225 results about "Pt nanoparticles" patented technology

The invention discloses a platinum (Pt)/reduced graphite oxide (RGO) nano composite material and a preparation method and application thereof. According to the preparation method, graphite oxide (GO) and a platinum metal precursor are reduced in one step by radiation and induction of a gamma ray or an electronic beam, thus obtaining the Pt/RGO nano composite material with the Pt load capacity being 1.0wt% to 15wt%; Pt nano particles are uniformly distributed on an RGO sheet layer, and the average diameter of the Pt nano particles is 1.8 nanometers; and the particle sizes of the Pt nano particles are within 2 nanometers. By virtue of the load capacity of the nano particles of platinum metal, the reducing degree of the GO can be increased, the conductivity of a product is improved, and the surface utilization rate of the RGO sheet layer is increased. Compared with the GO and pure graphene, the nano composite material prepared by the method has higher specific capacitance and higher high-current multiplying power when being applied to a super-capacitor electrode material.

The invention discloses a catalyst of semiconductor nano particles/ N-doped graphene compound, and a preparation method thereof, and the catalyst is used for decomposing water in a photocatalysis mode. NGR is used as a carrier, tetrabutyl titanate is used as the raw material, TiO2 nano particles are loaded on the surface of the NGR in a solvothermal method, after cleaning and drying, TiO2/NGR compounds with the TiO2 nano particles evenly distributed on the two-dimensional plane of the NGR are obtained, a few of Pt nano particles are loaded on the TiO2/NGR compounds in a photo-deposition method, and the TiO2/NGR/Pt three-component photocatalyst is obtained. Compared with a compound prepared by pure TiO2 nano particles or reduction-oxidation graphene and TiO2 nano particles, the photocatalyst prepared in the novel method has the advantages that the partical size of each TiO2 nano particle is small, distribution is even, catalytic activity is high, stability is good, and using cycle is long.

The invention provides hydrotalcite-loaded nanometer platinum catalyst as well as a preparation method and application thereof. The preparation method of the hydrotalcite-loaded nanometer platinum catalyst comprises the following steps of: preparing magnesium-aluminum hydrotalcite crystal nucleus by utilizing an all-return liquid mixing membrane reactor, dispersing the crystal nucleus in an aqueous solution; adding an chloroplatinic acid aqueous solution and tetradecyl trimethyl ammonium bromide (TTAB) as well as a proper proportion reducing agent of NaBH4; controlling the reducing velocity and the growth of Pt nanometer particles by utilizing the protecting and stabilizing effect of the TTAB to the Pt<4+> ion; and gradually crystallizing the hydrotalcite while reducing the Pt<4+> ion to obtain the hydrotalcite-loaded nanometer platinum catalyst. The catalyst is obtained by loading nanometer particles on a hydrotalcite carrier, wherein the chemical formula of the hydrotalcite is as follows: MgxAly(OH)16CO3 nH2O; the platinum nanometer particle dimension is 2 nm-8nm; the nanometer particles are polyhedral or ellipsoidal in appearance; the loading capacity of the platinum is 0.5%-3%; and the dispersion degree on the carrier is 20%-50%. The hydrotalcite-loaded nanometer platinum catalyst can be used for catalytic hydrogenation reaction of unsaturated aldehyde (cinnamyl aldehyde), wherein water is used as solvent, the conversation rate of the reactant cinnamyl aldehyde is 75%-95% and the selectivity of the product cinnamyl alcohol is 75%-95%.

The invention discloses preparation of a high-activity graphene-load platinum catalyst and application of the catalyst to a hydrogenation reaction of an aromatic nitro-compound, in particular to a high-activity catalyst used in a hydrogenation reaction of an aromatic nitro-compound and a preparation method thereof. A carrier of the catalyst is graphene; and an active ingredient is metal platinum.Specific to the current situation of small application range of graphene and large difficulty in large-scale preparation and application, ethylene glycol is taken as a reducing agent in the method, and Pt nanoparticles are successfully and uniformly loaded on a graphene oxide nano-sheet and are applied to the hydrogenation reaction of the aromatic nitro-compound, so that the high-activity graphene-load platinum catalyst represents catalytic activity which is remarkably superior to that of a Pt catalyst loaded with a normal carbon carrier.

