232 results about "Oxygen reduction" patented technology

A bimetal active site doped carbon-based catalyst, which is particularly a ZnMn-N-C catalyst. The ZnMn-N-C catalyst is prepared by using 1H-1,2,3-triazole, manganous nitrate and zinc chloride as reaction raw materials, subjecting same to a solvothermal reaction and then to drying to obtain a Mn-MET-ZnCl2 powder, and then sequentially subjecting the powder to primary pyrolysis, a sulfuric acid treatment and secondary pyrolysis. By respectively using 1H-1,2,3-triazole and zinc chloride as a mesopore forming agent and a micropore forming agent, and adjusting the pore-forming sequence and controlling the pore-forming process by means of pyrolysis, a large number of mesopores are preferentially formed, and then a large number of micropores are uniformly distributed in the mesopores, thereby forming a hierarchical pore channel structure and overcoming the problem of the collapse of the pore channel structure during the formation of the structure; and the obtained bimetal site doped carbon-based catalyst ZnMn-N-C has a high specific surface area of 1837.9 m2 / g and exhibits a good ORR activity (E1 / 2=0.867 V vs. RHE), and a primary zinc-air battery assembled by using the catalyst ZnMn-N-C as a positive oxygen reduction catalyst has a high energy density of 889 Wh / kg-1 Zn.

The invention provides a hydrogen fuel cell catalyst as well as a preparation method and application thereof, and relates to the technical field of catalysts, the catalyst comprises an N atom modified carbon carrier and platinum alloy nanoparticles loaded on the surface of the carbon carrier, the platinum alloy nanoparticles are binary or multicomponent alloys formed by Pt and metal M, the molar ratio of platinum to the metal M is (0-10): 1, and the molar ratio of platinum to metal M is (0-10): 1. The weight ratio of the N atom modified carbon carrier to the platinum alloy nanoparticles is (25-80): (75-20). According to the preparation method of the hydrogen fuel cell catalyst, the N-modified carbon-supported PtFe alloy is prepared by a two-step pyrolysis method, so that the use amount of Pt is effectively reduced, the cost is controlled, and the utilization rate of Pt is increased; through the strong coordination capability of the 1, 10-phenanthroline, the formed Fe-N-C layer can restrain the growth and agglomeration of the PtFe alloy nanoparticles, the adsorption to a reaction intermediate is weakened, and the oxygen reduction activity and stability of the alloy catalyst are improved.

The application discloses a preparation method of Fe single-atom and Cu cluster co-doped nitrogen-carbon material and application of the material in full-pH oxygen reduction electrocatalysis. The ZIF-8 with a three-dimensional and rich pore structure is used as a framework, and Fe@ZIF-8 is prepared by using a solvothermal method. Then, copper acetylacetonate is used as a copper source, and the copper acetylacetonate molecules dispersed in the gas phase are adsorbed on the surface of the ZIF-8 by using the rich pore structure of the ZIF-8 and the low sublimation temperature of the metal acetylacetonate salt. Finally, pyrolysis is carried out under nitrogen or inert atmosphere, so as to form the Fe single-atom and Cu cluster co-doped nitrogen-carbon material. The material is subjected to electrochemical test under acidic, neutral and alkaline conditions, and the material exhibits high oxygen reduction electrocatalysis performance in the full-pH range and has good stability. The material has good performance as a cathode catalyst in a fuel cell, an alkaline / neutral zinc-air battery, and has high application value.

