133results about How to "Improve oxygen reduction performance" patented technology

The invention relates to a catalyst with dispersed single platinum atoms and a preparation method of the catalyst, and aims at solving the technical problems that a precious metal oxygen reduction catalyst is high in preparation cost and low in utilization rate of platinum in the prior art. The catalyst with dispersed single platinum atoms is prepared by stirring, refluxing, evaporating, drying and grinding a carbon support, a nonmetal heteroatom reagent and a platinum compound as raw materials, and carrying out high-temperature treatment and interaction in a sliding rail furnace. A test result shows that the platinum element in the catalyst exists in a form of single atoms platinum; the catalytic activity is high; in acid and alkaline systems, the initial oxygen reduction potential and the half-wave potential are equivalent to those of a commercial carbon-supported platinum catalyst with the platinum content of 20%; other metal impurities are not introduced in the preparation process; and the stability is relatively good. The preparation method of the catalyst provided by the invention is relatively low in cost, simple and feasible. The catalyst is suitable for preparation of a fuel cell; the utilization rate of the platinum is greatly improved; the cost of the catalyst is reduced; and the commercialization process of the fuel cell can be promoted.

The invention relates to a hollow porous spherical platinum-silver alloy nano-material and a preparation method for the same. The nano-material is of a spherical structure with a porous shell and an internal cavity, the diameter of the spherical structure ranges from 5 nanometers to 500 nanometers, the inner diameter of the cavity ranges from 1 nanometer to 400 nanometers, the thickness of a porewall ranges from 1 nanometer to 50 nanometers, and the pore diameter ranges from 1 nanometer to 20 nanometers. Polyatomic alcohol, inorganic silver salt precursor, inorganic platinum salt precursor and polyvinylpyrrolidone are used as reaction raw materials, inorganic salt containing halogen ions and copper-containing inorganic salt are used as auxiliaries, and the hollow porous spherical platinum-silver alloy nano-material is synthesized by means of reaction. The preparation method is simple in process, convenient in operation, fine in repeatability and low in cost, and the obtained hollow porous spherical platinum-silver alloy nano-material can be used for the fields of chemical and electrochemical catalysis, chemical sensors, biomolecular sensors, information storage, fuel cells, solarcells and the like. Particularly, the hollow porous structure of the nano-material can be effectively applied to slow drug release and target-oriented drug delivery treatment.

The durability of a PEM fuel cell is improved by replacing carbon catalyst support materials in the cathode (and optionally both electrodes) with a titanium oxide support. The electrode thus preferably contains noble metal containing catalyst particles carried on catalyst support particles of titanium oxide. The catalyst-bearing titanium oxide particles are mixed with electrically conductive material such as carbon particles. The combination of platinum particles deposited on titanium dioxide support particles and mixed with conductive carbon particles provides an electrode with good oxygen reduction capacity and corrosion resistance in an acid environment.

The invention provides a nitrogen and iron modified carbon material, belonging to the technical field of composite materials. The material takes melamine and FeCl3 as modifiers, and active ingredients such as N, Fe and the like are doped in carbon powder / a carbon nano tube, so that the catalytic action of the carbon material on oxygen reduction reaction is effectively improved, and the carbon material has good catalytic activity. Therefore, the carbon material can be applied to oxygen reduction catalytic reaction of fuel cells as a catalyst material. Through experimental determination, the cathode electrodes of the fuel cells prepared from the material show better oxygen reduction properties than traditional commercial XC-72 carbon powder electrodes, and the oxygen reduction catalytic activity is obviously improved. The material is simple in preparation process, is environment-friendly and is a non-noble metal oxygen reduction catalyst with potential application.

