Abstract: Provided is a gas diffusion electrode equipped ion exchange membrane electrolyzer including an anode, an ion exchange membrane, and a cathode chamber in which a gas diffusion electrode is disposed, wherein the ion exchange membrane and a cathode chamber inner space in which the gas diffusion electrode is disposed are separated by a liquid retaining member, the outer periphery of the liquid retaining member is held in a void formed in a gasket or a cathode chamber frame constituting the cathode chamber, or the outer periphery and the end face of the outer periphery of the liquid retaining member are sealed, or the outer periphery of the liquid retaining member is joined to and integrated with the gasket.

Abstract: An electrode of an electrolysis cell for gas-producing electrochemical processes, which includes a plurality of horizontal lamella elements which in the manner of a flat C-profile consist of a flat central part and one or more flank parts, where one or more transition regions of any shape are arranged between the flat central part and the one or more flank parts, where the lamella elements have a plurality of through-openings, where the lamella elements have a flat surface without structural raised regions and depressions and the flat central part has a plurality of through-openings which are arranged in rows and arranged diagonally to one another.

Abstract: The current invention is to provide an oxygen gas diffusion cathode for brine electrolysis which reduces an initial electrolysis voltage and is excellent in the durability against short-circuit, and an electrolytic cell and an electrolytic method using the same. The oxygen gas diffusion cathode for brine electrolysis includes a gas diffusion layer 13 and a reaction layer 14 on one surface of an electro-conductive substrate 12, and an electro-conductive layer 15 on the opposite surface thereof. The present oxygen gas diffusion cathode reduces the resistance of the electro-conductive substrate 12 and supplies uniform current by mounting the electro-conductive layer 15.

Abstract: A highly stable aqueous solution having a molecular cluster with dimensions which are small enough to ensure substantial chemical-physical stability thereof for a relatively long time. To prepare the solution a fluid treatment device is used, which comprises at least one chamber (7) and at least one anode (4) and one cathode (3) arranged in the chamber (7). The anode (4) and cathode (3) are at least partly made of a first metallic material. At least one of the at least one cathode (3) and anode (4) comprises a coating of nanoparticles (5) of a second metallic material.

Abstract: The present invention relates to a method of operating an oxygen-consuming electrode as cathode for the electrolysis of alkali metal chlorides or hydrochloric acid, in an electrochemical cell, comprising feeding an oxygen-containing process gas to the electrode, wherein the oxygen-containing process gas is at least partly heated using a heat source from the electrolysis before contact with the oxygen-consuming electrode to a temperature which corresponds to not more than the temperature of the cathode space in the cell or is less than 50° C. below the temperature of the cathode space in the cell.

Abstract: Provided is a gas diffusion electrode equipped ion exchange membrane electrolyzer including an anode, an ion-exchange membrane, and a cathode chamber in which a gas diffusion electrode is disposed, wherein in a cathode gas chamber formed between a back plate of the cathode chamber and one side of the gas diffusion electrode opposite to the electrolytic surface, a gas-permeable elastic member is disposed between the gas diffusion electrode and the back plate, and the elastic member forms a conductive connection between the gas diffusion electrode and the back plate by making contact with corrosion-resistant conductive layers formed on the surfaces of a plurality of conductive members which are joined to the back plate.

Abstract: The invention relates to a current collector for electrochemical diaphragm or membrane-type cells, comprising a layer obtained by interlacing or weaving of a multiplicity of first sets of metal wires with a multiplicity of single metal wires or of second sets of metal wires and provided with substantially parallel corrugations. Such layer is coupled to a planar element consisting of a cloth or a flattened stocking formed by weaving of a single metal wire. The current collector is characterised by a low angular coefficient of the pressure/thickness ratio over a wide range of compression levels.

Abstract: The invention relates to an electrode for membrane electrolysis cells comprising a grooved metal support favouring the gas release and the electrolyte renewal on its surface. The grooved geometry of the support may be obtained by erosion of a metal sheet with abrasive media in a continuous process.

Abstract: Chlorine is produced by electrolysis of aqueous HCl, in a membrane electrolyzer, using cathodic mediators such as Fe(III) and/or Cu(II) chlorides and a non-catalysed 3-dimensional cathode, with the real surface area at least ten times higher than its projected area. The HCl electrolysis section is combined with an oxidizer for regeneration of the mediator, product water removal step and optional HCl recovery step. Under optimized conditions chlorine can be produced at very high current densities of 30 kA/m2, without initiating undesired H2 evolution reaction at the cathode.

Abstract: Object of the invention is an anodic structure for mercury cathode cells for the industrial electrolysis of sodium chloride. The new structure is constituted by a grid array comprising a multiplicity of vertically disposed and mutually parallel titanium blades, covered by an electrocatalytic coating specific for the discharge of chlorine. The ratio between the thickness and the height of the blades is comprised between 1:16 and 1:100 and the ratio between the surface of free passage between the blades and the projected surface is comprised between 15:17 and 25:30. The new grid array is perpendicularly fixed to new or existing frames having the function of mechanical support and current conduction to the grid array. Scope of the invention is simultaneously reducing the energetic consumption of the cell and the costs for restoring the exhausted electrocatalytic coating.

Abstract: A rhodium sulfide electrocatalyst formed by heating an aqueous solution of rhodium salt until a steady state distribution of isomers is obtained and then sparging hydrogen sulfide into the solution to form the rhodium sulfide and a membrane electrode assembly with the said electrode and a process for electrolyzing hydrochloric acid.

