Abstract

It is described a high-pressure alkaline electrolyzer for splitting water into hydrogen and oxygen, said electrolyzer comprising a stack of electrolysis cells (1), with channels supplying lye to the cathodes and anodes and channels conducting hydrogen from the cathodes and oxygen from the anodes. The electrolyzer includes first and second lye inlet channels (4a, 4b), a multitude of first intermediate lye channels (5a) conducting lye from the first lye inlet channel (4a) to each cathode (3a) in the stack, a multitude of second intermediate lye channels (5b) conducting lye from the second lye inlet channel (4b) to each anode (3b) in the stack, wherein the hydrogen conducting channels include a common hydrogen outlet channel (7a) and a multitude of intermediate hydrogen channels (8a) conducting hydrogen from each cathode (3a) to the common hydrogen outlet channel (7a), and the oxygen conducting channels include a common oxygen outlet channel (7b) and a multitude of intermediate oxygen channels (8b) conducting oxygen from each anode (3b) to the common oxygen outlet channel (7b).

IPC Classes  ?

• C25B 15/06 - Detection or inhibition of short circuits in the cell
• C25B 1/04 - Hydrogen or oxygen by electrolysis of water
• C25B 9/05 - Pressure cells
• C25B 9/23 - Cells comprising dimensionally-stable non-movable electrodesAssemblies of constructional parts thereof with diaphragms comprising ion-exchange membranes in or on which electrode material is embedded
• C25B 9/75 - Assemblies comprising two or more cells of the filter-press type having bipolar electrodes
• C25B 9/77 - Assemblies comprising two or more cells of the filter-press type having diaphragms

Abstract

The present invention relates to a method for producing an electrode for alkaline electrolysis based on a composition of metal sulfides on a Ni foam substrate. The metal can be Mo, Ni, Co, Fe and/or W. In a first step S1), there is performed a metal deposition, e.g. by electroplating, the metal, Me1/Me2, being Mo, Ni, Co, Fe, and/or W, on a Ni foam substrate resulting in a metal-Ni compound being formed on and/or in the Ni foam substrate. In a second step, S2) there is performed a sulfiding on the metal-Ni compound from the first step S1). The third step S3) is an optional repetition of S1 and/or S2 at least one time. The step S1) and step S2) thereby result in the formation of electrocatalytic active nano-sites with Me1-Me2-S—Ni compounds. It is found that these nano-sites are capable of reducing the so-called overpotential of the electrodes during alkaline water electrolysis, and the production of electrodes may be significantly simplified.

IPC Classes  ?

• C25B 11/052 - Electrodes comprising one or more electrocatalytic coatings on a substrate
• C25B 1/04 - Hydrogen or oxygen by electrolysis of water
• C25B 11/031 - Porous electrodes
• C25B 11/061 - Metal or alloy
• C25B 11/075 - Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalysts material consisting of a single catalytic element or catalytic compound
• C25D 5/40 - NickelChromium
• C25D 5/48 - After-treatment of electroplated surfaces
• C25D 5/50 - After-treatment of electroplated surfaces by heat-treatment

Abstract

The present invention relates to a method for producing an electrode for alkaline electrolysis based on a composition of sulfides on a Ni foam substrate. In a step. S2) there is performed a sulfiding on the Ni substrate. The step of sulfiding results in the formation of electrocatalytic active nano-sites with Ni—S compounds. It is found that these nano-sites are capable of reducing the so-called overpotential of the electrodes during alkaline water electrolysis, and the production of electrodes may be significantly simplified. In particular, already existing electrolyzer units may benefit from this invention by on-site application of the improved method.

IPC Classes  ?

• C25B 11/052 - Electrodes comprising one or more electrocatalytic coatings on a substrate
• C23C 8/02 - Pretreatment of the material to be coated
• C23C 8/08 - Solid state diffusion of only non-metal elements into metallic material surfacesChemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
• C23C 8/80 - After-treatment
• C25B 1/04 - Hydrogen or oxygen by electrolysis of water
• C25B 11/031 - Porous electrodes
• C25B 11/061 - Metal or alloy
• C25B 11/075 - Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalysts material consisting of a single catalytic element or catalytic compound
• C25D 5/10 - Electroplating with more than one layer of the same or of different metals
• C25D 5/12 - Electroplating with more than one layer of the same or of different metals at least one layer being of nickel or chromium
• C25D 5/40 - NickelChromium
• C25D 5/48 - After-treatment of electroplated surfaces
• C25D 5/50 - After-treatment of electroplated surfaces by heat-treatment

Abstract

It is described a high-pressure alkaline electrolyzer for splitting water into hydrogen and oxygen, said electrolyzer comprising a stack of electrolysis cells (1), with channels supplying lye to the cathodes and anodes and channels conducting hydrogen from the cathodes and oxygen from the anodes. The electrolyzer includes first and second lye inlet channels (4a, 4b), a multitude of first intermediate lye channels (5a) conducting lye from the first lye inlet channel (4a) to each cathode (3a) in the stack, a multitude of second intermediate lye channels (5b) conducting lye from the second lye inlet channel (4b) to each anode (3b) in the stack, wherein the hydrogen conducting channels include a common hydrogen outlet channel (7a) and a multitude of intermediate hydrogen channels (8a) conducting hydrogen from each cathode (3a) to the common hydrogen outlet channel (7a), and the oxygen conducting channels include a common oxygen outlet channel (7b) and a multitude of intermediate oxygen channels (8b) conducting oxygen from each anode (3b) to the common oxygen outlet channel (7b).

IPC Classes  ?

• C25B 1/04 - Hydrogen or oxygen by electrolysis of water
• C25B 9/05 - Pressure cells
• C25B 9/75 - Assemblies comprising two or more cells of the filter-press type having bipolar electrodes
• C25B 9/77 - Assemblies comprising two or more cells of the filter-press type having diaphragms
• C25B 15/08 - Supplying or removing reactants or electrolytesRegeneration of electrolytes