The application provides a preparation method of a platinum-cobalt alloy catalyst, which comprises the following steps: preparing a hexadecyl trimethyl ammonium bromide clear solution; preparing a platinum compound, a transition metal cobalt salt and a dimethyl imidazole dispersion solution; adding the dispersion solution into the hexadecyl trimethyl ammonium bromide clear solution in sequence, stirring, adding a carbon black, a ketchen black, a cabot black or a carbon nanotube slurry, and continuously stirring to obtain a mixed solution I; then centrifuging, vacuum drying and grinding the mixed solution I to obtain an intermediate powder; then performing a different temperature staged calcination on the intermediate powder under a reducing / inert atmosphere to obtain an ordered low platinum-cobalt alloy catalyst powder; and then performing an acid washing, suction filtration, vacuum drying and grinding on the ordered low platinum-cobalt alloy catalyst powder to obtain a catalyst product which can be used in a fuel cell. The platinum-cobalt alloy catalyst prepared by the application can be applied to a proton exchange membrane fuel cell as a cathode oxygen reduction catalyst, and the platinum-cobalt alloy catalyst can improve the utilization rate, catalytic activity and durability of the noble metal Pt in the fuel cell cathode ORR catalyst, and can reduce the manufacturing cost and use cost of the fuel cell.

This invention discloses a method for preparing a noble metal electrocatalyst supported on a non-noble metal material and its application. The preparation method includes: Step 1, dissolving a non-noble metal precursor and a noble metal precursor in a mixed solvent; Step 2, adding a carbon support and ultrasonically dispersing until homogeneous; Step 3, rotary evaporation to obtain a solid phase; Step 4, treating the solid phase with NH3 gas and then with Ar gas; Step 5, ultrasonically dispersing the treated solid phase in a sulfuric acid aqueous solution and refluxing to obtain a refluxed solid phase; Step 6, washing the refluxed solid phase with water until the pH of the filtrate is neutral, and drying the washed solid phase to obtain the noble metal electrocatalyst supported on a non-noble metal material. In electrochemical tests conducted in an HClO4 aqueous solution, this noble metal electrocatalyst supported on a non-noble metal material exhibits a half-wave potential above 0.875 V vs. RHE and a specific activity above 310 mA / mg. Pt It exhibits significantly enhanced catalytic activity for oxygen reduction reactions.

The application provides a Sn-doped Fe-N-C catalyst, a preparation method and application thereof. The catalyst comprises a carrier and Sn atoms and Fe atoms supported on the carrier, and the carrier is an N-doped carbon material. The application dopes the p-block metal Sn with stronger electronegativity into the Fe-N-C catalyst, forms an electron-withdrawing environment around the FeN4 site, reduces the electronegativity of the FeN4 site, and weakens the adsorption strength of the FeN4 site on the oxygen reduction intermediate. Meanwhile, the metal Sn is weaker in reactivity with hydrogen peroxide produced by the reaction of oxygen via a two-electron process than Fe, reduces the concentration of free radicals produced by the reaction, improves the stability of the carrier and active sites, and can effectively prevent the shedding of Fe. The application uses the catalyst as a cathode catalyst of a proton exchange membrane fuel cell, is low in cost, and can simultaneously meet the requirements of high catalytic activity and good stability.

The preparation method mainly comprises the following steps: dissolving chloroplatinic acid, lanthanum salt and manganese salt in water according to a certain proportion, adding a complexing agent, adjusting the pH value, and carrying out gelation, drying and high-temperature calcination to obtain a perovskite precursor; and treating in a reducing atmosphere, so that platinum atoms are selectively dissolved out from crystal lattices, high-dispersion platinum nanoparticles are formed on the surface, and finally, the composite catalyst with extremely low platinum loading capacity is obtained. According to the method, platinum species are stably anchored through the perovskite carrier, the platinum atom utilization rate and catalytic stability are remarkably improved, excellent electrocatalytic activity and durability are shown in the oxygen reduction reaction, and the method can be widely applied to energy conversion equipment such as zinc-air cells and fuel cells and has important practical application value.

This invention provides a tunnel kiln structure with an external air duct. The external air duct allows natural air to bypass the bricks in the reduction zone and directly enter the high-temperature firing zone, satisfying the oxygen requirements for sintering while avoiding disruption of the oxygen-deficient reduction environment in the cooling reduction section. The sealed box structure, consisting of a reduction zone made of a preferred high thermal conductivity metal and partition doors, forms a stable oxygen-deficient environment chamber from the reduction zone to the kiln outlet, ensuring that the brick blanks complete reduction cooling under oxygen-free conditions. This eliminates the need for a crane cover system, directly saving on equipment investment and maintenance costs. Preheating the natural air by the outer surface of the reduction zone effectively prevents irreversible damage to the finished product from cold air shocks. Furthermore, the absence of airflow within the reduction zone allows for pressure balance, creating a stable oxygen-deficient reduction cooling environment without the need for additional pressure regulating devices. Continuous feeding and discharging and chamber sealing can be maintained through at least one partition door, ultimately achieving the technical effects of reduced brick firing costs, increased production capacity, and no new pollution.

