A water electrolysis system includes a water supply unit, a KOH tank, a water electrolysis apparatus, and a control device. The water supply unit and the KOH tank supply an aqueous solution containing hydroxide ions of a predetermined concentration to a cathode of the water electrolysis apparatus. The water electrolysis apparatus includes a solid polymer electrolyte membrane, and a water electrolysis cell having an anode and a cathode provided on both sides of the solid polymer electrolyte membrane. The control device changes the voltage to increase while restricting a supply amount of a KOH aqueous solution to the cathode when a concentration of the KOH aqueous solution is higher than a predetermined reference concentration on the basis of information on correspondence between a voltage and current between the anode and the cathode and the concentration of the KOH aqueous solution on the cathode.

A water electrolysis system includes a water supply unit, a KOH tank, a water electrolysis apparatus, and a control device. The water supply unit and the KOH tank supply an aqueous solution containing hydroxide ions of a predetermined concentration to a cathode of the water electrolysis apparatus. The water electrolysis apparatus includes a solid polymer electrolyte membrane, and a water electrolysis cell having an anode and a cathode provided on both sides of the solid polymer electrolyte membrane. The control device changes the voltage to increase while restricting a supply amount of a KOH aqueous solution to the cathode when a concentration of the KOH aqueous solution is higher than a predetermined reference concentration on the basis of information on correspondence between a voltage and current between the anode and the cathode and the concentration of the KOH aqueous solution on the cathode.

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 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 invention relates to a method for producing a gas product containing oxygen, wherein a feedstock containing water is subjected to electrolysis to obtain a raw anode gas, which is rich in oxygen and contains hydrogen, and a raw cathode gas, which is low in oxygen and rich in hydrogen. The raw anode gas is at least partially subjected to a catalytic conversion of hydrogen to water to obtain a first mixture with depleted hydrogen content. A first part of the first mixture is returned to the raw anode gas downstream of the electrolysis and upstream of the catalytic conversion, and the gas product containing oxygen is formed using at least a second part of the first mixture. The invention also relates to a plant for carrying out a method of this type.

The invention relates to a method for producing a gas product containing oxygen, wherein a feedstock containing water is subjected to electrolysis to obtain a raw anode gas, which is rich in oxygen and contains hydrogen, and a raw cathode gas, which is low in oxygen and rich in hydrogen. The raw anode gas is at least partially subjected to a catalytic conversion of hydrogen to water to obtain a first mixture with depleted hydrogen content. A first part of the first mixture is returned to the raw anode gas downstream of the electrolysis and upstream of the catalytic conversion, and the gas product containing oxygen is formed using at least a second part of the first mixture. The invention also relates to a plant for carrying out a method of this type.

Methods and apparatus for controlling electrolysis in an electrolytic cell in order to maintain constant concentration of the disinfectant irrespective of the rate of electrolyte concentration or oxidant production in the electrolytic cell.

The present invention comprises a method for optimizing the consumption of an operating resource of ozone generators in which an oxygen-containing gas is conveyed through an existing gap between two conductors, between which there is a potential difference, wherein the ozone generator has a generator rated power P.sub.n that is achieved when the ozone generator has an electrical power P.sub.el=P.sub.el,max coupled and the oxygen-containing gas is conveyed through the gap with a gas flow φ.sub.N, such that the gas that flows through has an ozone concentration c.sub.ozN, wherein the method comprises the following steps: A) specify a required generator power P.sub.target, B) if 0<P.sub.target<P.sub.n, reduce both the electrical power P.sub.el=P.sub.el,actual<P.sub.el,max and the ozone concentration c.sub.oz,actual<c.sub.ozN, wherein P.sub.el,actual and c.sub.oz is selected in order to achieve the required generator power P.sub.target.

The present invention comprises a method for optimizing the consumption of an operating resource of ozone generators in which an oxygen-containing gas is conveyed through an existing gap between two conductors, between which there is a potential difference, wherein the ozone generator has a generator rated power P.sub.n that is achieved when the ozone generator has an electrical power P.sub.el=P.sub.el,max coupled and the oxygen-containing gas is conveyed through the gap with a gas flow φ.sub.N, such that the gas that flows through has an ozone concentration c.sub.ozN, wherein the method comprises the following steps: A) specify a required generator power P.sub.target, B) if 0<P.sub.target<P.sub.n, reduce both the electrical power P.sub.el=P.sub.el,actual<P.sub.el,max and the ozone concentration c.sub.oz,actual<c.sub.ozN, wherein P.sub.el,actual and c.sub.oz is selected in order to achieve the required generator power P.sub.target.

Disclosed is an electrochemical method for continuous regeneration of a Pt.sup.IV oxidant to furnish overall electrochemical methane oxidation. Cl-adsorbed Pt electrodes catalyze facile oxidation of Pt.sup.II to Pt.sup.IV without concomitant methanol oxidation. Exploiting this electrochemistry, the Pt.sup.II/IV ratio in solution is maintained via in situ monitoring of the solution potential coupled with dynamic modulation of the electric current. Remarkably, this method leads to sustained methane oxidation catalysis with ˜70% selectivity for methanol.