39results about How to "High quality activity" patented technology

The invention discloses a nano-grade composition, a preparation method thereof, and an application thereof as an electrochemical catalyst. The nano-grade composition provided by the invention is basically composed of a melamine derivative, a carbon material, and transition metal or transition metal alloy nano-cluster. The carbon material comprises at least one selected from conductive carbon black, activated carbon, carbon nano-horn, N-doped carbon nano-horn, carbon nano-tube, graphene, graphite and carbon fiber material. The metal nano-cluster is at least one selected from Pt, Ru, Pd, Rh and Ir nano-clusters. The alloy nano-cluster is nano-cluster formed by more than two elements selected from Pt, Ru, Pd, Rh, Ir, Fe, Cu and Ni. The mass percentage content of the transition metal or alloy nano-cluster is 0.1-90%. The size of the transition metal or alloy nano-cluster is 0.5-10nm. As a fuel cell catalyst, the nano-grade composition provided by the invention has excellent electrocatalytic activity upon reactions such as oxygen reduction and methanol oxidation.

The invention discloses a Pdx@Pt/C core-shell structure cathode catalyst for a fuel cell and a preparation method of the Pdx@Pt/C core-shell structure cathode catalyst. The method comprises the following steps: (1) adding a palladium precursor and a conductive carrier to N,N-dimethyl formamide or ethanol, carrying out ultrasonic mixing, and then adding borane.N,N-diethyl aniline or sodium borohydride, reacting at a room temperature for 0.5-1.5h, carrying out centrifugal washing and vacuum drying and then obtaining a carbon-supported Pd catalyst, namely Pd/C; and (2) ultrasonically dispersing the Pd/C prepared in the step (1) into a formic acid solution with the concentration of 1-5ml formic acid/20ml water, adding a water solution of a platinum compound at the atomic ratio of Pt to Pd being 1 to 1 or 1 to 2 or 1 to 3, reacting at the room temperature for 2-6h, and carrying out centrifugal washing and vacuum drying to obtain the product. The catalyst with high catalytic activity and stability is prepared by a primary cell reaction principle; the catalyst is lower than a pure Pt catalyst in cost; the preparation method is simple, convenient, mild in condition and easy to operate; and the problem that a high temperature and a surfactant are required for preparation of the core-shell structure catalyst by a conventional chemical reduction method is solved.

The invention discloses a Pt-based fuel cell cathode catalyst of a transition metal element doped with TiO2 and a carbon compound with high specific surface area as a carrier, and a preparation method of the Pt-based fuel cell cathode catalyst. The method comprises the steps of adding a Ti compound and a transition metal M precursor to water, adding carbon with high specific surface area, carrying out ultrasonic mixing evenly and then obtaining a composite oxide carbon carrier C-Ti<x>M<1-x>O<2> by using a hydrothermal method; and mixing a platinum compound water solution with the C-Ti<x>M<1-x>O<2> and obtaining a composite oxide carbon carrier-loaded nano Pt catalyst, namely a Pt/C-Ti<x>M<1-x>O<2> catalyst by adopting an impregnation method. Compared with commercial Pt/C, the prepared Pt/C-Ti<x>M<1-x>O<2> catalyst has higher catalytic activity and stability due to interaction between a metal and the carrier; the preparation method is simple and convenient, mild in condition and easy to operate; the problems of high surface Pt agglomeration degree and poor stability of the catalyst prepared by adopting a conventional impregnation method are solved; and the composite oxide carbon carrier-loaded nano Pt catalyst is a powder catalyst suitable for a proton exchange membrane fuel cell.

The invention provides a preparation method of a PtRu/C catalyst, and belongs to the field of catalyst preparation methods. The method comprises the following steps: dispersing a carbon carrier in water to obtain a first suspension; adding a chloroplatinic acid solution and a ruthenium chloride solution to the first suspension to obtain a second suspension; and pouring the second suspension into a sodium borohydride solution, and stirring at room temperature to obtain the PtRu/C catalyst. The invention also provides the PtRu/C catalyst. The PtRu/C catalyst has the characteristics of small particle size, uniform dispersion, and good methanol electrooxidation reaction catalysis performance. Experiments show that when the capacity of the PtRu/C catalyst prepared through the method is 30wt%, the mass activity of the catalyst in a methanol solution with sulfuric acid as an electrolyte reaches 447mA/mg, and is 1 time higher than the mass activity of commercial PtRu/C catalysts.

The invention discloses a preparation method and application of an iridium oxide nanoparticle catalyst. A mixed solution containing a polymer and an iridium-containing compound is uniformly applied toa treated conductive substrate; calcining in an air atmosphere is carried out to convert the iridium-containing compound into iridium oxide and the polymer is decomposed at the same time; the iridiumoxide nanoparticle material which is small in particle size, amorphous and of a porous structure is obtained, polymers remaining on the iridium oxide nanoparticle material are removed through a plasma generator, and the surfaces of iridium oxide nanoparticles are rich in hydroxyl. The film formed by the polymer in the mixed solution is utilized to solve the problem that the iridium-containing compound is agglomerated to form large particles when being calcined to generate the iridium oxide nanoparticles, thereby obtaining the small-particle-size iridium oxide nanoparticles. Besides, the plasma generator is used for removing residual polymers in the calcining process, the contact area of the iridium oxide nano particles is increased, and therefore the catalytic efficiency of the iridium oxide nano particles is improved.

