InGaN offers a route to high efficiency overall water splitting under one-step photo-excitation. Further, the chemical stability of metal-nitrides supports their use as an alternative photocatalyst. However, the efficiency of overall water splitting using InGaN and other visible light responsive photocatalysts has remained extremely low despite prior art work addressing optical absorption through band gap engineering. Within this prior art the detrimental effects of unbalanced charge carrier extraction/collection on the efficiency of the four electron-hole water splitting reaction have remained largely unaddressed. To address this growth processes are presented that allow for controlled adjustment and establishment of the appropriate Fermi level and/or band bending in order to allow the photochemical water splitting to proceed at high rate and high efficiency. Beneficially, establishing such material surface charge properties also reduces photo-corrosion and instability under harsh photocatalysis conditions.

A portable oxygen concentrator designed for medical use where the sieve beds, adsorbers, are designed to be replaced by a patient. The concentrator is designed so that the beds are at least partially exposed to the outside of the system and can be easily released by a simple user-friendly mechanism. Replacement beds may be installed easily by patients, and all gas seals will function properly after installation.

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 method for using a natural attapulgite is disclosed. The method includes using the natural attapulgite as a natural nano mineral enzyme. The results of the examples show that the natural attapulgite has peroxidase-like activity, catalase-like activity or superoxide dismutase-like activity, and good biocompatibility. Compared with protease, the natural attapulgite has the advantages such as large reserves, easy to obtain, low cost, high temperature resistance and wide range of pH value. Compared with a developed artificial nano enzymes, the natural attapulgite further has the advantages such as multi-function, natural non-toxic (from nature, no heavy metals), good biocompatibility, easy to obtain, no complex processing, and huge surface area which provides a place for cell growth and proliferation.

The invention relates to an internal combustion engine that comprises a first Brayton cycle comprising a mixed ionic-electronic conducting (MIEC) membrane that separates the O.sub.2 from the air such that the suctioned air current is free from N.sub.2; a second Brayton cycle combined in a binary manner with the first Brayton cycle and nested with a cycle selected from an Otto cycle and a diesel cycle performed by means of oxy-combustion. The second Brayton cycle transmits mechanical energy and thermal energy from exhaust gases to the first Brayton cycle. The first Brayton cycle provides to the second Brayton cycle compressed O.sub.2 from the MIEC membrane. By means of the present engine, the NOx emission into the atmosphere is prevented by the separation of N.sub.2 in the MIEC membrane.

An apparatus and method generate oxygen gas from sodium percarbonate and water including seawater. The apparatus includes a chamber, a valve system, and an output port. The valve system controls combining a quantity of the sodium percarbonate, a quantity of the water, a quantity of potassium iodide, and optionally a quantity of sodium sulfate decahydrate. A chemical reaction between the sodium percarbonate and the water in the chamber generates oxygen gas, which is output at an output port from the chamber. The potassium iodide is a catalyst for the chemical reaction and optionally the sodium sulfate decahydrate is a temperature moderator for the chemical reaction. A ratio between the water and the sodium percarbonate is in a range of 2.5 to 8 by weight. A ratio of the potassium iodide per liter of the water yields a molarity in a range of 0.25 to 1.25.

A device for conversion of carbon dioxide to oxygen, includes, in order, an axial compressor, a centrifuge compressor, a drum, an air pump, and a housing which provides an accommodating space to house the above assemblies together. The axial compressor and centrifuge compressor inhale the carbon dioxide rich air into the accommodating space, then the carbon dioxide rich air pass through the surface of the reactor drum which cause the carbon dioxide bouncing between the reactor drum and the wall of the accommodating space, the collisions of the carbon dioxide molecules will bend and break the molecule bond between carbon and oxygen to produce oxygen. The device, as mentioned earlier, provides a solution to the greenhouse effect, which eliminates the carbon dioxide and generates oxygen by physical method, and advances a design to enhance the conversion process, which has the potential of being enlargement.

The present disclosure is directed to the integration of direct air capture of carbon dioxide with thermochemical water splitting, the latter optionally driven by solar energy. The disclosure is also directed to a process comprising extracting carbon dioxide from an air stream by contacting the air-stream with an alkali metal ion-transition metal oxide of empirical formula A.sub.xMO.sub.2 (0.1<x≤1), where A represents the alkali metal ion comprising sodium ion, potassium ion, or a combination thereof and M comprises iron, manganese, or a combination thereof to form a transition metal composition comprising an oxidized ion extracted-transition metal oxide.

A portable oxygen concentrator designed for medical use where the sieve beds, adsorbers, are designed to be replaced by a patient. The concentrator is designed so that the beds are at least partially exposed to the outside of the system and can be easily released by a simple user-friendly mechanism. Replacement beds may be installed easily by patients, and all gas seals will function properly after installation.

A portable oxygen concentrator includes at least one separation mechanism and an oxygen storage tank, where the separation mechanism is connected to the oxygen storage tank and includes an air bag and a molecular sieve tank that is filled with a molecular sieve for adsorption. The air bag has an air inlet and an air outlet. The air bag is connected to the molecular sieve tank through a valve group, which includes a first single valve and a second single valve. The air bag is connected to the molecular sieve tank through the first single valve. Each of the two ends of the molecular sieve tank has at least one gas outlet. When an inner space of the air bag is compressed and expanded once, the molecular sieve in the molecular sieve tank adsorbs and desorbs once.