A device and a method for producing hydrogen and byproduct oxygen by using green electricity electrolyzed water are provided. The device comprises an oxygen purifying system, a heat exchange system, an air separation compression and expansion system, an air separation rectification system and a liquid oxygen storage system. The method comprises the following steps: first, purifying oxygen prepared by electrolyzing water by green electricity to remove impurities such as hydrogen, carbon monoxide, carbon dioxide and water in the oxygen, then feeding the pure oxygen into the heat exchange system, performing heat exchange liquefaction to obtain liquid oxygen, coupling the liquid oxygen generated by rectification of the air separation rectification system, and obtaining pressurized oxygen through the heat exchange system and the air separation compression and expansion system.

[Mn.sub.3SrO.sub.4] cluster compounds are synthesized in a single step from raw materials consisting of simple and inexpensive Mn.sup.2+, Sr.sup.2+ inorganic compounds and carboxylic acids by using permanganate anion as oxidant. This step can be followed by the synthesis of asymmetric biomimetic water splitting catalyst [Mn.sub.4SrO.sub.4] cluster compounds in the presence of water. The [Mn.sub.4SrO.sub.4] cluster compound can catalyze the splitting of water in the presence of an oxidant to release oxygen gas. The neutral [Mn.sub.3SrO.sub.4](R.sub.1CO.sub.2)6(R.sub.1CO.sub.2H).sub.3 cluster compound can serve as precursors for the synthesis of biomimetic water splitting catalysts, and can be utilized in the synthesis of different types of biomimetic water splitting catalysts. [Mn.sub.4SrO.sub.4](R.sub.1CO.sub.2).sub.8(L.sub.1)(L.sub.2)(L.sub.3)(L.sub.4) cluster compounds can serve as artificial water splitting catalysts, can be utilized on the surface of an electrode or in the catalyzed splitting of water driven by an anoxidant.

A device and a method for recovering by-product oxygen from water-electrolysis hydrogen production using a low-temperature method are provided, solving the waste problem of by-product oxygen in the green water-electrolysis hydrogen production system. The device according to the present disclosure comprises an oxygen clarifying system, a pressurizing and heat exchanging system, and a circulating gas compression and expansion refrigeration system. The recovering method according to the present disclosure comprises the following steps: first clarifying and purifying the by-product oxygen from water-electrolysis hydrogen production is to remove hydrogen, carbon monoxide, carbon dioxide, water and other impurities in the oxygen; and then, liquefying, pressurizing and heat exchanging the pure oxygen to obtain the product oxygen and liquid oxygen with required pressure. In the whole process, the cooling capacity is provided by the circulating gas expansion refrigeration system.

A noble metal-free water oxidation electrocatalyst can be stable and obtained from earth-abundant materials, e.g., using copper-colloidal nanoparticles. The catalyst may contain nanobead and nanorod morphological features with narrow size distribution. The onset for oxygen evolution reaction can occur at a potential of 1.45 V.sub.RHE (η=220 mV). Such catalysts may be stable during long-term water electrolysis and/or exhibit a high electroactive area, e.g., with a Tafel slope of 52 mV/dec, TOF of 0.81 s.sup.−1, and/or mass activity of 87 mA/mg. The copper may also perform CO.sub.2 reduction at the cathode side. The Cu-based electrocatalytic system may provide a flexible catalyst for electrooxidation of water and for chemical energy conversion, without requiring Pt, Ir, or Ru.

Provided is a method of separating carbon and oxygen isotopes by using a laser. In one preferred embodiment, the method includes performing a photolysis process on formaldehyde including a carbon or oxygen isotope by irradiation with ultraviolet light having a wavelength ranging from 340 nm to 360 nm to generate carbon monoxide having a carbon or oxygen isotope enriched therein and hydrogen, performing a catalytic reaction on the carbon monoxide having a carbon or oxygen isotope enriched therein and the hydrogen to synthesize carbon dioxide (CO.sub.2) and water (H.sub.2O) having a carbon or oxygen isotope enriched therein, and cooling the H.sub.2O to recover CO.sub.2 having a carbon isotope enriched therein or H.sub.2O having an oxygen isotope enriched therein.