The invention relates to a universal preparation method for an active site-electrode structure integrated air electrode. The universal preparation method is characterized in that various polymer microspheres having open internally-communicating hierarchical-pore structures are conjugated with active sites like noble metal groups, transition metal groups, and hetero atom-doped carbon groups in virtue of different treatment methods; the different treatment methods may be one or more selected from the group consisting of a carbon tetrachloride cross-linking method, a concentrated-sulfuric-acid sulfonation method, a carbon dioxide gas activation method, a dopamine coating method, an ammonia gas activation method, a polyaniline coating method, an in-situ precious-metal loading method, an in-situ transition metallide growth method and an in-situ heteroatom doping method. The universal method described in the invention can flexibly conjugate open internally-communicating hierarchical-pore electrode structures containing super-macro pores, macro pores, meso pores and micropores with a plurality of different highly-active catalytic sites by using appropriate methods, so the catalytic performance of the air electrode and the overall performance of a fuel cell and a metal-air battery are improved.

The invention discloses a method for preparing a bifunctional electro-catalyst from peanut hull, and belongs to the technical field of electro-catalysis. The method comprises the steps of adding an active agent, a carbon source and a nitrogen source into waste peanut hull biomass serving as a raw material to obtain exotic atom-doped porous carbon; adding a certain amount of metal doping agent, and performing secondary carbonization to obtain a metal and nitrogen co-doped porous carbon material, wherein the material has excellent oxygen reduction and oxygen evolution electro-catalysis performance. By adopting the cheap, readily available and environment-friendly peanut hull biomass as a raw material, the preparation process is innocuous and harmless. The bifunctional electro-catalyst can be applied to oxygen reduction and oxygen evolution.

The invention provides a preparation method and application of a nitrogen-doped porous carbon-coated cobalt nanoparticle composite material. The preparation method comprises the following steps: uniformly dispersing a carbon source precursor, a nitrogen source precursor and soluble salt of transition metal ions in a solvent according to a ratio, then performing drying to obtain a solid powder precursor, and calcining the solid powder precursor in a protective atmosphere to obtain black powder, namely the composite material. The composite material has efficient oxygen reduction catalysis performances and can be applied to proton exchange membrane fuel cells, alkaline fuel cells and metal-air batteries. The catalyst has the advantages that a pore structure is generated in the heat treatmentprocess and is uniformly dispersed; the carbon source, the nitrogen source and the metal source interact with one another to stabilize active elements and effectively improve the catalytic activity. Compared with a catalyst with commercial carbon as a carbon source, the prepared composite material has better oxygen reduction catalytic activity and is an efficient non-noble metal oxygen reduction catalyst.

The invention relates to a nano-composite air electrode catalyst for a zinc-air battery and a preparation method of the nano-composite catalyst, belonging to the technical field of zinc-air batteries. The nano-composite catalyst is composed of manganese dioxide, nano-silver, a carbon nano tube and a carbon material in the mass ratio of (0-0.5) to (0-0.5) to 1 to (1.75-2.75), wherein the mass of manganese dioxide and the mass of nano-silver cannot be zero at the same time. Due to the addition of nanometer materials such as nano-silver and the carbon nano tube, the wettability of the nano-composite catalyst is improved, and the reduction reaction of oxygen in a three-phase boundary formed by electrolyte, catalyst material and oxygen is facilitated; meanwhile, the composite catalyst formed by manganese dioxide and nano-silver has oxygen reduction effect higher than that of a single catalyst. The nano-composite catalyst adopts the preparation technology comprising the steps of pretreatment, granulation, ultrasonic dispersion and ball-milling treatment, the operation is simple and efficient, and the application prospect is good.

The invention provides an iron and nitrogen doped non-noble metal catalyst, and belongs to the technical field of new materials. The non-noble metal catalyst is obtained by using saccharose as a carbon source, 6-benzyladenine as a nitrogen source and ferric chloride as an activating agent through carbonization treatment, wherein the nitrogen content of the non-noble metal catalyst is 5.3-8.4%. The oxygen reduction tests find that compared with conventional commercial XC-72 carbon powder, the iron and nitrogen doped non-noble metal catalyst has better oxygen reduction performance. Therefore, the iron and nitrogen doped non-noble metal catalyst can serve as a cathode catalyst material to be applied to the oxygen reduction catalytic reduction of fuel cells.

