1585results about How to "Improve catalytic stability" patented technology

The invention belongs to the field of preparation and application of energy source materials and discloses a nitrogen-doped carbon nanotube / Co composite catalyst and a preparation method and application thereof. The preparation method includes: 1), respectively preparing melamine, cobalt salt and P123 into water solutions; 2), adding the melamine solution into the P123 solution, stirring for mixing, adding the cobalt salt solution, stirring for mixing, performing ultrasonic treatment, and heating while stirring until water is evaporated to obtain a precursor material; 3), pre-calcining the precursor material at 200-400 DEG C in an inert gas atmosphere, calcining at 450-600 DEG C and at 750-900 DEG C respectively, using an acid solution for soaking, cleaning, and drying to obtain the composite catalyst. The catalyst is high in oxygen reduction and oxygen evolution catalytic activity and stability and has high hydrogen evolution catalytic activity and stability in an acidic condition. The preparation method is simple, extensive in raw material source, low in cost and suitable for large-scale production. The composite catalyst is used in the field of integrated regenerative fuel cells.

The invention relates to a metal-coated oxide nano core-shell structure catalyst and a preparation method thereof, and in particular relates to a nano fuel cell catalyst with a core-shell structure, and a preparation method of the nano fuel cell catalyst. The invention aims at solving the problems that the conventional fuel cell catalyst is not high in catalytic activity and stability as well as low in cost at the same time. According to the metal-coated oxide nano core-shell structure catalyst, metal uniformly covers a shell, and oxide nano-particles are used as an inner core. The preparation method comprises the steps of: 1, preparing uniform, transparent and stable mixed solution; 2, blending and mixing; 3, adding reducing agent into the mixture; 4, adding extraction agent into the mixture; and 5, carrying out centrifugal washing and drying to obtain the metal-coated oxide nano core-shell structure catalyst. The invention is mainly used for preparing the metal-coated oxide nano core-shell structure fuel cell catalyst.

The invention discloses a method for preparing a monodisperse metal atom / graphene composite material employing electrochemical dissolved graphite. The method comprises the steps of (1) preparing an electrode from a graphite-based material; (2) electrolyzing the prepared electrode in an electrolytic cell, carrying out solid-liquid separation and recycling an electrolyte; (3) further stripping the solid obtained by separation and carrying out solid-liquid separation to obtain a crude monodisperse metal atom / graphene composite material; (4) separating and purifying the crude monodisperse metal atom / graphene composite material; and (5) carrying out thermal treatment on the composite material obtained in the step (4) under inert atmosphere protection and cooling and drying the material to obtain a monodisperse metal atom / graphene composite catalyst. The preparation method is simple in process steps, high in efficiency and low in energy consumption, and massive production can be 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 cerium component which enhances the stability and sulfur reduction activity of the catalyst. The molecular sieve is normally a faujasite such as USY. The primary sulfur reduction component is normally a metal of Period 3 of the Periodic Table, preferably vanadium. 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 present invention is generally related towards methods for preparing and using a more stable synthesis catalysts. In particular, the present invention is directed towards treating synthesis catalysts with low levels of oxygen to deactivate the smaller more unstable metal crystallites present in the catalyst matrix. The process can be carried out either prior to and / or simultaneously with the synthesis reaction.

A method for preparing a VOCs catalytic combustion catalyst comprises the following steps: preparing a solution A containing at least one metal compound, preparing a solution B contain organic ligand, adding the solution B to the solution A, and stirring the solution B and the solution A to obtain a mixed solution, wherein the organic ligand is at least one of carboxylic acid or imidazole organic matters; putting a carrier in the mixed solution, and carrying out 50-200DEG C constant temperature impregnation for 2-8h to obtain an MOF / carrier material; preparing a solution C containing at least one metal compound, and loading the treated MOF / carrier material in the solution C to carry out loading; ageing the above prepared material for 12h, drying the aged material at 60-100DEG C for 3-5h, and roasting the dried material in 500-800DEG C air for 4-8h; and washing the roasted material with distilled water or deionized water, and drying the washed material at 60-110DEG C for 8-24h to obtain the metal oxide catalyst.

The invention relates to a nitrogen-doped nano carbon electrocatalyst for a fuel cell, and preparation and application of the nitrogen-doped nano carbon electrocatalyst. The electrocatalyst is prepared by adopting the steps of: with phenylamine as a reaction precursor, mixing the phenylamine, a surfactant and a soluble transition metal salt and then polymerizing under acidic and high-oxidization conditions, carrying out high-temperature carbonization on the polymer under the protection of an inert gas and / or ammonia atmosphere after drying, and finally carrying out acid treatment. The preparation method of the electrocatalyst is simply and easily controlled, and the mass production is easily realized. The nitrogen-doped nano carbon electrocatalyst has better oxygen reduction catalytic activity, stability and selectivity in an acidic medium fuel cell compared with Pt / C, and has higher catalytic activity and stability in an alkaline medium fuel cell compared with commercialized Pt / C. In addition, the nitrogen-doped nano carbon electrocatalyst also has the advantages of low cost and high anti-poisoning property, and is capable of replacing platinum to be used as a fuel cell oxygen reduction electrocatalyst.

