Abstract: Processes for electrolysis of alkali metal chlorides with oxygen-consuming electrodes having startup and shutdown conditions which prevent damage to the constituents of the electrolysis cell.

Abstract: An oxygen-consuming electrode for use in chloralkali electrolysis, having a novel coating, the production thereof, an electrolysis cell comprising the oxygen-consuming electrode and parameters for the startup and shutdown of the electrolysis apparatus, compliance with which prevents damage to the cell.

Abstract: The present invention relates to an electrode that includes an electrically conducting substrate based on a valve metal having a main proportion of titanium, tantalum or niobium, and an electrocatalytically active coating comprising up to 50 mol % of a noble metal oxide or noble metal oxide mixture and at least 50 mol % of titanium oxide. The coating includes a minimum proportion of oxides of anatase structure determined by a ratio of the signal height of the most intensive anatase reflection in an x-ray diffractogram (CuK? radiation) after subtraction of a linear background to the signal height of the most intensive rutile reflection in the same diffractogram, wherein the ratio is at least 0.6.

Abstract: An improved catalyst coating comprising electrocatalytically active components based on ruthenium oxide and titanium oxide, especially for use in chloralkali electrolysis, is described. A production process for the catalyst coating and a novel electrode is also described.

Abstract: An oxygen-consuming electrode is described, more particularly for use in chloralkali electrolysis, comprising a novel catalyst coating, as is an electrolysis apparatus. Also described is a production process for the oxygen-consuming electrode and the use thereof in chloralkali electrolysis or fuel cell technology. The oxygen-consuming electrode comprises at least an electrically conductive support, an electrical contact site and a gas diffusion layer comprising a catalytically active component, characterized in that the coating at least one fluorinated polymer, silver in the form of silver particles and silver oxide in the form of silver oxide particles, which is produced in a selected precipitation step.

Abstract: A gas diffusion electrode is described, especially for use in chloralkali electrolysis, said gas diffusion electrode having finely divided components on the liquid side. The electrode is notable for a low perviosity to gases and a lower operating voltage.

Abstract: A process is described for the production of graphite electrodes coated predominantly with noble metal for electrolytic processes, especially for the electrolysis of hydrochloric acid, wherein the surface of a graphite electrode is coated with an aqueous solution of a noble metal compound and then tempered at 150 to 650° C. in the presence of reducing and/or extensively oxygen-free gases.

Abstract: The present invention relates to a process for the preparation of chlorine by gas phase oxidation using a supported catalyst based on ruthenium, characterised in that the catalyst support has a plurality of pores having a pore diameter>50 nm and carries nanoparticles containing ruthenium and/or ruthenium compounds as catalytically active components.

Abstract: The present invention relates to an oxygen-consuming electrode comprising at least one support element in the form of a sheet-like structure and a coating comprising a gas diffusion layer and a catalytically active component, wherein the oxygen-consuming electrode is additionally coated with a fluoropolymer which is soluble in solvents.

Abstract: The present invention relates to an electrode comprising an electrically conductive substrate and a catalytically active layer, wherein the catalytically active layer is based on two catalytically active components and comprises iridium, ruthenium or titanium as metal oxide or mixed oxide or mixtures of the oxides, wherein the total content of ruthenium and/or iridium based on the sum of the elements iridium, ruthenium and titanium is at least 10 mol %, and wherein the electrode comprises at least one oxidic base layer which is applied to the electrically conductive substrate and is impermeable to aqueous electrolytes comprising NaCl and/or NaOH and/or HCl.

Abstract: An oxygen-consuming electrode includes a support in the form of a sheet-like structure and a coating including a gas diffusion layer and a catalytically active component, wherein the support is based on a material having a conductivity of less than 1000 S/cm, measured at 20° C. The supports are simple to produce and have a low weight and good processability in the production of the oxygen-consuming electrodes.

Abstract: The present invention relates to an oxygen-consuming electrode comprising a support in the form of a sheet-like structure and a coating comprising a gas diffusion layer and a catalytically active component, wherein the support is based on a material which can be at least partly removed by dissolution, decomposition, melting and/or vaporization. Furthermore, the use of this oxygen-consuming electrode in chloralkali electrolysis or fuel cell technology is described.

Abstract: The present invention relates to an electrode that includes an electrically conducting substrate based on a valve metal having a main proportion of titanium, tantalum or niobium, and an electrocatalytically active coating comprising up to 50 mol % of a noble metal oxide or noble metal oxide mixture and at least 50 mol % of titanium oxide. The coating includes a minimum proportion of oxides of anatase structure determined by a ratio of the signal height of the most intensive anatase reflection in an x-ray diffractogram (CuK? radiation) after subtraction of a linear background to the signal height of the most intensive rutile reflection in the same diffractogram, wherein the ratio is at least 0.6.

Abstract: The present invention relates to a gas diffusion electrode that includes an electrically conductive carrier, and a porous coating based on an electrochemically active catalyst and a hydrophobic material, wherein the electrode has a first side facing an oxygen-containing gas and a second side facing an alkaline electrolyte, wherein the catalyst comprises a noble metal as a catalytically active component, wherein the hydrophobic material comprises a hydrophobic polymer, and wherein the coating comprising the catalyst has a pore volume from 10 to 500 mm3/g, and a pore diameter in the range from 100 to 10,000 nm.

Abstract: An electrode material, an electrode and a process for hydrogen chloride electrolysis based on platinum metal as catalyst, in which the electrode material has a nanosize mixture of platinum particles and silver particles, is described.

Abstract: Apparatus for hydrogen chloride electrolysis, comprising a cathode that has a layer of nitrogen-doped carbon nanotubes having functional groups containing nitrogen.

Abstract: A process is described for the production of graphite electrodes coated predominantly with noble metal for electrolytic processes, especially for the electrolysis of hydrochloric acid, wherein the surface of a graphite electrode is coated with an aqueous solution of a noble metal compound and then tempered at 150 to 650° C. in the presence of reducing and/or extensively oxygen-free gases.

Abstract: Processes for the production of chlorine by multi-stage oxidation, for example, by thermal reaction of hydrogen chloride with oxygen using catalysts or by non-thermal activated reaction of hydrogen chloride with oxygen, in which the gas mixture formed in the reaction, comprising the target products chlorine and water, unreacted hydrogen chloride and oxygen, and possibly other secondary constituents, such as carbon dioxide and nitrogen, (a) is cooled to condense hydrochloric acid as an aqueous solution of hydrogen chloride and (b) the aqueous solution of hydrogen chloride formed is separated from the gas mixture, characterised in that (c) the separated aqueous solution of hydrogen chloride is fed at least partially to an electrochemical oxidation in which at least part of the hydrogen chloride is oxidised to chlorine, (d) the chlorine gas occurring in step d) is optionally added to the gas mixture occurring in step c), (e) the residues of water present in the gas mixture from steps c) and e), in particular by

Abstract: Processes are disclosed comprising: (a) providing a gas phase comprising hydrogen chloride and oxygen; and (b) oxidizing the hydrogen chloride with the oxygen in the presence of a catalyst comprising tin dioxide and at least one oxygen-containing ruthenium compound.

Abstract: Oxidation catalysts which comprise at least one constituent active in the catalysis of oxidation reactions, and a support for said constituent, characterized in that the support includes carbon nanotubes; are disclosed along with processes for their use including the oxidation of hydrogen chloride. Such catalysts can exhibit a higher stability and activity than that of catalysts of the state of the art.