Abstract: A gas-diffusion electrode (cathode) in contact with an ion-exchange membrane partitioning an electrolytic cell for producing caustic soda, etc., by electrolysis into an anode chamber and a cathode chamber (gas chamber). The gas-diffusion electrode is divided into plural electrode members in the horizontal direction with an interval provided between adjacent electrode members. Electrolyte guide plates may be disposed on the electrode members or between the adjacent electrode members. An aqueous caustic soda solution formed in the electrolysis smoothly is removed from the gas-diffusion electrode without clogging the electrode.

Abstract: An electrode for electrolysis comprising an electrode base material and an electrode substance having an electrically conductive diamond structure covering the surface of the electrode base material. The electrode substance having an electrically conductive diamond structure may be a diamond containing an impurity selected from boron, phosphorus and graphite. Alternatively, the electrode substance having an electrically conductive diamond structure may comprise a composite of a diamond and an electrically conductive material. In a preferred embodiment, the electrode further comprises an interlayer comprising at least one of the carbide of a valve metal and silicon carbide disposed between the electrode base material and the electrode substance having an electrically conductive diamond structure. Also disclosed is an electrolytic cell having two chambers including an anode chamber and a cathode chamber partitioned by an ion-exchange membrane.

Abstract: A gas-diffusion cathode disposed in contact with an ion-exchange membrane partitioning an electrolytic cell into an anode chamber and a cathode chamber, wherein at least one guide piece is disposed in the gas-diffusion cathode and a salt water electrolytic cell using the above-described gas-diffusion cathode. By using the above-described gas-diffusion cathode for salt water electrolysis, an aqueous caustic alkali solution formed descending in the direction of gravity in the cathode changes direction of movement by contact with a guide piece, whereby the decreased electrode performance resulting from the hindrance of the supply of raw material gas and the discharge of the gas formed caused by the retention of the descending caustic alkali solution is prevented and a large-sized electrolytic cell can be used without problems generally encountered in conventional electrolytic systems.

Abstract: A liquid-permeable gas-diffusion cathode adapted for caustic soda electrolysis in contact with an ion-exchange membrane partitioning an electrolytic cell into an anode chamber and a cathode gas chamber. Plural horizontal concave grooves and/or convex portions are provided in an interval with one another on the surface of the gas-diffusion cathode facing the gas chamber. Plural vertical concave grooves may also be provided in an interval on the surface of the cathode crossing the horizontal grooves and/or convex portions. Aqueous caustic soda solution thus formed flows downward along the grooves, etc., without covering other portions of the cathode surface, and is easily released therefrom without clogging perforations in the gas-diffusion layer of the cathode.

Abstract: An electrolytic cell for producing sodium hydroxide, etc., which is partitioned by an ion-exchange membrane into an anode chamber and a cathode chamber, wherein at least one of a anode and a cathode is closely contacted to the ion-exchange membrane to form a gas diffusion electrode, and a current supplying means having guides for removing sodium hydroxide, etc., formed at the surface of the gas diffusion electrode is disposed therein closely contacting the gas diffusion electrode.By having a current supplying means having removing guides, sodium hydroxide formed at the surface of the gas diffusion electrode is separated therefrom and removed, whereby the supply of the raw material gas and removal of the produced gas can be smoothly performed without clogging perforations of the gas diffusion electrode with the sodium hydroxide.

Abstract: A method of producing a gas diffusion electrode by forming a thin layer comprising a carbon power and a silver powder on the surface of a substrate comprising silver, copper, nickel or stainless steel and fluorinating the thin layer make the carbon water repellent.The gas diffusion electrode can be stably used for a long period of time in sodium chloride electrolysis, etc., without clogging the passage of gas and lowering the water repellency of the electrode.

Abstract: A gas diffusion electrode is constituted by forming a porous layer comprising a super-fine particle catalyst of silver or gold and a fluorine-containing material on a substrate and connecting a gas-liquid permeable collector to the substrate.The gas diffusion electrode can be used stably as an oxygen cathode for a sodium chloride electrolysis, etc., for a long period of time without causing decreased water repellency of the fluorine-containing material in the gas diffusion electrode and without lowering the activity of the electrode substance.

Abstract: A salt water electrolysis process for electrolyzing an aqueous alkali chloride solution capable of preventing the deterioration of a gas diffusion cathode is disclosed. A cation-exchange membrane having closely disposed to one surface thereof an insoluble metal anode and having closely adhered or mechanically attached to the opposite surface thereof a liquid permeable gas diffusion cathode is disposed in an electrolytic cell, and electrolysis is carried out while supplying salt water to the anode chamber and an oxygen-containing gas containing water as steam or fine water droplets to the cathode chamber, and an alkali hydroxide is obtained from the cathode chamber. The water-containing gas directly reaches the gas diffusion cathode and since the alkali hydroxide and the alkali carbonate formed at the surface of the cathode are dissolved in the water in the gas and removed from the electrolytic cell, deterioration of the gas diffusion cathode can be prevented.

Abstract: The present invention relates to an electrolytic electrode comprising a core material made of a valve metal, a dense electrically conductive tin oxide layer formed on the core material, an .alpha.-lead dioxide layer formed on the tin oxide layer, and a .beta.-lead dioxide layer formed on the .alpha.-lead dioxide layer. The present invention also relates to a method for preparing the electrolytic electrode.

