EP0046447A1
Expired / Lapsed
EP
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Electrode with electrocatalytic surface and method of manufacture
Assignee: De Nora SpA
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Filing: 1981-08-11
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Granted: —
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Expires: 2001-08-11
Abstract
Abstract An electrode for use in electrolytic processes comprises a base of film-forming metal such as titanium with an operative outer electrocatalytic surface which is an integral surface film of a compound of the titanium base, usually the oxide, incorporating a platinum-group metal electrocatalyst, preferably iridium, rhodium, palladium and/or ruthenium as metal or oxide. The surface film is formed by the application of a dilute solution of a thermodecomposable iridium, rhodium and/or ruthenium compound containing an agent such as HC1 which attacks the titanium base and converts metal from the base into ions which are converted to the compound in a subsequent heating step. The concentrations of this agent and of the thermodecomposable compound and the number of applied layers are such that during heating the electrocatalyst formed from the decomposed compound is incorporated fully in the surface film formed from the base. The base is usually in sheet form, but may also be a powder.
Inventors
- 👤 Henri B. Beer
- 👤 Jean M. Hinden
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 06:59
CPC Classifications
C; C25; C25C; C25C7/00; C25C7/02; C25B; C25B11/00; C25B11/04; C25B11/051; C25B11/073; C25B11/091; C25B11/093
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
195 words
An electrode for use in electrolytic processes comprising a base of film-forming metal with an operative electrocatalytic outer surface formed as an integral surface film of the film-forming metal base incorporating therein a platinum-group metal or compound thereof as electrocatalyst, characterized in that said electrocatalytic outer surface is formed by applying to the surface of the film-forming metal base at least one layer of a solution of at least one thermodecomposable compound of a platinum-group metal, drying and heating each applied layer to decompose said compound(s) in a similar manner to methods known per se for the formation of platinum-group metal and platinum-group metal oxide coatings, wherein said solution contains an agent which attacks the film-forming metal base and converts metal from the base into ions which are converted into a compound of the film-forming metal during the heating step, the concentration of said agent and of the platinum-group metal compound(s) in the solution and the number of applied layers being such that during the heating of each layer including the last one the electrocatalyst formed from the decomposed compound is incorporated fully in the surface film of film-forming metal compound formed from the base.
Claim 2
Dependent Claim
195 words
An electrode for use in electrolytic processes comprising a base of film-forming metal with an operative electrocatalytic outer surface formed as an integral surface film of the film-forming metal base incorporating therein a platinum-group metal or compound thereof as electrocatalyst, characterized in that said electrocatalytic outer surface is formed by applying to the surface of the film-forming metal base at least one layer of a solution of at least one thermodecomposable compound of a platinum-group metal, drying and heating each applied layer to decompose said compound(s) in a similar manner to methods known per se for the formation of platinum-group metal and platinum-group metal oxide coatings, wherein said solution contains an agent which attacks the film-forming metal base and converts metal from the base into ions which are converted into a compound of the film-forming metal during the heating step, the concentration of said agent and of the platinum-group metal compound(s) in the solution and the number of applied layers being such that during the heating of each layer including the last one the electrocatalyst formed from the decomposed compound is incorporated fully in the surface film of film-forming metal compound formed from the base.
Claim 3
Dependent Claim
17 words
The electrode of claim 1, wherein the surface film of the film-forming metal base consists of oxide.
Claim 4
Dependent Claim
21 words
The electrode of claim 1, wherein the surface film of the film-forming metal base consists of carbide, nitride, hydride or boride.
Claim 5
Dependent Claim
38 words
The electrode of claim 1, 2 or 3, wherein the electrode base is sheet-like and the surface film contains up to 0.5 g/m 2 , as metal, of the electrocatalyst per projected surface area of the electrode base.
Claim 6
Dependent Claim
19 words
The electrode of claim 1, 2 or 3, wherein said film contains iridium and/or rhodium as metal or oxide.
Claim 7
Dependent Claim
35 words
The electrode of claim 1, 2 or 3, wherein said film contains (a) iridium and/or rhodium and (b) ruthenium as metals or oxides in a metal weight ratio (a):(b) of from 4:1 to 1:4, ;,
Claim 8
Dependent Claim
17 words
The electrode of claim 1,,2, 3, 5 or 6, wherein the electrode base is formed of particles.
Claim 9
Dependent Claim
33 words
An electrode for use in electrolytic processes comprising particles of a film-forming metal each having an integral electrocatalytic and electroconductive surface film of oxide of the film-forming metal containing a platinum-group metal electrocatalyst.