The invention relates to a carbon fiber supported metal catalyst as well as a preparation method and an application thereof. The materials such as graphene nano belt, a multi-arm carbon nano tube and graphene are adopted as graphitization template-based additives, and composite carbon fiber with high graphitization degree and high conductivity is obtained by electrostatic spinning and wet spinning processes and a high-temperature carbonization process, wherein the preferential amount of the template-based additives is 0.5-5% by weight; the high-graphitization composite carbon fiber is used as a carrier of the catalyst, and a metal / carbon nano fiber catalyst for a fuel cell is obtained by reduction; the catalyst has a large initial electrochemical-activity surface area and strong CO toxicity resistance; the current density attenuation is reduced in a 30 minutes of chronoamperometry test, and the catalyst shows higher electrochemical activity, higher current density and better electrochemical stability; and moreover, the catalyst taking the high-graphitization carbon fiber as a carrier shows remarkably high durability.

The invention discloses a foamed nickel-loaded iron-cobalt-nickel metal nano-catalyst and a preparation method and application thereof. The method comprises the following steps: cutting foamed nickel,washing and drying for later use; dissolving three metal salts of cobalt nitrate, ferrous nitrate and nickel nitrate, ammonium fluoride and urea into deionized water; performing stirring to obtain ahydrothermal solution; then adding the pretreated foamed nickel and the prepared hydrothermal solution into a high-pressure reaction kettle, vertically putting the foamed nickel into the bottom of thehigh-pressure reaction kettle after the foamed nickel is inserted into a polytetrafluoroethylene base, fastening the high-pressure reaction kettle, putting the high-pressure reaction kettle into a blast drying oven, carrying out first-step hydrothermal treatment, performing cooling to room temperature, performing washing and drying to obtain an intermediate product; and putting the prepared precursor into a reaction kettle, carrying out a second-step hydrothermal reaction, performing cooling to room temperature, and performing washing and drying. The preparation method provided by the invention has good economy and environmental protection property, and the prepared product has excellent electro-catalytic oxygen evolution performance, high strength and good stability, and can be applied to the field of water electrolysis oxygen evolution.

The invention provides a preparation method and application of a hollow mesoporous structure NiCoS polyhedron, and belongs to the technical field of clean energy preparation. The preparation method comprises the following steps that 1, divalent cobalt salt and 2-methylimidazole are dissolved in a methanol solution and then subjected to still standing, and ZIF-67 is obtained; 2, the ZIF-67 and nickel nitrate are mixed and stirred and then subjected to centrifugation and vacuum drying, and a middle body ZIF-67 / NiCo-LDH is obtained; and 3, the middle body is dispersed in an ethanol solution, thenthioacetamide is added for stirring, a mixed solution is placed in a reaction kettle for hydrothermal reaction, precipitation obtained after reaction is subjected to centrifugal washing and vacuum drying and then calcined in the protective atmosphere, and the hollow mesoporous structure NiCoS polyhedron is obtained. The preparation method of the hollow mesoporous structure NiCoS polyhedron has the advantages that the method is simple, going green and environmentally friendly, low in cost and easy to operate and control, and the preparation method is suitable for industrialized continuous large-scale production; and a raw material involved in the preparation method is environmentally friendly, low in price and excellent in performance, and large-scale application is expected to achieve.

The invention relates to a mesoporous nanosheet structure ferronickel selenide material supported on carbon fiber cloth and a preparing method. The mesoporous nanosheet structure ferronickel selenide material can serve as a brine electrolysis catalytic oxygen evolution active material, ferronickel selenide mesoporous nanosheets are staggered and linked on carbon nanofibers to form a three-dimensional network structure, the ferronickel selenide mesoporous nanosheets are 1-3 micrometers long and 25-45 nanometers thick, and the diameter of the carbon nanofibers is 10-13 micrometers. The mesoporous nanosheet structure ferronickel selenide material has the advantages that the mesoporous nanosheet structure ferronickel selenide material supported on the carbon fiber cloth and serving as an oxygen evolution electrode has excellent catalytic activity and stability and is a potential application material for a high-catalytic-performance brine electrolysis catalytic oxygen evolution catalyst. The reaction conditions are mild, based on the unique advantages of a mesoporous structure and selenide, a controllable secondary hydrothermal method is adopted, and by changing the hydrothermal time, the mesoporous material supported on the carbon fiber cloth is prepared and meets the requirement of green chemistry; the requirement for equipment is low, which is beneficial for marketization popularization.

The invention relates to a preparation method and application of a graphene based porous carbon supported metallic catalyst. The preparation method comprises the following steps: preparing graphene based porous silicon dioxide from graphene oxide as a base; preparing graphene based porous carbon from graphene based porous silicon dioxide as a template; using graphene based porous carbon as a carrier supported metallic catalyst; centrifuging, washing and drying. The graphene based porous carbon supported metallic catalyst, provided by the invention, has an excellent electro-catalytic property and can be used as an electrode material of a fuel cell.