93 results about "Hydrogen oxidation reaction" patented technology

The invention belongs to the technical field of metal electrocatalysts, and provides a preparation method and application of a nitrogen-doped carbon-supported metal nano-particle electrocatalyst withuniform particle size for alkaline hydroxidation reaction. The nitrogen-containing ligand and the carbon material are used as the nitrogen source and the carbon source, the nitrogen-doped carbon carrier contains more metal nanoparticle attachment sites is simply and quickly prepared through carbonization. As the metal salt is adsorbed in advance and the reduction temperature of the metal salt is controlled, the purpose of control the reduction rate of the metal salt is achieved, and the metal nanoparticles are uniformly dispersed on the carrier. A surfactant is not used in the invention, and the reagent used is safe and harmless. The preparation process of the invention is simple and easy, the synthesis cost is low, and the large-scale production is easy. The supported highly dispersed nano-electrocatalyst prepared by the invention has high electrocatalytic activity and is suitable for alkaline fuel cell anodic hydrogenation reaction.

The invention belongs to the technical field of metal electrocatalysts, and relates to a preparation method of a low-platinum metal spherical nanoparticle electrocatalyst with uniform nitrogen-doped carbon supported particle size and an application. The method comprises the following steps: dispersing platinum metal salt, M metal salt and a nitrogen-containing ligand into a solvent, and performingultrasonic treatment to obtain a uniform solution; putting the uniform solution into a water bath, and performing stirring at 20-90 DEG C; adding a carbon carrier dispersed in the solvent, carrying out ultrasonic treatment, performing stirring at 20-120 DEG C, and evaporating the solvent to dryness to obtain a black mixture; after drying and grinding, performing carbonizing for 0.1-3 hours at thetemperature of 200-1100 DEG C in an inert atmosphere; changing inert gas into reducing gas, and etching precipitates attached to the surfaces of the metal particles. According to the preparation method disclosed by the invention, a surfactant does not need to be used, and the prepared nitrogen-doped carbon-supported low-platinum metal spherical nanoparticle electrocatalyst with uniform particle size has higher electrocatalytic activity and is suitable for an anodic hydrogen oxidation reaction of a hydroxyl exchange membrane fuel cell.

The invention belongs to the technical field of noble metal electrocatalysts, and particularly relates to a preparation method of a carbon-supported Pt/M heterostructure nanowire electrocatalyst and an application. The preparation method comprises the following steps: dispersing platinum metal salt, transition metal M salt and a surfactant into an organic reagent with reducibility, performing ultrasonic treatment, adding a structure directing agent, and performing ultrasonic treatment; under a certain atmosphere, replacing air in a reaction system; raising the temperature and maintaining for 1-5 hours at a certain temperature; performing cooling and centrifugal washing to obtain Pt/M heterostructure nanowires, and dispersing the Pt/M heterostructure nanowires in a solution for later use; dispersing a carbon carrier into the solution, and performing ultrasonic treatment to obtain turbid liquid; adding the dispersed Pt/M heterostructure nanowire, and carrying out ultrasonic treatment; and performing centrifugal washing and drying to obtain the electrocatalyst. The Pt/M heterostructure nanowire with high dispersion and high yield is prepared by regulating and controlling the reducibility of the organic reagent, controlling the reaction atmosphere and regulating the surfactant, and is suitable for the hydrogen oxidation reaction of the hydroxyl exchange membrane fuel cell anode.

The invention provides a method for synthesizing VIII first-row transition metal and molybdenum/tungsten double-metal carbide catalyst at low temperature and belongs to the technical field of material preparation and application. The method is characterized in that double-metal oxide is obtained through hydrothermal treatment, and carbon-thermal hydrogen reduction is performed to prepare pure-phase double-metal carbide. Compared with a traditional arc-melting method and a programmed-temperature reduction method, the method has the advantages that the method is low in temperature, simple to operate, energy-saving, small in product particle, little in surface carbon pollution, and the like; the method is promising in application prospect; the prepared double-metal carbide catalyst is applicable to hydrogenation, dehydrogenation, hydrogenolysis, deoxidization, methane syngas, isomerization, ammonia decomposition, hydrogen evolution reaction, hydrogen oxidation reaction, oxygen reduction reaction, water gas transformation, catalyst carriers and the like.

