Abstract: A gas diffusion layer for a fuel cell includes a conductive microparticle layer and a base material layer. The conductive microparticle layer is formed with first pores of no less than 0.5 ?m and no more than 50 ?m and second pores of no less than 0.05 ?m and less than 0.5 ?m. Pores are also formed in the base material layer. A total volume of the second pores is no less than 50% and less than 100% of a total volume of all of the pores in the conductive microparticle layer. By properly setting a pore size D1 of pores having a maximum volume ratio from among the first pores, water passages are formed in the first pores separately from gas passages formed in the second pores.

Abstract: The present invention provides an electrochemical gas sensor that can restrict to the extent possible interference errors.

Abstract: A process for producing a reaction layer material or gas feed layer material for a gas diffusion electrode, which comprises the steps of: dispersing a gas diffusion electrode raw material excluding polytetrafluoroethylene in to an organic solvent to prepare a dispersion; adding polytetrafluoroethylene to the dispersion to prepare a mixture; and mixing the mixture. In the process, polytetrafluoroethylene is added in the form of dispersion or fine powder.

Abstract: A method for manufacturing a gas diffusion electrode for use as an oxygen cathode in a chlor-alkari electrolytic and in a fuel cell in a short time through a simple operation, a gas diffusion electrode, and a fuel cell employing the gas diffusion electrode as a compositional material. A gas diffusion electrode material principally comprising micro particles of fluororesin dispersed in dispersion medium is deposited, by electrophoresis, on the surface of a conductive base material to form a porous deposit containing fluororesin serving as the gas supply layer and/or the reaction layer of the gas diffusion electrode.

Abstract: A reaction layer material for a gas diffusion electrode and a production process therefor, which is obtained by mixing a polytetrafluoroethylene dispersion with a surfactant-containing aqueous solution containing hydrophilic fine particles and a hydrophobic carbon black, each dispersed therein satisfying the relationships: 0.5<D<2 and rs<2rp, wherein D=rc/rp, rs represents the average particle diameter of the hydrophilic fine particles dispersed in the surfactant-containing aqueous solution, rc represents the average particle diameter of the hydrophobic carbon black dispersed in the surfactant-containing aqueous solution, and rp represents the average particle diameter of polytetrafluoroethylene fine particles in the polytetrafluoroethylene dispersion to be used; and then adding a self-organizing agent to the mixture and mixing therewith. A jet mill is used for dispersing the hydrophobic carbon black.

Abstract: A gas diffusion cathode suitable for oxygen cathodes in an ion-exchange membrane type brine electrolytic bath, a gas diffusion cathode with a gas chamber and a brine electrolytic bath using it. A gas diffusion electrode is supported on a metal frame and gas diffusion electrode is joined to the metal frame via a silver member or a silver surface-carrying member. The joining portions are free from liquid or gas leakage, thereby to eliminate the need of a packing between the gas diffusion electrode and the electrolytic bath frame. At least two openings are provided in the metal frame and a gas diffusion electrode is joined by hot-pressing to each opening via a silver member or a silver surface-carrying member to provide a large gas diffusion electrode.

Abstract: A gas diffusion electrode assembly comprising: a gas diffusion electrode; and a metallic or resinous edging material bonded to a peripheral part of the electrode. The invention also relates to a gas diffusion electrode assembly comprising: a gas diffusion electrode; and a metallic terminal bonded to the electrode. The invention further relates to a gas diffusion electrode assembly comprising: a gas diffusion electrode; and a structure for connection, which comprises a combination of a thin silver sheet and a reinforcing material comprising a tough metal as a base, the structure for connection being bonded to a peripheral part of the gas diffusion electrode. Also disclosed are processes for producing these gas diffusion electrode assemblies.

Abstract: A sodium chloride electrolytic cell is provided, comprising a gas diffusion electrode that allows smooth supply and discharge of catholyte for electrolyzing sodium chloride and allows oxygen gas to come in good contact therewith. The sodium chloride electrolytic cell comprises an anode chamber having an anode into which an aqueous solution of sodium chloride and a cathode chamber having the foregoing gas diffusion electrode for producing an alkaline aqueous solution, the anode chamber and the cathode chamber being divided by an ion exchange membrane. The sodium chloride electrolytic cell is arranged to effect electrolysis in such a manner that there occurs no pressure differential between the catholyte chamber and the gas chamber in the gas diffusion electrode. Further, a nickel mesh substance is fitted in a concave portion having the same size as that of the gas diffusion electrode formed in the central portion of a thin nickel plate.

Abstract: Disclosed herein is a gas diffusion electrode comprising a reaction layer and a gas diffusion layer attached to each other characterized in that a plurality of apertures or a concave convex surface is provided on or through the electrode to facilitate the flowing of an electrolyte. In this electrode, a large volume of an electrolyte and a gas can flow even though the interelectrode distance is small so that a reaction can be promoted to elevate the efficiency.

Abstract: Disclosed is a bubble collection type gas electrode having projections for collecting gas bubbles on the surface of the electrode. This electrode provides a sufficient contact between the bubbles and the gas diffusion layer so that the bubbles are likely to permeate the gas diffusion layer to reach the interface between the gas diffusion layer and a reaction layer so that an amount of the bubbles required for effecting the reaction may be supplied to obtain a satisfactory current density. The electrode may comprise a reaction layer having a plurality of projections, without a gas diffusion layer.

