EP0040897A1 - Process for electrode fabrication having a uniformly distributed catalyst layer upon a porous substrate - Google Patents
Process for electrode fabrication having a uniformly distributed catalyst layer upon a porous substrate Download PDFInfo
- Publication number
- EP0040897A1 EP0040897A1 EP81300306A EP81300306A EP0040897A1 EP 0040897 A1 EP0040897 A1 EP 0040897A1 EP 81300306 A EP81300306 A EP 81300306A EP 81300306 A EP81300306 A EP 81300306A EP 0040897 A1 EP0040897 A1 EP 0040897A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- substrate
- sulfur dioxide
- solution
- electrode
- palladium
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Ceased
Links
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/042—Electrodes formed of a single material
- C25B11/043—Carbon, e.g. diamond or graphene
- C25B11/044—Impregnation of carbon
Definitions
- This invention relates to a process for preparing electrodes for the anodic oxidation of sulfur dioxide and of the type in which and a platinum group metal- containing catalyst solution is coated onto a high-surface-area porous substrate and dried thus forming a -film on the substrate surface.
- the present invention resides in a process for preparing electrodes for the anodic oxidation of sulfur dioxide and of the type in which a platinum group metal containing catalyst solution is coated onto a high-surface-area porous substrate and dried, thus forming a film on the substrate surface, characterized by:
- a pressure differential of 100-100 milli-meters of. mercury is applied across the substrate and the latter is radiantly heated.
- the sulfur cycle hydrogen generation system of Fig. 1 is a typical use of the sulfur dioxide oxidation electrode of this invention.
- an electrolyzer 1 contains an aqueous solution of sulfuric acid 2 which is saturated with 50 2 .
- Direct current is applied to the solution through an anode 3 (made by the process described herein) and a cathode 4.
- Sulfuric acid and hydrogen gas are generated at the anode 3 and the cathode 4, respectively.
- Inlets 5 and 6 are provided for the addition of more dilute sulfuric acid and additional sulfur dioxide.
- the hydrogen product leaves by outlet 7 where it separates from the sulfuric acid. Unconsumed sulfur dioxide leaves by outlet 8 with the more concentrated sulfuric acid solution, and both are recycled.
- a portion of the sulfuric acid from outlet 8 passes to vaporizer 9 where water is evaporated and its concentration is increased.
- the concentrated sulfuric acid then passes to oxygen generator 10 where the sulfuric acid is heated over a catalyst, for example, of platinum or vanadium pentoxide, to decompose it into water, sulfur dioxide, and oxygen which pass to oxygen recovery unit 11.
- a catalyst for example, of platinum or vanadium pentoxide
- oxygen recovery unit 11 the sulfur dioxide is separated from the oxygen by lowering the temperature to condense the sulfur dioxide into a liquid.
- the sulfur dioxide and the water are then returned to inlet 6 of the electrolytic cell 1, thus completing the cycle.
- a hydrogen-ion-permeable membrane 12 separates the fluid around the anode 3 from the fluid around the cathode 4.
- Fig. 6 The appearance and microstructures of a typical carbon (plate) substrate are illustrated in Fig. 6. These inexpensive carbon substrates provide good porosity, electrical conductivity and mechanical strength. While anodes of carbon (graphite) catalyzed with fine platinum particles -have been used for preparation of sulfuric acid from sulfur dioxide, commercially available platinum-coated carbon electrodes have been found to have an extremely non-uniform coating of platinum. All such electrodes had, as shown in Fig. 5, areas which were clearly uncoated.
- a five by five centimeter porous carbon substrate (mean pore size approximately nine microns) was activated by oxidation in a concentrated nitric acid (13.5 normal at 80°C) .
- the oxidized carbon substrate 13 was mounted (as shown in Fig. 3) in a lucite holder 14 using a seal around the perimeter of the substrate. The substrate was then positioned in a horizontal plane with its underside exposed to a cavity 18 that was connected to a vacuum pump.
- the palladium-covered carbon substrate prepared as above is further treated, for example, at a temperature of 400-500°C in a stream of helium gas containing 5% oxygen.
- Fig. 4 also illustrates the use of a positive pressure cavity 22 (as opposed to the vacuum cavity of Fig. 3) as a means for applying the pressure differential across the substrate 13.
- a positive pressure cavity 22 as opposed to the vacuum cavity of Fig. 3
- the pressure could be applied by a pump directly to the coating solution (thus the pressure chamber 22 would be completely filled with fluid) or by using sufficient depth of solution to provide the pressure hydrostatically. Neither of these techniques, however, lend themselves to radiant heating from the side to which the solution is applied and thus the arrangement of Fig. 3 is preferred.
- the differential pressure should be less than about 100 millimeters of mercury if carbon substrates are used to avoid damage to the substrate.
- a differential pressure of 10-30 millimeters of mercury is used with carbon substrates.
- Other types of substrates e.g. a sub-. strate sintered from finely divided titanium powder
- the upper limit of the pressure differential is determined by the strength of the substrate.