The invention discloses a preparation method of a nitrogen-doped carbon nanofiber loaded gold nanoparticle oxygen reduction catalyst. The preparation method comprises the following steps: soaking bacterial cellulose into deionized water until the bacterial cellulose is neutral, draining off water, adding a dopamine solution, stirring in a constant-temperature water bath at 50 DEG C, adding a Tri-HCl buffer solution with a pH value of 8.5, and continuing to stir, so as to finally obtain a bacterial cellulose and dopamine compound; and carrying out freeze drying on the bacterial cellulose and dopamine compound, putting the compound into a tubular furnace, carrying out high-temperature carbonization so as to obtain nitrogen-doped carbon nanofibers, and loading the nitrogen-doped carbon nanofibers with gold nanoparticles by virtue of a sodium borohydride chemical reduction method, so as to obtain the nitrogen-doped carbon nanofiber loaded gold nanoparticle oxygen reduction catalyst. The preparation method of the catalyst is simple, and the oxygen reduction property of the catalyst is excellent under alkali conditions. Compared with a Pt catalyst, the catalyst is relatively low in cost and good in stability.

The invention provides a carbon material with a nitrogen, fluorine and transition metal co-doped graphene structure. Melamine, polytetrafluoroethylene and a metal salt are taken as raw materials for mixing and uniform grinding to prepare and obtain a nitrogen, fluorine and transition metal co-doped carbon material by employing a one-step carbonization method. The carbon material shows a graphene or graphene-like structure; the nitrogen, fluorine and metal elements are uniformly distributed, and the carbon material has excellent oxygen reduction and oxygen evolution performances. The one-step carbonization preparation method comprises the following steps of: 1) mixing of the raw materials; and 2) one-step carbonization method. The carbon material provided by the invention has excellent oxygen reduction and oxygen evolution performances. Besides, the excellent oxygen reduction and oxygen evolution performances of the material can be improved through regulation of the synergistic effect among the nitrogen, the fluorine and transition metal. The one-step carbonization method is good in repeatability, simple in process and easy to operate. The carbon material has wide application prospects in the fuel cell and metal-air cell electrode catalysis and the direction of functional carbon materials.

A method for synthesizing a supported ternary platinum alloy catalyst belongs to the technical field of chemical energy sources.A transition metal is introduced to a platinum catalyst and can adjust spacing of platinum atoms and change an electronic environment around platinum, and unique geometric effect and electronic effect will be resulted in.This change will directly affect adsorption activation energy of platinum surface with an oxygen bearing substance, thus affecting catalytic activity of platinum.

The invention discloses a preparation method of a fuel cell Pt / Graphene catalyst. The method comprises the following steps: (1) preparing graphite oxide by use of an improved Hummers method; (2) grinding the graphite oxide into powder, and calcining the powder in a muffle furnace to obtain expanded graphite oxide; (3) preparing a graphene load Pt catalyst by use of a microwave-assisted ethylene glycol method. According to the preparation method, the Pt / Graphene catalyst is prepared by taking the expanded graphite oxide as the precursor of the reaction, and a dispersing auxiliary agent is not added in the reaction process; the method has the advantage that the graphene of the product can be more thoroughly reduced, and the catalytic activity of the catalyst is prevented from being influenced by the residual dispersing auxiliary agent, so that the product has better oxygen reduction performance.

The invention provides a triazin ring containing covalent organic microporous polymer. The triazin ring containing covalent organic microporous polymer with gas adsorption properties has quite high nitrogen content and a microporous structure, the contact area between the gas and the polymer is greatly increased, and the adsorption efficiency is greatly improved; in addition, the triazin ring containing covalent organic microporous polymer only needs zinc as a catalyst and is cheap and environmental friendly, and after action, the pure polymer can be obtained by simple filtration and cleaning;the polymer material has good application prospect in the fields of adsorption and the like.

The invention relates to a method for preparing a graphene based non-metallic oxygen reduction catalyst. The graphene based non-metallic oxygen reduction catalyst is a graphene based oxygen reduction catalyst doped with non-metallic hetero-atom, the non-metallic hetero-atom comprises N, S, B and / or I, the method comprises the followings: oxidized graphene is prepared to be oxidized graphene solution with the concentration of 0.1 to 5 mg / ml; at the temperature of 70 to 120 DEG C, the oxidized graphene solution is stirred for 1 to 3 hours and then a reducing agent containing non-metallic hetero-atom is added, the temperature is kept to be 70 to 120 DEG C, stirring is performed continuously for 18 to 48 hours so as to achieve in-situ doping of the non-metallic hetero-atom during graphene reduction-oxidation; centrifugation, washing and drying are performed on the solid so as to obtain the graphene based non-metallic oxygen reduction catalyst.

