72 results about "Cathodic catalyst" patented technology

The invention provides a preparation method of a bimetal organic framework composite material. According to the preparation method, the methanol solution of 2-methylimidazole is added into a zinc salt-containing solvent, and the methanol solution and the zinc salt-containing solvent are stirred uniformly, an obtained mixed solution stands still, so that ZIF-8 can be obtained; the methanol solutionof 2-methylimidazole is added into a solvent containing a proper amount of ZIF-8 and cobalt salt, and the methanol solution and the solvent are uniformly stirred, and an obtained mixed solution stands still, so that a bimetal organic framework precursor ZIF-8@ZIF-67 is obtained; the precursor is transferred into a tubular furnace so as to be subjected to high-temperature annealing, and porous carbon of a core-shell structure is obtained through derivation; the porous carbon material is mixed with PDDA, an obtained mixture is stirred, and the mixture is compounded with graphene oxide; and an obtained product is subjected to freeze-drying and high-temperature annealing sequentially, so that a porous carbon / graphene composite material is obtained. The porous carbon material prepared by the method disclosed by the invention is uniformly distributed on a graphene sheet layer; the composite material is good in stability and low in cost; and when the composite material is applied to an MFC cathode catalyst, the composite material shows good electrochemical catalytic performance.

The invention discloses a preparation method and application of a nitrogen and phosphorus codoped carbon oxygen reduction catalyst for a microbial fuel cell. The preparation method comprises the following steps: soaking cellulose by an ammonium phosphate compound brine solution, carrying out suction filtration, drying, and carbonizing under the protection of high-purity nitrogen, thereby obtaining nitrogen and phosphorus codoped carbon which serves as a cathode catalyst of the microbial fuel cell. The preparation method provided by the invention has the advantages that the catalyst is prepared by taking natural cellulose which is recyclable and is wide in source as a carbon source and taking cheap and nontoxic ammonium phosphate compound salt as a nitrogen source and a phosphorus source via a direct carbonization method, and can greatly improve the output power of the cell as the catalyst of the microbial fuel cell; the method is simple in preparation, is low in cost, and provides possibility for the scale production of the microbial fuel cells.

The invention discloses a cathodic catalyst for a lithium air battery and a preparation method thereof. The cathodic catalyst comprises a transition metal coordination complex and a carbon black carrier, wherein the transition metal complex is obtained by reacting cobalt salt or manganese salt with a nitrogenous ligand; the cathodic catalyst provides a catalytic center for the formation and the decomposition of lithium peroxide in the charge-discharge process of the lithium air battery; and the lithium air battery prepared by using the cathodic catalyst shows very good catalytic activity and stability, has the first circle discharge capacity reaching 4870 mAh / g<-1> (unit mass of active substances) when the current density is 0.05 mAcm<-1>, and has the discharge voltage stabilized to be 2.8 V. In the cathodic catalyst disclosed by the invention, the low-cost nitrogenous ligand is taken as a raw material; and compared with a noble metal catalyst or a macrocyclic compound catalyst generated by coordinating porphyrin and phthalocyanine with transition metal, the cathodic catalyst has the advantages of simple preparation process, good process repeatability, low cost and the like and can be used in the field of cathode materials of the lithium air battery.

The invention relates to a preparation method of a oxygen reduction catalyst and aims to provide a preparation method of a macroporous carbon oxygen reduction catalyst containing sulfur, nitrogen and transition metal element. The method comprises the following steps: adding a thiourea solution into a glucose solution, dropwise adding hydrochloric acid in water bath, and reacting to obtain a glucose thiourea prepolymer solution; adding a suspension containing transition metal salt and a nano-CaCO3 powder into the solution, heating to react and spray-drying to obtain a catalyst precursor; heating to carry out deep polymerization and carbonization; and cooling, ball-milling, removing a template by the use of hydrochloric acid, rinsing and drying to obtain a product. The transition metal element is added before the formation of a porous material such that more catalytic centers can be formed and distribution of catalytic centers is more uniform. The catalyst has large specific surface area, good conductivity and high catalytic activity, and is especially suitable for high current working condition. A synthesized non-noble metal catalyst can be applied to various fuel cells and also can be used as a cathode catalyst of an air cell. Costs are low.

