A multilayer cation exchange membrane for use in a chloralkali process comprising an carboxylate layer comprising a fluorinated ionomer containing carboxylate groups on one side of the membrane, an exterior sulfonate layer comprising a fluorinated ionomer containing sulfonate groups on the side of the membrane opposite the carboxylate layer, and an interior sulfonate layer comprising a fluorinated ionomer containing to sulfonate groups between the carboxylate layer and the exterior sulfonate layer, the exterior sulfonate layer having an ion exchange ratio greater than about 11.3, and the interior sulfonate layer having an ion exchange ratio less than about 11.

A method and system for electrochemically regenerating hydroxide (MOH) and carbon dioxide (CO.sub.2) from an alkali metal carbonate (M.sub.2CO.sub.3) via an electrochemical reactor that can replace a conventional thermochemical causticizing operation in a DAC system. The electrochemical reactor comprises: a cathode having an inlet for receiving an electrolyte feed stream comprising MOH, M.sub.2CO.sub.3 and H.sub.2O, and an outlet for discharging an electrolyte product stream comprising MOH, M.sub.2CO.sub.3, H.sub.2O and H.sub.2; a porous hydrophilic transport barrier in adjacent contact with the cathode; a porous hydrophilic anode in adjacent contact with the transport barrier configured and operable to generate CO.sub.2 in the presence of MOH while suppressing their recombination; a porous hydrophobic CO.sub.2 and O.sub.2 separation barrier in adjacent contact with the anode; and a product gas exit channel in adjacent contact with the CO.sub.2 and O.sub.2 separation barrier and for discharging an anode product stream comprising at least CO.sub.2.

A method and system for electrochemically regenerating hydroxide (MOH) and carbon dioxide (CO.sub.2) from an alkali metal carbonate (M.sub.2CO.sub.3) via an electrochemical reactor that can replace a conventional thermochemical causticizing operation in a DAC system. The electrochemical reactor comprises: a cathode having an inlet for receiving an electrolyte feed stream comprising MOH, M.sub.2CO.sub.3 and H.sub.2O, and an outlet for discharging an electrolyte product stream comprising MOH, M.sub.2CO.sub.3, H.sub.2O and H.sub.2; a porous hydrophilic transport barrier in adjacent contact with the cathode; a porous hydrophilic anode in adjacent contact with the transport barrier configured and operable to generate CO.sub.2 in the presence of MOH while suppressing their recombination; a porous hydrophobic CO.sub.2 and O.sub.2 separation barrier in adjacent contact with the anode; and a product gas exit channel in adjacent contact with the CO.sub.2 and O.sub.2 separation barrier and for discharging an anode product stream comprising at least CO.sub.2.

An electrolyzer cell comprises a first half cell with a first electrode, a second half cell with a second electrode, a separator separating the first half cell from the second half cell, wherein a compressive load is applied between the separator and the first electrode or between the separator and the second electrode, or between both the first and second electrodes and the separator, and a nanoporous support structure located between the first electrode and the separator.

A start-up process for conditioning an electrolysis system containing ionically conductive membrane, such as a polyelectrolyte multilayer coated proton exchange membranes, to reduce the break-in period is described. The conditioning involves heating the electrolysis feed, the electrolysis system, or both at a temperature above the desired operating temperature to achieve faster startup. In some cases, the voltage is controlled to avoid damage to the sample.

A start-up process for conditioning an electrolysis system containing ionically conductive membrane, such as a polyelectrolyte multilayer coated proton exchange membranes, to reduce the break-in period is described. The conditioning involves heating the electrolysis feed, the electrolysis system, or both at a temperature above the desired operating temperature to achieve faster startup. In some cases, the voltage is controlled to avoid damage to the sample.

[Problem] To provide a stacked structure including electrodes that can effectively prevent misalignment between units. [Solution] A stacked structure 2 including electrodes 232, 332, 412, 233, 333, 422, wherein multiple units 23, 33, 24, 41, 42 including flat units are stacked and fastened by fasteners 25, the respective units 23, 33, 24, 41, 42 comprising frame-shaped fastening portions 237a, 237b, 337a, 337b, 247a, 247b, 417a, 417b, 427a, 427b on outer peripheral portions on both surfaces thereof, being stacked by the surfaces of the respective fastening portions 237a, 237b, 337a, 337b, 247a, 247b, 417a, 417b, 427a, 427b being pressed against each other, and being formed so that the width of fastening portions 247a, 247b, 337a, 337b, 427a, 427b on one unit is different from the width of fastening portions 237a, 237b, 417a, 417b on another unit.

A separator for alkaline electrolysis comprising a porous support (10) and a first (20b) and second (30b) porous layer provided on respectively one side and the other side of the porous support, characterized in that the porous support has a thickness (d1) of 150 μm or less and the total thickness (d2) of the separator is less than 250 μm. Also a method is disclosed wherewith such a separator may be prepared.

A separator for alkaline electrolysis comprising a porous support (10) and a first (20b) and second (30b) porous layer provided on respectively one side and the other side of the porous support, characterized in that the porous support has a thickness (d1) of 150 μm or less and the total thickness (d2) of the separator is less than 250 μm. Also a method is disclosed wherewith such a separator may be prepared.

An electrochemical reaction device of an embodiment includes: an electrochemical reaction cell 1 that includes: a first electrode having a first flow path, a second electrode having a second flow path, and a separating membrane sandwiched between the first electrode and the second electrode; a liquid tank that contains a liquid to be treated supplied to the second flow path of the second electrode; a first pipe that connects an inlet of the second flow path and the liquid tank; a second pipe that connects an outlet of the second flow path and the liquid tank; and a backflow suppression mechanism that is provided in the second pipe to prevent backflow of the liquid to be treated flowing in the second pipe or reduce a backflow speed.