The invention provides a method for synthesizing carvacrol by limo nene epoxides. The method comprises the following steps: step 1, under the action of a Lewis acid catalyst A, limo nene epoxide is heated up for open-loop rearrangement reaction to produce isodihydrocarvone, after reaction, white oil is added into the reaction liquid, vacuum distillation is conducted to obtain an isodihydrocarvone end product, and the catalyst A remains in the residue; step 2, isodihydrocarvone prepared in the step 1 and a catalyst B are dissolved in a solvent, the solvent is heated up for dehydrogenation oxidation to produce carvacrol, the reaction process is monitored by gas chromatography, when the content of isodihydrocarvone is 30-40%, the reaction is terminated, the catalyst B is filtered and separated out, vacuum distillation is performed on the filtrate, isodihydrocarvone and the solvent which are not subjected to reaction are reclaimed, and distillation is further conducted to obtain a carvacrol end product. The raw material is low in price and easily accessible, the synthesis process is environment-friendly, the catalysts can be recycled, and the method provided by the invention is suitable for industrial production.

The invention belongs to the technical field of electrocatalysts, and discloses a platinum monatomic hydrogen oxidation reaction electrocatalyst based on reactant enrichment and a preparation method thereof. The platinum monatomic hydrogen oxidation reaction electrocatalyst is a hollow core-shell structure electrocatalyst which is composed of monatomic distribution noble metal as a catalytic activity center and a porous nitrogen-doped hollow carbon shell, and has the noble metal loading capacity of 1-12%. The Pt1@PNC catalyst is finally prepared by preparing a Ptx < + >/SiO2 intermediate and a Pt1/SiO2@PNC intermediate. The preparation method disclosed by the invention is simple and convenient to operate and low in cost. The metal platinum in the prepared Pt1@ PNC catalyst is in a monatomic state and is uniformly distributed on the inner surface of the PNC, so that the adsorption and oxidation rate of hydrogen on the surface of a Pt1 active center is improved, and the Pt1@PNC catalyst shows excellent hydrogen oxidation reaction activity and stability under a relatively low potential. The catalyst is suitable for being applied to electro-catalytic hydrogen oxidation reaction and hydrogen evolution reaction as a catalyst.

The invention relates to a catalyst used to hydroxide in the ammonium hydroxide process of ethylbenzene. Wherein, it adds rare-earth element into platinum and tin system, to improve the hydrogen transfer rate and the selectivity of aromatic hydrocarbons.

The invention relates to a supported nano-metal catalyst for hydrogen oxidation reaction in an alkaline medium and a synthesis method thereof. The catalyst is a ruthenium-nickel bimetallic catalyst. According to the method, oleylamine and methylbenzene are used as solvents, p-dimethylaminobenzaldehyde is used as a reducing agent, and a series of nano particles with the Ru:Ni feeding ratio rangingfrom 1:9 to 9:1 are prepared respectively. The nanoparticles are loaded on activated carbon to prepare a corresponding carbon-loaded bimetallic nano catalyst, and then the performance of the catalystas a hydrogen oxidation electrocatalyst is researched, and the catalyst is found to obtain very good catalytic activity in an alkaline membrane fuel cell.

