Asahi Kasei Kogyo Kabushiki Kaisha

Hiroyuki Shiroki

Mitsuo Yoshida

Shinsaku Ogawa

Yasuhide Noaki

An improved hydrogen-evolution electrode having thereon a coating containing an oxide of at least one metal selected from nickel and cobalt and further containing a chromium component in a proportion, in terms of atomic percentage, of 0.5 to 20% has been found to exhibit extremely low hydrogen overvoltage and to have not only high catalytic activity but also high durability. Such a hydrogen-evolution electrode can be produced by melt-spraying onto a substrate a mixture of a powder of at least one member selected from the first group consisting of nickel, cobalt, oxides of nickel and cobalt, hydroxides of nickel and cobalt, organic acid salts of nickel and cobalt and inorganic acid salts of nickel and cobalt and a powder of at least one member selected from the second group consisting of chromium, an oxide of chromium, a hydroxide of chromium, an organic acid salt of chromium and an inorganic acid salt of chromium. In the production, when the above-mentioned mixture is subjected to granulation and the obtained granules are melt-sprayed, there can be obtained the desired electrode having excellent properties with respect to catalytic activity and durability in high spraying yield.

Hydrogen-evolution electrode

A hydrogen-evolution electrode having a coating comprising at least one metal oxide selected from the group consisting of nickel oxide and cobalt oxide and at least one metal selected from the group consisting of nickel and cobalt has been found to exhibit extremely low hydrogen overvoltage and to have not only high catalytic activity but also high durability.

Reducing the content of iodine in an aqueous brine solution to less than 1 ppm prior to electrolysis in an electrolytic cell separated into an anode chamber and a cathode chamber by a cation exchange membrane improves the electrolytic performance thereof.

Electrolysis of sodium chloride with the use of ion exchange membranes

A sodium chloride feed solution containing an iron cyanide complex is subjected to purification to reduce the content of iron cyanide complex to not more than 0.5 ppm before it is fed as anolyte into an ion-exchange membrane electrolytic cell. The iron cyanide complex is preferably converted by oxidative decomposition to iron ions for removal. By use of such a purified sodium chloride as starting material, electrolysis of sodium chloride using an ion-exchange membrane can be performed for a long term at a constant electrolysis voltage.

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Nobeoka, Japan

Hiroyuki Shiroki