Abstract: 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.

Abstract: A solid electrolyte comprises a compound represented by a formula MgxAl2-yMyOz, where M is at least one selected from the group consisting of Si, Ge, Sn, Pb, Ti, and Zr; 0<x<1; 0.125?y?0.5; and 3.8?z?4.1.

Abstract: In one form, a photoelectrochemical cell comprising a p-type sensitized photocathode including a sensitizer dye and a water-based electrolyte. In another form, the sensitizer dye and an adjacent semiconductor may have a reduction potential that is sufficiently high to either reduce a desired chemical feedstock in the cell or reduce protons in the water to hydrogen gas. The semiconductor to which the sensitizer dye is affixed may be nickel oxide. The photoelectrochemical cell can include a sensitized photocathode and an electrolyte that contains an electron acceptor, where light illumination of the sensitized photocathode results in reduction of the electron acceptor. The electrolyte can include water.

Abstract: A production method for natural gas according to the invention includes a step of adiabatically compressing a raw natural gas containing helium gas, a step of separating the helium gas from the raw natural gas by passing the adiabatically-compressed raw natural gas through a separation membrane unit, a step of conveying the raw natural gas from which the helium gas has been separated to a terminal through a pipe line, and a step of pressing the helium gas separated from the raw natural gas into an underground storage formation.

Abstract: A high purity ceramic oxygen generator incorporating a module utilizing a plurality of tubular ceramic membrane elements and configured to operate in: (i) a pressurizing mode to separate oxygen from an oxygen containing feed stream when an electric potential difference is applied to induce oxygen ion transport in an electrolyte thereof; and (ii) an idle mode when the electric potential difference is removed. The ceramic oxygen generator further includes one or more manifolds as well as one or more automatic purge valves located upstream of the oxygen receiving tank. The purge valve is opened for a pre-set duration upon initiation of the pressurization mode to purge any nitrogen or other contaminating gas that diffuses into the ceramic oxygen generator during idle mode thereby ensuring the desired purity level of oxygen is received by the oxygen receiving tank.

Abstract: An ion-conducting composite electrolyte is provided comprising path-engineered ion-conducting ceramic electrolyte particles and a solid polymeric matrix. The path-engineered particles are characterized by an anisotropic crystalline structure and the ionic conductivity of the crystalline structure in a preferred conductivity direction H associated with one of the crystal planes of the path-engineered particle is larger than the ionic conductivity of the crystalline structure in a reduced conductivity direction L associated with another of the crystal planes of the path-engineered particle. The path-engineered particles are sized and positioned in the polymeric matrix such that a majority of the path-engineered particles breach both of the opposite major faces of the matrix body and are oriented in the polymeric matrix such that the preferred conductivity direction H is more closely aligned with a minimum path length spanning a thickness of the matrix body than is the reduced conductivity direction L.

Abstract: A device for the concurrent oxygen generation and control of carbon dioxide for life support system involves two stages, where a first stage removes CO2 from an exhalent side of a ventilation loop and a second stage employs Ceramic Oxygen Generators (COGs) to convert CO2 into carbon and O2. The first stage includes a plurality of chambers and means to switch the ventilation loop through at least one of the chambers, where CO2 removal is carried out before discharge of the CO2 depleted gas to an inhalant side of the ventilation loop, and to exclude the ventilation loop from the remaining chambers of the first stage, where these chambers are placed in communication with the second stage. The second stage has two portions separated by the COGs such that CO2 and the formed carbon remain on an intake portion from the O2 rich atmosphere on the exhaust side, which is plumbed via a metering valve to introduce the O2 rich atmosphere to the inhalant side of the ventilation loop.

