291 results about "Platinum based catalysts" patented technology

Provided is a heat conductive silicone grease composition including (A) 100 parts by mass of an organopolysiloxane containing 2 or more alkenyl groups bonded to silicon atoms within each molecule, (B) an organohydrogenpolysiloxane containing 2 or more hydrogen atoms bonded to silicon atoms within each molecule, in sufficient quantity to provide from 0.1 to 5.0 hydrogen atoms bonded to silicon atoms within the component (B) for each alkenyl group within the component (A), (C) 100 to 2,200 parts by mass of a heat conductive filler, (D) an effective quantity of a platinum-based catalyst, and (E) an effective quantity of an addition reaction retarder, in which the component (C) includes more than 90% by mass and no more than 100% by mass of an indium powder with an average particle size of 0.1 to 100 μm. Also provided is a heat conductive silicone cured product obtained by curing the above composition by heating at a temperature equal to, or greater than, the melting point of the indium powder. Further provided is an electronic device including an electronic component, a heat radiating member, and a heat conductive member including the above cured product disposed between the electronic component and the heat radiating member. Still further provided is a method of curing the above composition. Even further provided is a method of forming a heat conductive member between an electronic component and a heat radiating member. The above heat conductive silicone grease composition generates a suitably thin cured product with excellent thermal conductivity that prevents problems such as the contamination of components other than the coated component, and the leakage of oily materials from the product if used over extended periods.

The invention relates to an iron and nitrogen doped carbon black catalyst and a preparation method of the iron and nitrogen doped carbon black catalyst, and solves the technical problems that the preparation method of an oxygen reduction catalyst with carbon as the carrier is complex, and requirements for devices are high. The catalyst of the invention is prepared in the following processes: carbon blacks are mixed with melamine evenly through ball milling technique; and the mixed material is doped with iron atoms due to the use of ball milling technique, the iron atoms and nitrogen atoms are enabled to be doped into a stratified structure of the carbon blacks after a high-temperature treatment, and the iron and nitrogen doped carbon black catalyst is formed. The catalyst is very high in oxygen reduction activity, much higher than platinum base catalysts in oxygen reduction initial potential and half wave potential, and higher than the prior oxygen reduction catalyst with the carbon as the carrier in oxygen reduction activity. The preparation method of the iron and nitrogen doped carbon black catalyst is simple, practical, and low in cost. Therefore, the oxygen reduction catalyst is suitable for being used to prepare fuel cells.

The invention relates to a low-hardness glue-dispensing shaping shielding conductive adhesive as well as a preparation method and application thereof. The conductive adhesive comprises the following components in parts by weight: (A) 100 parts of organic polysiloxane of which each molecule comprises at least two alkenyl; (B) 2-10 parts of the organic polysiloxane of which each molecule comprises at least two silicon-hydrogen bonds and a hydrolysable group; (C) 100-350 parts of metal base conductive fillers; (D) 0.001-0.005 parts of Pt-based catalyst; and (E) 0.1-2.0 parts of aluminum compounds or zirconium compounds or titanium compounds. Compared with the prior art, the conductive adhesive provided by the invention has the advantages of low hardness, high conductivity, high shielding performance, strong shaping ability, excellent adhesiveness and the like.

An electrically conductive silicone rubber composition comprises, at least, (A) 100 parts by weight of an organopolysiloxane having at least two alkenyl groups per molecule, (B) an organopolysiloxane having at least two silicon-bonded hydrogen atoms per molecule (an amount sufficient to cure the present composition), (C) a platinum based catalyst (an amount sufficient to promote the cure of the present composition), (D) 50 parts by weight to 5,000 parts by weight of a metal based electrically conductive filler, and (E) 5 parts by weight to 500 parts by weight of spherical silicone rubber particles with a surface active agent content of not more than 0.3 wt %.

Provided is a heat conductive silicone grease composition, including: an organopolysiloxane containing 2 or more alkenyl groups bonded to silicon atoms within each molecule, an organopolysiloxane with a specific structure and with a kinematic viscosity at 25° C. of 10 to 10,000 mm²/s, an alkoxysilane containing specific substituent groups, an organohydrogenpolysiloxane containing 2 or more SiH groups within each molecule, a heat conductive filler, a platinum-based catalyst, and an addition reaction retarder. The heat conductive silicone grease composition exhibits high thermal conductivity, has excellent fluidity prior to curing and therefore exhibits favorable workability, is capable of filling fine indentations and therefore reduces contact resistance, and is also able to prevent oil separation and bleeding of the heat conductive material following curing, meaning the composition exhibits excellent heat radiation performance and reliability. Also, the heat conductive silicone grease composition exhibits improved durability under conditions of high temperature and high humidity, and thereby exhibits further improved reliability during actual use.