A method for producing a cathode material for rechargeable lithium-air batteries, which has a cathode catalyst loaded onto carbon, includes: a step of sonicating a mixed solution including a carbon having a specific surface area of 20 to 1,500 m2 / g, a surfactant and a solvent, and a step of in situ synthesis of the cathode catalyst by (1) adding a cathode catalyst raw material to the mixed solution and (2) adding a solution containing an oxidant to the mixed solution to cause in situ precipitation of the cathode catalyst onto the carbon, the catalyst having a wire form in which the short axis length is smaller than that of the carbon and is 2 to 50 nm and the long axis length is longer than that of the carbon and is 5 to 200 nm.

The invention relates to the field of hydrogen production through water electrolysis, and discloses a method for producing hydrogen through electrolysis of water vapor. The method comprises: under theaction of direct current, carrying out a reduction reaction on a cathode side to produce hydrogen, and carrying out an oxidation reaction on an anode side to produce oxygen, wherein the electrolyteson the anode side and the cathode side are water vapor with a temperature of 100-200 DEG C, the cathode side and the anode side are isolated by an electrode assembly, and the electrode assembly is anion exchange membrane with two side surfaces respectively coated with a cathode catalyst and an anode catalyst. According to the invention, by adopting the method, the low-heating-value waste heat steam with a temperature of 100-200 DEG C can be effectively utilized, the quick start-stop requirement can be met, the electrolysis device can be simplified, the electrolysis efficiency can be improved,and the energy consumption can be reduced.

The invention belongs to the field of zinc air batteries, and discloses a method for preparing an iron / copper aza graphene zinc air battery cathode catalyst, comprising the following steps of: (1) mixing iron oxyhydroxide, copper hydroxide, graphene oxide and graphite phase carbon nitride (g-C3N4), and adding sodium alginate to obtain a gel; (2) placing the gel into a quartz tube closed at one end, vacuumizing the quartz tube by a centrifugal pump, and calcining the quartz tube in a muffle furnace at 750 to 950 degrees centigrade for 10 to 20 minutes, and then cooling the quartz tube at room temperature; (3) immersing a black solid obtained in the previous step in a hydrochloric acid for 8 to 12 hours at 50 to 80 degrees centigrade, washing a product with deionized water and ethanol to neutral, drying the product, placing the dried black powders in the quartz tube closed at one end, vacuumizing the quartz tube, calcining the quartz tube at 750 to 850 degrees centigrade for 10 to 20 minutes, and cooling the product to obtain the iron / copper aza graphene. The method is convenient and efficient. The prepared catalyst is an amorphous structure, and has high electrocatalytic oxygen reduction activity and good stability, and has a very good application prospect.

The invention relates to a preparation method of a kind of modified silicon gel absorbing agent used for protecting on-vehicle fuel batteries, which belongs to the branch of the non-metallic inorganic material technology and is applied to the field of gas absorption and separation. The preparation method uses 3-aminopropyl triethoxysilane as amino modifying agents, uses tetraethoxy silane as silicon gel precursors, and prepares and obtains modified silicon gel with uniformly decorated amino groups in a porous silicon gel framework through adding a certain number of amino modifying agents in the gel forming stage. The absorbing agent can be used for removing a trace amount of sulfur dioxide in the air, so cathodic catalysts of on-vehicle proton exchange membrane fuel batteries are protected from the poisoning effect of the sulfur dioxide. Compared with the prior art, the invention has the following advantages that: (1) the obtained absorbing agent has better capability for absorbing the trace amount of sulfur dioxide than active carbon fiber, the effect is shown through longer penetrating time and larger saturation adsorption capacity, in addition, the absorbing agent still has good absorbing capability when the humidity is lower; and (2) the obtained absorbing agent has simple and convenient preparation method, the operation is easy, the condition is mild, and the effects of energy saving and environment protection can be obtained.