Abstract: A method and apparatus for producing a carbon monoxide containing product in which cathode and anode sides of an electrically driven oxygen separation device are contacted with carbon dioxide and a reducing agent, respectively. The carbon dioxide is reduced to carbon monoxide through ionization of oxygen and the reducing agent lowers the partial pressure of oxygen at the anode side to partially drive oxygen ion transport within the device through the consumption of the oxygen and to supply heat. The lowering of oxygen partial pressure reduces voltage and therefore, electrical power required to be applied to the device and the heat is supplied to heat the device to an operational temperature and to the reduction of the carbon dioxide occurring at the cathode side. The device can be used as part of an integrated apparatus in which the carbon dioxide is supplied from a waste stream of a process plant.

Abstract: A composite oxygen transport membrane having a dense layer, a porous support layer and an intermediate porous layer located between the dense layer and the porous support layer. Both the dense layer and the intermediate porous layer are formed from an ionic conductive material to conduct oxygen ions and an electrically conductive material to conduct electrons. The porous support layer has a high permeability, high porosity, and a high average pore diameter and the intermediate porous layer has a lower permeability and lower pore diameter than the porous support layer. Catalyst particles selected to promote oxidation of a combustible substance are located in the intermediate porous layer and in the porous support adjacent to the intermediate porous layer. The catalyst particles can be formed by wicking a solution of catalyst precursors through the porous support toward the intermediate porous layer.

Abstract: The present invention generally relates to conducting materials such as mixed ionically and electrically conducting materials. A variety of materials, material compositions, materials with advantageous ratios of ionically and electrically conducting components, structures including such materials, and the like are provided in accordance with the invention. In one aspect, the invention relates to conducting ceramics for electrochemical systems and, in particular, to mixed ionically and electrically conducting ceramics which can be used, for example, for electrochemical systems and, in particular, to mixed ionically and electrically conducting ceramics which can be used, for example, for hydrogen gas generation from a gasified hydrocarbon stream. One aspect of the invention provides a material comprising a first phase comprising a ceramic ionic conductor, and a second phase comprising a ceramic electrical conductor.

Abstract: An oxygen generator includes a monolithic body having first and second channels extending longitudinally therein. An electrode is operatively disposed in the first channels and a counter-electrode is operatively disposed in the second channels. The second channels are formed in the monolithic body so each second channel is electrically isolated from, yet adjacent to a first channel, resulting in an alternating configuration of first and second channels. The first channels have fluid or oxygen flowing therethrough, while the second channels have the other of oxygen or fluid flowing therethrough. An output manifold, having an oxygen collection area separated from a fluid collection area, operatively engages with the monolithic body. The oxygen collection area receives substantially pure oxygen from one of the second or first channels, and the fluid collection area receives oxygen-depleted fluid from the other of the first or second channels.

Abstract: Ion transport membrane system comprising (a) a pressure vessel comprising an interior, an exterior, an inlet, an inlet conduit, an outlet, and an outlet conduit; (b) a plurality of planar ion transport membrane modules disposed in the interior of the pressure vessel and arranged in series, each membrane module comprising mixed metal oxide ceramic material and having an interior region and an exterior region, wherein the inlet and the outlet of the pressure vessel are in flow communication with exterior regions of the membrane modules; (c) a gas manifold having an interior surface wherein the gas manifold is in flow communication with the interior region of each of the planar ion transport membrane modules and with the exterior of the pressure vessel; and (d) a liner disposed within any of the inlet conduit, the outlet conduit, and the interior surface of the gas manifold.

Abstract: A device for the concurrent oxygen generation and control of carbon dioxide for life support system involves two stages, where a first stage removes CO2 from an exhalent side of a ventilation loop and a second stage employs Ceramic Oxygen Generators (COGs) to convert CO2 into carbon and O2. The first stage includes a plurality of chambers and means to switch the ventilation loop through at least one of the chambers, where CO2 removal is carried out before discharge of the CO2 depleted gas to an inhalant side of the ventilation loop, and to exclude the ventilation loop from the remaining chambers of the first stage, where these chambers are placed in communication with the second stage. The second stage has two portions separated by the COGs such that CO2 and the formed carbon remain on an intake portion from the O2 rich atmosphere on the exhaust side, which is plumbed via a metering valve to introduce the O2 rich atmosphere to the inhalant side of the ventilation loop.