Disclosed is a catalyst having excellent durability and high oxygen-reducing ability, which is not corroded in an acidic electrolyte or at high potentials. Specifically disclosed is a catalyst composed of a titanium oxycarbonitride. The titanium oxycarbonitride preferably has a composition represented by the following formula: TiCxNyOz (wherein x, y and z represent atomic number ratios satisfying 0 < x = 1.0, 0 < y = 1.0, 0.1 = z < 2.0, 1.0 < x + y + z = 2.0 and 2.0 = 4x + 3y + 2z). The catalyst is preferably used for fuel cells.

The invention relates to a nitrogen-doped graphene hollow microsphere (NGHM) preparation method. Polystyrene microspheres as templates, graphene as a carbon source and melamine as a nitrogen source are calcined to form NGHM. The prepared NGHM has good oxygen reduction reaction (ORR) catalytic performances. Compared with the commercial Pt / C catalyst, the NGHM has slightly lower OPP onset potential and the same ORR limiting current density. Compared with Pt / C, the NGHM has higher stability and toxicity resistance and has a lower cost. The prepared NGHM can completely replace the commercial Pt / C.

Provided is an oxygen reduction catalyst having a high oxygen reduction performance. An oxygen reduction catalyst according to the present embodiment includes a transition metal oxide to which an oxygen defect is introduced, and a layer that is provided on the transition metal oxide and that contains an electron conductive substance. A method for producing an oxygen reduction catalyst according to the present embodiment includes heating a transition metal carbonitride as a starting material in an oxygen-containing mixed gas. In addition, a method for producing an oxygen reduction catalyst according to the present embodiment includes heating a transition-metal phthalocyanine and a carbon fiber powder as starting materials in an oxygen-containing mixed gas.

The invention discloses a carbon tubular oxygen reduction cathode microbial fuel cell and a preparation method thereof. The carbon tubular oxygen reduction cathode microbial fuel cell comprises an anode and a cathode and is characterized in that the cathode adopts a bamboo charcoal tube, wherein the outer surface of the bamboo charcoal tube is coated with polytetrafluoroethylene emulsion with the concentration of 5-10% and a partition membrane with pore size less than 1 m um is mounted on the inner surface of the bamboo charcoal tube; the outer side of the cathode is wound with a titanium wire, the anode is inserted in the bamboo charcoal tube along the axial direction of the bamboo charcoal tube, and the anode adopts carbon cloth, a carbon brush, carbon paper, carbon felt, a carbon rod or graphite flake; an end plate is arranged at each of the two ends of the cathode and the end plates are fixed with bolts; an electrolyte inlet is formed in one of the end plates and an electrolyte outlet is formed in the other end plate. Since a natural and cheap porous material is used as a precursor and a structural material, the fuel cell is low in cost and has good application prospect.

The invention provides a rigid porous framework polymer with gas adsorption performance. A monomer is triaryl tricyano imidazole of R substitution, and R is hydrogen or alkyl with 1-5 carbon atoms. The invention provides a preparation method of the porous polymer and application of the porous framework polymer to the field such as oxygen reduction, hydrogen storage, adsorption and separation. The porous polymer materials have high nitrogen content and a micro-pore structure, the contact area between gas and the polymer is greatly increased, adsorption efficiency is improved, and the rigid porous framework polymer has good oxygen reduction performance under the carbon-forming condition and has good application prospects in the field such as oxygen reduction, hydrogen storage, adsorption and separation.

This invention provides a fuel cell electrode catalyst in which at least one transition metal element and at least one chalcogen element are supported on a conductive support, wherein the fuel cell electrode catalyst comprises a core portion comprising a transition metal crystal and a shell portion comprising surface atoms of the transition metal crystal particle and chalcogen elements coordinating to the surface atoms, and the outer circumference of the core portion is being partially covered with the shell portion. The fuel cell electrode catalyst has a high level of oxygen reduction performance, high activity as a fuel cell catalyst and comprises a transition metal element and a chalcogen element.