The invention provides a nanometer bismuth catalyst and a preparation method and application thereof. The nanometer bismuth catalyst comprises a substrate and an active agent loaded on the substrate,wherein the active agent is nanometer bismuth with an exposed crystal face (001), (012), (104) or (110). The nanometer bismuth catalyst is prepared by using an interface confinement reduction method;when the prepared nanometer bismuth catalyst is used as a cathode catalyst of a flowing electrolytic tank to electrocatalytically reduce nitrogen so as to synthesize ammonia, Faraday efficiency is upto 18.3%, and an ammonia production rate is 605.5 [mu]g / mg<-1>Bi<h<-1>>; and thus, the limitations of low efficiency, low current efficiency and the like of electrochemical ammonia synthesis in the prior art are overcome, and a commercial value is obtained.

The invention relates to the field of hydrogen production through water electrolysis, and discloses a method and a device for producing hydrogen through water electrolysis. The method comprises: underthe action of direct current, carrying out a reduction reaction on a cathode side to produce hydrogen, and carrying out oxidation reaction on an anode side to produce oxygen, wherein the electrolyticsolution on the cathode side and the electrolytic solution on the anode side have pH difference, the cathode side and the anode side are isolated by an electrode assembly, and the electrode assemblyis an ion exchange membrane with two side surfaces respectively coated with an anode catalyst and a cathode catalyst. According to the invention, the ion exchange membrane can selectively permeate anions or cations, and the pH difference between the electrolytic solutions on the cathode side and the electrolyte on the anode side can accelerate the ion conduction rate, so that the electrolysis efficiency is improved, and the energy consumption is reduced.

The invention relates to a fuel cell membrane electrode with a renewable function and a preparation method thereof. The fuel cell membrane electrode with the renewable function is characterized in that a porous carbon adsorption layer is additionally arranged between a catalyst layer at the cathode side of the membrane electrode and a proton exchange membrane, wherein the porous carbon adsorption layer is composed of porous carbon materials and perfluorosulfonic acid proton exchange resin. Different from the background art, in the invention, the porous carbon adsorption layer is additionally arranged between the cathodic catalyst layer of the traditional fuel cell and the proton exchange membrane, thereby adsorbing or intercepting metal particles or ions which are transferred or diffused into the membrane to achieve the purpose of preventing the metal particles or ions from being transferred to the membrane side or into the membrane. Meanwhile, more importantly, catalyst noble metal particles (comprising metal particles adsorbed by transferring and metal particles generated after catalyst noble metal ions are reduced) which are adsorbed by the porous carbon adsorption layer can be also deposited on the porous carbon adsorption layer to form a new catalyst layer, thereby improving the service life of the fuel cell membrane electrode.

Disclosed is a flat fuel cell assembly, comprising a membrane cell assembly, a cathodic porous collector layer, an anodic porous collector layer and an air blocking material layer; wherein the membrane cell assembly is provided with a proton exchange membrane, an anodic catalyst layer, a cathodic catalyst layer, an anodic gas diffusion layer and a cathodic gas diffusion layer; the anodic catalyst layer and the athodic catalyst layer are respectively arranged at the two sides of the proton exchange membrane; the anodic gas diffusion layer and the cathodic gas diffusion layer are arranged respectively on the anodic gas diffusion layer and the cathodic gas diffusion layer; the cathodic porous collector layer is arranged at one side of the cathodic gas diffusion layer and the anodic porous collector layer is arranged at one side of the anodic gas diffusion layer; in addition, the air blocking material layer is arranged on the cathodic gas diffusion layer and is provided with at least one hole which is exposed at the surface of the cathodic porous collector layer.

