SU715646A1 - Method of manufacturing porous electrode for electrochemical processes - Google Patents

Description

The invention relates to the field of the electrochemical production of hydrogen, in particular, to the methods of preparing and preparing the electrodes used in electrolyzers for an electrolysis device for water or aqueous solutions of salt.

A known method for producing electrodes with reduced overvoltage of hydrogen evolution by applying a Ni-W alloy on the surface of the Ni-coated electrode 1.

The disadvantage of this method is that the obtained electrodes have a relatively high suppression of hydrogen evolution.

There is also known a method for producing active electrodes, comprising

in that the base metal is nano- with a catalytically inactive meta.ll, the bimetal is heated to -; Increasing mutual diffusion, and then coating metal 2 .V is leached from the resulting surface alloy.

On nickel electrodes obtained by this method at 20 ° C and a current density of 2000 A / m, the tendency for hydrogen evolution from a 30% KOH solution is fr -0,250 V, relative to

hydrogen electrode (p. -v, -e,), and at a current density of 2000 A / m and 70 ° C, fr -0.148 V, OVE, t; e. the overvoltage of hydrogen evolution on the electrodes obtained in this way is also quite large, which is a disadvantage of the known electrode.

The purpose of the invention is to reduce the overpotential of hydrogen evolution.

The goal is achieved. after treatment of the surface nickel alloy with an alkali solution, the electrode is subjected to cadmium plating.

A catalytically inactive metal is deposited on a nickel base, the bimetal obtained is heated to increase interdiffusion, a metal is catalytically leached from the formed surface alloy, then the electrode is washed and metallic cadmium is deposited, for example, by electroplating, in an amount of 0.9-10 mg . on 1 cm of the VISIBLE surface.

The method is carried out as follows.

On the surface of nickel foil. (100 mkm), pre-degreased and purified by known methods, electroplated zinc

(30 microns). Next, the electrode is heat treated for four hours in air at and leached at 40 ° C until the gassing stops. The obtained electrode is washed with water and electroplated by applying cadmium and calculating 4 mg of Cd per 1 s of the visible surface.

Electrodes are tested as cathodes during electrolysis of a 6 M KOH solution. With the potential power of hydrogen, the current density of A / m is Chr -0.116 V (o.e.), and at 70 ° C it is -0.050 V. The resulting electrode operates under a load of 200 mA / cm for more than 350 hours with almost no field floor settings,

Thus, the proposed method of electroplating can reduce the cationic potential of hydrogen evolution under conditions close to the conditions of water electrolysis, by 134 MB. In addition, the electrodes are nonpyrophic and can be stored in a dry form.

Claims (1)

Invention Formula A method of manufacturing a porous electrode for electrochemical processes, comprising obtaining a nickel surface alloy on a nickel base with a catalytically inactive metal, followed by leaching of the latter, which is different. By that, with the aim of reducing the overpotential of hydrogen evolution, the electrode is added to the electrode. It is covered with 0.9 1-0 mg metal cadmium per 1 see the visible surface of the electrode. 5 Sources. Information, taken into account in the examination 1, USSR SSR certificate of authorship No. 425980, cl. From 25V 11 / 00.30.04,74. 20 ; ., -; . / 2, USSR author's certificate No. 206094, cl. C 22 V 31/00, 10/17/66 (prototype.).