The invention belongs to the field of energy materials, and discloses a heteroatom doped cobalt-molybdenum binary metal carbide nano composite material as well as a preparation method and applicationthereof. The composite material is abbreviated as D-Co2Mo4C, wherein D is doped heteroatoms P, N, B, Sn or Se. The preparation method comprises the following steps of: adding a pretreated support material into a transition metal precursor solution of cobalt salt, molybdenum salt and a heteroatom dopant; carrying out ultrasonic treatment to uniformly mixing the materials; carrying out hydrothermalreaction at 90-180 DEG C; performing cleaning, drying; and carrying out heat treatment on a obtained composite material intermediate product at 600-1200 DEG C in a reducing atmosphere or a protectiveatmosphere. The composite material disclosed by the invention has efficient hydrogen oxidation reaction catalytic activity in alkalinity, has the potential of being applied to an anode of an anion exchange membrane fuel cell, and has a certain positive effect on promoting the development of a novel fuel cell. The composite material is applied to the field of electrocatalysis as a non-noble metal catalyst for a hydrogen oxidation reaction in an alkaline medium.

A chemovoltaic cell converts chemical energy generated by an in-situ molecular hydrogen oxidation reaction into electrical energy by creating a chemically induced nonequilibrium electron population on a catalytic surface of a Schottky structure, followed by charge separation and electric power generation using the Schottky contact.

The present invention relates to an electro-catalyst M′_aIrbM_c, wherein M′ is selected from the group consisting of Pt, Ta and Ru, and wherein the molar ratio a:b is within the range of 85:15 to 50:50 and the molar ratio a:c is within the range of 50:50 to 95:5, both calculated as pure metal and wherein M is selected from metals from Groups 3-15 of the Periodic System of Elements. The present invention further relates to an electrode comprising a support and the electro-catalyst. The present invention further relates to the use of the electro-catalyst and/or the electrode in electrochemical processes which comprise an oxygen reduction reaction (ORR), an oxygen evolution reaction (OER), a hydrogen evolution reaction (HER), a hydrogen oxidation reaction (HOR), a carbon monoxide oxidation reaction (COR) or a methanol oxidation reaction (MOR).

The invention discloses a method for synthetizing carvacrol through enediol. The method comprises the following steps of (1) dissolving the enediol and a catalyst A into a solvent, heating to enable the enediol to produce dehydration, ring-opening and rearrangement reactions, generating iso-dihydrocarvone, after reaction, neutralizing pH to be 7 to 8 through aqueous alkali, standing for layering, and carrying out organic phase vacuum distillation to obtain an iso-dihydrocarvone finished product; (2) dissolving the iso-dihydrocarvone prepared through the step (1) and a catalyst B into a solvent, heating to produce dehydrogenation oxidation reaction, generating the carvacrol, filtering and separating the catalyst B, carrying out filter liquor vacuum distillation to obtain a carvacrol finished product. According to the method for synthetizing the carvacrol through the enediol provided by the invention, the raw materials are convenient in source, low in price and easy to obtain; the synthetic process is green and environmentally friendly; post-processing purification only depends on rectification, so that the process is simple; the catalysts can be recycled so as to be suitable for industrial production.

A method and article of manufacture including a catalytic substrate with a surface layer providing balanced active sites for adsorption/dissociation of H₂ and adsorption of OH_ad for use in AFCs.

The invention relates to the technical field of electrochemistry and provides a ligand-protected Pt6 sub-nanocluster and a preparation method thereof, and a catalyst and a preparation method and application thereof. According to the method, a phosphine compound is used as a ligand, a weakly polar solvent with the polarity value of 1-5 is used as a solvent of the ligand, an amine complex is used asa reducing agent, the number of Pt atoms in the cluster is accurately controlled under the cooperation of the phosphine compound, the weakly polar solvent and the amine complex, and synthesis of thePt6 sub-nanocluster is achieved. The carbon-loaded Pt6 sub-nanocluster catalyst provided by the invention comprises a carbon carrier and a ligand-protected Pt6 sub-nanocluster loaded on the carbon carrier, and under the protection of the ligand, the Pt6 sub-nanocluster can stably exist and is not easy to agglomerate in the catalytic process; the carbon-supported Pt6 sub-nanocluster catalyst provided by the invention has ultrahigh quality activity and good stability for hydrogen oxidation reaction, the quality activity and durability of the catalyst are higher than those of a commercial Pt/C catalyst, and the catalyst has a wide application prospect.