The invention provides a cathode catalyst for hollow nano water electrolysis, and a preparation method thereof. The method comprises the following steps: 1, adding potassium ferricyanide into a mixedsolution of a cobalt salt and sodium citrate according to the molar ratio of the cobalt salt to the potassium ferricyanide of (0.1-1): (0.2-0.5), then standing still, separating an obtained product, and sequentially washing and drying to obtain a prussian blue-like compound; and 2, carrying out annealing treatment on the prussian blue-like compound and NaH2PO2 under a protective gas according to amass ratio of (0.2-0.4): (1-2) to obtain the cathode catalyst for hollow nano-electrolysis of water. The method is uniform in reaction heating, simple and easy to operate and easy to control, the used raw materials are low in cost, the target product is easy to obtain, and the prepared catalyst is of a hollow structure and has excellent electrocatalytic activity and cathode reaction stability.

The invention belongs to the field of zinc-air batteries, and particularly relates to a preparation method of a multi-transition metal nitride zinc-air battery cathode material and an application of the multi-transition metal nitride zinc-air battery cathode material in the field of zinc-air batteries. The preparation method specifically comprises the following steps: dissolving guanidine carbonate and transition metal salt in water to obtain a transition metal salt solution; freeze-drying the obtained transition metal salt solution to obtain a spongy solid; and finally, calcining the spongy solid at high temperature under the protection of inert gas to obtain a multi-transition metal nitride porous reticular material. The multi-transition metal nitride porous reticular material can be used as an oxygen reduction electrocatalyst and shows excellent stability. As a zinc-air battery air cathode catalyst material, the catalyst material shows relatively strong charging and discharging long-term cyclicity, and has a very considerable actual application prospect. In addition, the synthesis method is simple to operate and high in universality.

The invention discloses a preparation method of a crown-like multistage PdAg nanodendrite, a material obtained through the preparation method and an application of the material as an oxygen reductioncathode catalyst. The preparation method comprises the steps of adding a Pd-based metal precursor, an Ag-based metal precursor and 1-naphthol into a solvent, mixing evenly and then standing for reaction; and separating, washing and drying generated precipitates to obtain the crown-like multistage PdAg nanodendrite. The method disclosed by the invention is mild in condition, relatively high in yield and suitable for commercial production. The obtained crown-like multistage PdAg nanodendrite has the advantages of excellent electrocatalytic activity and stability as the oxygen reduction cathode catalyst.

The invention discloses a Pt nanoparticle loaded molybdenum dioxide / nickel hydroxide nanosheet array structure material, a preparation method and application thereof. The preparation method comprisesthe following steps of: dissolving a nickel salt, a molybdenum salt, a reducing agent and a platinum source aqueous solution in ammonia water, adding methanol, uniformly stirring the substances, continuously adding the platinum source aqueous solution, uniformly mixing the substances, transferring the mixed solution into a reaction kettle, obliquely putting foamed nickel into the solution, carrying out solvothermal reaction, performing cooling to room temperature after the reaction is finished, and washing and drying the product to obtain a product. MoO2 in the product has metallicity, so thatMoO2 exists in the material as an electron donor, Schottky barriers between Ni(OH)2 and a foamed nickel substrate and between Ni(OH)2 and Pt nanoparticles are greatly reduced, and electron transfer in the reaction process is accelerated; meanwhile, high-valence Mo ions can well stabilize active Ni<2+> ions on an interface, so that the catalytic stability of the material is further improved; as acathode catalyst material for hydrogen evolution or total hydrolysis reaction, the catalyst has the advantages of high catalytic activity, excellent stability and simple preparation process.

The invention discloses a nano lithium manganite loaded carbon material cathode catalyst used for oxygen reduction of an air electrode as well as a preparation method of the nano lithium manganite loaded carbon material cathode catalyst. The nano catalyst is obtained by mixing organic dispersion solutions of potassium hypermanganate, lithium hydroxide and a carbon material through liquid-phase ultrasounds and carrying out a one-step hydrothermal reaction. Nano lithium manganite prepared by the method is uniformly loaded on the surface of the carbon material, and grains have uniform sizes and high purity. The catalyst can be applied to a metal-air battery and other energy conversion systems needing the oxygen reduction of the air electrode, and has relatively high coulombic efficiency, excellent multiplying power charge-discharge performances and good battery circulating stability; and the method for preparing the catalyst is simple, has good process repeatability, is low in cost and is suitable for industrial large-scale production.

