Abstract: The invention relates to a sulphide catalyst for electrochemical reduction of oxygen particularly stable in chemically aggressive environments such as chlorinated hydrochloric acid. The catalyst of the invention comprises a noble metal sulphide single crystalline phase supported on a conductive carbon essentially free of zerovalent metal and of metal oxide phases, obtainable by reduction of metal precursor salts and thio-precursors with a borohydride or other strong reducing agent.

Abstract: A cathode for electrolytic processes, particularly suitable for hydrogen evolution in chlor-alkali electrolysis comprises a metal substrate provided with a catalytic coating made of two layers containing palladium, rare earths (such as praseodymium) and a noble component selected between platinum and ruthenium. The rare earth percent amount by weight is lower in the outer layer than in the inner layer.

Abstract: The invention relates to a cathode for electrolytic processes provided with a catalytic coating based on ruthenium crystallites with highly controlled size falling in a range of 1-10 nm. The coating can be produced by physical vapour deposition of a ruthenium or ruthenium oxide layer.

Abstract: The invention relates to a device for breaking the electrical continuity of the stream of caustic soda produced in mercury-cathode chlor-alkali plants. The device is comprised of a vessel internally subdivided into three compartments by two flow-conveying septa, the three compartments being in communication and defining a caustic soda tortuous flow-path allowing the centrifugal deposition of mercury microdroplets released by the upstream amalgam decomposer.

Abstract: The invention relates to a method of manufacturing of metal electrodes for electrolytic applications by means of a continuous deposition of a layer of noble metals upon metal substrates by a physical vapour deposition technique.

Abstract: There is disclosed an inlet and outlet end-box design for mercury cathode chlor-alkali electrolysis cells of extended lifetime, comprising a composite mechanical structure consisting of a carbon steel bottom entirely supporting the mechanical solicitations, a plastic cover, and a hydraulic head device for washing the mercury and the amalgam. The device is partially extractable thereby allowing the withdrawal of foreign materials accumulated during operation with no need for opening the end-boxes.

Abstract: The invention relates to an electrode for electrolytic applications, optionally an oxygen-evolving anode, obtained on a titanium substrate and having a highly compact dual barrier layer comprising titanium and tantalum oxides and a catalytic layer. A method for forming the dual barrier layer comprises the thermal decomposition of a precursor solution applied to the substrate optionally followed by a quenching step and a lengthy thermal treatment at elevated temperature.

Abstract: An anode provided with an electrocatalytic coating comprising tin, preferably tetravalent and in form of mixed oxide, prepared by the method for the manufacturing of an electrode, comprising applying a solution of a precursor for the pyrolytic formation of a tin-containing coating to a substrate of a valve metal, followed by the execution of thermal treatment, wherein the precursor solution comprises stannic hydroxychloride and a method of preparing the same.

Abstract: The invention relates to a catalytic coating suitable for oxygen-evolving anodes in electrochemical processes. The catalytic coating comprises an outermost layer with an iridium and tantalum oxide-based composition modified with amounts not higher than 5% by weight of titanium oxide.

Abstract: The invention relates to a cathode for electrolytic processes with evolution of hydrogen comprising a metal substrate with a noble metal-based activation layer and two protective layers, one interposed between the activation layer and the substrate and one external, containing an electroless-depositable alloy of a metal comprising one of nickel, cobalt and iron with a non-metal selected from phosphorus and boron, with the optional addition of a transition element selected between tungsten and rhenium.

Abstract: The invention is relative to an electrode for gas evolution in electrolytic and electrometallurgical industrial applications, made of a metal substrate having a surface morphology characterized by a combination of micro-roughness and macro-roughness which favors high adherence of a superficial catalytic layer in order to prevent detachment of the same and passivation of the substrate even under critical operating conditions.

Abstract: An electrode for high overvoltage oxygen anodic evolution is described comprising a substrate of titanium or other valve metal, a first protective interlayer containing valve metal oxides, a second interlayer containing platinum or other noble metal, and an outer layer comprising tin, copper and antimony oxides. The electrode of the invention may be employed as anode in waste water treatment.

Abstract: A structure of cathodic fingers for a chlor-alkali diaphragm cell with improved voltage and faradic efficiency is described, characterized in that a sheet provided with projections is inserted inside each finger. The interwoven wire mesh or the perforated sheet, forming each finger, is secured by a conductive connection, preferably by welding, to the top of each projection, thereby providing optimal uniformity of the electrical current distribution. The projections have a shape preferably equivalent to spherical caps, disposed in a quincuncial pattern. The internal volume of each finger is subdivided by the sheet provided with projections into two portions wherein both the free upward motion of hydrogen bubbles and the free longitudinal motion of the separated hydrogen take place towards the cell perimetrical chamber.

Abstract: The invention relates to an amalgam decomposer for mercury cathode chlor-alkali cells. The amalgam decomposer of the invention contains a filling of carbon steel rings whose external surface is provided with a catalytic coating for amalgam decomposition consisting of one or more electrically conductive metals carbides. The internal surface of the rings is free of catalytic coating and wettable by the amalgam, while the external carbide catalytic coating is not wettable by the amalgam thereby favoring hydrogen evolution.

Abstract: The invention relates to a method for roughening the surface of a metal sheet used as electrode support in industrial electrochemical applications, and an electrode made by such method. Mechanical roughening is imparted by skin-passing the sheet between two rollers of a rolling mill, at least one of which is patterned according to a predetermined profile to be transferred by compression to the surface of the metal sheet.

Abstract: The invention relates to a cathode for hydrogen evolution in electrolysis cells, for instance chlor-alkali cells or cells for producing chlorate or hypochlorite, obtained starting from a substrate of nickel or other conductive material galvanically coated with nickel co-deposited with an amorphous molybdenum oxide.

Abstract: The invention relates to an electrode formulation comprising a catalytic layer containing tin, ruthenium, iridium, palladium and niobium oxides applied to a titanium or other valve metal substrate. A protective layer based on titanium oxide modified with oxides of other elements such as tantalum, niobium or bismuth may be interposed between the substrate and the catalytic layer. The thus obtained electrode is suitable for use as an anode in electrolysis cells for chlorine production.

Abstract: The invention relates to an anode comprising a titanium alloy substrate coated with noble metals by thermal decomposition of precursors thereof. The alloy of the substrate includes elements which can be oxidised during the thermal decomposition step, allowing electrical energy savings and a prolonged duration in industrial electrolytic processes. The anode of the invention is suitable for chlor-alkali electrolysis, allowing to produce chlorine with a lower oxygen content and a lower energy consumption than the anodes of the prior art.

Abstract: A cathodic member for electrochemical cells used in hypochlorite production comprises a zirconium plate coated with a zirconium oxide layer, which is particularly suitable for minimising the decomposition of the hypochlorite product while ensuring a prolonged lifetime. The coated zirconium plate can be used as the cathodic plate in a monopolar cell, or can be welded to a titanium plate for use in a bipolar configuration.

Abstract: The invention relates to a gas-diffusion electrode for chlor-alkali electrolysis cells integrated in a percolator of plastic porous material suitable for being vertically crossed by a downward flow of electrolyte. The electrode comprises a catalytic composition based on silver and/or nickel mixed to a polymeric binder, directly supported on the percolator without any interposed reticulated metal current collector.