SU537125A1 - Electrode for electrolysis of an alkali aqueous solution and method for its manufacture - Google Patents

Description

one

The invention relates to the field of technical electrochemistry, in particular to the manufacture of electrodes for the electrolysis of an aqueous alkali solution.

Electrodes in the form of nickel-plated steel plates or grids 1, which in a number of cases are activated with noble metals 2, are widely used for this process. These electrodes have either low electrochemical activity or high cost.

Electrodes for the electrolysis of an aqueous alkali solution are known, containing a nickel or steel substrate with an active layer in the form of a nkel – ruthenium alloy or a cobalt – ruthenium alloy.

The disadvantages of this electrode are the use of an alloy containing a noble metal, as well as the difficulty of applying galvano coatings of uniform thickness on large-sized electrodes.

The aim of the invention is to create an alkali electrode for electrolysis of an aqueous solution, which has improved electrochemical properties and does not contain a noble metal in the active layer.

This is achieved by using a porous cobalt-nickel-phosphorus alloy applied as an active layer of the electrode.

on a metal substrate by chemical reduction. The development of the alloy surface is carried out by aluminization followed by leaching.

Example. Industrial steel, nickel-plated steel or nickel mesh, used as electrodes in the electrolysis of water, is coated with an alloy of cobalt-nickel-phosphorus in a solution of the following composition, g / l: cobalt chloride 21, nickel chloride 9, sodium hypophosphate 30, sodium citrate 100 , ammonium chloride 50. Deposition of the fusion phase is carried out at 90 ° C, the pH of the solution is 9.5 and maintained during the process by the addition of a 25% ammonia solution. Load density

The items covered in the bath are

0.5 dm2 / l.

The electrode with the precipitated alloy is subjected to aluminization at a temperature of 700-800 ° C for 1-2 hours, followed by leaching in 5 n. KOH solution at 90 ° C for 10 hours. Electrodes made by the proposed

the method was tested in a solution containing 160 g / l of sodium hydroxide at a current density of 9 a / dm and an electrolyte temperature of 70 ° C. Electrochemical activity was evaluated relative to non-activated nickel

electrode. Under comparable conditions, the reduction in the overvoltage of the evolution of hydrogen and oxygen for a known electrode is 0.30 V and for the proposed electrode, respectively, 0.31 and 0.37 V.

The proposed electrode is characterized by a low value of overvoltage of the release of oxygen and hydrogen and can be successfully used in the industrial electrolysis of aqueous solutions of polymers.

Claims (3)

1. Electrode for electrolysis of an aqueous solution of an ielite, containing a metal substrate, mainly nickel, and an active layer deposited on it in the form of an alloy, characterized in that, in order to improve the electrochemical properties of the electrode and its cheapening, a porous alloy of cobalt is used - nickel-phosphorus. 2. A method of manufacturing an electrode according to claim 1 by depositing an active layer in the form of an alloy on a metal substrate, characterized in that, in order to obtain a developed surface, a cobalt-nickel-phosphorus alloy is applied to the electrode substrate by chemical reduction followed by aluminizing and leaching the surface . Sources of information taken into account in the examination: 1. Yakimenko, LM and others. Electrolysis of water, M. Chemistry, 1970, p. 130. 2. The patent of Switzerland No. 340810, cl. 12i 13/04, 1959. 3. Avt. St. No. 328931, cl. At 01k 1/00, 1970.