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.

The invention provides an iridium-based multi-component nano-porous catalyst as well as a preparation method and application thereof, belongs to the technical field of catalytic materials, and solves the defects of low anode electrolysis efficiency, large use amount of noble metal in the catalyst and relatively high cost of a water electrolysis hydrogen production catalyst in the prior art. The iridium-based multi-element composite nano-porous catalyst comprises iridium and/or iridium oxide and further comprises an oxide compounded with the iridium and/or iridium oxide, the oxide has conductivity, and the dielectric constant of the oxide is smaller than 80 F/m. The catalyst provided by the invention has low overpotential and high mass activity, the use amount of precious metal iridium can be reduced, and the energy consumed by oxygen evolution reaction is less.

The invention provides a transition metal doped anode catalyst as well as a preparation method and application thereof. The method comprises the following steps: treating carbon nanotubes with acetoneand sulfuric acid to obtain pretreated carbon nanotubes; mixing an alcohol solvent, tetra-n-butyl titanate, a stabilizer, metal acetate and the pretreated carbon nanotube under an organic acid condition, heating to obtain a precursor, and roasting in an ammonia atmosphere to obtain TiMN/NCNTs, wherein M is a transition metal; depositing platinum on the TiMN/NCNTs by adopting a pulse electro-deposition method to obtain the TiMN-coated Pt/NCNTs. According to the anode catalyst prepared by the method, titanium nitride doped with transition metal is used as a core; a layer of platinum is deposited on titanium nitride doped with transition metal through a pulse electro-deposition method, the transition metal is introduced into the titanium nitride to adjust the surface electronic structure ofthe titanium nitride, the synergistic effect between the platinum and a nitride core is enhanced, and the catalytic performance is improved. Good stability and anti-poisoning capability are also realized.

The invention provides a preparation method and application of a platinum-carbon quantum dot/multi-walled carbon nanotube composite material. According to the method, platinum nanoparticles (Pt NP) and carbon quantum dots (CQDs) are prepared in situ under the auxiliary action of an electric field, and the Pt NP and the CQDs are subjected to subsequent thermal adjustment in the process of loading the Pt NP and the tetrabutylammonium hydroxide (TBAOH) by controlling electrolytic voltages (30V, 20V, 10V and 5V) and electrolytes (tetrabutylammonium tetrafluoroborate (TBABF4), tetrafluoride (TBACF3SO3)) and tetrabutylammonium fluoride). Thus, the Pt-CQDs/MWCNT composite catalyst is obtained. The adopted synthesis process is simple, in-situ synthesis is adopted, the prepared platinum-carbon quantum dot/multi-walled nanotube composite material is an electrocatalyst, and the mass activity of a hydrogen evolution reaction (HER) and an ethanol oxidation reaction (EOR) of a PtCQDs/MWCNT catalystis 14.8 times higher than that of commercially available Pt/C (the overpotential is -40 mV) and 5.6 times higher than that of a front peak.

The invention relates to a preparation method and application of a fibronectin-functional cell composite type microencapsulation transplant. The method includes: selecting an adult or an SPF mammal as a functional cell donor, separating cells with specific functions from the adult or the SPF mammal, and purifying the separated cells; using an FN serum-free culture medium to perform in-vitro culture on the purified functional cells so as to obtain a large amount of high-quality active functional cells through amplification; using the microencapsulation immune isolation technology to jointly embed fibronectin and the functional cells into an APA micro-capsule according to a certain proportion so as to form the fibronectin-functional cell composite type microencapsulation transplant. The preparation method has the advantages that technical difficulties that high-quality active functional cells are insufficient, allosome or xenogeneic immunological rejection exists, the surviving period of transplanted functional cells in a receptor is short, the long-term treatment effect is poor, and the like in the current clinical application using cell transplanting to treat serious diseases such cardiovascular disease and diabetes can be solved, and a new technical manner and method using the cell transplanting to treat various serious diseases is provided.

Provided is a catalysts comprising a Ta layer having an outer layer with a layer comprising Pt directly thereon, wherein the Ta layer has an average thickness in a range from 0.04 to 30 nanometers, wherein the layer comprising Pt has an average thickness in a range from 0.04 to 50 nanometers, and wherein the Pt and Ta are present in an atomic ratio in a range from 0.01:1 to 10:1. Catalyst described herein are useful, for example, in fuel cell membrane electrode assemblies.

The invention provides a nano-catalyst for electrochemical preparation of hydrogen peroxide, and a preparation method and application of the nano-catalyst. The preparation method comprises the following steps: preparing a seed solution; preparing a growth solution; preparing gold nanoparticles; preparing gold-platinum nanometer particles; and preparing the nano-catalyst for electrochemical preparation of hydrogen peroxide. The catalyst prepared by the preparation method provided by the invention can be used for catalyzing a reaction for electrochemical preparation of hydrogen peroxide, and theselectivity of hydrogen peroxide is 95% or above.