The invention discloses a preparation method of a cobaltosic oxide and carbon quantum dot composite material, which comprises the following steps: firstly, preparing carbon quantum dots: crushing disposable chopsticks into sawdust as a carbon source, adding deionized water, and carrying out hydrothermal reaction at 180 DEG C for 6 hours to obtain a carbon quantum dot solution. The preparation method of the cobaltosic oxide / carbon quantum dot composite material comprises the following steps: adding Co (NO3) 2.6 H2O into a treated carbon quantum dot solution, adjusting the ratio of carbon quantum dots to Co (NO3) 2.6 H2O, adding urea as a precipitator and hexadecyl trimethyl ammonium bromide as an active agent, and synthesizing the cobaltosic oxide / carbon quantum dot composite material. The method is simple in process, convenient to operate and low in cost and the defects of complex process, high cost and the like of an ORR oxygen evolution cathode catalyst in the prior art are overcome.

A microfuel cell includes a substrate and a plurality of spaced-apart PEM dividers extending outwardly to define anodic and cathodic microfluidic channels. An anodic catalyst / electrode lines at least a portion of the anodic microfluidic channels, and a cathodic catalyst / electrode lines at least a portion of the cathodic microfluidic channels. Each anodic and cathodic catalyst / electrode may extend beneath an adjacent portion of a PEM divider in some embodiments. Alternately, the microfuel cell may include a plurality of stacked substrates, in which a first substrate has first microfluidic fuel cell reactant channels. A PEM layer may be adjacent the first surface of the first substrate, an anodic catalyst / electrode layer may be adjacent one side of the PEM layer, and a cathodic catalyst / electrode layer may be adjacent an opposite side of the PEM layer. An adhesive layer may secure the first substrate to an adjacent substrate defining at least a second microfluidic fuel cell reactant channel.

The invention discloses a V-Ni3FeN / Ni (at) N-GTs full electrolysis water electric catalyst constructed on the basis of doping and heterojunction strategies. The preparation method comprises the following steps: firstly, growing a V-doped Ni Fe precursor on a nitrogen-doped graphene tube carrier through a hydrothermal method, then heating to 470 DEG C in a tubular furnace, introducing ammonia gas, and nitriding for 2 hours to obtain the electrocatalyst consisting of V-doped Ni3FeN and Ni nanoparticles grown on the nitrogen-doped graphene tube in situ, namely V-Ni3FeN / Ni-N-GTs. Based on the synergistic effects of effective regulation and control of V doping on Ni and Fe electronic structures in Ni3FeN, rearrangement of charges induced by a heterojunction interface of V-Ni3FeN and Ni, good conductivity of a nitrogen-doped graphene tube carrier and the like, the electrocatalyst shows excellent electrocatalytic activity and stability in hydrogen evolution reaction and oxygen evolution reaction in an alkaline medium; the catalyst can be used as an anode catalyst and a cathode catalyst at the same time, is used for catalyzing a full hydrolysis reaction, can reach the current density of 10mA cm <-2 > only by needing the cell voltage of 1.55 V, and shows excellent stability.

The invention discloses a preparation method of a spinel type oxide catalyst. One or two transition metals of cobalt, iron, nickel, manganese, copper, chromium and zinc and aluminum are jointly heatedto a molten state by adopting a vacuum induction melting furnace, cooling is performed to obtain a rod-shaped alloy ingot, a vacuum melt-spinning device is employed for melting for blow casting intoa corresponding alloy strip, carrying out dealloying treatment on the alloy strip in an alkaline solution to obtain a dealloyed product, and in order to improve the crystallinity and stability of thematerial, the dealloyed product is placed in a tubular furnace for high-temperature annealing treatment in an air atmosphere, thus obtaining the spinel type oxide catalyst. The invention also relatesto application of the electrode material. The obtained catalyst has a multi-metal mixed valence state, can significantly enhance the conductivity of the material, shows good electrocatalytic activityto oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) in an alkaline environment, has good stability, and can be used as a cathode catalyst of a chargeable and dischargeable metal-airbattery.