The invention discloses a Pt/ZIF-67 composite used for catalyzing hydrolysis of ammonia borane for hydrogen production. The Pt/ZIF-67 composite is prepared by mixing chloroplatinic acid with a metal organic framework ZIF-67 and then carrying out one-step reduction. The structure of the Pt/ZIF-67 composite retains the frame structure of ZIF-67; the average size of Pt nanoparticles is 1-2 nm, the Ptnanoparticles are uniformly distributed, and no obvious Pt metal characteristic diffraction peak occurs according to XRD detection results. A preparation method comprises the following steps: step 1)preparation and activation of the ZIF-67; and step 2) loading of the Pt nanoparticles: adding the activated ZIF-67 into water for ultrasonic dispersion, adding chloroplatinic acid, and then adding anaqueous NaBH4 solution drop by drop, and subjecting a product to filtering, washing and drying. As the Pt/ZIF-67 composite is applied to catalysis of the hydrolysis of ammonia borane for hydrogen production, the turn over frequency (TOF) of a reaction rate reaches 70-100 mol H2 min<-1> Pt mol<-1>, and activation energy is 30-40 kJ mol<-1>. The synergistic effect of the ZIF-67 and the Pt nanoparticles brings in better catalytic performance. Therefore, the Pt/ZIF-67 composite has good application prospects in the field of hydrogen production.

The present invention relates to a platinum nanometer composite catalyst, preparation and an application thereof. According to the catalyst, a lot of catalysis activity centers Pt nanoparticles are supported on a SiO2 small sphere carrier to form a SiO2/Pt core structure, and the outer surface of the SiO2/Pt core structure is coated with a layer of mesoporous zirconium dioxide shell to form a SiO2/Pt/ZrO2 core-shell structure. According to the present invention, with application of the catalyst in an aniline preparation reaction through nitrobenzene hydrogenation at a reaction temperature of 200-400 DEG C and a carbon monoxide catalysis oxidation reaction, the catalyst can be continuously and circularly used more than 20 cycles, and the catalysis activity basically remains unchanged; and the catalyst has characteristics of high efficiency, stability, recycling and easy recovery, wherein the catalyst is suitable for high temperature reactions with harsh reaction conditions with the protection effect of the mesoporous zirconium dioxide shell.

The invention provides a method for improving the stability of a fuel cell catalyst and the utilization rate of the catalyst, which belongs to the technical field of fuel cells. A layer of conductive polyaniline with conjugated large pai bond structure is modified on the carbon surface of a Pt/C (platinum/carbon) catalyst through the in-situ chemical oxidation polymerization method, on the one hand, migration, aggregation and growth of Pt nano-particles on the surface of a carbon carrier can be prevented by utilizing strong interaction between polyaniline and the Pt nano-particles, and the stability of the catalyst can be further improved; on the other hand, the polyaniline is an excellent proton-electron conductor and simultaneously has excellent oxygen permeability, by covering the polyaniline on the carbon carrier, the probability of exposing the Pt nano-particles on a three-phase reaction interface of the fuel cell can be increased, and the utilization rate of the catalyst can be further improved. The method is simple and easy for operation, the production cost is low, and the catalyst prepared by adopting the invention can be applied in the fuel cells taking proton exchange membranes as electrolytes. The fuel cells manufactured by using the invention can be widely applied in electric vehicles, various spacecrafts, portable electronic equipment such as cameras, notebook computers, electric toys and the like.