Abstract: Ion transport membrane oxidation system comprising an enclosure having an interior and an interior surface, inlet piping having an internal surface and adapted to introduce a heated feed gas into the interior of the enclosure, and outlet piping adapted to withdraw a product gas from the interior of the enclosure; one or more planar ion transport membrane modules disposed in the interior of the enclosure, each membrane module comprising mixed metal oxide material; and a preheater adapted to heat a feed gas to provide the heated feed gas to the inlet piping, wherein the preheater comprises an interior surface. Any of the interior surfaces of the enclosure, the inlet piping, and the preheater may be lined with a copper-containing metal lining. Alternatively, any of the interior surfaces of the inlet piping and the preheater may be lined with a copper-containing metal lining and the enclosure may comprise copper.

Abstract: Disclosed herein are a system and a method for the production of hydrogen. The system advantageously combines an independent high temperature heat source with a solid oxide electrolyzer cell and a heat exchanger. The heat exchanger is used to extract heat from the molecular components such as hydrogen derived from the electrolysis. A portion of the hydrogen generated in the solid oxide electrolyzer cell is recombined with steam and recycled to the solid oxide electrolyzer cell. The oxygen generated on the anode side is swept with compressed air and used to drive a gas turbine that is in operative communication with a generator. Electricity generated by the generator is used to drive the electrolysis in the solid oxide electrolyzer cell.

Abstract: The present invention provides a method for producing negatively charged oxygen atoms comprising: placing a negative electrode (3) on a surface of a member (2) made of calcium-aluminum composite oxide, proximately placing a positive electrode (10) on a side of the member opposite to the surface on which the negative electrode is placed, supplying oxygen to the negative electrode side, and applying voltage between the negative electrode and the positive electrode so as to extract negatively charged oxygen atoms (A) from the side where the positive electrode (10) is placed. The present invention also provides an apparatus for producing negatively charged oxygen atoms which is used for the above method.

Abstract: A method of operating an integrated hydrogen production and processing system is provided. The method includes operating an electrolyzer to produce hydrogen from water and utilizing heat generated from the electrolyzer to increase a temperature of an electrolyte in a first mode of operation. The method also includes heating the electrolyte in a second mode of operation by extracting heat from a hydrogen compressor to increase or maintain the temperature of the electrolyte during periods when electrolysis is not performed in the electrolyzer or during startup of the electrolyzer.

Abstract: In one embodiment, the electrochemical system comprises an electrochemical cell and hydrogen storage in fluid communication with the hydrogen electrode, the hydrogen storage comprising at least one of carbon nanotubes and carbon nanofibers. In one embodiment, the method for operating an electrochemical cell system, comprises introducing water to an oxygen electrode and electrolyzing the water to form oxygen, hydrogen ions and electrons, wherein the hydrogen ions migrate to a hydrogen electrode. The hydrogen ions can then be reacted with the electrons to form hydrogen gas that is stored in at least one of carbon nanotubes and carbon nanofibers.

Abstract: An electrochemical cell system includes a hydrogen electrode; an oxygen electrode; a membrane disposed between the hydrogen electrode and the oxygen electrode; and a compartmentalized storage tank. The compartmentalized storage tank has a first fluid storage section and a second fluid storage section separated by a movable divider. The compartmentalized storage tank is in fluid communication with the electrochemical cell. Further, an electrochemical cell includes a hydrogen electrode; an oxygen electrode; an electrolyte membrane disposed between and in intimate contact with the hydrogen electrode and said oxygen electrode; an oxygen flow field disposed adjacent to and in intimate contact with the oxygen electrode; a hydrogen flow field disposed adjacent to and in intimate contact with the hydrogen electrode; a water flow field disposed in fluid communication with the oxygen flow field; and a media divider disposed between the oxygen flow field and the water flow field.

