An electrode catalyst for a water electrolysis cell includes a catalyst and a polymer of intrinsic microporosity, and the polymer of intrinsic microporosity is neutral.

A method includes collecting exhaust gas comprising carbon dioxide (CO.sub.2) at a wellsite to provide a collected exhaust gas, separating CO.sub.2 from the collected exhaust gas to provide a separated CO.sub.2, and forming urea utilizing at least a portion of the separated CO.sub.2. A system for carrying out the method is also provided.

A method includes collecting exhaust gas comprising carbon dioxide (CO.sub.2) at a wellsite to provide a collected exhaust gas, separating CO.sub.2 from the collected exhaust gas to provide a separated CO.sub.2, and forming urea utilizing at least a portion of the separated CO.sub.2. A system for carrying out the method is also provided.

Disclosed is a method for preparing a metal-carbon composite. The method includes synthesizing a planarized ligand compound via planarization-modification of a polyphenol-based ligand compound; synthesizing a metal-organic composite via hydrothermal synthesis of a mixed solution of the planarized ligand compound and metal ions; drying the metal-organic composite to prepare precursor powders; and carbonizing the precursor powders.

Disclosed is a method for preparing a metal-carbon composite. The method includes synthesizing a planarized ligand compound via planarization-modification of a polyphenol-based ligand compound; synthesizing a metal-organic composite via hydrothermal synthesis of a mixed solution of the planarized ligand compound and metal ions; drying the metal-organic composite to prepare precursor powders; and carbonizing the precursor powders.

An electrode catalyst layer for electrochemical cells includes a first catalyst layer and a second catalyst layer. The first catalyst layer has a cell resistance measured at 80° C. and 40% RH lower than that of the second catalyst layer. The electrode catalyst layer for electrochemical cells is used with the first catalyst layer being disposed on an electrolyte membrane side relative to the second catalyst layer. It is preferable that a first catalytically active component contained in the first catalyst layer and a second catalytically active component contained in the second catalyst layer each independently contain at least one element selected from the group consisting of platinum, palladium, ruthenium, and iridium.

An electrode catalyst layer for electrochemical cells includes a first catalyst layer and a second catalyst layer. The first catalyst layer has a cell resistance measured at 80° C. and 40% RH lower than that of the second catalyst layer. The electrode catalyst layer for electrochemical cells is used with the first catalyst layer being disposed on an electrolyte membrane side relative to the second catalyst layer. It is preferable that a first catalytically active component contained in the first catalyst layer and a second catalytically active component contained in the second catalyst layer each independently contain at least one element selected from the group consisting of platinum, palladium, ruthenium, and iridium.

Electrochemical systems and methods for cleaving C—C bonds are disclosed. In performing the method, a reactant adsorption electrical potential, a C—C bond breaking electrical potential, and a desorption electrical potential are sequentially applied to an electrode pair contacting a composition initially containing a target chemical reactant, such as a polymer or alkane. As a result of performing the method, one or more desired chemical products, such as smaller alkane-containing molecules, are released from the electrode into the region between the electrode pairs. The method may be performed at ambient temperatures using renewable electricity.

The disclosure provides a novel electrocatalytic membrane reactor and use thereof in preparation of high-purity hydrogen. The electrocatalytic membrane reactor adopts an H-shaped electrolytic tank in which a cathode chamber is isolated from an anode chamber through a diaphragm, a membrane electrode is used as an anode, an auxiliary electrode is used as a cathode, a direct-current regulated power supply supplies a constant current, and the flow of a reaction solution is realized through a pump. In the disclosure, electrocatalysis is coupled with a membrane separation function, an oxygen evolution reaction is replaced with an organic electrochemical oxidation reaction in the anode chamber so as to reduce the overpotential of the oxygen evolution reaction, and a hydrogen evolving reaction is performed in the cathode chamber to prepare high-purity hydrogen.

In a case where an alkali aqueous solution is used as an electrolyte, provided are an oxygen catalyst excellent in catalytic activity and composition stability, an electrode having high activity and stability using this oxygen catalyst, and an electrochemical measurement method that can evaluate the catalytic activity of the oxygen catalyst alone. The oxygen catalyst is an oxide having peaks at positions of 2θ=30.07°±1.00°, 34.88°±1.00°, 50.20°±1.00°, and 59.65°±1.00° in an X-ray diffraction measurement using a CuKα ray, and having constituent elements of bismuth, ruthenium, sodium, and oxygen. An atom ratio O/Bi of oxygen to bismuth and an atom ratio O/Ru of oxygen to ruthenium are both more than 3.5.