Abstract: A method of separating and recovering 18F from 18O water at high purity and efficiency while maintaining the purity of the 18O water. By using a solid electrode (1) as an anode and a container (electrodeposition vessel) (2) made of platinum as a cathode, 18F in a solution (4) is electrodeposited on the solid electrode surface by applying a voltage. Then, by using the solid electrode (1) on which 18F is electrodeposited as a cathode and a container (recovery vessel) (5) holding pure water therein as an anode, 18F is recovered in the pure water by applying a voltage of opposite polarity to that of the electrodeposition. In this process, little 18O water is lost. The initial concentration of the 18O water is maintained even after the electrodeposition of 18F, so that the 18O water can be repeatedly used as an irradiation target for production of 18F.

Abstract: An electrode for electrolyzing an electrolyte comprising an ammonium fluoride (NH4F)-hydrogen fluoride (HF)-containing molten salt and having a composition ratio (HF/NH4F) of 1 to 3 to prepare a nitrogen trifluoride (NF3) gas and an electrolyte for use in the preparation of NF3 gas, and a preparation method of the NF3 gas by the use of the electrode and the electrolyte. The electrode comprises nickel having 0.07 wt % or less of Si content and containing a transition metal other than nickel. The electrolyte also contains a transition metal other than nickel.

Abstract: A process for electrolyzing an aqueous solution of hydrochloric acid to chlorine in an electrochemical cell provided with an anode compartment and a cathode compartment including at least one gas diffusion cathode comprising an electrically conductive web provided on at least one side thereof with a coating of a catalyst for the electroreduction of oxygen comprising rhodium sulfide and optionally containing at least one fluorinated binder incorporated therein, comprising introducing aqueous hydrochloric acid containing contaminant species into the anode compartment and oxygen into the cathode compartment while impressing a direct electric current on the cell.

Abstract: The invention relates to a process for electrochemically converting anhydrous hydrogen halide, such as hydrogen chloride, hydrogen fluoride, hydrogen bromide and hydrogen iodide, to essentially dry halogen gas, such as chlorine, fluorine, bromine and iodine gas, respectively. In a preferred embodiment, the present invention relates to a process for electrochemically converting anhydrous hydrogen chloride to essentially dry chlorine gas. This process allows the production of high-purity chlorine gas. In this process, molecules of essentially anhydrous hydrogen chloride are transported through an inlet of an electrochemical cell. The molecules of the essentially anhydrous hydrogen chloride are oxidized at the anode of the cell to produce essentially dry chlorine gas and protons, which are transported through the membrane of the cell. The transported protons are reduced at the cathode to form either hydrogen gas, water or hydrogen peroxide.

Abstract: A bipolar metal electrode for the electrolysis of hydrochloric acid, comprising a nickel alloy cathode plate and a titanium anode mesh coupled together by a hydrogen barrier, where the hydrogen barrier is an aluminum plate, where the titanium anode mesh is connected to a titanium backplate by a plurality of titanium supports and where the titanium backplate is spaced apart from the nickel alloy cathode plate by the aluminum plate. An electrolyser comprising one or more bipolar electrodes according to present invention. A method of producing chlorine from hydrochloric acid comprising providing one or more bipolar metal electrodes according to the present invention or an electrolyser according to the present invention, and contacting the one or more bipolar electrodes or the electrolyser with hydrochloric acid.

Abstract: The invention relates to a novel rhodium sulfide catalyst for the reduction of oxygen in industrial electrolyzers. The catalyst is highly resistant towards corrosion and poisoning by organic species, thus resulting particularly suitable for use in aqueous hydrochloric acid electrolysis, when technical grade acid containing organic contaminants is employed.

Abstract: A gas diffusion electrode comprising an electrically conductive web provided on at least one side thereof with a coating containing a rhodium--rhodium oxide catalyst on a carbon black support and a method for the preparation of the rhodium--rhodium oxide catalyst.

Abstract: The improved method for the production of chlorine from aqueous solutions of hydrochloric acid in a membrane electrolysis cell comprises a cathode compartment equipped with a gas diffusion cathode fed with air or enriched air or oxygen and an anodic compartment with an anode provided with an electrocatalytic coating for chlorine evolution. Said anode compartment is fed with an aqueous solution of hydrochloric acid having a maximum concentration of 20% and a maximum temperature of 60.degree. C., and containing an oxidizing compound having a redox potential of at least 0 Volts NHE and preferably 0.3-0.6 Volts NHE. A suitable oxidizing compound is trivalent iron in concentrations comprised in the range of 100-10,000 ppm. Both the anodic and cathodic compartment of the cell and their internal structures are made of titanium or alloys thereof, such as 0.2%. titanium-palladium.

Abstract: A particular anode comprising an electrochemically active material selected from the group consisting of the oxides of the elements tin, germanium and lead and mixtures comprising at least one of the respective oxides of such elements is useful in an electrochemical cell for the direct production of essentially dry halogen gas from essentially anhydrous halogen halide, or in a process for such production of essentially dry halogen gas. This cell or process may be used to produce halogen gas such as chlorine, bromine, fluorine and iodine from a respective anhydrous hydrogen halide, such as hydrogen chloride, hydrogen bromide, hydrogen fluoride and hydrogen iodide.

Abstract: A particular anode comprising an electrochemically active material selected from the group .[.comprising.]. .Iadd.consisting of .Iaddend.the oxides of the elements tin, germanium and lead and mixtures comprising at least one of the respective oxides of such elements is useful in an electrochemical cell for the direct production of essentially dry halogen gas from essentially anhydrous halogen halide, or in a process for such production of essentially dry halogen gas. This cell or process may be used to produce halogen gas such as chlorine, bromine, fluorine and iodine from a respective anhydrous hydrogen halide, such as hydrogen chloride, hydrogen bromide, hydrogen fluoride and hydrogen iodide.