ADVANCED LOW HYDROGEN OVERVOLTAGE CATHODE FOR CHLOR-ALKALI ELECTROLYSIS CELLS

An advanced low hydrogen overvoltage cathode has been developed for use in chlor-qalkali electrolysis cells. The cathode is made by composite-coating a novel ternary Raney nickel electrocatalyst on a variety of substrates. The results of many performance tests in laboratory cells as well as commercial calls are reported. The cathode exhibits a low hydrogen overvoltage (50-70 mV at 90 degree C, at 30 A dm** minus **2 in a 35 wt% NaOH), excellent stability under cell short-circuiting conditions and a considerably long cathode life, up to the present four years in commercial plants. The excellent stability of the cathode against cell shutdown conditions has been discussed.