Claims
- 1. In the photolytic method for producing hydrogen from water by treatment with a reducing species capable of donating electrons to water, the improvement which comprises: conducting the reduction step in the presence of a stabilized and finely dispersed catalyst of particle size no greater than 500 .ANG. which comprises one or more Noble metals in finely divided form in intimate admixture with a water permeable protective agent adsorptive to said metal and selected from the group consisting of:
- (1) a homopolymer derived from an acyclic olefin of 2-3 carbon atoms substituted by hydroxy, carboxy, lower alkyleneoxy or an ester or amide derivative;
- (2) a copolymer derived from the reaction of an aralkene with an unsaturated acyclic dicarboxylic acid or a lower alkylene oxide;
- (3) an hydrocarbyl moiety of 10-20 carbon atoms substituted by one or more polar groups; and
- (4) a polysaccharide.
- 2. The method of claim 1 wherein the Noble metal is one or more of platinum, palladium, rhodium, ruthenium, iridium, osmium, silver or gold and the protective agent is (1) a homopolymer derived from an acyclic olefin of 2-3 carbon atoms substituted by hydroxy, carboxy or an ester or amide derivative thereof; (2) a copolymer derived from the reaction of an aralkene with an unsaturated acyclic dicarboxylic acid of 4-6 carbon atoms or a lower alkylene oxide; (3) a hydrocarbyl of 14-18 carbon atoms substituted by tri-lower alkylammonium halide; or (4) a hydroxy alkylcellulose.
- 3. The method of claim 1 wherein the protective agent is polyvinyl alcohol, a polyacrylic acid ester or polyacrylic acid amide; the copolymer derived from the reaction of an aralkene with a lower alphatic unsaturated dicarboxylic acid or lower alkylene oxide; an alkyl tri-lower alkylammonium halide; or hydroxy lower alkylcellulose.
- 4. The method of claim 1 wherein the protective agent is polyvinyl alcohol, polyacrylic acid hydrazide or cetyltrimethylammonium halide.
- 5. The method of claim 1 wherein the Noble metal is platinum or palladium and the protective agent is polyvinyl alcohol or polyacrylic acid hydrazide.
- 6. The method of claim 1 wherein the metal is platinum.
- 7. The method of claim 1 wherein the metal is platinum and the protective agent is one or more of polyvinyl alcohol; a copolymer derived from the reaction of styrene with a lower aliphatic unsaturated dicarboxylic acid or lower alkylene oxide; an alkyl tri-lower alkylammonium halide; or hydroxy-lower alkylcellulose.
- 8. The method of claim 1 wherein the metal is platinum and the protective agent is polyvinyl alcohol; a copolymer derived from the reaction of styrene with maleic anhydride or hydroxy-lower alkylcellulose.
- 9. The method of claim 1 wherein the metal is colloidal platinum or colloidal palladium and the protective agent is polyvinyl alcohol or a copolymer derived from the reaction of styrene with maleic anhydride.
- 10. The method of claim 1 wherein the metal is colloidal platinum and the protective agent is a copolymer of styrene and maleic anhydride.
- 11. The method of claim 1 wherein the catalyst is a polyvinyl alcohol stabilized platinum catalyst.
- 12. A method for the photolytic production of hydrogen from water which comprises:
- subjecting an aqueous solution containing photosensitizer to irradiation with light from the visible region of the spectrum to afford an excited state of the photosensitizer molecule; and
- contacting said excited state photosensitizer with an electron acceptor to afford a reduced acceptor species which, in said aqueous solution in the presence of an electron donor and a stabilized metal catalyst in colloidal form, reduces water to form hydrogen gas; said catalyst comprising a Noble metal dispersed in said aqueous solution in finely divided form of no greater than 500 .ANG. diameter particle size admixed with a water permeable protective agent selected from the group consisting of (1) a homopolymer derived from an acyclic olefin of 2-3 carbon atoms substituted by hydroxy, carboxy or lower alkyleneoxy or an ester, amide, or acid addition salt thereof; (2) a copolymer derived from the reaction of an aralkene with an unsaturated acyclic dicarboxylic acid or with a lower alkylene oxide; or (3) an hydrocarbyl moiety of 10-20 carbon atoms substituted by one or more polar groups; and (4) a polysaccharide.
- 13. The method of claim 12 wherein said Noble metal is platinum, palladium, rhodium, ruthenium, iridium, osmium, silver or gold or mixtures thereof; and the protective agent is (1) a homopolymer derived from an acyclic olefin of 2-3 carbon atoms substituted by hydroxy, carboxy or an ester of amide derivative thereof; (2) a copolymer derived from the reaction of an aralkene with an unsaturated acyclic dicarboxylic acid of 4-6 carbon atoms or a lower alkylene oxide; (3) an hydrocarbyl of 14-18 carbon atoms substituted by tri-lower alkylammonium halide; or (4) a hydroxy-alkylcellulose.
- 14. The method of claim 12 wherein the protective agent is polyvinyl alcohol, a polyacrylic acid ester or polyacrylic acid amide; a copolymer derived from the reaction of an aralkene with a lower aliphatic unsaturated dicarboxylic acid or lower alkylene oxide; an alkyl tri-lower alkylammonium halide; or hydroxy-lower alkylcellulose.
- 15. The method of claim 12 wherein the protective agent is polyvinyl alcohol, polyacrylic acid hydrazide or cetyltrimethylammonium halide.
- 16. The method of claim 12 wherein the Noble metal in colloidal form is selected from among platinum or palladium and the protective agent is polyvinyl alcohol or polyacrylic acid hydrazide.
- 17. The method of claim 12 wherein the metal is platinum.
- 18. The method of claim 12 wherein the metal is platinum and the protective agent is polyvinyl alcohol; a copolymer derived from the reaction of styrene with a lower aliphatic unsaturated dicarboxylic acid or lower alkylene oxide; an alkyl tri-lower alkylammonium halide; or hydroxy-lower alkylcellulose.
- 19. The method of claim 12 wherein the metal is platinum and the protective agent is polyvinyl alcohol; a copolymer derived from the reaction of styrene with maleic anhydride; or hydroxy-lower alkylcellulose.
Priority Claims (2)
Number |
Date |
Country |
Kind |
7931250 |
Sep 1979 |
GBX |
|
8022338 |
Jul 1980 |
GBX |
|
Parent Case Info
This is a division of application Ser. No. 06/184,673, filed Sept. 5, 1980, now U.S. Pat. No. 4,394,293.
Non-Patent Literature Citations (1)
Entry |
C & E News, Aug. 1, 1977, pp. 15-16. |
Divisions (1)
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Number |
Date |
Country |
Parent |
184673 |
Sep 1980 |
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