The invention relates to a method for separating gases which comprises: a first step in which a gas fuel stream comprising combustible substances that produce gas products when oxidised, and an oxygen-rich inlet stream are passed through at least two modules of oxygen-separating ceramic membranes, such that the two streams come into contact through the membranes and exchange heat; a second step of selective diffusion of oxygen from the oxygen-rich stream to the fuel stream, such that the outlet streams from the membrane modules are an oxygen-depleted or completely oxygen-free stream and a partially or completely oxidised stream; and a third step of recovery of at least two separate outlet streams of at least two gases selected from oxygen, nitrogen, carbon dioxide and hydrogen.

A noble metal-free water oxidation electrocatalyst can be stable and obtained from earth-abundant materials, e.g., using copper-colloidal nanoparticles. The catalyst may contain nanobead and nanorod morphological features with narrow size distribution. The onset for oxygen evolution reaction can occur at a potential of 1.45 V.sub.RHE (η=220 mV). Such catalysts may be stable during long-term water electrolysis and/or exhibit a high electroactive area, e.g., with a Tafel slope of 52 mV/dec, TOF of 0.81 s.sup.−1, and/or mass activity of 87 mA/mg. The copper may also perform CO.sub.2 reduction at the cathode side. The Cu-based electrocatalytic system may provide a flexible catalyst for electrooxidation of water and for chemical energy conversion, without requiring Pt, Ir, or Ru.

[Mn.sub.3SrO.sub.4] cluster compounds are synthesized in a single step from raw materials consisting of simple and inexpensive Mn.sup.2+, Sr.sup.2+ inorganic compounds and carboxylic acids by using permanganate anion as oxidant. This step can be followed by the synthesis of asymmetric biomimetic water splitting catalyst [Mn.sub.4SrO.sub.4] cluster compounds in the presence of water. The [Mn.sub.4SrO.sub.4] cluster compound can catalyze the splitting of water in the presence of an oxidant to release oxygen gas. The neutral [Mn.sub.3SrO.sub.4](R.sub.1CO.sub.2)6(R.sub.1CO.sub.2H).sub.3 cluster compound can serve as precursors for the synthesis of biomimetic water splitting catalysts, and can be utilized in the synthesis of different types of biomimetic water splitting catalysts. [Mn.sub.4SrO.sub.4](R.sub.1CO.sub.2).sub.8(L.sub.1)(L.sub.2)(L.sub.3)(L.sub.4) cluster compounds can serve as artificial water splitting catalysts, can be utilized on the surface of an electrode or in the catalyzed splitting of water driven by an anoxidant.

A method and system for producing hydrogen using an oxygen transport membrane based reforming system is disclosed. The system of the invention comprises at least two reactors in the form of sets of catalyst containing tubes: a first set of tubes comprising at least one reforming catalyst containing reforming reactor configured to produce a synthesis gas stream, and a second set of tubes comprising a reactively driven and catalyst containing oxygen transport membrane reactor configured to generate and radiate heat to the reforming reactor.

The synthesis gas product is further treated in a separate high temperature water gas shift reactor and optionally in a separate low temperature water gas shift reactor. Hydrogen is produced from the resulting hydrogen-enriched gas using hydrogen PSA. A distinctive feature of this OTM configuration is that no portion of the syngas is fed to the OTM reactor, which allows reforming to be conducted in the reforming reactors at much higher pressures. The synthesis gas stream is directed to the water gas shift (WGS) reactor where H2/CO ratio increases from about 4.7 to about 21. Since the WGS reaction is exothermic, the shifted syngas leaves the reactor at a higher temperature, typically about 410 C. This shifted syngas is used to heat the NG feedstock in the NG heater to about 370 C., and then used to preheat boiler feed water (BFW). Syngas leaving the BFW heater is at about 175 C. It is cooled down to about 40 C. in a syngas cooler fed by cooling water. The cooled syngas then enters a knock-out drum where water is removed from the bottoms as process condensate and recycled for use within the process.

The invention relates to a process for the concentration of oxygen in extraterrestrial atmospheres having low oxygen concentrations, using a thermochemical cyclic process.