A method of forming a hydrocarbon product and hydrogen gas comprises introducing CH.sub.4 to a positive electrode of an electrochemical cell comprising the positive electrode, a negative electrode, and a proton-conducting membrane between the positive electrode and the negative electrode. The proton-conducting membrane comprises an electrolyte material having an ionic conductivity greater than or equal to about 10.sup.−2 S/cm at one or more temperatures within a range of from about 150° C. to about 600° C. A potential difference is applied between the positive electrode and the negative electrode of the electrochemical cell to produce the hydrocarbon product and the hydrogen gas. A CH.sub.4 activation system and an electrochemical cell are also described.

The invention relates to a metallic bipolar plate for use in an electrochemical cell, wherein the bipolar plate comprises an electrically conductive graphene-like coating. The graphene-like coating has a layer thickness between 10 nm and 1 μm. Chemical synthesis is initially carried out to produce the graphene-like coating according to the invention comprising one or more at least partially reduced graphene oxide layers. Proceeding from graphite powder, a graphite oxide powder is initially produced, which is subsequently converted into a stable graphene oxide (GO) suspension by way of ultrasonic dispersion. By depositing this suspension on a metallic carrier substrate (bipolar plate), thin graphene oxide layers can then be applied and subsequently be reduced to obtain at least partially reduced graphene oxide (rGO), which is referred to as graphene-like. This coating advantageously has sufficient stability and the necessary electrical conductivity for use in an electrochemical cell.

The invention relates to a metallic bipolar plate for use in an electrochemical cell, wherein the bipolar plate comprises an electrically conductive graphene-like coating. The graphene-like coating has a layer thickness between 10 nm and 1 μm. Chemical synthesis is initially carried out to produce the graphene-like coating according to the invention comprising one or more at least partially reduced graphene oxide layers. Proceeding from graphite powder, a graphite oxide powder is initially produced, which is subsequently converted into a stable graphene oxide (GO) suspension by way of ultrasonic dispersion. By depositing this suspension on a metallic carrier substrate (bipolar plate), thin graphene oxide layers can then be applied and subsequently be reduced to obtain at least partially reduced graphene oxide (rGO), which is referred to as graphene-like. This coating advantageously has sufficient stability and the necessary electrical conductivity for use in an electrochemical cell.

An electrochemical cell having a composite alkali ion-conductive electrolyte membrane. Generally, the cell includes a catholyte compartment and an anolyte compartment that are separated by the composite alkali ion-conductive electrolyte membrane. The composite electrolyte membrane includes a layer of alkali ion-conductive material and one or more layers of alkali intercalation compound which is chemically stable upon exposure to a chemically reactive anolyte solution or catholyte solution thereby protecting the layer of alkali ion-conductive material from unwanted chemical reaction. The layer of alkali intercalation compound conducts alkali ions. The cell may operate and protect the alkali ion-conductive material under conditions that would be adverse to the material if the intercalation compound were not present. The composite membrane may include a cation conductor layer having additional capability to protect the composite electrolyte membrane from adverse conditions.

An electrochemical cell having a composite alkali ion-conductive electrolyte membrane. Generally, the cell includes a catholyte compartment and an anolyte compartment that are separated by the composite alkali ion-conductive electrolyte membrane. The composite electrolyte membrane includes a layer of alkali ion-conductive material and one or more layers of alkali intercalation compound which is chemically stable upon exposure to a chemically reactive anolyte solution or catholyte solution thereby protecting the layer of alkali ion-conductive material from unwanted chemical reaction. The layer of alkali intercalation compound conducts alkali ions. The cell may operate and protect the alkali ion-conductive material under conditions that would be adverse to the material if the intercalation compound were not present. The composite membrane may include a cation conductor layer having additional capability to protect the composite electrolyte membrane from adverse conditions.

