The present invention realizes industrially excellent effects such that when electric power having a large output fluctuation, such as renewable energy, is used as a power source, electrolysis performance is unlikely to be deteriorated and excellent catalytic activity is retained stably over a longer period of time, and in addition, the present invention provides a technique that enables forming a catalyst layer of an oxygen generation anode, which gives such excellent effects, with a more versatile materials and by a simple electrolysis method. Provided are an alkaline water electrolysis method including supplying an electrolyte obtained by dispersing a catalyst containing a hybrid nickel-iron hydroxide nanosheet (NiFe-ns) being a composite of a metal hydroxide and an organic substance to an anode chamber and a cathode chamber, and using the electrolyte for electrolysis in each chamber in common, an alkaline water electrolysis method including supplying an electrolyte obtained by dispersing a catalyst containing the NiFe-ns to an anode chamber and a cathode chamber, and performing electrolytic deposition of the NiFe-ns in the electrolytic cell during operation to electrolytically deposit the NiFe-ns on a surface of an electrically conductive substrate having a catalyst layer formed on a surface of an oxygen generation anode, thereby recovering and improving electrolysis performance, and an alkaline water electrolysis anode.

The present disclosure relates to a transition metal-doped nickel phosphide nanostructure, a method for preparing the same, and a catalyst for electrochemical water decomposition including the transition metal-doped nickel phosphide nanostructure. More specifically, a transition metal-doped nickel phosphide nanostructure can be prepared by converting a zinc oxide nanostructure grown on a substrate vertically by hydrothermal synthesis to a transition metal-doped nickel oxide nanostructure by cation exchange and then phosphorizing the nickel oxide. The transition metal-doped nickel phosphide nanostructure of the present disclosure is advantageous in that it has superior catalytic activity and conductivity due to large surface area. In addition, when used as a catalyst for water decomposition under an alkaline condition, it has a low overvoltage and can have excellent catalytic activity for hydrogen evolution reaction or oxygen evolution reaction.

The present disclosure relates to a transition metal-doped nickel phosphide nanostructure, a method for preparing the same, and a catalyst for electrochemical water decomposition including the transition metal-doped nickel phosphide nanostructure. More specifically, a transition metal-doped nickel phosphide nanostructure can be prepared by converting a zinc oxide nanostructure grown on a substrate vertically by hydrothermal synthesis to a transition metal-doped nickel oxide nanostructure by cation exchange and then phosphorizing the nickel oxide. The transition metal-doped nickel phosphide nanostructure of the present disclosure is advantageous in that it has superior catalytic activity and conductivity due to large surface area. In addition, when used as a catalyst for water decomposition under an alkaline condition, it has a low overvoltage and can have excellent catalytic activity for hydrogen evolution reaction or oxygen evolution reaction.

A method of producing an electrocatalyst, comprising the steps of: a) electrodeposition or electrochemical plating of an alloy comprising nickel and a second metal on a copper, nickel or other metal substrate; and b) electrochemical or chemical dissolution of deposited second metal to obtain a nanoporous structure on the copper, nickel or other metal substrate.

A method of producing an electrocatalyst, comprising the steps of: a) electrodeposition or electrochemical plating of an alloy comprising nickel and a second metal on a copper, nickel or other metal substrate; and b) electrochemical or chemical dissolution of deposited second metal to obtain a nanoporous structure on the copper, nickel or other metal substrate.

An alkaline electrolyser device for hydrogen production includes a first and a second electric charge battery substantially identical. Each electric charge battery has a first electrode of copper, silver or their alloys, coated with zinc, a second electrode with a ferrous catalyst, and an alkaline aqueous solution in which the first and second electrodes are immersed. An output opening placed in correspondence of the second electrode is suitable to allow the escape from the battery of gases which develop in correspondence of the second electrode. The batteries are short-circuited with an electric power supply member placed between the first or the second electrodes, with a predefined polarity such that the voltage across the electrodes is higher than 1.3 V. In this configuration, the first battery undergoes a discharging process producing hydrogen gas, whilst, contextually, the second battery undergoes a charging process generating oxygen gas. When the discharge cycle of the first battery is completed, the polarity of the electric power supply is inverted, so that the second battery begins to discharge producing hydrogen gas and, at the same time, the first battery recharges producing oxygen gas. The polarity inversion is repeated cyclically so that oxygen and hydrogen are produced alternately in the two batteries.

A catalyst comprising a porous electrically conductive substrate (such as a foam, carbon fibre paper and carbon fibre cloth) and a porous metallic composite of amorphous NiMoP coating at least a portion of the surface or multiple surfaces of the substrate. The composite preferably forms a continuous layer which coats the surfaces and pores of the substrate. Also methods for preparing and using the catalyst, for example in electrolytic water splitting.

A catalyst comprising a porous electrically conductive substrate (such as a foam, carbon fibre paper and carbon fibre cloth) and a porous metallic composite of amorphous NiMoP coating at least a portion of the surface or multiple surfaces of the substrate. The composite preferably forms a continuous layer which coats the surfaces and pores of the substrate. Also methods for preparing and using the catalyst, for example in electrolytic water splitting.

The invention provides a method of reducing dinitrogen to produce at least one haloamine compound, the method comprising: contacting a cathode comprising a dinitrogen-activating electrocatalytic composition with an electrolyte; providing dinitrogen, a reducible source of halogen and a source of hydrogen for reaction at the cathode; and applying a potential at the cathode sufficient to reduce the dinitrogen on the dinitrogen-activating electrocatalytic composition in the presence of the reducible source of halogen and the source of hydrogen, thereby producing at least one haloamine compound.

A device for performing electrolysis of water is disclosed. The device comprising: a semiconductor structure comprising a surface and an electron guiding layer below said surface, the electron guiding layer of the semiconductor structure being configured to guide electron movement in a plane parallel to the surface, the electron guiding layer of the semiconductor structure comprising an InGaN quantum well or a heterojunction, the heterojunction being a junction between AlN material and GaN material or between AlGaN material and GaN material; at least one metal cathode arranged on the surface of the semiconductor structure; and at least one photoanode arranged on the surface of the semiconductor structure, wherein the at least one photoanode comprises a plurality of quantum dots of In.sub.xGa.sub.(1−x)N material, wherein 0.4≤x≤1. A system comprising such device is also disclosed.