Abstract: Flow-through capacitors are provided with one or more charge barrier layers. Ions trapped in the pore volume of flow-through capacitors cause inefficiencies as these ions are expelled during the charge cycle into the purification path. A charge barrier layer holds these pore volume ions to one side of a desired flow stream, thereby increasing the efficiency with which the flow-through capacitor purifies or concentrates ions.

Abstract: Solid membranes comprising an intimate, gas-impervious, multi-phase mixture of an electronically-conductive material and an oxygen ion-conductive material and/or a mixed metal oxide of a perovskite structure are described. Electrochemical reactor components, such as reactor cells, and electrochemical reactors are also described for transporting oxygen from any oxygen-containing gas to any gas or mixture of gases that consume oxygen. The reactor cells generally comprise first and second zones separated by an element having a first surface capable of reducing oxygen to oxygen ions, a second surface capable of reacting oxygen ions with an oxygen-consuming gas, an electron-conductive path between the first and second surfaces and an oxygen ion-conductive path between the first and second surfaces. The element may further comprise (1) a porous substrate, (2) an electron-conductive metal, metal oxide or mixture thereof and/or (3) a catalyst.

Abstract: An electrochemical cell system includes a hydrogen electrode; an oxygen electrode; a membrane disposed between the hydrogen electrode and the oxygen electrode; and a compartmentalized storage tank. The compartmentalized storage tank has a first fluid storage section and a second fluid storage section separated by a movable divider. The compartmentalized storage tank is in fluid communication with the electrochemical cell. Further, an electrochemical cell includes a hydrogen electrode; an oxygen electrode; an electrolyte membrane disposed between and in intimate contact with the hydrogen electrode and said oxygen electrode; an oxygen flow field disposed adjacent to and in intimate contact with the oxygen electrode; a hydrogen flow field disposed adjacent to and in intimate contact with the hydrogen electrode; a water flow field disposed in fluid communication with the oxygen flow field; and a media divider disposed between the oxygen flow field and the water flow field.

Abstract: The invention relates generally to ceramic oxygen generating modules, and more particularly, to an apparatus and method for controlling a duty cycle for each of a plurality of ceramic oxygen generating modules in a modular ceramic oxygen generating system.

Abstract: An electrochemical cell that receives an inlet stream of air and produces an outlet stream of a high oxygen concentration of gas. The cell is made up of a plurality of layers and preferably a porous electrolyte comprised of yttria stabilized zirconia (YSZ) that allows only oxygen ions to pass therethrough and which is covered on its sides with electrodes comprised of lanthanum strontium manganate (LSM) which in turn are coated with a layer of platinum to aid in the even distribution of the electrical current. An electrical current is passed through the electrodes to produce a voltage difference therebetween. The layers of YSZ and LSM are formed by a sol-gel process.

Abstract: The present invention provides an ion conducting ceramic membrane selectively permeable to a gas, for instance oxygen and a method of treating such a membrane to improve permeation through the membrane. The membrane is formed by a mass of a substance through which ions of the gas migrate. The mass has two opposed surfaces where dissociation and ionization of the gas occurs and gas ions release electrons and recombine to form molecules of the gas, respectively. At least one of said two opposed surfaces is treated by a removal of surface material to produce surface irregularities of increased area and therefore an increase in total surface area of a treated surface to in turn increase permeation of the gas. Preferably, both surfaces of the membrane are treated by chemical etching techniques, although sand blasting and ion etching are other possible surface treatments in accordance with the present invention.

Abstract: A gas generator comprising a layer of first material are provided with a layer of second material on one surface and a layer of third material on the other opposing surface is provided. The application of an external potential results in the flow of gas from one side of the generator to another due to the properties of the materials presented. The use of an electrolyte material as the first material and mixed conductors as the second and/or third materials is particularly beneficial in obtaining high flow rates. The use of the generator to produce oxygen for injection into a methane stream is particularly preferred.