The invention provides a preparing method of a limited-range catalyst modified through atomic layer deposition and application.The atomic layer deposition technology is utilized, an ultra-thin oxide layer, Pt nanometer particles and a thick oxide layer are deposited on a carbon nanometer fiber template successively, then calcination is carried out in air to remove the carbon nanometer fiber template, and a Pt-based catalyst with oxide ultra-thin modification and the limited range within an oxide nanometer tube is obtained.The prepared catalyst greatly overcomes the defect that the site of a traditional catalyst metal-oxide interface is limited; compared with a limited-range Pt catalyst without ultra-thin modification and a Pt catalyst with the unlimited range, the limited-range Pt catalyst with ultra-thin modification has the best reduction hydrogenation activity to tetranitro-phenol, and the method can be popularized in preparation of other multi-phase catalysts.

The invention discloses a Pt/MOx catalyst and an application thereof in toluene catalytic combustion. The preparation method of the catalyst comprises the steps that: Pt2(dba)3 is added to the propylene glycol carbonate, such that a mixture is obtained; the mixture is subjected to a stirring reaction under room temperature in 1-3MPa hydrogen atmosphere; stirring is stopped after 1-2h, and the solution is fetched, such that a solution comprising Pt nano-particles is obtained; the obtained solution comprising Pt nano-particles is mixed with a metal oxide carrier; magnetic stirring is carried out, such that the Pt nano-particles are completed adhered to the metal oxide carrier; the solution is filtered, and washing and drying are carried out, such that the Pt/MOx catalyst is obtained. The Pt/MOx catalyst provided by the invention can be applied in toluene catalytic combustion. With the synthesis method of the catalyst provided by the invention, waste gas or waste water is not product, and environment cost is low, such that expanded-scale industrialized production can be carried out. The prepared catalyst has high activity and good stability. With the catalyst, low-concentration toluene can be completely oxidized into carbon dioxide and water under low temperature, and no other product is produced.

The invention relates to a preparation method of a fuel-cell catalyst Pt/WO3/C. According to the catalyst, XC-72 is used as an active component carrier, Pt nano particles are used as a main active component, mesoporous WO3 is used as an assistant, the quality percent of Pt in the catalyst is 10-30 percent, and the mol ratio of Pt to W is 1:0.1-1:1. The preparation method comprises the steps of pouring reduced Pt/ethylene glycol slurry to a carbon carrier added with the mesoporous metal oxide WO3 to obtain a Pt/WO3/C electrocatalyst; preparing the mesoporous WO3 by adopting a molecular sieve template method. The prepared Pt/WO3/C can be used as cathode and anode catalysts of a proton exchange membrane fuel cell.

The invention discloses a method for green and efficient preparation of a graphite phase carbon nitride nanosheet and application. The method comprises the following steps: taking a layered graphite phase carbon nitride material as a raw material, and modifying Pt nanoparticles on the surface of graphite phase carbon nitride, so as to obtain Pt/graphite phase carbon nitride; putting the Pt/graphite phase carbon nitride into a tube furnace, and feeding high-temperature water vapor to treat the Pt/graphite phase carbon nitride, so as to obtain the graphite phase carbon nitride nanosheet. The method is simple in processes, mild and controllable in conditions, and high in the yield of the graphite phase carbon nitride nanosheet. The specific surface area of the formed graphite phase carbon nitride nanosheet is obviously increased, charge separation is obviously improved, and the graphite phase carbon nitride nanosheet has excellent photocatalytic performance.

The invention relates to a Pt@SiO2 catalyst and a preparing method thereof, particularly a Pt@SiO2 nanosphere having a yolk-eggshell-type structure and having a core containing Pt nano particles and organic functional groups. A silica nanosphere having a core-shell structure is prepared by adopting a mesoporous silica sphere as an inner core and by adsorbing the Pt nano particles, adding an organosilane coupling agent under alkaline conditions, stirring, filtering and drying. The microenvironment in the nanosphere can be hydrophilic, hydrophobic and super-hydrophobic. The loading amount of the Pt nano particles is adjustable in a range of 0.1-5%. Distribution of the Pt nano particles can be controlled on the inner core or a cavity. The method is characterized by simple steps, short time, and easily adjustable loading amounts and composition of the nano particles. The prepared nanosphere is high in specific surface area and pore volume, uniform in particle size and good in dispersity. The prepared catalyst shows good catalytic activity in cyclohexene hydrogenation and can be recycled.

