Electrode and method of preparing same
AssigneePPG Industries, Inc.
InventorsWilliam W. Carlin, Debra S. Marzec
Life of this patent
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Abstract
Disclosed are electrodes, e.g., cathodes useful for the preparation of alkali metal halates. The electrodes comprise a substrate selected from the group consisting of titanium, steel, copper, nickel and silver and, in one embodiment, a coating of a Group VIII metal oxide selected from the group consisting of ruthenium, cobalt, rhodium, iridium, nickel, palladium and platinum. In a further embodiment, the coating also contains at least one Group IV metal oxide, e.g., titanium and tin.
Claims34
In an electrode having a titanium substrate with a ruthenium containing coating thereon, the improvement wherein said coating is substantially free of deposited titanium and comprises:
- (1) a first oxide layer, deposited on said substrate and comprising a major portion of ruthenium and a minor portion of tin;
- and
- (2) a second oxide layer, atop said first layer, comprising a major portion of ruthenium and minor portions of tin and palladium.
In a bipolar electrolyzer having a plurality of bipolar electrodes, parallel to and spaced from each other, each of said bipolar electrodes comprising a titanium plate having an anodic portion and a coated cathodic portion whereby the cathodic portion of one bipolar electrode faces the anodic portion of a prior bipolar electrode and the anodic portion of the bipolar electrode faces the cathodic portion of a subsequent bipolar electrode, the improvement wherein said cathodic coating is substantially free of deposited titanium and comprises:
- (1) a first oxide layer, deposited on said plate and comprising a major portion of ruthenium and a minor portion of tin;
- and
- (2) a second oxide layer, atop said first layer, comprising a major portion of ruthenium and minor portions of tin and palladium.
In a bipolar electrolyzer having a plurality of anodes extending into the electrolyzer from one end thereof, a plurality of cathodes extending into the electrolyzer from an opposite end thereof, and a plurality of bipolar electrode blades, each of said bipolar electrode blades having a cathodic portion, and an anodic portion, said anodes, cathodes and bipolar electrode blades being mutually parallel, the first group of bipolar electrode blades being arrayed between and parallel to the anodes and having the cathodic portions thereof opposed to the anodes and the anodic portions thereof remote from the anodes, the last group of bipolar electrode blades being arrayed between and parallel to the cathodes and having the anodic portions thereof opposed to the cathodes and the cathodic portions thereof remote from the cathodes, the improvement wherein said bipolar electrode blades comprise:
- (a) a titanium substrate, and
- (b) a coating thereon substantially free of deposited titanium and comprising:
- (1) a first oxide layer, deposited on said substrate and comprising a major portion of ruthenium and a minor portion of tin;
- and
- (2) a second oxide layer, atop said first oxide layer, comprising a major portion of ruthenium and minor portions of tin and palladium.
In a method of electrolyzing alkali metal chloride brine comprising passing electrical current from an anode to a cathode in a common electrolyte, evolving anodic and cathodic products and forming chlorate ion, the improvement wherein said cathode comprises:
- (a) a titanium substrate;
- and
- (b) a coating thereon, substantially free of deposited titanium, comprising:
- (1) a first oxide layer, deposited on said substrate and comprising a major portion of ruthenium and a minor portion of tin;
- and
- (2) a second oxide layer, atop said first oxide layer, comprising a major portion of ruthenium and minor portions of tin and palladium.
A method of preparing an electrode on a titanium substrate comprising:
- (a) depositing a first composition consisting essentially of a solvent, a thermally decomposable ruthenium compound and a thermally decomposable tin compound onto the titanium substrate, and decomposing the ruthenium compound and tin compound in an oxidizing atmosphere, to form a first oxide layer comprising a major portion of ruthenium and a minor portion of tin;
- and
- (b) thereafter depositing a second composition consisting essentially of a solvent, a thermally decomposable ruthenium compound, a thermally decomposable tin compound, and a thermally decomposable palladium compound atop the first oxide layer, and decomposing the ruthenium compound, tin compound, and palladium compound in an oxidizing atmosphere to form a second oxide layer comprising a major portion of ruthenium and minor portions of tin and palladium.
An electrode for an electrolytic cell comprising:
- (a) a substrate selected from the group consisting of titanium, copper, and silver, and
- (b) a coating substantially free of deposited titanium and comprised of a first oxide layer on said substrate of a major amount of ruthenium and a minor amount of tin, and a second oxide layer atop said first layer of a major amount of ruthenium and minor amounts of tin and palladium.
Dependencies are inferred from the claim text.