The application relates to the technical field of graphene, in particular to platinum-loaded nitrogen-doped graphene as well as a preparation method and application thereof. The preparation method of the platinum-loaded nitrogen-doped graphene comprises the following steps: mixing graphene oxide, a platinum salt and a solvent to form a mixed solution, and then performing a hydrothermal reaction to prepare graphene oxide-platinum salt composite powder; mixing the graphene oxide-platinum salt composite powder with an amino compound, and performing ball milling to prepare amino-modified graphene oxide-platinum salt composite powder; and performing microwave irradiation on the amino-modified graphene oxide-platinum salt composite powder to prepare platinum-loaded nitrogen-doped graphene. The preparation process is simple, and the prepared platinum-loaded nitrogen-doped graphene has good oxygen reduction catalytic activity.

This method maintains electronic conductivity and oxygen reduction reactions while suppressing the decrease in gas diffusion performance due to sintering. [Solution] An electrochemical element in which an electrode layer 2, an electrolyte layer 4, and a counter electrode layer 6 are stacked in the order described, and the air electrode or oxygen generating electrode, which is either the electrode layer 2 or the counter electrode layer 6, has an active layer 6a in which an oxidation-reduction reaction is carried out from the side of the electrolyte layer 4 and a diffusion layer 6b for diffusing gas, wherein the diffusion layer 6b is composed of a mixture of particulate LSCF and CoMn metal oxide, which is a metal oxide containing particulate Co and Mn.

The invention relates to a preparation method of a PtGaGe alloy-loaded oxygen-doped carbon nanotube and application of the PtGaGe alloy-loaded oxygen-doped carbon nanotube in electro-catalytic oxygen reduction.The preparation method comprises the steps that firstly, the oxygen-doped carbon nanotube is prepared through a carboxylation method, and then platinum nitrate tetraammine, gallium nitrate and ammonium hexafluorogermanate are evenly mixed; the preparation method comprises the following steps: adding a PtGaGe alloy into an aqueous solution of an oxygen-doped carbon nanotube while continuously stirring, uniformly stirring at room temperature, freeze-drying, and roasting in a tubular furnace to finally realize successful loading of the PtGaGe alloy, thereby obtaining PtGaGe / OCNTs. As a novel preparation method, the trimetal alloy can be successfully prepared under the low-temperature condition, and the preparation method has the advantages of being simple in preparation process, mild in reaction condition, controllable in alloy variety and content and the like. According to the invention, the unique double p-d orbital hybridization characteristic in the ternary PtGaGe alloy is utilized, the electron structure of platinum is cooperatively regulated and controlled, the atom utilization rate and the catalytic efficiency of the ternary PtGaGe alloy are simultaneously improved, and the tradeoff relationship between activity and selectivity is successfully broken through.

The invention relates to the technical field of sewage treatment, in particular to a greenhouse gas emission control method and system applied to sewage nitrification treatment.The greenhouse gas emission control method is implemented in an aerobic treatment unit in a sewage digestion treatment system, and in the aerobic treatment unit, the sewage is subjected to nitrification treatment; arranging a front-section measuring point and a rear-section measuring point along the main flow direction of the mixed liquid, and periodically acquiring a first nitrite concentration time sequence at the front-section measuring point and a second nitrite concentration time sequence at the rear-section measuring point respectively; respectively configuring a front-section oxygen supply device and a rear-section oxygen supply device based on the front-section measuring point and the rear-section measuring point, controlling an oxygen supply base line of the front-section oxygen supply device based on the change trend of the first nitrite concentration time sequence and the second nitrite concentration time sequence, and controlling a short-time oxygen reduction control window of the rear-section oxygen supply device; wherein the oxygen supply base line is a preset oxygen supply level executed by the front-section oxygen supply device, and the short-time oxygen reduction control window carries out oxygen supply reduction or intermittent time arrangement for the rear-section oxygen supply device.

