Other

Tanaka Kikinzoku Kogyo K.k.

Nagakazu Furuya

Satoshi Motoo

Masahiro Watanabe

Koji Saiki

Shinji Katayama

Kenzo Yamaguchi

Hiroaki Aikawa

Akihiro Sakata

Satoshi Motoo, Deceased

Natsuko Motoo, Executor

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.

Process for producing gas diffusion electrode material

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 r <2r , wherein D&equals;r /r , r represents the average particle diameter of the hydrophilic fine particles dispersed in the surfactant-containing aqueous solution, r represents the average particle diameter of the hydrophobic carbon black dispersed in the surfactant-containing aqueous solution, and r 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. The liquid obtained by adding and mixing the self-organizing agent is spray-dried or is applied by spraying.

Gas diffusion electrode material, process for producing the same, and process for producing gas diffusion electrode

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.

Gas diffusion electrode and brine electrolytic bath

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.

Gas diffusion electrode assemblies and processes for producing the same

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.

Soda electrolytic cell provided with gas diffusion electrode

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.

Gas diffusion electrode

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.

Bubble collection type gas electrode

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.

Process for preparing reaction layer of gas permeable electrode

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.

Gas permeable member

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.

Electrolytic method of preparing compounds with a gas permeable electrode

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. Another aspect of the invention is process for converting a ionic valence number which comprises supplying an aqueous solution containing an ion to the reaction layer side of a gas permeable membrane formed by joining a catalyst-supporting reaction layer with a gas permeable layer; supplying an oxidizing or a reducing gas to the gas permeable side; and converting the valence number of the ion in the aqueous solution containing the said ion.

Process for converting ferrous ions to ferric ions

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. The resulting material exhibits superior catalytic performance because catalysts contained in the hydrophilic minute particles are neither liberated nor made to flow so that the initial catalytic activities are substantially maintained even after a relatively long period of use.

Process for preparing raw materials for reaction layer of gas permeable

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. Another aspect of the invention is process for converting an ionic valence number which comprises supplying an aqueous solution containing an ion to the reaction layer side of a gas permeable membrane formed by joining a catalyst-supporting reaction layer with a gas permeable layer; supplying an oxidizing or a reducing gas to the gas permeable side; and converting the valence number of the ion in the aqueous solution containing the said ion.

Process for converting ionic valence number

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.

Process for reducing uranyl salt

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.

Growing community of inventors

Yamanashi, Japan

Nagakazu Furuya