A cell includes: a membrane electrode assembly; and a pair of separators. The membrane electrode assembly includes a polymer electrolyte membrane, an anode catalyst layer on a first main surface of the polymer electrolyte membrane, and a cathode catalyst layer on a second main surface. The anode catalyst layer contains a first catalyst material having activity against a hydrogen oxidation reaction and a first electrically conductive material whose electrical resistance under a hydrogen atmosphere and under an oxygen atmosphere are different from each other. The cathode catalyst layer contains a second catalyst material having activity against an oxygen reduction reaction and a second electrically conductive material different from the first electrically conductive material. An electrical resistance of the cell when the anode catalyst layer is under oxygen atmosphere is more than twice the electrical resistance of the cell when the anode catalyst layer is under hydrogen atmosphere.

The invention discloses a porous carbon loaded small-size precious metal nanoparticle composite material, and a porous carbon self-reduction preparation method and application of the composite material. An aqueous solution containing porous carbon and a metal salt is stirred, a self-reduction reaction is conducted on the metal salt under the action of the porous carbon in a stirring adsorption process, the metal nanoparticles obtained by reduction are loaded on porous carbon, and aftertreatment is conducted to obtain the porous carbon loaded metal nanoparticle composite material. The reduction potential of the porous carbon is lower than the reduction potential of the metal. Porous carbon which is low in price, easy to obtain, large in specific surface area, good in electrical conductivity, low in reduction potential and rich in surface functional groups is adopted as a self-reducing agent and a carrier, and the small-size precious metal nanoparticle composite porous carbon material high in dispersity is synthesized. Compared with other synthesis methods, the method has the advantages of effective reduction of the cost, simplicity, clear product, and facilitation of large-scale production; and the composite material obtained by the invention has excellent electrocatalytic hydrogen evolution and hydrogen oxidation reaction activity.

Methods are disclosed for starting up a fuel cell system from starting temperatures below 0° C. The methods apply to systems comprising a solid polymer electrolyte fuel cell stack whose cathodes comprise an oxygen reduction reaction (ORR) catalyst and whose anodes comprise both a hydrogen oxidation reaction (HOR) catalyst and an oxidation evolution reaction (OER) catalyst. In the methods, from the beginning of starting up until the fuel cell temperature reaches 0° C., the fuel cell stack current is kept sufficiently low such that the current density drawn does not exceed the stack's capability for the oxidation evolution and the oxygen reduction reactions to occur at the anode and cathode respectively (i.e. current density drawn is less than the stack's maximum OER/ORR current density).

The invention discloses a carbon-supported non-platinum palladium ruthenium tungsten nanoparticle catalyst for alkaline hydroxide reaction, and a preparation method and application thereof, and belongs to the technical field of electrocatalysts. The non-platinum palladium ruthenium tungsten electrocatalyst which is uniformly dispersed and uniform in particle size is prepared through a water bath reaction which does not need any surfactant and is simple and easy to operate, the catalyst is cleaned through a large amount of deionized water, and finally the non-platinum electrocatalyst with low noble metal loading capacity (10-20 wt%) is obtained. The prepared supported catalyst is formed by uniformly dispersing non-platinum-palladium-ruthenium-tungsten nano-particle crystals on the surface of a carbon carrier. The performance of the catalyst and the high-potential oxidation resistance of ruthenium are adjusted by adding different metal precursor salts into a mixed system. The obtained nanocrystal particles are very small, the size uniformity and dispersity are excellent, the electrochemical activity specific surface area and intrinsic activity are high, and the method is suitable for the hydrogen oxidation reaction of the anode side of the alkaline fuel cell.