Abstract: There are provided a gaseous-diffusion electrode which can exhibit sufficient gas-supplying ability and gas-discharging ability and an excellent durability even when partly immersed in an electrolysis solution; and an electrochemical reactor using the gaseous-diffusion electrode. A porous membrane 15 which is permeable to gas but not to an electrolysis solution is fixed to the surface of the gaseous-diffusion layer 13 of a gaseous-diffusion electrode 11 obtained by joining a reaction layer 12 supporting a catalyst metal and a gaseous-diffusion layer 13 to each other, so as to cover the surface of the gaseous-diffusion layer 13. When a gas passageway member 17 serving as gas passageway to the gaseous-diffusion layer 13 is inserted between the surface of the gaseous-diffusion layer 13 and the porous membrane 15, the gas-supplying ability and the gas-discharging ability becomes greatly improved.

Abstract: Disclosed herein is a process for preparing a reaction layer of a gas permeable electrode which comprises mixing carbon powder and a hydrophobic binding agent, hot-pressing the mixture and cooling the mixture under the hot-pressing conditions or immediately after the hot-pressing. The reaction layer prepared according to the present invention possesses connected electrolyte passages and gas passages so that all the electrolyte penetrates the electrolyte passages and all the gas penetrates the gas passages, whereby excellent contact efficiency is obtained so as to achieve improved catalyst performance.

Abstract: Disclosed herein is a gas permeable member, in particular a gas permeable electrode, carrying a metal complex on a reaction layer thereof. A central metal of the complex may be selected from lead, chromium, iron, cobalt, nickel, copper, zinc, platinum, palladium, manganese, tin, vanadium or the like. The selectivity of a reaction employing the gas permeable member depends on the central metal so that the gas permeable member can be employed in a wide range of applications including electrolytic reduction of carbon dioxide by suitably selecting the central metal of the complex.The complex, for instance a Pc-complex, may be deposited from sulfuric acid by diluting the sulfuric acid by water to be uniformly dispersed in the reaction layer.

Abstract: A method of electrolytically producing an organic compound is disclosed, wherein an organic solvent and an electrolyte which is dissolved therein is placed in an anodic or cathodic chamber. The chambers are separated by a semi-permeable membrane. At least one of the electrodes is a gas permeable electrode which includes a reaction layer joined together with the gas permeable layer. The reaction layer is composed of minute hydrophilic and hydrophobic carbon black, and the gas permeable layer is composed of minute hydrophobic carbon black.

Abstract: Enclosed herein is an apparatus for converting an ionic valence number which comprises a gas permeable membrane comprising a catalyst-supporting reaction layer and a hydrophobic gas permeable layer having fine pores; a solution chamber retaining an aqueous solution containing an ion, and the respective supply port and discharge port for the supply and the discharge of the aqueous solution containing the ion, which are located on the reaction layer side of the gas permeable membrane; and a gas chamber retaining an oxidizing gas or a reducing gas, and the respective supply port and discharge port for the supply and the discharge of the oxidizing or reducing gas, which are located on the gas permeable layer side of the gas permeable membrane.

Abstract: Disclosed herein are processes for preparing a raw material dispersion and raw material powders for producing reaction layers of a gas permeable electrode. The raw materials are prepared in one aspect of the invention by mixing fine particles containing a surface-active agent, freezing the mixture to a temperature the surface-active agent loses at least part of its function and then thawing out the same. The resulting material exhibits superior catalytic performance because the particles are dispersed uniformly by lack of the function of surfaceactive agent at the time of freezing.The raw materials are prepared in another aspect of the invention by mixing hydrophilic minute particles coated with ion exchange resin, PTFE and hydrophobic fine powders.

Abstract: Enclosed herein is an apparatus for converting an ionic valence number which comprises a gas permeable membrane comprising a catalyst-supporting reaction layer and a hydrophobic gas permeable layer having fine pores; a solution chamber retaining an aqueous solution containing an ion, and the respective supply port and discharge port for the supply and the discharge of the aqueous solution containing the ion, which are located on the reaction layer side of the gas permeable membrane; and a gas chamber retaining an oxidizing gas or a reducing gas, and the respective supply port and discharge port for the supply and the discharge of the oxidizing or reducing gas, which are located on the gas permeable layer side of the gas permeable membrane.

Abstract: A process for reducing an uranyl salt solution to an uranous salt solution employing a gas diffusion membrane comprising a reaction layer and a gas supply layer. The uranyl salt solution can be reduced to the corresponding uranous salt solution in the reaction layer of the membrane by a hydrogen gas supplied from the gas supply layer with the reduced power consumption.

Abstract: Disclosed herein is a gas permeable electrode which comprises a gas permeable layer and a reaction layer, the reaction layer comprising hydrophobic portions and hydrophilic portions. Electrolyte penetrates into the reaction layer and does not penetrate into the gas permeable layer, and only the gas produced on the electrode and the gas supplied penetrate into the gas permeable layer. The gas can be released from the rear side of the electrode and the reaction surface thereof is never covered with the gas.

Abstract: Disclosed herein is a gas sensor comprising a membrane for gas sensing which comprises a selective gas permeable membrane and a reaction layer attached thereto; and a counter electrode separated from the reaction layer of the membrane across an electrolyte; the reaction layer having the function of an electrode and comprising fine hydrophilic portions and fine hydrophobic portions.The specific gas in mixed gases having permeated the selective gas permeable membrane is immediately dissolved in the electrolyte having penetrated into the reaction layer and is ionized and the ion in the electrolyte moves to the counter electrode closely positioned to the reaction layer so that the specific gas concentration can be detected by means of the voltage difference or the like.