Abstract: A ceramic membrane element for an oxygen separator is formed from a ceramic material represented by the structure: A1-xA′xB1-yB′yO3-z where A is a lanthanide element; A′ is a suitable lanthanide element dopant; B is selected from the group consisting of titanium, vanadium, chromium, manganese, iron, cobalt, nickel, zinc and mixtures thereof; B′ is copper; x is between 0.4 and 0.8; y is between 0.1 and 0.9; and z is>0 (and determined by stoichiometry). When B includes cobalt in an amount greater than 0.1, the included iron content is less than 0.05. The membrane element selectively transports oxygen ions therethrough at a relatively low temperature, with a flux detected at about 600° C. This enables the oxygen separator to be operated at lower temperatures than convention separators that frequently have operating temperatures in excess of 900° C. Mechanical stability may be enhanced by the addition of a second phase to the ceramic.

Abstract: A process for preparing a solid composite electrolyte comprising at least one compound of the BIMEVOX family is provided. The process comprises at least one step of preparing a mixture of one or more compounds of the BIMEVOX family with one or more chemically inert compounds, at least one step of compacting the mixture obtained, and at least one sintering step during which the temperature reached, over a nonzero time interval, has a value greater than the optimum sintering temperature for the compound of the BIMEVOX family.

Abstract: The invention concerns a method for decreasing the oxygen content of the atmosphere above photographic processing baths. The method comprises using a solid electrolyte which is a compound of bismuth, vanadium or another transition metal. The oxidation in air is thus minimized and the life of the bath is extended.

Abstract: Process for separating oxygen from a gas mixture containing it employs a solid-electrolyte electrochemical cell, where the cell includes a homogeneous structure of one or more BIMEVOX derivatives, with dynamic electrodes created "in situ" that are reversible and self-adaptive, and at least two current collectors.

Abstract: A single-crystal solid oxide material, rather than a polycrystalline ceramic, is used for electrolytic and fuel-cell applications. For the electrolytic production of oxygen from carbon dioxide, a yttria-stabilized zirconia crystal is coated with platinum electrodes and encased in a platinum structure to provide a thermally stable electrolytic cell. A multilayered device is constructed by stacking crystals and spacers in alternating arrangement and by plumbing the active surfaces of the crystals in parallel through perforations drilled directly in the solid-oxide crystals, so that manifolding and sealing problems are minimized.

Abstract: An electrochemical device for separating oxygen from an oxygen-containing gas comprises a plurality of planar ion-conductive solid electrolyte plates and electrically-conductive gas-impermeable interconnects assembled in a multi-cell stack. Electrically-conductive anode and cathode material is applied to opposite sides of each electrolyte plate. A gas-tight anode seal is bonded between the anode side of each electrolyte plate and the anode side of the adjacent interconnect. A regulating electrode, applied to the anode side of each electrolyte plate between the anode seal and the edge of the anode, eliminates anode seal failure by maintaining the 24-hour anode seal power density below about 1.5 .mu.W/cm.sup.2. A gas-tight seal is applied between the cathode sides of each electrolyte plate and the adjacent interconnect such that the anode and cathode seals are radially offset on opposite sides of the plate.

Abstract: An electrochemical process for extracting oxygen from an oxygen-containing gas which uses an electrochemical cell having two zones separated by a multi-component membrane made from intimate, gas-impervious, multi-phase mixture of an electronically conductive phase and an oxygen ion-conducting phase. In one zone a gas containing oxygen is passed in contact with the membrane. In the other zone a gas capable of reacting with oxygen is passed in contact with the membrane.

