Abstract: Chlorine is generated by electrolyzing aqueous alkali metal chloride in a cell wherein the anode and cathode are separated by and in contact with an ion exchange diaphragm and wherein the anode and/or cathode contains particles of an electroconductive catalytic material along with particles of an electroconductive extender bonded to the membrane.

Abstract: A process for fabricating a unitary membrane-electrode structure by attaching an electrode to a permselective membrane while the latter is in a non-hydrated (and essentially non-dissociated) form. The electrode, in the form of a bonded aggregate of catalytic and polymeric binder particles, is attached to a membrane having less than 0.01 grams of matrix water per gram of dry membrane by the application of heat and pressure. The membrane is then hydrated causing the membrane to swell by a controlled amount and converting it to the dissociated form. A membrane-electrode structure fabricated in this manner is particularly useful in the electrolysis of alkali metal halides because it is characterized by improved cathodic current efficiency and by reduced susceptibility to permeation of gaseous hydrogen.

Abstract: A halogen, such as chlorine, is generated by electrolysis of an aqueous solution of an alkali metal halide such as sodium chloride, in a cell having anolyte and catholyte chambers separated by a solid polymer electrolyte in the form of a stable, selectively cation permeable, ion exchange membrane. One or more catalytic electrodes including at least one thermally stablized, reduced oxide of a platinum group metal are bonded to the surface of the membrane. An aqueous brine solution is brought into contact with the anode and water or an aqueous NaOH solution is brought into contact with the cathode. The brine is electrolyzed to produce chlorine at the anode and hydrogen and caustic at the cathode. The cell membrane preferably has an anion rejecting cathode side barrier layer which rejects hydroxyl ions to block back migration of caustic to the anode thereby enhancing the cathode current efficiency of the cell and of the process.

Abstract: A gas generating apparatus and method is described which utilizes a novel catalytic oxygen evolving electrode for such electrochemical systems as electrolysis cells and oxygen concentration cells. The electrochemical cells include a catalytic cathode and an improved catalytic anode positioned on opposite sides of, and in electrical contact with, a cation exchange membrane. A source of direct current potential between the cathode and the anode and means for removing gas from at least one of the electrodes are provided. The improved catalytic anode is a ternary platinum group reduced metal oxide alone or in combination with platinum group metals and/or platinum group metal oxides or mixtures of the foregoing having at least one valve metal component such as titanium, hafnium, zirconium, niobium, tantalum and tungsten.

Abstract: A halogen, such as chlorine, is generated by electrolysis of an aqueous solution of an alkali metal halide such as sodium chloride, in a cell having anolyte and catholyte chambers separated by a solid polymer electrolyte in the form of a stable, selectively cation permeable, ion exchange membrane. One or more catalytic electrodes including at least one thermally stabilized, reduced oxide of a platinum group metal are bonded to the surface of the membrane. An aqueous brine solution is brought into contact with the anode and water or an aqueous NaOH solution is brought into contact with the cathode. The brine is electrolyzed to produce chlorine at the anode and hydrogen and caustic at the cathode. The cell membrane preferably has an anion rejecting cathode side barrier layer which rejects hydroxyl ions to block back migration of caustic to the anode thereby enhancing the cathode current efficiency of the cell and of the process.

Abstract: A gas generating apparatus and method is described which utilizes a novel catalytic oxygen evolving electrode for such electrochemical systems as electrolysis cells and oxygen concentration cells. The electrochemical cells include a catalytic cathode and an improved catalytic anode positioned on opposite sides of, and in electrical contact with, a cation exchange membrane. A source of direct current potential between the cathode and the anode and means for removing gas from at least one of the electrodes are provided. The improved catalytic anode is a ternary platinum group reduced metal oxide alone or in combination with platinum group metals and/or platinum group metal oxides or mixtures of the foregoing having at least one valve metal component such as titanium, hafnium, zirconium, niobium, tantalum, and tungsten.

Abstract: A gas generating apparatus and method is described which utilizes a novel catalytic oxygen evolving electrode for such electrochemical systems as electrolysis cells and oxygen concentration cells. The electrochemical cells include a catalytic cathode and an improved catalytic anode positioned on opposite sides of, and in electrical contact with, a cation exchange membrane. A source of direct current potential between the cathode and the anode and means for removing gas from at least one of the electrodes are provided. The improved catalytic anode is a ternary platinum group reduced metal oxide alone or in combination with platinum group metals and/or platinum group metal oxides or mixtures of the foregoing having at least one valve metal component such as titanium, hafnium, zirconium, niobium, tantalum and tungsten.

Abstract: A gas generating apparatus and method is described which utilizes a novel catalytic oxygen evolving electrode for such electrochemical systems as electrolysis cells and oxygen concentration cells. The electrochemical cells include a catalytic cathode and an improved catalytic anode positioned on opposite sides of, and in electrical contact with, a cation exchange membrane. A source of direct current potential between the cathode and the anode and means for removing gas from at least one of the electrodes are provided. The improved catalytic anode is a ternary platinum group reduced metal oxide alone or in combination with platinum group metals and/or platinum group metal oxides or mixtures of the foregoing having at least one valve metal component such as titanium, hafnium, zirconium, niobium, tantalum, and tungsten.

Abstract: A halogen, such as chlorine, is generated by electrolysis of an aqueous solution of an alkali metal halide such as sodium chloride, in a cell having anolyte and catholyte chambers separated by a solid polymer electrolyte in the form of a stable, selectively cation permeable, ion exchange membrane. One or more catalytic electrodes including at least one thermally stabilized, reduced oxide of a platinum group metal are bonded to the surface of the membrane. An aqueous brine solution is brought into contact with the anode and water or an aqueous NaOH solution is brought into contact with the cathode. The brine is electrolyzed to produce chlorine at the anode and hydrogen and caustic at the cathode. The cell membrane preferably has an anion rejecting cathode side barrier layer which rejects hyroxyl ions to block back migration of caustic to the anode thereby enhancing the cathode current efficiency of the cell and of the process.

Abstract: A gas generation apparatus is described which utilizes a novel catalytic oxygen evolving electrode for such electrochemical systems as electrolysis and oxygen concentrator cells. The oxygen concentration and the electroylsis cells include a catalytic cathode, an improved catalytic anode containing an active reduced platinoid electrocatalyst containing 5 to 60% ruthenium. The cathode and the novel catalytic anode are positioned on opposite sides of a cation exchange membrane with a source of direct current potential being connected between the two electrodes to concentrate gases such as oxygen or generate gases by an electrolysis process.