The invention discloses a platinum/attapulgite nano supported catalyst, and a preparation method and an application thereof. A carrier of the catalyst is attapulgite (ATP), and an active component is Pt nanoparticles with the average particle size of 4-6 nm. The average mass fraction of Pt in the catalyst is about 0.5%-1%, and the residual component of the catalyst is ATP. The preparation method comprises the steps: firstly adopting an acid to treat mineral impurities on the surface of ATP, and drying for standby application; with polyvinylpyrrolidone and other polymers as stabilizers, adopting reducing agents to reduce chloroplatinic acid, and thus obtaining a Pt sol; adding the treated ATP into the Pt sol, stirring, filtering, drying, and thus finally obtaining the Pt/ATP nano supported catalyst. The catalyst prepared by the method has quite high catalytic activity on reduction of nitrophenol into aminophenol.

The invention relates to a method for preparing novel carbon nano-fiber platinum catalyst, belonging to the field of nano-composite and catalysis. The preparation method comprises the steps as follows: acid-mixing disposal is carried out on the surface of the carbon nano-fiber; a polar group is led in the surface of the carbon fiber so as to form a generation site for Pt nano-particle; furthermore, the method adopts a chemical reduction method of glycol to prepare composite of Pt/carbon nano-fiber with uniform distribution of particle; the particle size of the Pt nano-particle is 3-5nm and the content of Pt is 10-40wt%; the Pt is uniformly distributed on the surface of the carrier; the method has good application prospect on ion membrane electrolyzer or fuel cell, thus pushing the modernized industrial development.

The method provides a non-Au carrier type catalyst for catalytic oxidation of carbon monoxide at room temperature and preparation method thereof. The catalyst adopts one or more oxides among TiO2, Al2O3,ZrO2, CeO2, SiO2 and Fe2O3 as carriers, Pt nanoparticles as active components and CoB amorphous alloy as auxiliary. The preparation method comprises two steps: preparing the intermediate containing CoB amorphous alloy and preparing the carrier type catalyst containing CoB and Pt. The catalyst is used for substitution for conventional nano Au carrier type catalyst to remove CO at room temperature or Co in the hydrogen-enriched atmosphere in a fuel cell. By introducing the CoB amorphous alloy into the catalyst, the catalytic oxidation performance of carbon monoxide at room temperature of the catalyst is improved; the application temperature of the catalyst is greatly reduced; and application range of the catalyst is widened. The preparation method is simple and facilitates major popularization.

The invention relates to a preparation method of a direct methanol fuel cell anode composite membrane catalyst, which comprises the following steps: previously preparing functional modified graphene, and pretreating a glassy carbon electrode substrate; carrying out layer-by-layer selfassembly on the functional modified graphene and polyoxometalate on the electrode to obtain a composite membrane of which the outermost layer is the functional modified graphene and polyoxometalate; and carrying out in-situ electrodeposition to obtain the anode composite membrane catalyst composed of the Pt nanoparticles, functional modified graphene and polyoxometalate. The composite membrane catalyst provided by the invention is prepared for the first time, and can be used as a direct methanol fuel cell anode catalyst. Compared with the pure platinum catalyst, the introduction of the functional modified graphene and polyoxometalate obviously enhances the electrocatalytic activity and CO poisoning resistance of the composite membrane catalyst; and the preparation method is simple, and has the advantage of lower cost. The invention provides a novel direct methanol fuel cell anode catalyst.

