrate is a semi-conductor having a band gap of no more than 2.0 eV.
Claim 14
Dependent Claim
20 words
An electrode according to claim 12 in which the semiconductor has a band gap from 1.0 eV to 2.0 eV.
Claim 15
Dependent Claim
21 words
An electrode according to claim 13 in which the semiconductor is selected from silicon and compounds of gallium, molybdenum or tungsten.
Claim 16
Dependent Claim
26 words
An electrode according to claim 14 in which the compounds are selected from gallium arsenide, gallium phosphide, molybdenum sulfide, molybdenum selenide, tungsten sulfide or tungsten selenide.
Claim 17
Dependent Claim
23 words
An electrochemical cell comprising: an electrode as defined in claim 1; a counter electrode a body of electrolyte in communication with both electrodes.
Claim 18
Dependent Claim
19 words
A cell according to claim 16 in which the counterelectrode is a semiconductor containing a film of said polymer.
Claim 19
Independent Claim
44 words
A method of forming a modified electrode comprising the step of depositing by in situ polymerization a film of electrolyte permeable, charge-mediating conductive polymer containing quaternized bipyridyl groups and cross-links between unsaturated groups on different polymer chains on the surface of a conductive substrate.
Claim 20
Independent Claim
44 words
A method of forming a modified electrode comprising the step of depositing by in situ polymerization a film of electrolyte permeable, charge-mediating conductive polymer containing quaternized bipyridyl groups and cross-links between unsaturated groups on different polymer chains on the surface of a conductive substrate.
Claim 21
Dependent Claim
16 words
A method according to claim 18 further including the step of dispersing catalyst throughout the film.
Claim 22
Dependent Claim
28 words
A method according to claim 19 in which the catalyst is formed by impregnating the film with a solution of a reducible precursor salt and reducing the salt.
Claim 23
Dependent Claim
25 words
A method according to claim 18 in which the substrate is a plate of semi-conductor having a band gap of no more than 2.0 eV.
Claim 24
Dependent Claim
38 words
A modified photoelectrode comprising a solid semi-conductor having a band gap below 2.0 eV coated with a film of polyquaternary, bipyridyl polymer containing cross-links between unsaturated groups on different chains and a dispersion of fine, hydrogen producing catalyst.
Claim 25
Dependent Claim
38 words
A modified photoelectrode comprising a solid semi-conductor having a band gap below 2.0 eV coated with a film of polyquaternary, bipyridyl polymer containing cross-links between unsaturated groups on different chains and a dispersion of fine, hydrogen producing catalyst.
Claim 26
Independent Claim
67 words
A method of photolysing water comprising placing an electrode comprising a solid semiconductor having a band gap below 2.0 eV coated with a film of polyquaternary, bipyridyl polymer containing cross-links between unsaturated groups on different chains and a dispersion of fine, hydrogen producing catalyst, and a counterelectrode in aqueous electrolyte; illuminating the coated electrode with solar energy; photolysing water to produce hydrogen gas; and collecting said gas.
Claim 27
Independent Claim
67 words
A method of photolysing water comprising placing an electrode comprising a solid semiconductor having a band gap below 2.0 eV coated with a film of polyquaternary, bipyridyl polymer containing cross-links between unsaturated groups on different chains and a dispersion of fine, hydrogen producing catalyst, and a counterelectrode in aqueous electrolyte; illuminating the coated electrode with solar energy; photolysing water to produce hydrogen gas; and collecting said gas.
References Cited (Backward Citations)
US4379740A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-11-07 | 1987-05-09 | 1987-11-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-11-07 | 1991-05-09 | 1991-11-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-11-07 | 1995-05-09 | 1995-11-08 | $7700.00 | Window Closed / Lapsed |