A high-load cobalt-based single-atom catalyst for oxygen reduction and its preparation method are disclosed, belonging to the field of electrocatalysis technology. This method utilizes the cage structure in ZnCo-ZIF to encapsulate nitrogen-rich metal molecules, followed by high-temperature carbonization under nitrogen conditions to obtain the catalyst. Benefiting from the separating effect of Zn metal nodes in ZIF and the spatial confinement effect of the ZIF cages, as well as the high nitrogen content in the guest molecule, a cobalt-based single-atom catalyst with a loading of 4.0 wt% was prepared. Furthermore, compared to traditional preparation methods, the catalyst prepared using a mixed solvent exhibits a small particle size, resulting in a high specific surface area that fully exposes the active sites. The large specific surface area allows for the full exposure of the high-load metal atom active sites, thus demonstrating excellent performance in the oxygen reduction reaction, with a half-wave potential of 0.88 V and a limiting current density of 6.0 mA·cm⁻¹ in 0.1 M KOH electrolyte. ‑2 .

The present application belongs to the technical field of fuel cell electrocatalysts, and particularly relates to a bromine-modified iron-nitrogen-carbon oxygen reduction electrocatalyst with high iron loading and atomic dispersion, and a preparation method and application thereof. The electrocatalyst is a porous carbon-based material, and contains carbon, nitrogen, bromine and iron elements, wherein the iron is anchored in the nitrogen-doped carbon substrate in the form of atomic dispersion. The preparation method comprises the following steps: dissolving a Fe-based metal macrocycle compound in an organic solvent, mixing the organic solvent with an aqueous solution containing 2-methyl imidazole and a Br-containing precursor, and adding an aqueous solution containing a zinc salt and a surfactant for co-assembly to obtain a precursor; and pyrolyzing the precursor to obtain a bromine-modified Fe-N-C electrocatalyst. Compared with the Fe-N-C electrocatalyst without bromine modification, the electrocatalyst can effectively regulate the local coordination environment of iron sites, and has the advantages of atomic dispersion, high iron loading and excellent oxygen reduction reaction activity, and can be used in fuel cells and related electrochemical energy conversion devices.

The present embodiment is a fuel cell including at least a membrane electrode assembly including an electrolyte membrane, an anode catalyst layer disposed on one surface of the electrolyte membrane, and a cathode catalyst layer disposed on the other surface of the electrolyte membrane, wherein the cathode catalyst layer includes at least an electrochemical oxygen reduction electrode catalyst including a catalyst metal having oxygen reduction activity and a modifier that modifies the catalyst metal, wherein the modifier is at least one selected from a nitrogen-containing cyclic organic compound and a polymer thereof, and includes a decomposition inhibitor that suppresses decomposition of the modifier in at least one selected from an electrolyte membrane, an anode catalyst layer, and a cathode catalyst layer.

The application belongs to the technical field of nanomaterials and electrocatalysis, and particularly relates to a one-dimensional nanowire structure monatomic alloy catalyst, a preparation method and application. The catalyst comprises a carrier and an active component, the structure of the active component is that Pt is dispersed in the form of monatomic on the surface of a nanowire of a base metal M, the M comprises one or more of Au, Ag, Ru, Pd, Rh, Ir and Os, and the active component is anchored on the carrier. The catalyst has an excellent one-dimensional nanowire structure with outstanding stability, the preparation process is simple, the effective product yield is high, and the prepared platinum-based catalyst material has superior oxygen reduction electrocatalytic performance and stability.