The invention belongs to the field of fuel cells, and relates to a method for preparing a high-loading catalyst Pt/CNTs, which comprises the following steps of: preparing 50g/l solution of glucose; transferring the prepared solution of glucose into a reaction kettle, adding an AAO template into the reaction kettle, reacting for 8h at the temperature of 160 DEG C, taking the template out, repeatedly washing the template to be clean with distilled water, then performing carbonization treatment on the template for 3 hours in nitrogen atmosphere at the temperature of 700 DEG C, and dissolving the template in solution of NaOH to obtain CNTs with two open ends and regular arrangement; and mixing the prepared CNTs and 10g/l H2PtCl6 in the mass ratio of 26 to 1, uniformly stirring the mixture, standing the mixture for 2 to 32 days, and then performing heating reflux for 4h to obtain the high-loading catalyst Pt/CNTs. The method realizes the self-reduction, reduces Pt metal salt to Pt nano-particles, and prepares the high-loading catalyst Pt/CNTs by adjusting standing time; and the catalyst has good electro-catalytic performance on the reduction of oxygen.

The invention provides an electro-catalyst Pt/amTiO2/rGO and a preparation method, and belongs to the technical field of fuel-cell catalysts. The preparation method comprises the following steps: firstly, an improved sol-gel method is adopted to prepare TiO2-GO (graphene oxide) sol, the sol is volatilized naturally in water bath at the temperature of 25 DEG C, and a GO complex amTiO2/GO uniformly modified by amorphous TiO2 is obtained; and then chloroplatinic acid is taken as a platinum source, ethylene glycol is taken as a solvent and a reducing agent, Pt nanoparticles are loaded on amTiO2/GO with an impregnation reduction method, meanwhile, GO is reduced to reduced GO rGO, and the electro-catalyst Pt/amTiO2/rGO is obtained. For the catalyst, an amTiO2 modifier is uniformly dispersed on the surface of rGO, one function of the amTiO2 modifier is to solve the corrosion problem of rGO, another function is to increase the dispersion degree of the loaded Pt nanoparticles, meanwhile, the electrical conductivity of amTiO2 is improved by rGO, so that performance advantages of rGO and amTiO2 can be played sufficiently, the electrocatalytic activity and stability of the catalyst are improved, and the precious metal Pt is used efficiently. The electro-catalyst Pt/amTiO2/rGO and the preparation method have the advantages of simple technology, easiness in operation and environmental protection.

The invention discloses a Pt-TiO2/CNTs catalyst, which takes Pt nanoparticles as an active component and TiO2/CNTs as a compound carrier. The preparation steps are as follows: using TiCl4 and carbon nano tube (CNT) as raw materials, performing hydro-thermal synthesis to obtain a H2TiO3/CNTs compound, carrying out hot treatment to obtain a TiO2/CNTs compound under the nitrogen atmosphere, performing secondary hydro-thermal hot treatment on the TiO2/CNTs compound obtained from the first hot treatment to obtain a TiO2/CNTs compound carrier, dispersing the TiO2/CNTs compound carrier in a glycol solution containing sodium acetate and H2PtCl6, heating and refluxing, and loading uniform platinum nanoparticles on the TiO2/CNTs compound carrier. The Pt-TiO2/CNTs catalyst obtained in the invention has high and stable electro catalytic activity on oxidization of methanol.

The invention discloses nitrogen-doped carbon nanocage-coated platinum nanoparticles (Pt@NCNCs) as a methanol-tolerant oxygen-reduction electrocatalyst. With the NCNCs, which are uniform in nitrogen distribution, high in purity and high in quality and have independent intellectual property, prepared by a chemical vapor deposition method as a carrier, anchoring and coordination effects of nitrogen can be directly utilized without surface pretreatment on the carrier; and the Pt nanoparticles are extremely evenly coated with an NCNCs cage to form a York-shell catalytic material. The oxygen-reduction electrocatalyst is simple in preparation process and friendly to environment. The oxygen-reduction catalytic activity is equivalent to the best result reported by the existing literature. Remarkably, the catalyst has complete methanol tolerance while a commercial Pt/C catalyst and an NCNCs-loaded Pt metal nanoparticles catalyst are extremely poor in methanol tolerance. The stability performance is good and far better than that of the Pt/C catalyst and the Pt/NCNCs catalyst.

