Abstract: A method of operating an electrolytic cell in which cathodic hydrogen formation is suppressed by contacting the catalytic cathode with air or other oxygen-containing gas. The cells are of two types: (1) those in which a membrane is present as a distinct body to seperate the anode from the catalytic cathode; and (2) those in which the catalytic cathode and membrane are in combination as a single body; both of which types contain an ion permeable membrane to divide the said cell into an anolyte zone containing aqueous anolyte and a catholyte zone containing aqueous catholyte and a catalyst. The method of this invention provides for passing current through said anolyte and said catholyte while contacting said catalyst with an oxygen-containing gas to eliminate the formation of hydrogen gas. When alkali metal halide solutions are employed, halogen gas is evolved at the anode and alkali metal hydroxide is produced at the cathode.