The Dow Chemical Company

Charles W Becker

Richard N Beaver

Stephen L Kelly

Richard N Beaver, Deceased

Carl E Byrd, Deceased

Cathodes useful in an electrolytic cell, such as a chlor-alkali cell, are disclosed which have a metallic-surfaced substrate coated with a catalytic coating composition. In one aspect, the catalytic coating includes a base layer of at least one primary electrocatalytic metal with particles of at least one electrocatalytic metal oxide entrapped therein. In another aspect, at least one upper oxide layer is formed on the base layer. Each upper oxide layer includes a substantially heterogeneous mixture of at least one primary electrocatalytic metal oxide and at least one secondary electrocatalytic metal oxide. The catalytic coatings are tightly adherent to the underlying substrate, resist loss during cell operation and exhibit low hydrogen overvoltage potentials. Disclosed are methods for preparing the above-described cathodes. Also disclosed is a method for reducing the hydrogen overvoltage potential of an electrolytic cell by placing an electrocatalytic metal/metal oxide particle coating on a metallic-surfaced cathode.

Electrocatalytic cathodes and methods of preparation

The electrolysis of brine in electrolytic chlor-alkali diaphragm cells is performed using polymeric fluorocarbon-bonded mixtures of chrysotile asbestos and crocidolite asbestos as the diaphragm material. These diaphragms are particularly effective in permitting operation of the cells at low pH, thereby extending the life of graphite anodes.

Brine electrolysis using bonded asbestos diaphragms

Improved asbestos diaphragms for use in electrolytic chlor-alkali cells are prepared by using polymeric fluorocarbons as binders for mixtures of chyrsotile asbestos and crocidolite asbestos.

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Angleton, TX, United States of America

Charles W Becker