Abstract: The present invention relates to a combined cycle system of enhanced efficiency. The system comprises a top stage, such as a fuel cell, a partial oxidation reactor or a heat engine, and an oxygen-enriching device, such as a temperature swing adsorption device or a chemical reactor bed device, as its bottom stage. The bottom stage uses waste heat produced by the top stage to enrich the oxygen content of air that is inputted to the bottom stage, thereby producing an oxygen-enriched gas mixture as the bottom stage output. This output mixture constitutes a superior oxidant which is fed back as an input for the top stage, thus enhancing the energy conversion efficiency, cheapness, and compactness of the combined cycle system as compared to that of ordinary fuel cells, partial oxidation reactors and heat engines that use unenriched air as their oxidant input.

Abstract: An article for the separation, storage and delivery of substantially pure oxygen, comprises a closed walled, hollow container wherein at least a portion of at least one wall of the container is an oxygen separation material, providing a sole means for transporting substantially all oxygen into the container. An apparatus for the delivery of oxygen comprises means for transferring oxygen from a fluid containing oxygen to at least one such container at elevated temperature and pressure. The apparatus can provide means for transporting said the substantially pure oxygen-bearing container, means for storing said the container, and means for extracting oxygen from the container. A process includes filling the article with substantially pure oxygen, and, storing the substantially pure oxygen within the container for a selected period of time. The process may include releasing the oxygen from the container.

Abstract: An electrochemical device for separating oxygen from an oxygen-containing gas comprises a plurality of planar ion-conductive solid electrolyte plates and electrically-conductive gas-impermeable interconnects assembled in a multi-cell stack. Electrically-conductive anode and cathode material is applied to opposite sides of each electrolyte plate. A gas-tight anode seal is bonded between the anode side of each electrolyte plate and the anode side of the adjacent interconnect. A biasing electrode, applied to the anode side of each electrolyte plate between the anode seal and the edge of the anode, eliminates anode seal failure by minimizing the electrical potential across the seal. The seal potential is maintained below about 40 mV and preferably below about 25 mV. A gas-tight seal is applied between the cathode sides of each electrolyte plate and the adjacent interconnect such that the anode and cathode seals are radially offset on opposite sides of the plate.

Abstract: A method of controlling an oxygen generation device of the kind including a ceramic membrane through which an electrical current is passed whilst ambient air is supplied to one side of the membrane, the membrane allowing oxygen in the supplied air to diffuse therethrough by ionic transport when the membrane is at or above an operating temperature, at a rate dependant upon the electrical current, there being a plenum or the like to recover the oxygen at a second side of the membrane, the method comprising regulating the electrical current passing through the membrane by switching the electrical current on and off and varying the proportion of current-on time in a given time interval (t) in dependence upon a feedback signal.

Abstract: A thermophotovoltaic (TPV) system converts thermal or radiant heat into oxygen and electricity for use in a variety of applications. The TPV system and method for efficiently generating-oxygen and electric power through the combustion of fossil fuels with little or no nitrogen oxides or other undesirable combustion by-products. Combustion temperatures are kept at about 1,700.degree. C. or lower while burning a reactant mixture having an air/fuel ratio of greater than about 3:1. Heat from combustion products can be recycled and recuperated without concern for excessive increases in combustion temperature and subsequent combustor/emitter degradation. The generated oxygen may be harvested for commercial use as well as for introduction back into the TPV system.As a by-product of this improved TPV system, we have discovered an inexpensive, environmentally-friendly, and commercially viable method for generating pure oxygen molecules and electricity.

Abstract: A composite structure comprising:(i) a solid electrolyte which is an O.sup.2- anion conductor and essentially impermeable to gases;(ii) a cathode; and(iii) an anode, wherein the cathode and anode are porous to gases and wherein the electrolyte is in contact with the cathode and anode,wherein at least one of the cathode and anode is a voluminal electrode comprising (a) at least one BIMEVOX compound and (b) an electronic conductor, forming a distinct solid phase, dispersed in the BIMEVOX compound so as to define, within respective volumes of the voluminal electrode, a plurality of triple contact points between an ambient gaseous atmosphere, the electrolyte, and the electronic conductor.

