1583results about How to "Improve catalytic stability" patented technology

The invention discloses a monodisperse metal atom/graphene composite catalyst and a preparation method and application thereof. The catalyst is formed by loading monodisperse metal atoms on/in graphene, wherein the content of the monodisperse metal atoms is 0.0001wt%-5.0wt%; the content of heteroatom doped graphene is 95wt%-99.9999wt%; and the content of heteroatom in graphene is 0wt%-90wt%. The monodisperse metal atom/graphene composite catalyst is obtained through an electrochemical method, and the preparation method is simple, easy to operate and control, low in cost, high in efficiency, good in quality, high in security and favorable for industrial production. The composite catalyst has the characteristics of high activity and good stability when being applied to electro-catalytic oxygen reduction, and has better comprehensive performance and good application prospects relative to commercial 20wt% of Pt/C.

The invention discloses a preparation method of a catalytic wet oxidation catalyst and a treatment method of organic wastewater. The preparation method comprises the following steps of: (1) taking a porous inert material as a carrier, and performing pre-impregnation treatment on the carrier by adopting an organic acid solution; and (2) preparing an impregnating solution with a water-soluble compound containing transition metal elements and a water-soluble compound containing auxiliary elements, impregnating the carrier after treatment in the step (1) with the impregnating solution, drying in shade for 12-48 hours in air at appropriate humidity, then drying and roasting to obtain a final catalyst. When the catalyst prepared by the method disclosed by the invention is used for high-concentration organic wastewater, the characteristics of high activity, good stability and the like are realized, and the energy consumption and the investment can be reduced.

A supported silver catalyst and use thereof in a process for producing an alkylene oxide, such as ethylene oxide, by the direct oxidation of an alkylene with oxygen or an oxygen-containing gas, wherein the catalyst provides improved stability and improved resilience to reactor upsets and timely recovery to substantially pre-upset levels of catalyst activity and/or efficiency. In some embodiments, the catalyst also exhibits improved activity. A catalyst capable of producing ethylene oxide at a selectivity of at least 87 percent while achieving a work rate of at least 184 kg/h/m3 at a temperature of no greater than 235° C. when operated in a process where the inlet feed to a reactor containing the catalyst comprises ethylene, oxygen, and carbon dioxide, wherein the concentration of carbon dioxide in the inlet feed is greater than or equal to 2 mole percent.

The main componens of copper base catalyst are copper, zinc, nickel, magnesium, aluminium, chromium, iron and partial oxide of rare earth metal, in which (by oxide content) CuO is 20-55%, ZnO, NiO or MgO is 20-55%, Cr2O3, Al2O3 of Fe2O3 is 10-40% and rare earth metal oxide is 0-10%. Said catalyst can be made up by roasting catalyst precursor with hydrotalcite-like structure obtained by coprecipitation of salts of various metals. Said catalyst can effectively treat industrial organic waste water containing phenol, sulfosalicylic acid, H-acid and surfactant, etc., not only possesses higher catalytic activity, but also can control the loss of active components.

The invention relates to a nano carbon doped electrocatalyst for a fuel cell, and application of the nano carbon doped electrocatalyst. The electrocatalyst is prepared by adopting the steps of: complexing a nitrogen-containing and/or boron-containing organic precursor and a transition metal salt to form a composite; adding nano carbon as a carrier, and heating and reacting a mixture by adopting a microwave radiation method; and after the reaction is complete, filtering and drying, placing a product obtained after the reaction in an inert atmosphere and/or reducing atmosphere, and treating at a high temperature of 500-1500 DEG C to obtain the nano carbon doped electrocatalyst. The nano carbon doped electrocatalyst is very low in cost, high in activity and stability and excellent in anti-poisoning capacity.

The invention discloses a methane reforming catalyst for the production of hydrogen and a preparation method thereof, which more particularly relates to a Ni methane vapor reforming catalyst for the production of hydrogen which takes a nanometer cerium zirconium composite oxide as the carrier and the corresponding preparation method, and belongs to the methane reforming catalyst field. The catalyst comprises 5-30 wt% of active Ni, 0-10 wt% of noble metal catalytic promoter, 0-10 wt% of rare earth and/or the catalytic promoter of alkaline earth oxide, 50-95 wt% of nanometer cerium zirconium composite oxide carrier with the particle diameter of 5-20 nm. The invention is characterized by simple preparation method, high reactivity, strong anti carbon performance, good stability, low cost, etc.; when the invention is applied to the methane vapor reforming catalyst for producing hydrogen, the requirements of industrialization on catalyst reactivity and usage life can be satisfied. The invention can be largely applied in fuel cell-hydrogen area.

The present invention relates to a catalyst for preparing hydrocarbons of carbon dioxide and more particularly, the Fe—Cu—K/γ—Al₂O₃ catalyst prepared by impregnation which enables producing hydrocarbons in high yield for more than 2000 hours due to its excellent activity and stability.