The invention provides a method for preparing a nitrogen carbon material by using animal waste, and belongs to the technical field of a novel material. The method comprises the following steps: by taking the animal waste as a raw material, carrying out primary carbonization treatment under protection of nitrogen after naturally airing, so as to obtain a carbon material; crushing the carbon material to be added in a salpeter solution; carrying out activating treatment for 20-24 hours under agitation; washing into a neutral state by using deionized water, baking, and then adding to an FeCl3 / C2H5OH solution to agitate for 0.5-1 hour; further carrying out ball milling after directly drying; finally, carrying out secondary carbonization treatment under protection of nitrogen, so as to obtain the nitrogen carbon material. The material is high in nitrogen content, and displays better oxygen reduction performance when being applied to oxygen reduction reaction of a fuel cell as the oxygen reduction catalyst. Therefore, the nitrogen carbon material can be applied to the oxygen reduction reaction of the fuel cell as the oxygen reduction catalyst.

The invention relates to a preparation method and application of a fuel cell catalyst. Electrochemical dealloying is performed. The synthesis method adopts a continuous reduction method, and includesthe steps that a triblock copolymer P123 serves as a protecting agent, and sodium borohydride serves as a reducing agent; a certain amount of P123 is taken and dissolved in redistilled water, a cobaltchloride solution is added to the P123 solution, before reaction, nitrogen is introduced to remove oxygen, continuous stirring is performed, and the reaction temperature is controlled to be room temperature (30 DEG C); a sodium borohydride solution is slowly dropwise added to the reaction liquid, 30 minutes after dropwise adding, a mixed solution of chloroauric acid and potassium chloropalladateis slowly dropwise added to the reaction liquid, and the reaction is stopped after lasting 4 hours; the reaction liquid is centrifuged and washed three to five times to obtain the ternary CoAuPd alloycatalyst for fuel cells. The special ternary CoAuPd alloy catalyst has excellent methanol catalytic oxidation performance and oxygen reduction catalytic activity after electrochemical gradient dealloying and is a fuel cell catalyst with broad development prospects.

The invention discloses a preparation method of a Fe / Fe3C nanoparticle-loaded porous nitrogen-doped carbon-based oxygen reduction catalyst, which comprises the following steps of by using SiO2 as a hard template, carrying out polymerization reaction on hydroxymethylated melamine and ferric acetylacetonate to prepare the novel Fe / Fe3C nanoparticle-loaded porous nitrogen-doped carbon-based oxygen reduction catalyst. The polymer containing iron, nitrogen and carbon is synthesized through polymerization reaction of hydroxymethylated melamine and ferric acetylacetonate, the graphitization degree of carbon can be effectively improved through Fe / Fe3C species formed in the pyrolysis process, the electrical conductivity of the material is enhanced, and then the catalytic activity of the catalytic material is improved. The specific surface area of the Fe / Fe3C nanoparticle-loaded porous nitrogen-doped carbon-based oxygen reduction catalyst prepared by the method is 1084 m<2>g<-1>, the average pore diameter is 7 nm, and the Fe / Fe3C nanoparticle-loaded porous nitrogen-doped carbon-based oxygen reduction catalyst has excellent oxygen reduction performance.

The invention discloses a nitrogen-doped porous carbon-coated non-noble metal alloy composite oxygen reduction catalyst and a preparation method thereof. Dimethyl imidazole is dropwise added into a mixed solution of a soluble transition metal salt and ethyl orthosilicate, and washing is carried out after a complete reaction to obtain a precipitate; drying and sintering are carried out to obtain precursor powder; and finally alkaline treatment is carried out to obtain the catalyst. The preparation method has the advantages of simple preparation method, uniform distribution of active sites, large specific surface area and the like, and is beneficial to promotion of practical application of metal air batteries.

