A substrate is coated with a solution of metal oxide precursor compounds and an etchant for etching the substrate, the metal oxide precursor compounds are thermally concentrated by removing volatiles therefrom, and the so-concentrated metal oxides precursors are thermally oxidized in-situ on the substrate. The so-formed compositions are useful, e.g., as electrode material in electrochemical apparatuses and processes.

Preparation and use of electrodes

A cathode for use in an electrolytic cell which comprises a metallic substrate, preferably of nickel alloy, and a coating thereon of a mixture of at least one platinum group metal and at least one platinum group metal oxide, the coating comprising from 2% to 30% by weight of platinum group metal. In the electrolysis of water or an aqueous solution eg. an alkali metal chloride solution, the cathode has a low hydrogen over- voltage.

Cathode for use in electrolytic cell

Cathodes comprising a conductive metal substrate, such as a ferrous metal or titanium, having thereon an intermediate protective layer and an overcoating of a mixture of platinum and another noble metal are prepared. These cathodes function in aqueous alkali metal salt solution electrolytic cells or alkali metal halate electrolytic cells to reduce the cathode overvoltage in comparison with conventional ferrous metal electrodes.

Noble metal-coated cathode

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.

Electrode and method of preparing same

The invention relates to a cathode for the electrolytic production of hydrogen. The cathode comprises an active surface consisting of a metal oxide obtained by the thermal decomposition of a thermally decomposable compound of a metal chosen from amongst cobalt, iron, manganese or nickel. The cathode is particularly suitable for the electrolysis of aqueous sodium chloride solutions in cells with a permeable diaphragm.

Cathode for the electrolytic production of hydrogen

An active coating comprised of a mixture of palladium oxide and zirconium dioxide deposited on a metal substrate selected from a group consisting of iron, nickel, cobalt and alloys thereof, results in a lower hydrogen overpotential at the cathode in the electrolysis of aqueous alkali metal halide solutions. Salts of the component metals of the coating are deposited on the cathode surface preferably by painting. The coating metals are then converted to the corresponding metal oxides through the heating of the coating and substrate to 300° to 600° C in an oxidizing atmosphere such as air or oxygen. The coating results in a lowering of the hydrogen discharge overpotential at the cathode surface of about 50 to 100 millivolts as compared with the hydrogen discharge overpotential for the mild steel substrate commonly used as a cathode in electrolysis cells.

James R. Brannan

Papers

Coated cathode for electrolysis cells