A nanofibrous catalyst and method of manufacture. A precursor solution of a transition metal based material is formed into a plurality of interconnected nanofibers by electro-spinning the precursor solution with the nanofibers converted to a catalytically active material by a heat treatment. Selected subsequent treatments can enhance catalytic activity.

The invention relates to a hydroxyl oxidize iron-nickel-iron hydrotalcite integrated oxygen evolution electrode applicable to alkaline mediums and a preparation method and application thereof. The electrode is applicable to the oxygen evolution reaction in the water-electrolytic hydrogen making process under catalytic alkaline conditions. The hydroxyl oxidize iron-nickel-iron hydrotalcite integrated oxygen evolution electrode and the preparation method and application thereof have the advantages as follows: the nickel-iron hydroxide integrated electrode is shape-controlled, the preparation process is simple and under mild conditions, and the electrode can be used for a water electrolytic tank for hydrogen production from water splitting under external bias potentials; the prepared hydroxyloxidize iron-nickel-iron hydrotalcite integrated oxygen evolution electrode further has a better performance when being used in an alkaline solid polymer electrolyte (AEM) water electrolytic tank; and besides, an extensive utilization value in achieved in regenerative fuel cells (RFC), photoelectro-catalytic devices and electrolytic hydrogen generators.

The invention discloses a method for preparing a three-dimensional carbon framework embedded nano platinum-based alloy catalyst, and aims to solve the problems that a conventional Pt-based catalyst is low in activity, poor in stability and Pt utilization rate. According to the method, in the growth process of a zeolite imidazolate framework structural material (ZIF), Pt nanoparticles modified by a surfactant are uniformly wrapped in a ZIF structure, the high-temperature reduction process is precisely regulated, the ZIF carbonization, metal reduction and alloying process is controlled, and thus a catalyst structure of a three-dimensional carbon framework embedded nano platinum alloy is constructed. According to the method, the structural shrinkage effect of the carbonization process is smartly utilized, the ZIF structure is converted into a three-dimensional through carbon framework pore structure, the range limiting function of a ZIF framework at high temperature is smartly utilized, platinum particles and metal ions in the ZIF structure are subjected to in-situ alloying and embedded into the framework structure, then the three-dimensional catalyst of a pore-communicated framework and a nano-grade platinum alloy particle embedded structure is formed, the activity and the stability of the catalyst are greatly improved, and the utilization rate of Pt is greatly increased.

The invention discloses a method for preparing a mercury-free catalyst for the synthesis of vinyl chloride by acetylene method. In the method, the active components of the catalyst are highly dispersed and bonded to the surface of the carrier by carrying out surface modification treatment on the catalyst carrier and applying ultrasonic loading technology. On the group, a firm load is formed in the internal pores of the carrier, so that while improving its catalytic performance and stability, it can greatly reduce the loading of the required active components and reduce the cost of the catalyst. The method is especially suitable for preparing supported noble metal catalysts. The supported noble metal catalysts prepared by the method of the present invention can reach and exceed the catalytic activity of the currently used mercuric chloride catalysts in the case of a very small amount of loading. And stability, has industrial application value, and is of great significance in environmental protection and promoting the sustainable development of my country's polyvinyl chloride industry.

The invention relates to a metal-free nitrogen-doped functionalized mesoporous carbon catalyst and preparation method and applications thereof. A precursor of the metal-free nitrogen-doped functionalized mesoporous carbon catalyst comprises the following components in percentage by mass: 20-85% of template agent, 10-75% of nitrogen compound, and 5-50% of transition metal salt. The nitrogen compound is carbonized at high temperature under the existence condition of transition metal, to form a high-nitrogen-content pyridine and graphite nitrogen (Nx-C) composite structure, and the catalytic activity of oxygen can be remarkably enhanced; the transition metal in the nitrogen-doped mesoporous carbon catalyst can be removed through acid pickling, so that the inactivation (corrosion) of the catalyst containing the transition metal under the conditions of strong acid and strong alkali can be avoided, the characteristics of being high in stability, not easy to poison and the like can be achieved, and the metal-free nitrogen-doped functionalized mesoporous carbon catalyst has excellent application prospects in the fields of treating waste water of fuel batteries, metal-air batteries, supercapacitors, energy-storage batteries, microbial fuel cells, and the like.

The invention provides a preparation method of heteroatom doped graphene-based material supported noble metal nanoparticles. The preparation method comprises steps as follows: preparation of a heteroatom doped graphene-based material: a graphene-based material is subjected to ultrasonic treatment, a heteroatom precursor is added, heteroatom doping is performed in a hydrothermal kettle at the temperature of 150-200 DEG C, and the heteroatom doped graphene-based material is obtained; preparation of the heteroatom doped graphene-based material supported noble metal nanoparticles: the heteroatom doped graphene-based material is dissolved in deionized water and subjected to ultrasonic treatment, a stabilizer and a metal precursor are added, metal in the metal precursor is platinum, palladium, gold or silver, the mixture is continuously stirred, pH is adjusted to range from 8 to 14, a reduction agent is added, the mixture is continuously stirred, and the heteroatom doped graphene-based material supported noble metal nanoparticles are obtained after vacuum drying. The synergistic effect of the heteroatom and the carrier on noble metal is used, the activity and the stability of a catalyst are effectively improved, and a preparation process is simple and suitable for industrial production and has higher economic value.