The invention provides a molybdenum disulfide nanosheet, a preparation method and application thereof and a method for degrading halogenated antibiotics through electrochemical reduction. The synthesized thin-layer molybdenum disulfide nanosheet serves as a cathode catalyst in electrochemical reduction, halogenated antibiotics difficult to degrade in the water environment can be efficiently removed, accumulation of the antibiotics in the water environment is remarkably degraded, an economical and efficient application method is provided for effectively blocking drug-resistant gene transfer, and the application prospect is wide. Experimental results show that the synthesized thin-layer molybdenum disulfide nanosheet is used as a cathode material in electrochemical reduction, and halogenated antibiotics in sewage can be effectively degraded within 4 hours.

The invention discloses a preparation method of a porous carbon electrode, which comprises the following steps: adequately mixing water, polytetrafluoroethylene, black carbon and polymethylmethacrylate microspheres with the particle sizes of 5-250 mum, processing the obtained mixture into a needed shape, drying and determining the nature of the obtained mixture, and then, soaking the obtained mixture in a microsphere solvent or removing the polymethylmethacrylate microspheres by utilizing an extractive distillation method, and drying to obtain the porous carbon electrode. The porous carbon electrode prepared by the embodiment of the invention has an aperture and a porosity which are easy to control; further, pore structures are regular and orderly, so that a capacitor adopting the porous carbon electrode has the discharge capacity which is 12%-60% higher than that of a conventional similar container; furthermore, an organic solvent used in the preparation method can be utilized repeatedly and is energy-saving and environment-friendly; and in addition, as no expensive cathodic catalyst is necessary to be added, the production cost is decreased.

The invention discloses an iron doped cobaltosic oxide nano-film. The iron doped cobaltosic oxide nano-film is characterized in that a base of the film is formed by a piece of FTO conducting glass, and an iron doped cobaltosic oxide nano-composite material is deposited on the FTO conducting glass, and is composed of an upper nano flower-shaped structure and a lower three-dimensional multi-hole structure. The iron doped cobaltosic oxide nano material is prepared by a simple environment-friendly synthetic method, is utilized as an electrochemical catalyst of oxygen reduction, and is applied to an alkaline fuel cell platinum-free cathode catalyst.

The invention relates to the technical field of building materials, and aims to provide a preparation method of a manganese phthalocyanine modified oxhorn-shaped carbon-based catalyst. The preparationmethod comprises the following steps: calcining a mixture of ammonium bromide and melamine to obtain carbon nitride, and pyrolyzing in a nitrogen atmosphere; and cleaning and drying the product to obtain the oxhorn-shaped carbon-based catalyst; dispersing the manganese phthalocyanine modified oxhorn-shaped carbon-based catalyst into an N-N-dimethylformamide solution, performing ultrasonic treatment, adding manganese phthalocyanine molecules, performing ultrasonic treatment, stirring, cleaning and drying to obtain the manganese phthalocyanine modified oxhorn-shaped carbon-based catalyst. The product provided by the invention has rich porous structure, high specific surface area, high content of pyridine nitrogen and pyrrole nitrogen active sites and good conductivity, and is an efficient cathode catalyst. The carbon-based catalyst with the horn-shaped structure has a tip effect to enrich charges under the action of an electric field, so that the efficient reduction reaction of CO2 is promoted. Manganese single atoms in phthalocyanine manganese molecules are used as active sites, so that the reaction energy barrier of reducing CO2 into an intermediate product COOH * is reduced, theconversion reaction of CO2 into a CO gas product is promoted, and the Faraday efficiency is high.