A mixed conducting ceramic element comprises a plurality of tubes each having interior and exterior surfaces, a closed end and an open end. A tube support member receives the open ends of the tubes. The ceramic element has a general composition of A.sub.xA′.sub.x′A″.sub.x″B.sub.yB′.sub.y′B″.sub.y″O.sub.3-z, where A, A′ and A″ are selected from Group II elements or the Lanthanoids, and B, B′ and B″ are selected from the d-block transition metals, and wherein 0<x≦1, 0<x′≦1, 0<x″≦1, 0<y≦1, 0<y′≦1, 0<y″≦1, x+x′+x″≈1, y+y′+y″≈1, and z is selected so that the resultant composition is charge neutral. The ceramic element can be a composite consisting of two or more component materials, wherein one component is predominantly an electronic conductor and another is predominantly an ionic conductor. The ceramic element may also be a composite material containing at least one component material having a chemical composition of A.sub.xA′.sub.x′A″.sub.x″B.sub.yB′.sub.y′B″.sub.y″O.sub.3-z.

A mixed conducting ceramic element comprises a plurality of tubes each having interior and exterior surfaces, a closed end and an open end. A tube support member receives the open ends of the tubes. The ceramic element has a general composition of A.sub.xA′.sub.x′A″.sub.x″B.sub.yB′.sub.y′B″.sub.y″O.sub.3-z, where A, A′ and A″ are selected from Group II elements or the Lanthanoids, and B, B′ and B″ are selected from the d-block transition metals, and wherein 0<x≦1, 0<x′≦1, 0<x″≦1, 0<y≦1, 0<y′≦1, 0<y″≦1, x+x′+x″≈1, y+y′+y″≈1, and z is selected so that the resultant composition is charge neutral. The ceramic element can be a composite consisting of two or more component materials, wherein one component is predominantly an electronic conductor and another is predominantly an ionic conductor. The ceramic element may also be a composite material containing at least one component material having a chemical composition of A.sub.xA′.sub.x′A″.sub.x″B.sub.yB′.sub.y′B″.sub.y″O.sub.3-z.

Herein discussed is an electrochemical reactor comprising a first electrode, wherein the first electrode is liquid when the reactor is in operation; a second electrode having a metallic phase and a ceramic phase, wherein the metallic phase is electronically conductive and wherein the ceramic phase is ionically conductive; and a membrane, wherein the membrane is positioned between the first and second electrodes and is in contact with the first and second electrodes, wherein the membrane is mixed conducting. Also discussed herein is a method of producing hydrogen or carbon monoxide comprising: (a) providing an electrochemical reactor having an anode, a cathode, and a membrane between the anode and the cathode, wherein the anode is liquid when the reactor is in operation and wherein the membrane is mixed conducting; (b) introducing a feedstock to the anode; (c) introducing a stream to the cathode, wherein the stream comprises water or carbon dioxide.

Herein discussed is an electrochemical reactor comprising a first electrode, wherein the first electrode is liquid when the reactor is in operation; a second electrode having a metallic phase and a ceramic phase, wherein the metallic phase is electronically conductive and wherein the ceramic phase is ionically conductive; and a membrane, wherein the membrane is positioned between the first and second electrodes and is in contact with the first and second electrodes, wherein the membrane is mixed conducting. Also discussed herein is a method of producing hydrogen or carbon monoxide comprising: (a) providing an electrochemical reactor having an anode, a cathode, and a membrane between the anode and the cathode, wherein the anode is liquid when the reactor is in operation and wherein the membrane is mixed conducting; (b) introducing a feedstock to the anode; (c) introducing a stream to the cathode, wherein the stream comprises water or carbon dioxide.

Apparatuses and methods for performing coupled chemical and electrochemical reactions are disclosed. An electrochemical cell has a first reaction chamber configured to perform a chemical reaction and an anode chamber configured to perform an electrochemical reaction. The first reaction chamber and the anode chamber are separated by a first membrane. The first membrane acts as a cathode of the cell, a hydrogen-selective layer and a catalyst. The first membrane may comprise a layer of palladium or a palladium alloy. An ion exchange membrane separates the first membrane and the anode chamber. The chemical and electrochemical reactions may respectively be hydrogenation and dehydrogenation reactions.