The invention relates to the technical field of electrocatalysts. The invention discloses a monatomic iron-nitrogen co-doped carbon electrocatalyst as well as a preparation method and application thereof. Iron in the catalyst is wrapped in pores of a metal organic framework ZIF-8 containing a micropore and/or mesoporous structure in a monatomic iron-nitrogen coordination form, and the catalyst comprises micropores with pore diameters lower than 3nm, mesopores with pore diameters of 3-5nm and mesopores with pore diameters of 29-32nm. The preparation method of the vcomprises: (1) adding iron phthalocyanine into a 2-methylimidazole solution; (2) adding a zinc nitrate solution, and mixing to obtain a ZIF-8 packaged iron phthalocyanine composite material; and (3) calcining and pickling the composite material to obtain the electrocatalyst. The macroscopic morphology of the catalyst is a regular dodecahedron, the catalyst is regular and good in repeatability, and when the catalyst is applied,an electrolyte can achieve mass transfer through rich mesoporous structures in the catalyst, and high selectivity, high activity and low overpotential of CO preparation through electro-catalysis of CO<2> are achieved.

The sulfur content of liquid cracking products, especially the cracked gasoline, of the catalytic cracking process is reduced by the use of a sulfur reduction catalyst composition comprising a porous molecular sieve which contains a metal in an oxidation state above zero within the interior of the pore structure of the sieve as well as a rare earth component which enhances the cracking activity of the cracking catalyst. The molecular sieve is normally a faujasite such as USY. The primary sulfur reduction component is normally a metal of Period 4 of the Periodic Table, preferably vanadium. The rare earth component preferably includes cerium which enhances the sulfur reduction activity of the catalyst. The sulfur reduction catalyst may be used in the form of a separate particle additive or as a component of an integrated cracking/sulfur reduction catalyst.

The invention relates to a non-noble metal mercury-free catalyst for acetylene hydrochlorination reaction, a preparation method and application thereof. The preparation method comprises the steps of: 1) preparing a mixed solution of a copper salt, an ammonium salt and phosphoric acid, or a mixed solution of a copper salt, an ammonium salt and phosphate; 2) adding activated carbon into the mixed solution obtained in step 1 for soaking; 3) spin-drying the soaked activated carbon, and conducting heating and drying to obtain the catalyst. Through the synergistic effect of multiple components, the catalyst prepared by the method provided by the invention acquires good catalytic stability and high low-temperature activity, and under a reaction temperature of 130DEG C and the existing mercury catalyst running pressure condition and feeding intensity, more than 96% of conversion per pass and more than 99% of vinyl chloride selectivity can be obtained. As the technical conditions of the catalyst for acetylene hydrochlorination reaction are similar to those of the existing mercury catalyst, renovation of existing equipment is unnecessary, and the mercury catalyst can be replaced easily on the existing equipment.

The invention discloses an oxygen reduction and oxygen evolution Co2P@NPC double-function compound catalyst and a preparation method and application thereof. The compound catalyst comprises N-P-codoped carbon layer coated Co2P nano rods and/or nano particles. The preparation method includes: evaporating and drying the solution of cobalt acetate, concentrated phosphoric acid and urea, and performing high-temperature treatment under protective atmosphere to obtain the compound catalyst. The preparation method has the advantages that the method is simple, low in cost and beneficial to industrial production; the prepared oxygen reduction and oxygen evolution Co2P@NPC double-function compound catalyst is applicable to fuel cell and water decomposition, high in activity and good in stability, the catalytic performance of the compound catalyst is close to that of a commercial precious metal 20wt% Pt/C and RuO2 catalyst, and the compound catalyst is promising in application prospect.

The invention relates to a method for preparing a load type high-dispersion multi-component precious metal nanoparticle catalyst. The method comprises the steps of 1) under inert atmosphere, uniformly stirring a solvent and a surface active agent, then adding a precious metal precursor solution, rising the temperature, reacting for a certain period of time, cooling to the room temperature, adding normal hexane, and performing extraction layering; 2) uniformly mixing the obtained upper layer nanoparticle solution with a carrier, and stirring or performing ultrasonic treatment; and 3) centrifugating, washing and drying or baking the mixed solution to obtain the catalyst. For the precious metal catalyst, even under a relatively high carrying amount, relatively good precious metal nanoparticle dispersion degree can be still guaranteed; the particle sizes of the particles are uniformly distributed; the precious metal carrying amount is controlled easily and accurately; the particle sizes and the components of multi-component particles can be controlled; and the catalysis application range is wide. The process is simple; the preparation cost is low; the applicability is high; and load-type high-dispersion precious metal and the multi-component precious metal nanoparticle catalyst can be prepared in a large scale.