A proton conductor contains a metal oxide that has a perovskite structure and that is represented by formula (1): A.sub.xB.sub.1-yM.sub.yO.sub.3-δ, where an element A is at least one element selected from the group consisting of Ba, Ca, and Sr, an element B is at least one element selected from the group consisting of Ce and Zr, an element M is at least one element selected from the group consisting of Y, Yb, Er, Ho, Tm, Gd, In, and Sc, δ indicates an oxygen deficiency amount, and 0.95≤x≤1 and 0<y≤0.5 are satisfied.

Herein discussed is a method of producing hydrogen or carbon monoxide comprising introducing a waste gas having a total combustible species (TCS) content of no greater than 60 vol % into an electrochemical (EC) reactor, wherein the EC reactor comprises a mixed-conducting membrane, wherein the membrane comprises an electronically conducting phase and an ionically conducting phase. Also disclosed herein is an integrated hydrogen production system comprising a waste gas source and an electrochemical (EC) reactor comprising a mixed-conducting membrane, wherein the membrane comprises an electronically conducting phase and an ionically conducting phase, wherein the waste gas source is configured to send its exhaust to the EC reactor, wherein the exhaust has a total combustible species (TCS) content of no greater than 60 vol %.

A metal-supported, planar cell arrangement (200) comprising at least one pair of cells (110a, 110b), each cell (110a, 110b) comprising a metal substrate (120a, 120b) having first and second sides and a porous region (124) providing fluid communication between the sides, planar cell chemistry layers (111, 112, 113) comprising fuel electrode, electrolyte, and air electrode layers being coated or deposited over, and supported by, the porous region (124) on the first side, wherein the metal substrates (120) are in a stacked arrangement with their cell chemistry layers (111, 112, 113) overlying each other such that either both their first sides, or, both their second sides face inwardly in a spaced, opposed relationship, the inwardly facing sides thereby defining a common first fluid volume (140) between them for one of fuel or oxidant.

To enable stable and efficient production of hydrogen. A hydrogen production apparatus according to an embodiment includes an electrolytic unit and an electrolysis power controller. The electrolytic unit produces hydrogen by electrolyzing steam using electric power supplied from an electric power source. The electrolysis power controller controls the supply of electric power from the electric power source to the electrolytic unit. Here, the electrolysis power controller determines whether an unsupplied time during which electric power from the electric power source to the electrolytic unit is not supplied exceeds a predetermined set time, and starts the supply of electric power from the electric power source to the electrolytic unit when the unsupplied time exceeds the set time.

To enable stable and efficient production of hydrogen. A hydrogen production apparatus according to an embodiment includes an electrolytic unit and an electrolysis power controller. The electrolytic unit produces hydrogen by electrolyzing steam using electric power supplied from an electric power source. The electrolysis power controller controls the supply of electric power from the electric power source to the electrolytic unit. Here, the electrolysis power controller determines whether an unsupplied time during which electric power from the electric power source to the electrolytic unit is not supplied exceeds a predetermined set time, and starts the supply of electric power from the electric power source to the electrolytic unit when the unsupplied time exceeds the set time.

An assembly includes a solid-oxide stack of the SOEC/SOFC type and a system for clamping the solid-oxide stack. This assembly also comprises one system for the coupling, gastight at high temperature, including a coupling flange to enable a gas inlet and/or outlet tube to pass, at least one clamping screw, provided with a clamping head, and a seal, positioned between said at least one of the top and bottom clamping plates and against the coupling flange.

An electrolyzer system includes a steam generator configured to generate steam, a stack of solid oxide electrolyzer cells configured to generate a hydrogen stream using the steam received from the steam generator, and a water preheater configured to preheat water provided to the steam generator using heat extracted from oxygen exhaust output from the stack.

An electrolyzer system includes a steam generator configured to generate steam, a stack of solid oxide electrolyzer cells configured to generate a hydrogen stream using the steam received from the steam generator, and a water preheater configured to preheat water provided to the steam generator using heat extracted from oxygen exhaust output from the stack.

Herein discussed is a method of producing hydrogen comprising introducing a metal smelter effluent gas or a basic oxygen furnace (BOF) effluent gas or a mixture thereof into an electrochemical (EC) reactor, wherein the EC reactor comprises a mixed-conducting membrane. In an embodiment, the method comprises introducing steam into the EC reactor on one side of the membrane, wherein the effluent gas is on the opposite side of the membrane, wherein the effluent gas and the steam are separated by the membrane and do not come in contact with each other.

Herein discussed is a method of producing hydrogen comprising introducing a metal smelter effluent gas or a basic oxygen furnace (BOF) effluent gas or a mixture thereof into an electrochemical (EC) reactor, wherein the EC reactor comprises a mixed-conducting membrane. In an embodiment, the method comprises introducing steam into the EC reactor on one side of the membrane, wherein the effluent gas is on the opposite side of the membrane, wherein the effluent gas and the steam are separated by the membrane and do not come in contact with each other.