The water electrolysis hydrogen production technology can produce green hydrogen on the basis of not consuming fossil energy, and the high-performance catalyst is adopted as an electrode material, so that the energy loss can be remarkably reduced, and the reaction efficiency is improved. The invention provides a nano fluffy NiMoCu catalyst and a preparation method thereof aiming at the current situation that the surface microstructure of the existing cathode catalyst is deficient and active sites are deficient, and belongs to the field of material preparation. According to the preparation method, an additive with a morphology adjusting effect is introduced into an electrolyte containing Ni, Mo and Cu elements, irregular particle bulges with nanoscale are distributed on the surface of the prepared nano fluffy NiMoCu catalyst, the prepared nano fluffy NiMoCu catalyst has sufficient reaction surface area and catalytic sites, the Tafel slope of the catalyst working in a 1M KOH solution is 70mV. Dec-1, the overpotential is 45mV when the current density is 10mA. Cm <-2 >, and the specific surface area of the catalyst is 10mA. Cm <-2 >. And the overpotential at a current density of 100 mA * cm <-2 > is 147 mV.

The invention discloses an aluminum-air battery cathode catalyst and a preparation method thereof. The preparation method comprises the steps: step 1, adding an Ag source compound, a Ni source compound, an acid-base buffer agent, a reducing agent and a surfactant into a solvent, and conducting a solvothermal reaction after mixing to obtain a reaction solution; step 2, adding a Mn source compound and a C source into the reaction solution obtained in the step 1, and carrying out ultrasonic stirring to obtain a catalyst precursor; drying the catalyst precursor, ball-milling the dried catalyst precursor and sieving the milled catalyst precursor to obtain precursor powder; and calcining and cooling the precursor powder to obtain the aluminum-air battery cathode catalyst. The preparation methodis simple, the raw materials are low in price, and the production cost of the battery material is greatly reduced; moreover, the Ag-Ni double-doped carbon-loaded manganese catalyst is prepared, the catalytic activity is further improved on the basis of maintaining the high catalytic activity of the Ag-based catalyst, and the oxygen reduction performance is excellent, so that the discharge performance of the aluminum-air battery is improved.

The invention relates to a method for producing hydrogen by coupling dicarboxylic acid prepared by electrocatalytic oxidation of cyclic alcohol / cyclic ketone, which comprises the specific steps of using a transition metal phosphide nano electrocatalyst as a cathode catalyst and an anode catalyst respectively, and adding cyclic alcohol / cyclic ketone into an electrolyte aqueous solution to assemble an electrolytic tank; and carrying out constant-voltage reaction for 1-20 hours at the voltage of 0.3-10V. Compared with the traditional process for preparing dicarboxylic acid by oxidizing cyclic alcohol / cyclic ketone with nitric acid, the method has the advantages that the transition metal phosphide nano electrocatalyst prepared by a simple method is used as an anode and a cathode, and the dicarboxylic acid is directly synthesized by applying constant voltage at room temperature and normal pressure, so that toxic and harmful gases such as N2O are not generated, and hydrogen co-production is realized. Meanwhile, the application range of the transition metal phosphide electrode material in the field of electrocatalytic organic synthesis is widened.

Provided is an apparatus containing, as a cathode catalyst, a metal oxide / carbon catalyst composition. The metal oxide / carbon catalyst composition includes 40 to 95 wt % porous Mn—Co spinel oxide nanoparticles of the formula MnxCo3-xO4. The nanoparticles have an octahedral morphology, an average particle size of 5-100 nm, and average pore sizes of 1-5 nm (where x is the atomic fraction of manganese and 3-x is the atomic fraction of cobalt). The metal oxide nanoparticles are supported on a carbon substrate that contains at least 96 atomic % carbon.

A unit consisting of a fuel cell, provided with a first ion-exchange membrane, and an electrolysis cell, equipped with a second ion-exchange membrane, capable of operating as an electrochemical hydrogen pump in which the electrolysis cell sucks in the discharge gas of the fuel cell anodic compartment which contains hydrogen as the main component, ionizes the hydrogen on a suitable anodic catalyst, sends the so formed protons across the second ion-exchange membrane to a suitable cathodic catalyst where the protons are reconverted to hydrogen which is mixed to the fuel cell hydrogen feed.