The invention belongs to the technical field of fuel cell cathode oxygen reduction catalysts, and particularly relates to a high-dispersion platinum group metal-transition metal mesoporous carbon catalyst and a preparation method and application thereof. The high-dispersion platinum-cobalt alloy mesoporous carbon catalyst is prepared in an ammonia water dipping coprecipitation-confinement reduction mode, the problems that in a traditional platinum-cobalt mesoporous carbon catalyst, the utilization rate of precious metal is low, and stability is poor are solved, efficient catalysis of a fuel cell ORR is achieved, and the application prospect is wide. The prepared high-dispersion platinum-cobalt mesoporous carbon catalyst has an ECSA attenuation rate of less than 10% in a disc electrode three-electrode test after long circulation for 60k circles, and has a potential of 0.678 V and 1.356 W / cm < 2 > in a proton exchange membrane fuel cell (PEMFC) test when the current density is 2000mA / cm < 2 >.

The invention discloses an oxygen reduction catalyst based on Nb-oxygen fluorine cluster confinement and pulse induction ordering as well as a preparation method and application of the oxygen reduction catalyst. The preparation method of the platinum-based multi-component alloy catalyst comprises the following steps: S1, adding ammonium niobate fluoride and hydrogen peroxide into a dispersion liquid containing a carbon carrier for reaction so as to introduce Nb-oxygen fluorine clusters on the surface of the carbon carrier in situ; s2, a platinum source, a cobalt source and a nickel source are added into a product obtained in the step S1, then ascorbic acid and sodium borohydride are added for a reaction, and Pt-Co-Ni alloy particles in the Nb-oxygen fluorine cluster confinement range are obtained; and S3, carrying out pulse Joule heating treatment on the product obtained in the step S2 so as to convert the alloy from a disordered structure into an ordered L12 phase, thereby obtaining the platinum-based multi-component alloy catalyst. The catalyst disclosed by the invention shows excellent oxygen reduction reaction activity and long-term stability when applied to the cathode of the proton exchange membrane fuel cell.

This invention belongs to the field of catalyst technology, specifically relating to a polyoxometalate-anchored cobalt single-atom catalyst, its preparation method, and its application. The invention uses a polyoxometalate as the anchoring substrate and electronic control unit. First, a cobalt-substituted polyoxometalate precursor is prepared via a coordination reaction, then composited with a ZIF-derived conductive carbon substrate, and finally reduced with hydrogen to obtain the target catalyst. This catalyst effectively inhibits cobalt single-atom aggregation, achieving a cobalt single-atom loading of 3.55 wt%. Under alkaline conditions, it exhibits excellent oxygen reduction catalytic activity, stability, and methanol resistance, with a half-wave potential of 0.826 V. When used in a zinc-air battery, it achieves an open-circuit voltage of 1.48 V and a flow rate of 239.6 mW / cm². 2 With maximum power density and excellent cycle stability, it can replace commercial platinum-carbon catalysts.

The application discloses an amorphous metal oxide-carbon composite material and application thereof in electrocatalytic oxygen reduction synthesis of H2O2, wherein the amorphous metal oxide-carbon composite material comprises porous carbon PC and amorphous metal oxide MO loaded on the porous carbon x The amorphous metal oxide-carbon composite material has excellent catalytic activity, double-electron ORR selectivity and long-time durability. Moreover, the preparation method of the amorphous metal oxide-carbon composite material has a simple technological process, the amorphous characteristic of the obtained metal oxide is extremely innovative, raw material cost is low, and the amorphous metal oxide-carbon composite material is beneficial to regulation and control, and is favorable to popularization of large-scale industrial utilization of electrocatalytic oxygen reduction preparation of H2O2.

The present application belongs to the technical field of fuel cell science and technology, and particularly relates to an oxygen reduction catalyst of carbon nanotube / covalent organic framework compound coupled polyaniline conductive polymer and a preparation method and application thereof. The present application takes thionine and 1,3,5-tri(p-formylphenyl)benzene as raw materials, prepares a covalent organic framework compound through a solvothermal synthesis method, combines the covalent organic framework compound with carbon nanotubes, and uses an in-situ chemical oxidation polymerization method to prepare a polyaniline-coated carbon nanotube / covalent organic framework compound material, so as to form a carbon nanotube / covalent organic framework compound coupled polyaniline conductive polymer functional material modified fuel cell cathode which has high conductivity and porosity. The method of the present application has low cost and strong operability. The prepared oxygen reduction catalyst has superior oxygen reduction catalytic performance, exhibits good electrochemical activity and stability, and can be used as a fuel cell cathode catalyst to improve the electrochemical performance in actual application.