The invention belongs to the technical field of fuel cell. The invention relates to a method for preparing a Pt catalyst with a carbon carrier as a carrier, comprising the following steps: preparing glucose solution with concentration being 50g/l, adding XC-72 with the concentration being 0.433-1.677g/l to the glucose solution so that the mass ratio of the two can be 30-100, switching the mixture into a reaction kettle to react for 12h at the temperature of 160 DEG C, and rinsing the product repeatedly and cleanly with distilled water to obtain the composite carrier C/XC-72; mixing the prepared composite carrier C/XC-72 and H2PtCl6 with the concentration being 10g/l according to mass ratio of 0.5-2, adding polyvinylpyrrolidone as protective agent with the mass ratio of polyvinylpyrrolidone to C/XC-72 being 1:4, stirring uniformly followed by heating and refluxing for 4h to obtain catalyst Pt/C/XC-72. The invention can realize self reduction by the characteristic of carrier C/XC-72, reduce Pt metal salt into Pt nano particles and have good electro-catalysis performance for oxygen reduction.

The invention provides a preparation method of a molecular sieve surface organic alkali etching and Pt-loaded catalyst. The Pt/molecular sieve catalyst is prepared by taking cheap ZSM-5 and other molecular sieves and a small amount of chloroplatinic acid as raw materials, firstly carrying out silicon dissolving etching treatment on the surfaces of the molecular sieves by using an organic alkali solution, and then loading Pt by adopting an ethylene glycol liquid phase reduction method. A proper amount of organic alkali is used for carrying out silicon dissolving etching treatment on the surfaces of the molecular sieves, so that a rich hierarchical pore structure is formed on the basis of not damaging a molecular sieve skeleton, dispersion and stabilization of Pt nanoparticles are facilitated, and the mass transfer properties of macromolecular reactants and products are improved. Besides, through the catalytic synergistic effect between rich acid sites on the surfaces of the molecular sieves and oxidation centers of high-dispersion Pt nanoparticles, the low-temperature oxidation performance of the catalyst on various VOCs pollutants can be remarkably improved, and the complete oxidation temperatures (when the conversion rate is 99%) of benzene and ethyl acetate are only 130 DEG C and 190 DEG C respectively. The Pt/molecular sieve catalyst is especially suitable for low-temperature catalytic combustion of industrially discharged chlorine-containing VOCs such as dichloroethane and non-chlorine-containing VOCs such as benzene and ethyl acetate, and has a good application prospect.

The invention discloses a preparation method of Pt nanoparticles. Using water to enhance the reducing ability of ethylene glycol, Pt nanoparticles can be obtained by reducing platinum salts at room temperature; the reducing ability of ethylene glycol can be adjusted by adjusting the volume ratio of water and ethylene glycol to achieve the purpose of controlling the morphology and particle size ofthe nanoparticles. The method of the invention has simple process, mild reaction condition and easy control, and is a simple, high-efficiency and low-energy Pt nanoparticle preparation method, and theprepared Pt nano particles can be widely applied to many fields including fuel cell catalysts.

The invention relates to a surface plasmon photocatalyst. According to the invention, precious metal Pt nanoparticles are grown at two ends of an Au nano rod, a CdS case layer is grown at a middle part of the Au nano rod, and the surface plasmon photocatalyst is constructed; a preparation method comprises the following steps: the Au nano rod is prepared through a seed growth method, silver nitrate, sodium hydroxide, ascorbic acid and a chloroplatinic acid solution are added in a cetyl trimethyl ammonium bromide aqueous solution of the Au nano rod for a reaction, centrifugation is carried out to obtain the products at two ends of the Au nano rod, the prepared Au nano rod solution with two ends grown with the Pt nanoparticles is added in a cadmium acetate and thioacetamide solution for the reaction, and centrifugation is carried out on a final product to obtain the surface plasmon photocatalyst with the two ends grown with Pt and the middle part grown with Cds of the Au nano rod. The photocatalysis material has excellent photocatalytic decomposition of water into hydrogen.