Abstract: Solid membranes comprising an intimate, gas-impervious, multi-phase mixture of an electronically-conductive material and an oxygen ion-conductive material and/or a mixed metal oxide of a perovskite structure are described. Electrochemical reactor components, such as reactor cells, and electrochemical reactors are also described for transporting oxygen from any oxygen-containing gas to any gas or mixture of gases that consume oxygen. The reactor cells generally comprise first and second zones separated by an element having a first surface capable of reducing oxygen to oxygen ions, a second surface capable of reacting oxygen ions with an oxygen-consuming gas, an electron-conductive path between the first and second surfaces and an oxygen ion-conductive path between the first and second surfaces. The element may further comprise (1) a porous substrate, (2) an electron-conductive metal, metal oxide or mixture thereof and/or (3) a catalyst.

Abstract: Negatively charged oxygen atoms can be generated by the steps of (A) supplying oxygen to a surface of a solid electrolyte, at which the surface is provided an electrode A', while supplying electric current to the electrode A', to thereby form oxygen ions; (B) causing the oxygen ions formed in step (A) to be transmitted through the solid electrolyte; (C) forming negatively charged oxygen atoms at a surface of the solid electrolyte, an opposite surface on which the electrode A' is provided, by providing electric current to an electrode A on the opposite surface, to thereby produce negatively charged oxygen atoms from the oxygen ions; and (D) applying voltage to an electrode B spaced from the electrode A, in an amount sufficient to generate an electric potential between the electrode A and the electrode B, thereby causing the negatively charged oxygen atoms to move in the direction of the electrode B. The apparatus of the present invention can be used for the above method.

Abstract: An electrochemical process for producing unsaturated hydrocarbon compounds from unsaturated hydrocarbon compounds and for extracting oxygen from a gas containing N.sub.2 O, NO, NO.sub.2, SO.sub.2, or SO.sub.3 is described. The process is characterized by the use of mixed metal oxide materials having a perovskite structure represented by the formula:A.sub.s A'.sub.t B.sub.u B'.sub.v B".sub.w O.sub.xwherein A represents a lanthanide or Y, or a mixture thereof; A' represents an alkaline earth metal or a mixture thereof; B represents Fe; B' represents Cr or Ti, or a mixture thereof; and B" represents Mn, Co, Vi, Ni or Cu, or a mixture thereof.

Abstract: The present invention relates to an electrochemical cell comprising a solid electrolyte conductive for O.sup.2- anions in contact with an anode and a cathode of identical or different composition, the electrolyte solid being comprised of a composition derived from Bi.sub.4 V.sub.2 O.sub.11 of which at least one of the cationic constituent elements is substituted by at least one substituting element chosen such that the gamma phase structural type of Bi.sub.4 V.sub.2 O.sub.11 is maintained, as well as the equilibrium of charges, at least one of the anode or the cathode including two parts, a first part being of a mixed electronic and ionic conductive material in contact with the solid electrolyte, the second part being an electronic conductive material superposed on the first part. The invention equally relates to the use of the electrochemical cell with a view towards the separation or the extraction of oxygen.

Abstract: The present invention relates to an electrochemical cell comprising a solid electrolyte which conducts O.sup.2- anions in contact with an anode and a cathode of identical or different composition, the solid electrolyte being comprised of a composition derived from Bi.sub.4 V.sub.2 O.sub.11 of which at least one of the constituent cationic elements is substituted by at least one substituting element such that the gamma phase structural type of Bi.sub.4 V.sub.2 O.sub.11 is maintained as well as the equilibrium of charges, at least one of the anode or of the cathode is a material containing at least one element of substitution of said composition derived from Bi.sub.4 V.sub.2 O.sub.11, that element being in a metallic or cationic state. The invention equally relates to the use of the electrochemical cell with a view towards the separation or extraction of oxygen.