Abstract: An electrolytic cell for obtaining a caustic alkali by closely contacting a gas diffusion electrode comprising a gas-liquid permeable metal substrate and a gas-liquid permeable collector connected to the substrate to a cation-exchange membrane while supplying an oxygen-containing gas from the opposite side of the cation-exchange membrane. Grooves for taking out a liquid containing a caustic alkali are formed in the contact surface of the gas diffusion electrode with the cation-exchange membrane.By the formation of the grooves, clogging of the perforations of the gas diffusion electrode with the caustic alkali so formed is prevented, whereby the gas supply can be smoothly carried out and the electrolysis can be stably carried out without reducing the cell voltage.

Abstract: An electrode structure containing an insoluble metal electrode which is used as an electrode for the electrolysis of an acidic aqueous solution under a high current density is disclosed. An elastic electroconductive material, containing an expanded metal, having formed thereon a corrosion-resistant electroconductive coating, is disposed between an electroconductive electrode substrate and an electrode having on the surface thereof a coating of an electrode material. They are fixed by a detachable fixing device from the surface of the electrode. The electrode can be exchanged when fixing the electrode structure to the electrolytic cell.

Abstract: An electrolytic ozone generator comprising anode chamber 3 and cathode chamber 4 partitioned by solid electrolyte 2, in which deionized water is electrolyzed in the cathode chamber while feeding air or oxygen-rich air to the cathode chamber through, for example, air holes 14. The air fed suppresses evolution of hydrogen gas thereby affording a saving of energy and eliminating the need a separate cooling mechanism. Furthermore, the air also decomposes ozone having entered the catholyte.

Abstract: A method and apparatus for water electrolysis is described, using an electrolytic cell comprising an anode compartment, a cathode compartment, and a diaphragm separating the anode and cathode compartments, comprising the steps of electrolyzing water to evolve oxygen or an ozone-containing oxygen gas in the anode compartment and hydrogen in the cathode compartment, thereby resulting in a net transfer of electrolyte from the anode compartment to the cathode compartment through the diaphragm, and recycling electrolyte from the cathode compartment to the anode compartment.

Abstract: A gas diffusion electrode comprisinga porous sheet substrate, at least the surface of which is formed by silver;a reaction layer formed on a first surface of the substrate, comprising a porous silver layer and a mixed layer further comprising a hydrophilic material and a hydrophobic material, the mixed layer being formed on a surface of the porous silver layer; and,a gas diffusion layer formed on a second surface of the substrate, comprising a hydrophobic material.The gas diffusion electrode can be stably used for, e.g., sodium chloride electrolysis for extended periods of time even under severe conditions.

Abstract: The present invention relates to a method of producing an electrolytic electrode containing the following steps: forming a lead plating layer on the surface of a metallic core material by using a lead electrolytic plating bath, where the metallic core material is the cathode; forming an .alpha.-lead dioxide layer on the lead plating layer by electrolysis using an alkaline bath containing a lead ion and using the core material as the anode; and forming a .beta.-lead dioxide layer on the .alpha.-lead dioxide layer by electrolysis using an aqueous lead nitrate solution and using the core material as the anode. The electrolytic electrode produced by the foregoing method is capable of electrolysis in an aqueous solution, in particular, in an aqueous corrosive solution containing fluorine ions.

Abstract: A gas diffusion electrode comprising a water permeable gas diffusion and reaction layer and a porous and electrically conductive electrode current collector having a water repellency bonded to the gas diffusion and reaction layer.

Abstract: There are provided an electrode substrate for electrolysis comprising an electrically conductive metallic base material and a coating layer having a thickness of from 10 to 200 .mu.m composed of a platinum group metal and partial oxides of a non-stoichiometric composition containing at least one kind of metal selected from the group consisting of titanium, tantalum and niobium, and oxygen formed on the surface of the base material and a method of producing the electrode substrate. The electrode substrate has a sufficient durability and a chemical stability under a high electric current density, and can be stably used for a long period of time for use under a cathodic polarization in an electrolysis, etc., with a positive-negative inversion, and the use in an electrolyte containing corrosive materials.

Abstract: The instant invention relates to a method for manufacturing an electrolytic electrode comprising a core material made of a valve material, forming a plasma flame-coated layer containing the oxides of titanium and tantalum on the surface of the core material, forming an interlayer containing platinum and the oxides of titanium and tantalum on the surface of the plasma flame-coated layer, forming an .alpha.-lead dioxide layer on the interlayer and forming a .beta.-lead dioxide layer on the .alpha.-lead dioxide layer.

Abstract: An insoluble electrode structural material comprising a tabular or curved electrode base plate having at least one thin plate-form insoluble metal electrode detachably fixed to at least a part of the surface of the base plate.

Abstract: The present invention is intended to prevent the formation of impurities such as chlorate in electrolysis using the ion exchange membrane method, without resorting to the addition of hydrochloric acid to counter the migration of alkali hydroxide from the cathode compartment to the anode compartment. The method of the present invention includes feeding a portion of an aqueous solution of an alkali chloride (as the raw material) into an auxiliary electrolytic cell of the cation exchange membrane type in which the anode is a hydrogen gas electrode, thereby effecting electrolysis to generate hydrochloric acid in the anode compartment, and then feeding the hydrochloric acid-containing aqueous solution of alkali chloride into the main electrolytic cell, thereby neutralizing the alkali hydroxide which migrates from the cathode compartment.