An adhesive for silicone rubber, comprising at least the following: A 100 parts by weight of an organopolysiloxane having an average of two or more alkenyl groups per molecule; B an organopolysiloxane having an average of two or more silicon bonded hydrogen atoms in each molecule, used in an amount such that the molar ratio of silicon bonded hydrogen atoms in component B to alkenyl groups in component A at which the molar ratio of the silicon bonded hydrogen atoms in this component to the alkenyl groups in component A is from 0.01 to 20 (i.e. from 1:100 to 20:1); C from 5 to 200 parts by weight of calcium carbonate powder with a BET specific surface area of from 5 to 50 m.sup.2g; and D a platinum-based catalyst, used in an amount capable of inducing curing in the present composition.

The invention discloses a noble metal catalyst for preparing propylene through propane dehydrogenation and a preparation method thereof, and is used for mainly solving the problems that a noble metal catalyst is prone to carbon deposition and deactivation at high temperature to affect the stability of the catalyst. The used catalyst can be represented by PtSnCa/Al2O3, that is to say, platinum and tin components are supported on an alumina carrier, and a second auxiliary agent calcium oxide is introduced, so as to improve the stability of the catalyst. The catalyst is adopted for catalysis of propane dehydrogenation to prepare propylene under conditions of the temperature of 590 DEG C and the pressure of less than 0.2 MPa, the life of the catalyst can reach 145 h, and the service life of the catalyst is greatly prolonged, so that the problem is relatively well solved. The catalyst is in favor of industrialized promotion of propane dehydrogenation for preparing propylene.

A curable organopolysiloxane composition is provided, which includes (A) an organopolysiloxane containing at least one silicon atom-bonded alkenyl group within each molecule, (B) an organohydrogenpolysiloxane, which contains, within each molecule, at least one silicon atom-bonded hydrogen atom at a molecular chain terminal, and at least two silicon atom-bonded hydrogen atoms at non-terminal positions within the molecular chain, and which satisfies the formula shown below:

(wherein, a represents the number of silicon atom-bonded hydrogen atoms at non-terminal positions within the molecular chain, and β represents the total number of silicon atoms within the component (B)), in sufficient quantity to provide from 0.1 to 5 silicon atom-bonded hydrogen atoms per silicon atom-bonded alkenyl group within the component (A), and (C) a platinum-based catalyst. The composition can be cured even at low temperatures, generates a cured product that suffers no surface wrinkling, and displays excellent storage characteristics

The invention discloses a platinum-based catalyst carrier of a proton exchange membrane cell (PEMFC) and a preparation method of the platinum-based catalyst carrier. The platinum-based catalyst carrier is a g-C3N4 nanosheet/quasi-graphene carbon composite material. The preparation method comprises steps as follows: (1), a g-C3N4 precursor and inorganic salt are weighed and mixed uniformly to obtain a mixture A; (2), the mixture A is put into nitrogen atmosphere of a tube furnace in a semi-sealed manner, is heated to 500-700 DEG C and remains at the temperature for 1-5 h to obtain a material B; (3), the material B is ground, then washed and filtered with super-pure water and subjected to vacuum drying to obtain a block-shaped g-C3N4 material C; (4), the g-C3N4 material is added to concentrated acid, subjected to ultrasonic-wave stirring, washed with super-pure water until the pH is neutral, and subjected to centrifugal drying to obtain a g-C3N4 nanosheet; (5), the g-C3N4 nanosheet and quasi-graphene carbon are weighed, added to an alcohol solution and subjected to ultrasonic dispersion, extraction filtration and freezing drying to obtain a composite material. The preparation method is simple and feasible, the precious metal carrying capacity of the platinum-based catalyst is promisingly reduced, and accordingly, the production cost of the fuel cell is reduced.

The invention relates to a catalyst used for preparing 1,3-propylene glycol through glycerin hydrogenolysis, and specifically relates to a preparation method and an application of a mesoporous-tungsten oxide-supported platinum-based catalyst. According to the invention, mesoporous tungsten oxide is adopted as a carrier, and active components such as metal platinum or other noble metals are highly dispersed on the surface of the carrier, wherein the theoretical content of the active components accounts for 0.1-40% of the mass of the carrier. The catalyst is characterized by good selectivity and high activity. With the catalyst, high-selectivity preparation of 1,3-propylene glycol can be realized through glycerin hydrogenolysis under hydrothermal conditions comprising a temperature of 120-300 DEG C and a hydrogen pressure of 0.1-15MPa.