An aircraft fuel system includes a first fuel storage tank arranged to store a first fuel, a fuel oxygen reduction unit arranged to generate a deoxygenated fuel from the first fuel, and a second fuel storage tank arranged to store the deoxygenated fuel generated by the fuel oxygen reduction unit, and being arranged to supply the deoxygenated fuel to an engine.

This invention discloses a method for preparing high-purity manganese dioxide, an oxygen electrode catalyst for zinc-air batteries. Addressing the environmental problems associated with using concentrated sulfuric acid or nitric acid as catalysts in the preparation of manganese dioxide for oxygen reduction batteries, as well as the corrosion of production equipment and safety hazards to operators during the production process, this invention proposes a method using a solid acid catalyst, acidic cation exchange resin, to replace concentrated sulfuric acid or nitric acid as the acid catalyst for preparing manganese dioxide for oxygen reduction batteries. Acidic cation exchange resins, especially strongly acidic cation exchange resins, contain sulfonic acid groups, which can completely ionize to release hydrogen ions, thus replacing sulfuric acid or nitric acid as the acid catalyst for preparing manganese dioxide. Furthermore, strongly acidic cation exchange resins can be regenerated and recycled.

The invention belongs to the technical field of polymer electrolyte membrane fuel cells, and provides preparation and application of a template-assisted derived electrocatalyst, metal macrocyclic compound self-assembly is performed on the surface of a metal organic framework material to form an ordered aggregate, and then high-temperature heat treatment is performed on the composite to prepare the corresponding electrocatalyst. The electrocatalyst prepared by the method does not form metal-based particles after being subjected to high-temperature heat treatment, so that metal aggregation is effectively avoided, the metal-nitrogen-carbon oxygen reduction active site density is improved, and the electrocatalyst has better oxygen reduction activity and stability in acidic and alkaline electrolytes. The preparation process of the catalyst adopted in the method does not need any acid treatment, the raw materials are rich in source, resources are saved, the cost is reduced, meanwhile, the preparation process of the non-noble metal electrocatalyst is simplified, and the prepared electrocatalyst has high oxygen reduction activity and durability and can be used in the field of polymer electrolyte membrane fuel cells.

The invention discloses an oxygen isolation reduction production method of a mud blank sintered product, and relates to the technical field of sintering processing. Firstly, green bricks are placed on a kiln car to be stacked into a brick pile, the kiln car containing the green bricks is pushed into an electric kiln, and a kiln door is closed; the electric kiln is started, and the temperature in the kiln is raised to 870-970 DEG C; when the temperature in the furnace is reduced to 600-900 DEG C, a furnace door is opened, the furnace is moved out of the kiln car, and a double-layer cylinder is hung on a brick pile of the kiln car; the double-layer cylinder comprises an inner cylinder and an outer cylinder; the two ends of the outer cylinder are open; the bottom end of the inner cylinder is open and the top end is closed; the brick pile is covered with an inner cylinder, and a gap between the inner cylinder and the outer cylinder is filled with solid powder; and when the temperature of the brick pile is less than or equal to 100 DEG C, lifting the double-layer cylinder to prepare a mud blank sintered product. When the method is used for producing the mud blank sintered product, the production cost can be reduced, and the production efficiency and the qualified rate of the sintered product can be improved.

