An apparatus (100) for producing an acidic aqueous solution includes: an electrodialyzer (110) that has a monovalent ion perm-selective ion-exchange membrane and separates wastewater containing chloride ions and alkali metal ions into electrodialysis concentrated water and electrodialysis diluted water by an electrodialysis treatment; an electrolyzer (120) includes an anode that that electrolyzes the electrodialysis concentrated water to produce an acidic aqueous solution; and a first circulator (13) that circulates at least some of the acidic aqueous solution to the wastewater supplied to the electrodialyzer (110), and that adjusts a pH of the wastewater supplied to the electrodialyzer to 3 to 9.

An apparatus (100) for producing an acidic aqueous solution includes: an electrodialyzer (110) that has a monovalent ion perm-selective ion-exchange membrane and separates wastewater containing chloride ions and alkali metal ions into electrodialysis concentrated water and electrodialysis diluted water by an electrodialysis treatment; an electrolyzer (120) includes an anode that that electrolyzes the electrodialysis concentrated water to produce an acidic aqueous solution; and a first circulator (13) that circulates at least some of the acidic aqueous solution to the wastewater supplied to the electrodialyzer (110), and that adjusts a pH of the wastewater supplied to the electrodialyzer to 3 to 9.

Proposed are a photoelectrochemical cell for producing hydrogen peroxide, a method of fabricating the same, and a method of producing hydrogen peroxide using the photoelectrochemical cell. The photoelectrochemical cell includes a photoanode including a photocatalyst, a cathode, and a solid polymer electrolyte layer disposed between the photoanode and the cathode and including a solid polymer electrolyte. The photoelectrochemical cell is for use in the production of hydrogen peroxide, and can produce hydrogen peroxide with electric energy generated from solar energy without requiring the supply of external electric energy.

Proposed are a photoelectrochemical cell for producing hydrogen peroxide, a method of fabricating the same, and a method of producing hydrogen peroxide using the photoelectrochemical cell. The photoelectrochemical cell includes a photoanode including a photocatalyst, a cathode, and a solid polymer electrolyte layer disposed between the photoanode and the cathode and including a solid polymer electrolyte. The photoelectrochemical cell is for use in the production of hydrogen peroxide, and can produce hydrogen peroxide with electric energy generated from solar energy without requiring the supply of external electric energy.

In an anode side electrolytic domain (130), a radial flow is formed from an outer peripheral opening (131) to an inner side opening (141) of an anode side mesh electrode (140). Flows horizontal to the electrode surface of the anode side mesh electrode 140 are formed. Gases such as ozone generated from water electrolysis in the anode side electrolytic domain (130) are dissolved in raw water in the anode side electrolytic domain (130), and anode side electrolytic water is generated. Gas such as ozone that has been atomized by the anode side mesh electrode (140) comes into contact with the raw water, and high concentration anode side electrolytic water is generated. The anode side electrolytic water generated in the anode side electrolytic domain (130) flows in the inner side opening (141) of the anode side mesh electrode (140).

A product container is provided. The product container includes a first product and an electrochemistry device configured to convert a portion of the first product into a second product, which is an unstable formulation.

A product container is provided. The product container includes a first product and an electrochemistry device configured to convert a portion of the first product into a second product, which is an unstable formulation.

A membrane-free electrochemical reactor and fuel-cell having a collection chamber between a first and second chamber, a mesoporous carbon paper cathode between the first chamber and the collection chamber, a mesoporous carbon paper anode between the second chamber and the collection chamber, the cathode is coated with an oxygen reduction reaction catalyst that imparts a two-electron partial reduction reaction to hydrogen peroxide, the anode is coated with an oxygen evolution reaction coating or a hydrogen oxidation reaction coating, oxygen/air input and output ports connected to the first chamber, KOH/water input and output ports connected to the second chamber that are in an open state under an electrolyzer mode, H.sub.2/water input and output ports connected to the second chamber that are in an open state under a fuel-cell mode, a second KOH/water input port connected to the collection chamber, and a hydrogen peroxide/KOH/water output port connected to the collection chamber.

A membrane-free electrochemical reactor and fuel-cell having a collection chamber between a first and second chamber, a mesoporous carbon paper cathode between the first chamber and the collection chamber, a mesoporous carbon paper anode between the second chamber and the collection chamber, the cathode is coated with an oxygen reduction reaction catalyst that imparts a two-electron partial reduction reaction to hydrogen peroxide, the anode is coated with an oxygen evolution reaction coating or a hydrogen oxidation reaction coating, oxygen/air input and output ports connected to the first chamber, KOH/water input and output ports connected to the second chamber that are in an open state under an electrolyzer mode, H.sub.2/water input and output ports connected to the second chamber that are in an open state under a fuel-cell mode, a second KOH/water input port connected to the collection chamber, and a hydrogen peroxide/KOH/water output port connected to the collection chamber.

A catalytic arrangement for an electrolyzer system or a fuel cell system includes a catalyst support unit and a catalyst layer, wherein the catalyst layer has a carbon matrix with a metal, non-metal and/or metalloid doping.