A method for preparing an azo compound includes a first step for producing an X.sub.b molecule by electrolyzing, in a reaction system, a first solution including a hydrazo compound and at least one type of M.sub.aX.sub.b; a second step for oxidizing the hydrazo compound with the generated X.sub.b molecule to obtain a second solution including an azo compound, M.sub.aX.sub.b, and HX; a third step for discharging the second solution outside the reaction system, and separating therefrom a third solution including M.sub.aX.sub.b and HX to obtain a solid azo compound; and a fourth step for introducing the third solution and an additional hydrazo compound equivalent to the hydrazo compound into the reaction system, and electrolyzing a fourth solution including the additional hydrazo compound, M.sub.aX.sub.b, and HX to produce an X.sub.b molecule.

Systems and methods for manufacturing and use of a two layer coated electrode are provided. The two layer coated electrode may comprise a substrate, a first coating layer, and a second coating layer. The first coating layer may comprise a mixture of iridium oxide and tin oxide, and the second coating layer may comprise a mixture of iridium oxide and tantalum oxide. The electrode may be used in, for example, an electrolytic cell.

Disclosed are cathodes comprising a conductive support substrate having an electrocatalyst coating containing nickel hosphide nanoparticles and a co-catalyst. The conductive support substrate is capable of incorporating a material to be reduced, such as CO.sub.2 or CO. A cocatalyst, either incorporated into the electrolyte solution, or into the conductive support, or adsorbed to, deposited on, or incorporated into the bulk cathode material, alters the electrocatalyst properties by increasing the carbon product selectivity through interactions with the reaction intermediates. Also disclosed are electrochemical methods for selectively generating hydrocarbon and/or carbohydrate products from CO.sub.2 or CO using water as a source of hydrogen

A process for preparing or regenerating peroxodisulfuric acid and its salts by electrolysis of an aqueous solution containing sulfuric acid and/or metal sulfates at diamond-coated electrodes without addition of promoters is described, with bipolar silicon electrodes which are coated with diamond on one side and whose uncoated silicon rear side serves as cathode being used.

A method and a device for electrochemical reduction of carbon dioxide for preparing a high-concentration formate salt. Carbon dioxide is continuously supplied to a cathode unit and is continuously supplied to a metal hydroxide to the anode unit. A voltage or current is applied to the cathode unit and the anode unit for reducing the carbon dioxide to obtain the formate salt.

Provided is a cathode for electrolysis comprising a conductive substrate and a Ru element-containing catalyst layer on the conductive substrate, wherein in the catalyst layer, the ratio of the maximum intensity of the Ru 3d 5/2 peak appearing between 281.4 eV and 282.4 eV to the maximum intensity of the Ru 3d 5/2 peak appearing between 280.0 eV and 281.0 eV, in an X-ray photoelectron spectroscopic measurement is 0.45 or more.

This disclosure provides a unique approach for the synthesis of non-stoichiometric, mesoporous metal oxides with nano-sized crystalline wall. The as-synthesized mesoporous metal oxide is very active and stable (durability>11 h) electocatalyst in both acidic and alkaline conditions. The intrinsic mesoporous metal oxide serves as an electrocatalyst without the assistant of carbon materials, noble metals, or other materials, which are widely used in previously developed systems. The as-synthesized mesoporous metal oxide has large accessible pores (2-50 nm), which are able to facilitate mass transport and charge transfer. The as-synthesized mesoporous metal oxide requires a low overpotential and is oxygen deficient. Oxygen vacancies and mesoporosity served as key factors for excellent performance.

A method of carbon dioxide hydrogenation comprises introducing gaseous water to a positive electrode of an electrolysis 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 650° C. Carbon dioxide is introduced to the negative electrode of the electrolysis cell. A potential difference is applied between the positive electrode and the negative electrode of the electrolysis cell to generate hydrogen ions from the gaseous water that diffuses through the proton-conducting membrane and hydrogenates the carbon dioxide at the negative electrode. A carbon dioxide hydrogenation system is also described.

A method of carbon dioxide hydrogenation comprises introducing gaseous water to a positive electrode of an electrolysis 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 650° C. Carbon dioxide is introduced to the negative electrode of the electrolysis cell. A potential difference is applied between the positive electrode and the negative electrode of the electrolysis cell to generate hydrogen ions from the gaseous water that diffuses through the proton-conducting membrane and hydrogenates the carbon dioxide at the negative electrode. A carbon dioxide hydrogenation system is also described.

A method of manufacturing a bifunctional electrocatalyst for overall water splitting comprising oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) by growing electrocatalyst comprising primarily metallic phosphides on three-dimensional substrate by: immersing the substrate in an iron nitrate solution to form a once disposed substrate; subjecting the once disposed substrate to thermal phosphidation with phosphorus powder under inert gas to grow metal phosphides thereupon and form a once subjected substrate; cooling the once subjected substrate to form a cooled, once subjected substrate; immersing the cooled, once subjected substrate in an iron nitrate solution to form a twice disposed substrate; and subjecting the twice disposed substrate to thermal phosphidation with phosphorus powder under inert gas to provide an electrode comprising the bifunctional electrocatalyst on the three-dimensional substrate. An electrode for overall water splitting having a substrate and a bifunctional electrocatalyst comprising primarily metallic phosphides on a surface of the substrate.