The invention discloses a preparation method of dendritic three-dimensional graphene and belongs to the technical field of nano material preparation. The preparation method comprises the steps of firstly, depositing nano Cu clusters or CuNi clusters in a mixed solution of CuSO4, NiSO4 and H2SO4 with a Cu sheet serving as a working electrode to obtain a graphene deposition substrate; secondly, putting nano metal clusters into ultra pure water to be cleaned multiple times, and then performing filtering and freeze-drying; thirdly, putting the freeze-dried nano metal clusters into a vacuum furnace, performing reduction treatment in hydrogen atmosphere at the temperature of 800-1000 DEG C, then performing graphene deposition treatment in hydrogen and methane mixed atmosphere at the temperature of 800-1000 DEG C, and removing the alloy substrate through an ammonium persulfate solution or a ferric trichloride solution to obtain dendritic graphene. The invention further discloses a series of dendritic three-dimensional graphene obtained through the method. The dendritic three-dimensional grapheme is characterized in that one end is open, and other ends are closed. The graphene has outstanding oxygen reduction performance.

The invention belongs to the technical field of fuel cells, and particularly relates to a platinum-cobalt alloy carbon catalyst for a proton exchange membrane fuel cell and a preparation method of the platinum-cobalt alloy carbon catalyst. The preparation method of the platinum-cobalt alloy carbon catalyst comprises a pretreatment process and a reaction process. The obtained crude platinum-cobalt alloy catalyst is subjected to post-treatment, a post-treatment solution A is added into the crude platinum-cobalt alloy catalyst during post-treatment, after treatment is conducted for 0.5-200 h at the temperature of 0-80 DEG C, part of a solvent is removed, then a post-treatment solution B is added, after continuous treatment is conducted for 0.5-200 h at the temperature of 0-80 DEG C, washing is conducted, and drying at 20-85 DEG C is conducted to obtain the platinum-cobalt alloy carbon catalyst. According to the prepared crude platinum-cobalt alloy catalyst, unalloyed elements and impurities on the surface of the catalyst can be removed through post-treatment, raw materials used in the preparation process are environmentally friendly, the preparation technology is high in operability, and commercialization is easy to achieve; and the prepared platinum-cobalt alloy catalyst is excellent in catalytic activity, good in oxygen reduction performance and high in power density when applied to a single battery.

The invention relates to a preparation method and a product of a heteroatom-doped graphene / carbon-based material with a core-shell structure, and belongs to the technical field of materials. The preparation method is a template-like method; a carbon-based material serves as a core and graphene oxide serves as a shell, through a cationic surfactant serving as a bridge, the carbon-based material isconnected with the graphene oxide, finally a heteroatomic source is added, and after rotary evaporation drying, the graphene oxide is converted into heteroatom-doped graphene by the high-temperature calcination, so that the finally prepared material has a wrapped structure and is high in oxygen reduction catalytic activity and porosity. The carbon-based material in the material acts as a current collector, and the heteroatom-doped graphene uniformly distributed on the surface serves as an oxygen reduction active site, thereby ensuring that the finally prepared material is high in oxygen reduction catalytic activity and excellent in conductivity, facilitating the diffusion and transmission rate of oxygen and electrons inside a catalyst, and improving the oxygen reduction performance of thecatalyst. The material with simple preparation technology and low cost is suitable for large-scale industrial production.

The invention discloses a porous nitrogen-doped carbon sphere material with an ultralow cobalt atom content as well as a preparation method and application of the porous nitrogen-doped carbon sphere material. According to the preparation method, ethylenediamine tetraacetic acid disodium cobalt salt which is simple and easy to obtain is selected as a cobalt source, dopamine hydrochloride is selected as a nitrogen source, and a porous nitrogen-doped carbon sphere with an ultralow cobalt atom content is obtained through polymer encapsulation and pyrolysis. The porous nitrogen-doped carbon spheresynthesized by the method has a high specific surface area and considerable defect states, which is beneficial for a surface oxygen reduction catalytic reaction, so the catalytic activity of an electrocatalyst is effectively enhanced. The obtained material shows excellent oxygen reduction activity, has good cycling stability and certain methanol toxicity resistance, can generate huge economic benefits and social benefits, and has wide application prospects.