The invention discloses a platinum-based catalyst carrier of a direct methanol fuel cell and a preparation method thereof. The catalyst carrier is a graphite-like carbon nitride modified carbon compound material. The preparation method comprises the following steps: 1. weighing a graphite-like carbon nitride precursor and a carbon material; mixing uniformly to obtain a mixture A; 2. putting the mixture A into a pipe type nitrogen atmosphere in a semi-sealed manner and raising the temperature to 500-700 DEG C at the temperature raising rate of 2-10 DEG C per minute and keeping for 1-5 hours to obtain a material B; and 3. washing the material B by using ultrapure water and filtering; and drying in vacuum to obtain the graphite-like carbon nitride modified carbon compound material. With the adoption of the method for modifying graphite-like carbon nitride on the surface of the carbon material, the modification ratio of the graphite-like carbon nitride can be conveniently adjusted and controlled so that the carrier material keeps an excellent conductive performance. Furthermore, the catalytic activity and the stability can be obviously improved by the catalysis promotion effect of the graphite-like carbon nitride and the strong adsorption effect to PtRu metal nano particles.

The invention discloses a catalyst for catalyzing and oxidizing oxynitride in flue gas, which is prepared by using mesoporous silica as a vector, one or mixture of two of kalium and molybdenum as a doping component and platinum as an active component by adopting an equal-volume stepwise impregnation method. The invention also discloses a process for preparing the catalyst, and simultaneously discloses application of the catalyst in flue gas denitration process. Under the action of the catalyst, by utilizing oxygen contained in the flue gas per se, nitrogen oxide is oxidized into nitrogen dioxide which is easily dissolved in water, so that the oxidizability of nitric oxide in the flue gas can be improved, and the flue gas is absorbed and denitrated by utilizing alkali liquor. The kalium and polybdenum doped platinum-based catalyst prepared by the process has catalytic oxidation performance obviously superior to an undoped platinum-based catalyst, and has high denitration efficiency; and under the catalytic oxidation action of the kalium and polybdenum doped platinum-based catalyst, the NOx oxidizability in the oxidized flue gas is just between 45 and 65 percent, and the denitration side product nitrite can be reclaimed so as to realize recycling of the denitration product.

The invention discloses a quaternary platinum-based catalyst used for production of propylene through propane dehydrogenation, and a preparation method and an application thereof. The catalyst treats alumina processed by an alkaline gas as a carrier, precious metal Pt and metal Sn as active components, and M1 and M2 as assistants, M1 is one selected from Na, K, Rb, Mg, Ca and Sr, and M2 is one selected from La, Ce, Pm, Sm, Ti, Ga, In, Zn and Fe. The finally obtained catalyst comprises 0.2-0.3wt% of Pt, 0.1-2wt% of Sn, 0.5-2wt% of M1 and 0.5-2wt% of M2. The preparation method of the catalyst comprises the following steps: preprocessing the alumina carrier by the alkaline gas, and loading Pt, Sn, M1 and M2 through an impregnation process. The catalyst prepared through the method has the advantages of low price, simple operation, high reaction activity, good propylene selectivity, long single-use life and the like when the catalyst is used to catalyze a production reaction of propylene through propane dehydrogenation.

The invention relates to LED packaging silicone rubber, particularly relates to the high-refractive-index LED packaging silicone rubber, and belongs to the adhesive technical field. The high-refractive-index LED packaging silicone rubber includes a component A and a component B, and the weight ratio of the component A to the component B is 10 to 1. The component A includes the following raw material components in parts by weight: 80-90 parts of methyl phenyl vinyl silicon resin, 8-18 parts of vinyl dimethyl diphenyl polysiloxane, 0.1-0.3 part of a platinum-based catalyst, and 1-5 parts of an adhesive. The component B includes the following raw material components in parts by weight: 40-60 parts of methyl phenyl hydrogen-containing silicon resin, 40-60 parts of hydrogen-terminated diphenyl polysiloxane, and 0.1-0.3 part of an inhibitor. The high-refractive-index LED packaging silicone rubber has the beneficial effects of high hardness, vulcanization resistance, excellent adhesion, excellent hot and cold shock resistant performance and the like.

Heat-curable silicone compositions employing a reactive silicone, a silicone hydride crosslinker and a catalyst system which includes a rhodium-based catalyst, a stabilizing system are disclosed. A combination of rhodium and platinum-based catalysts are employed as well. The compositions are low temperature curing and are capable of providing low coefficient of thermal expansion compositions. A stabilizer system which includes in combination a peroxide and an acetylenic compound is also disclosed.

Provided is a curable organopolysiloxane composition which includes (A) an organopolysiloxane containing at least 2 alkenyl groups bonded to silicon atoms within each molecule, (B) an organohydrogenpolysiloxane containing at least 2 hydrogen atoms bonded to silicon atoms within each molecule, (C) gallium and/or an alloy thereof, with a melting point within a range from 0 to 70° C., optionally (D) a heat conductive filler with an average particle size within a range from 0.1 to 100 μm, (E) a platinum based catalyst, and (F) an addition reaction control agent. The composition is useful as a material capable of forming a layer with excellent thermal conductivity that is sandwiched between a heat generating electronic component and a heat radiating member.