Claim 10
Dependent Claim
33 words
An electrode for use in electrolytic processes comprising particles of a film-forming metal each having an integral electrocatalytic and electroconductive surface film of oxide of the film-forming metal containing a platinum-group metal electrocatalyst.
Claim 11
Dependent Claim
16 words
The electrode of claim 7 or 8, wherein said particles are supported on a conductive support.
Claim 12
Dependent Claim
16 words
The electrode of claim 7 or 8, wherein said particles are associated with a current feeder.
Claim 13
Independent Claim
191 words
A method of forming an electrode for use in electrolytic processes comprising a base of film-forming metal with an operative electrocatalytic outer surface formed as an integral surface film of the film-forming metal base incorporating therein a platinum-group metal or compound thereof as electrocatalyst, characterized by applying to the surface of the film-forming metal base at least one layer of a solution of at least one thermodecomposable compound of a platinum-group metal, drying and heating each applied layer to decompose said compound(s) in a similar manner to methods known per se for the formation of platinum-group metal and platinum-group metal oxide coatings, wherein said solution contains an agent which attacks the film-forming metal base and converts metal from the base into ions which are converted into a compound of the film-forming metal during the heating step, the concentration of said agent and of the platinum-group metal compound(s) in the solution and the number of applied layers being such that during the heating of each layer including the last one the electrocatalyst formed from the decomposed compound is incorporated fully in the surface film of film-forming metal compound formed from the base.
Claim 14
Independent Claim
191 words
A method of forming an electrode for use in electrolytic processes comprising a base of film-forming metal with an operative electrocatalytic outer surface formed as an integral surface film of the film-forming metal base incorporating therein a platinum-group metal or compound thereof as electrocatalyst, characterized by applying to the surface of the film-forming metal base at least one layer of a solution of at least one thermodecomposable compound of a platinum-group metal, drying and heating each applied layer to decompose said compound(s) in a similar manner to methods known per se for the formation of platinum-group metal and platinum-group metal oxide coatings, wherein said solution contains an agent which attacks the film-forming metal base and converts metal from the base into ions which are converted into a compound of the film-forming metal during the heating step, the concentration of said agent and of the platinum-group metal compound(s) in the solution and the number of applied layers being such that during the heating of each layer including the last one the electrocatalyst formed from the decomposed compound is incorporated fully in the surface film of film-forming metal compound formed from the base.
Claim 15
Dependent Claim
41 words
12, The method of claim 11, wherein the electrode base is sheet-like and each applied layer of the solution contains up to 0,2 g/m 2 as metal of iridium, rhodium and/or ruthenium compound per projected surface area of the electrode base.
Claim 16
Dependent Claim
31 words
The method of claim 11 or 12, wherein the solution contains compounds of (a) indium and/or rhodium and (b) ruthenium in a metal weight ratio (a):(b) of from 4:1 to 1:4.
Claim 17
Dependent Claim
42 words
The method of claim 12, wherein from 2 to 5 layers of the solution are applied, each followed by heating to between about 400°C to 600°C for about 5 to 15 minutes, the final layer possibly being heated for a longer period.
Claim 18
Dependent Claim
28 words
The method of claim 14, wherein the final surface film contains up to 0.5 g/m2 as metal of the electrocatalyst per projected surface area of the electrode base.
Claim 19
Dependent Claim
24 words
The method of claim 11, wherein the solution contains said agent and said platinum-group metal compound in a molar ratio from 1:1 to 100:1.
Claim 20
Dependent Claim
15 words
The method of claim 16, wherein said molar ratio is selected between 3:1 and 30:1.
Claim 21
Independent Claim
18 words
The method of any one of claims 11, 13, 16 or 17, wherein the electrode base is particulate.
Claim 22
Dependent Claim
28 words
The method of claim 18, wherein the drying step is carried out in at least two separate stages to drive off all solvent from the particulate film-forming metal.
Claim 23
Dependent Claim
22 words
The method of claim 18 or 19, comprising the further step of applying the surface-activated particulate film-forming metal onto a conductive support.
Claim 24
Dependent Claim
28 words
21, The method of any one of claims 11 to 20, wherein the heating is carried out in air to form a surface film of film-forming metal oxide,
Claim 25
Independent Claim
38 words
The method of any one of claims 11 to 20, wherein the heating is carried out in a carbon, nitrogen, hydrogen or boron-containing non-oxidizing atmosphere to form a surface film of film-forming metal carbide, nitride, hydride or boride.
References Cited (Backward Citations)
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