Herein discussed is a hydrogen production system comprising: a catalytic partial oxidation (CPDX) reactor; a steam generator; and an electrochemical (EC) reactor; wherein the CPDX reactor product stream is introduced into the EC reactor and the steam generator provides steam to the EC reactor; and wherein the product stream and the steam do not come in contact with each other in the EC reactor. In an embodiment, the EC reactor generates a first product stream comprising CO and CO.sub.2 and a second product stream comprising H.sub.2 and H.sub.2O, wherein the two product streams do not come in contact with each other.

Herein discussed is a hydrogen production system comprising: a catalytic partial oxidation (CPDX) reactor; a steam generator; and an electrochemical (EC) reactor; wherein the CPDX reactor product stream is introduced into the EC reactor and the steam generator provides steam to the EC reactor; and wherein the product stream and the steam do not come in contact with each other in the EC reactor. In an embodiment, the EC reactor generates a first product stream comprising CO and CO.sub.2 and a second product stream comprising H.sub.2 and H.sub.2O, wherein the two product streams do not come in contact with each other.

The present invention provides a water electrolysis method comprising: supplying at least water into an electrolysis cell which includes a solid polymer electrolyte membrane, and an anode and a cathode disposed sandwiching the solid polymer electrolyte membrane therebetween; and providing a potential P between the anode and the cathode to generate oxygen from the anode, wherein an oxidation catalyst containing at least one of first transition metals is present on at least a part of a surface of the anode, and the potential P satisfies P1<P<P2, wherein P1 indicates a lowest potential at which oxygen is generated from the anode, and P2 indicates a lowest potential P2 at which a quantitative index of a dissolved chemical species derived from the oxidation catalyst begins to show potential dependence.

The present invention provides a water electrolysis method comprising: supplying at least water into an electrolysis cell which includes a solid polymer electrolyte membrane, and an anode and a cathode disposed sandwiching the solid polymer electrolyte membrane therebetween; and providing a potential P between the anode and the cathode to generate oxygen from the anode, wherein an oxidation catalyst containing at least one of first transition metals is present on at least a part of a surface of the anode, and the potential P satisfies P1<P<P2, wherein P1 indicates a lowest potential at which oxygen is generated from the anode, and P2 indicates a lowest potential P2 at which a quantitative index of a dissolved chemical species derived from the oxidation catalyst begins to show potential dependence.

Disclosed herein are methods and systems that relate to electrochemically producing hydrogen gas by maintaining a steady-state pH differential of greater than 1 between an anode electrolyte and a cathode electrolyte in a hydrogen-gas generating electrochemical cell.

A method for producing ultra-pure hydrogen is provided which includes heating water for stripping argon from the water; and separating the argon-stripped water into an oxygen stream and a hydrogen stream, wherein the hydrogen stream includes an ultra-pure hydrogen stream. A related system for producing an ultra-pure hydrogen stream is also provided which includes a container in which argon is stripped from water by steam; at least one electrolyzer cell to be contacted by the argon-stripped water; wherein the at least one electrolyzer cell provides an oxygen stream and a hydrogen stream with an argon content less than 0.25 ppm.

A method for producing ultra-pure hydrogen is provided which includes heating water for stripping argon from the water; and separating the argon-stripped water into an oxygen stream and a hydrogen stream, wherein the hydrogen stream includes an ultra-pure hydrogen stream. A related system for producing an ultra-pure hydrogen stream is also provided which includes a container in which argon is stripped from water by steam; at least one electrolyzer cell to be contacted by the argon-stripped water; wherein the at least one electrolyzer cell provides an oxygen stream and a hydrogen stream with an argon content less than 0.25 ppm.

A system for hydrogen generation includes at least one cabinet defining a first volume, a second volume, and a third volume, where the first volume, the second volume and the third volume are fluidically isolated from each other, a water circuit located in the first volume, an electrochemical module including an electrolyzer electrochemical stack located in the second volume, a hydrogen circuit located in the third volume, at least one first fluid connector fluidly connecting the water circuit and the electrolyzer electrochemical stack, and at least one second fluid connector fluidly connecting the electrolyzer electrochemical stack and the hydrogen circuit.

A system for hydrogen generation includes at least one cabinet defining a first volume, a second volume, and a third volume, where the first volume, the second volume and the third volume are fluidically isolated from each other, a water circuit located in the first volume, an electrochemical module including an electrolyzer electrochemical stack located in the second volume, a hydrogen circuit located in the third volume, at least one first fluid connector fluidly connecting the water circuit and the electrolyzer electrochemical stack, and at least one second fluid connector fluidly connecting the electrolyzer electrochemical stack and the hydrogen circuit.

Disclosed herein are methods and systems that relate to oxidizing a metal ion of a metal oxyanion or a non-metal ion of a non-metal oxyanion from a lower oxidation state to a higher oxidation state at an anode and generate hydrogen gas at the cathode. The metal oxyanion with the metal ion in the higher oxidation state or the non-metal oxyanion with the non-metal ion in the higher oxidation state may be then subjected to a thermal reaction or a second electrochemical reaction, to form oxygen gas as well as to regenerate the metal oxyanion with the metal ion in the lower oxidation state or the non-metal oxyanion with the non-metal ion in the lower oxidation state, respectively.