An electrochemical cell has a membrane located between two flow field plates. On a first side of the membrane, there is a porous support surrounded by a seal between the membrane and the flow field plate. There is a gap between the porous support and the seal at the surface of the membrane. On a second side of the membrane, there is a seal between the membrane and the flow field plate located inside of the gap in plan view. The electrochemical cell is useful, for example, in high pressure or differential pressure electrolysis in which the second side of the membrane will be consistently exposed to a higher pressure than the first side of the membrane.

The hydrogen production apparatus includes: a rectifier supplied with first electrical power from outside, and that outputs direct-current second electrical power; an electrolyzer supplied with the second electrical power and that carries out electrolysis of an alkaline aqueous solution; a pure water tank that retains a pure water; a pure water pipe connected between the pure water tank and an electrolyzer, allowing the pure water to be distributed from the pure water tank to the electrolyzer; an inert gas cylinder that contains an inert gas; and a first valve connected between the inert gas cylinder and the pure water pipe, is the first valve being closed when the first electrical power is supplied, and being open when the first electrical power is not supplied. The inert gas is introduced into the pure water pipe by opening the first valve.

A method for manufacturing nitride catalyst is provided, which includes putting a Ru target and an M target into a nitrogen-containing atmosphere, in which M is Ni, Co, Fe, Mn, Cr, V, Ti, Cu, or Zn. The method also includes providing powers to the Ru target and the M target, respectively. The method also includes providing ions to bombard the Ru target and the M target for depositing M.sub.xRu.sub.yN.sub.2 on a substrate by sputtering, wherein 0<x<1.3, 0.7<y<2, and x+y=2, wherein M.sub.xRu.sub.yZ.sub.2 is cubic crystal system or amorphous

Provided are an electrolyzer having excellent durability against reverse current. The electrolyzer 300 includes an anode 314, an anode chamber 310 housing the anode 314, a cathode 330, a cathode chamber 320 housing the cathode 330, and a diaphragm that separates the anode chamber 310 and the cathode chamber 320, wherein a reverse current absorption body 334 formed of a sintered compact containing nickel is disposed in at least one of an inside of the cathode chamber 320 and an inside of the anode chamber 310, and the reverse current absorption body 334 is not directly coupled to the cathode 330 and the anode 314 but is electrically connected to at least one of the cathode 330 and the anode 314.

Provided is an electrocatalyst for anion exchange membrane water electrolysis, including a carbonaceous material, and nickel electrodeposited on the carbonaceous material, wherein nickel is partially substituted with platinum and the substitution with platinum provides increased hydrogen evolution activity as compared to the same electrocatalyst before substitution with platinum. Also provided are a method for preparing the electrocatalyst and an anion exchange membrane water electrolyzer using the same. The nickel electrocatalyst coated with an ultralow loading amount of platinum for anion exchange membrane water electrolysis shows excellent hydrogen evolution activity and has a small thickness of catalyst, thereby providing high mass transfer and high catalyst availability. In addition, the electrocatalyst uses a particle-type electrode to facilitate emission of hydrogen bubbles generated during hydrogen evolution reaction and oxygen bubbles generated during oxygen evolution reaction, and requires low cost for preparation to provide high cost-efficiency.

An apparatus includes a proton-conducting electrolyte membrane, an anode, a cathode, a first flow path which is disposed on the anode and through which an anode fluid containing hydrogen as a constituent element flows, a second flow path which is disposed on the cathode and through which hydrogen flows, a voltage applicator, a detector which detects a hydrogen cross leak amount passing through the membrane, where the detector detects the hydrogen cross leak amount from, a natural potential of one electrode of the cathode and the anode after forming a state where hydrogen is present at the one electrode and hydrogen is not present at the other electrode of the cathode and the anode, or a current flowing between the anode and the cathode when the voltage is applied from the voltage applicator in a state where the first flow path and the second flow path are both sealed off.

Provided is an electrolytic apparatus capable of pressurizing hydrogen gas produced by the electrolytic apparatus and removing impurities in the produced hydrogen gas.

In the electrolytic apparatus, gas compression means 101 including an ejector 110, a storage tank 103 storing a circulation liquid, a circulation pipe 105 circulating a fluid mixture of hydrogen gas and the circulation liquid to the ejector, and a circulation pump 104 is provided in a discharge line 12 for hydrogen gas produced by electrolysis, a hydrogen gas discharge pipe 106 and a first valve V1 are provided in the storage tank 103, impurities in the hydrogen gas are transferred to the circulation liquid to remove the impurities from the hydrogen gas, and a pressure of the hydrogen gas stored in the storage tank 103 is raised by controlling a flow rate of the circulation liquid circulated from the storage tank 103 to the ejector 110 and opening and closing of the first valve V1.

An electrode includes a base material, and a catalyst layer provided on the base material, the catalyst layer including a plurality of catalyst units having a porous structure. The catalyst layer has a first catalyst layer provided near the base material, the first catalyst layer including a plurality of the catalyst units dispersed at a first dispersion degree. The catalyst layer has a second catalyst layer provided above the first catalyst layer, the second catalyst layer including a plurality of the catalyst units dispersed at a second dispersion degree. The second dispersion degree is different from the first dispersion degree.

A system for providing hydrogen includes a first electrochemical cell or stack including a first cathode and a first anode separated by a first proton exchange membrane. A first inlet is in communication with the anode side of the first electrochemical cell or stack. The first inlet receives a first gas including hydrogen. A liquid composition on a liquid flow path is in communication with the cathode side of the first electrochemical cell or stack. The liquid composition includes water and a water-compatible redox compound. A second electrochemical cell stack including a second cathode and a second anode separated by a second proton exchange membrane is disposed with the anode side of the second electrochemical cell or stack in communication with the liquid flow path. A hydrogen outlet in communication with the cathode side of the second electrochemical cell or stack dispenses hydrogen from the system.

In a water electrolysis system and a method of controlling the water electrolysis system, a control device places a high pressure water discharge solenoid valve, a depressurizing solenoid valve, and a low pressure water discharge solenoid valve in the closed state. Further, a pressure acquisition unit obtains the electrolysis time pressure as a pressure in the low pressure water sealing container during production of hydrogen by a water electrolyzer. Further, the control device determines the occurrence of hydrogen leakage in a depressurizing line based on at least the electrolysis time pressure.