The application discloses a method for preparing hydrogen peroxide through electrocatalytic oxygen reduction, wherein an oligolayer graphene wrapped Ni catalyst is dispersed in a solvent and dropped on the surface of a rotating ring disc glassy carbon electrode, and after drying, the catalyst is used as a working electrode for preparing hydrogen peroxide through electrocatalytic oxygen reduction. The application adopts the oligolayer graphene wrapped Ni catalyst to produce hydrogen peroxide through electrocatalytic oxygen reduction, the catalyst is simple to prepare and easy to implement, and raw materials are cheap and easy to obtain. The obtained oligolayer graphene wrapped Ni catalyst has excellent selectivity and stability in the process of preparing hydrogen peroxide through electrocatalytic oxygen reduction in an acidic environment, and has important significance for industrialization of electrochemical preparation of hydrogen peroxide in an acidic environment.

The invention provides a cathode material and a preparation method and application thereof. The cathode material disclosed by the invention comprises the perovskite type ferrite core and the CeO2 nanoparticles covering at least part of the surface of the core, so that the cathode material has relatively high oxygen reduction catalytic activity; the Ca element is used for replacing the Sr element, the defect that the Sr element is prone to segregation in the high-temperature and long-term operation process can be overcome, the problem that the Sr element reacts with electrolyte to generate a high-resistance third phase is thoroughly solved, and the tolerance of the cathode material to CO2 in feed gas is further enhanced. The chemical formula of the cathode material is LaaCa (0.4-x) CexCobFecO (3-delta), element selection of the cathode material is limited, and the proportion of each element is limited in a specific range, so that the cathode material has relatively high oxygen reduction catalytic activity and long-term running structural stability, the electrochemical performance of the battery is enhanced, the overall impedance of the battery can be reduced, and the service life of the battery is prolonged. And the maximum power density of the battery is improved.

A fuel oxygen reduction unit for an engine is provided. The fuel oxygen reduction unit includes an inlet fuel line; a stripping gas source; a contactor selectively in fluid communication with the stripping gas source, the inlet fuel line, or both to form a fuel / gas mixture; and a separator that receives the fuel / gas mixture, the separator configured to separate the fuel / gas mixture into an outlet stripping gas flow and an outlet fuel flow; wherein a flow of stripping gas passes through the fuel oxygen reduction unit a single time.

The application discloses a preparation method of niobium-tungsten alloy spherical powder and a 3D printing method thereof, and belongs to the technical field of refractory metal material preparation. The preparation method obtains a uniformly-composition ingot by smelting niobium, tungsten, molybdenum and zirconium refractory metal raw materials, forms a hydride powder by mechanical crushing after hydrogenation treatment, adopts plasma spheroidization technology to prepare the spherical powder, then dehydrogenates the spherical powder at 450-750 DEG C for 1-3 hours, and finally obtains low-oxygen niobium-tungsten alloy spherical powder with oxygen content lower than 120 ppm by adding magnesium powder and treating the spherical powder in an inert atmosphere at 800-1100 DEG C for 2-5 hours. Compared with a traditional process, the application innovatively places the spheroidization treatment before the dehydrogenation and oxygen reduction process, utilizes the relatively smaller specific surface area of the spherical powder to improve the deoxygenation efficiency, and realizes oxygen content control in combination with magnesium powder heat treatment. The application solves the problems of high oxygen content and low powder yield in the traditional process, and provides material support for high-performance niobium-tungsten alloy components in the fields of aviation, aerospace and nuclear power.

This invention discloses a method for preparing an oxygen reduction catalyst composed of a nickel-cobalt-aluminum layered double hydroxide and a two-dimensional transition metal carbide, comprising the following steps: preparing a nickel-cobalt-aluminum layered double hydroxide and a two-dimensional transition metal carbide; attaching the nickel-cobalt-aluminum layered double hydroxide to the two-dimensional transition metal carbide, thereby successfully preparing the nickel-cobalt-aluminum layered double hydroxide combined with the two-dimensional transition metal carbide, and disclosing its application as a cathode catalyst for microbial fuel cells. The material prepared by this invention has high porosity, numerous reaction sites, good electrochemical stability, and high conductivity. Therefore, as a cathode catalyst for microbial fuel cells, it improves the efficiency of ion flow, ensures the stability of electrode cycling and power generation efficiency, thereby improving the performance of microbial fuel cells.