- the palladium or palladium oxide catalyst is preferred (although other platinum group of metals can also be uniformly deposited by the techniques described herein) and palladium is preferably deposited using radiant heating to 40-60°C.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Electrodes For Compound Or Non-Metal Manufacture (AREA)
- Catalysts (AREA)
- Inert Electrodes (AREA)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US15311080A | 1980-05-23 | 1980-05-23 | |
US153110 | 1998-09-15 |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0040897A1 true EP0040897A1 (en) | 1981-12-02 |
Family
ID=22545807
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP81300306A Ceased EP0040897A1 (en) | 1980-05-23 | 1981-01-23 | Process for electrode fabrication having a uniformly distributed catalyst layer upon a porous substrate |
Country Status (7)
Country | Link |
---|---|
EP (1) | EP0040897A1 (pt) |
JP (1) | JPS579889A (pt) |
AU (1) | AU6609981A (pt) |
BR (1) | BR8100253A (pt) |
CA (1) | CA1150231A (pt) |
ES (1) | ES502417A0 (pt) |
ZA (1) | ZA81173B (pt) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0066349A1 (en) * | 1981-06-01 | 1982-12-08 | Westinghouse Electric Corporation | Carbon cloth supported electrode |
EP0092603A1 (en) * | 1982-04-15 | 1983-11-02 | Westinghouse Electric Corporation | Method of making electrodes |
EP0683247A1 (de) * | 1994-05-20 | 1995-11-22 | Bayer Ag | Verfahren zur Herstellung stabiler Graphitkathoden für die Salzsäureelektrolyse |
GB2365023A (en) * | 2000-07-18 | 2002-02-13 | Ionex Ltd | Increasing the surface area of an electrode |
US7238841B2 (en) | 1997-02-28 | 2007-07-03 | E. I. Du Pont De Nemours And Company | Polymer-supported phosphorus ligands for catalysts |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1329153A (en) * | 1970-01-09 | 1973-09-05 | Solvay | Electrodes for electrochemical processes |
DE2002298B2 (de) * | 1970-01-20 | 1973-10-11 | Guenter Dipl.-Chem. 4134 Rheinberg Barthel | Verfahren zur Herstellung von Elektro den fur die technische Wasserelektrolyse |
US3778307A (en) * | 1967-02-10 | 1973-12-11 | Chemnor Corp | Electrode and coating therefor |
US4164457A (en) * | 1977-06-23 | 1979-08-14 | Kernforschungsanlage Julich Gesellschaft Mit Beschrankter Haftung | Method of recovering hydrogen and oxygen from water |
-
1981
- 1981-01-09 AU AU66099/81A patent/AU6609981A/en not_active Abandoned
- 1981-01-12 ZA ZA00810173A patent/ZA81173B/xx unknown
- 1981-01-13 CA CA000368368A patent/CA1150231A/en not_active Expired
- 1981-01-16 BR BR8100253A patent/BR8100253A/pt unknown
- 1981-01-23 EP EP81300306A patent/EP0040897A1/en not_active Ceased
- 1981-01-23 JP JP809781A patent/JPS579889A/ja active Pending
- 1981-05-22 ES ES502417A patent/ES502417A0/es active Granted
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3778307A (en) * | 1967-02-10 | 1973-12-11 | Chemnor Corp | Electrode and coating therefor |
GB1329153A (en) * | 1970-01-09 | 1973-09-05 | Solvay | Electrodes for electrochemical processes |
DE2002298B2 (de) * | 1970-01-20 | 1973-10-11 | Guenter Dipl.-Chem. 4134 Rheinberg Barthel | Verfahren zur Herstellung von Elektro den fur die technische Wasserelektrolyse |
US4164457A (en) * | 1977-06-23 | 1979-08-14 | Kernforschungsanlage Julich Gesellschaft Mit Beschrankter Haftung | Method of recovering hydrogen and oxygen from water |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0066349A1 (en) * | 1981-06-01 | 1982-12-08 | Westinghouse Electric Corporation | Carbon cloth supported electrode |
EP0092603A1 (en) * | 1982-04-15 | 1983-11-02 | Westinghouse Electric Corporation | Method of making electrodes |
EP0683247A1 (de) * | 1994-05-20 | 1995-11-22 | Bayer Ag | Verfahren zur Herstellung stabiler Graphitkathoden für die Salzsäureelektrolyse |
US5575985A (en) * | 1994-05-20 | 1996-11-19 | Bayer Aktiengesellschaft | Preparation of stable graphite |
CN1052038C (zh) * | 1994-05-20 | 2000-05-03 | 拜尔公司 | 适于在电解过程中作为阴极的石墨体的制备方法 |
US7238841B2 (en) | 1997-02-28 | 2007-07-03 | E. I. Du Pont De Nemours And Company | Polymer-supported phosphorus ligands for catalysts |
GB2365023A (en) * | 2000-07-18 | 2002-02-13 | Ionex Ltd | Increasing the surface area of an electrode |
GB2365023B (en) * | 2000-07-18 | 2002-08-21 | Ionex Ltd | A process for improving an electrode |
Also Published As
Publication number | Publication date |
---|---|
BR8100253A (pt) | 1982-01-12 |
ES8300878A1 (es) | 1982-11-01 |
AU6609981A (en) | 1981-11-26 |
ZA81173B (en) | 1982-04-28 |
CA1150231A (en) | 1983-07-19 |
JPS579889A (en) | 1982-01-19 |
ES502417A0 (es) | 1982-11-01 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
AK | Designated contracting states |
Designated state(s): BE CH DE FR GB IT LI NL SE |
|
17P | Request for examination filed |
Effective date: 19820601 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN REFUSED |
|
18R | Application refused |
Effective date: 19840604 |
|
RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: WEN-TONG, PETER LU |