32results about How to "Improve catalyst utilization" patented technology

The invention relates to a high-performance low-platinum cathode catalyst layer structure used for a fuel cell and application thereof. In the high-performance low-platinum cathode catalyst layer structure used for the fuel cell, Pt / C or PtMxOy / C serves as an electro-catalyst; a hydrophilic internal catalyst layer connected with a proton exchange membrane is formed by a Pt / C or PtMxOy / C catalyst (a second catalyst) prepared by a carbon carrier of which the specific area is 800 to 1,200 m<2> / g and a proton conductor serving as main components; and a hydrophobic external catalyst layer connected with a diffusion layer is formed by a Pt / C or PtMxOy / C catalyst (a first catalyst) prepared by a carbon carrier of which the specific area is 50 to 300 m<2> / g or a composite catalyst of the first catalyst and the second catalyst and a water repellent serving as the main components. The low-platinum cathode catalyst layer structure has the characteristics of less Pt dosage, thin thickness, high catalyst utilization rate and limiting current density, high stability and high durability.

The present specification relates to a carrier-nanoparticle complex, a catalyst including the same, an electrochemical cell or a fuel cell including the catalyst, and a method for preparing the same.

The invention provides a process for preparing diphenylamine by the coupling of condensation reaction and diphenylamine for increasing phenylamine once-through conversion ratio, wherein the condensation reaction and diphenylamine coupling apparatus employs 2-N fixed bed reactors through cascade connection, each reactor is filled with beta-zeolite molecular sieve catalyst, the reactor is equipped with a gas-liquid separator and a direct condenser on the top, the gas-liquid separator is equipped with liquid level display and control system, the operating pressure for each reactor is controlled between 1.5-3.0 MPa, the reaction temperature is controlled between 260-400 deg. C.

The invention provides a catalyst layer structure capable of effectively reducing fuel cell platinum (Pt) loading capacity. A catalyst layer is composed of a plurality of layers of single catalyst layers in different ingredients, and catalyst Pt loading capacity, ion conductor type, Pt loading capacity and a preparation process of each layer are different, so that the purposes of improving catalyst utilization rate and reducing the Pt loading capacity can be realized. In the reaction time of fuel cells, oxygen molecules diffuse from the catalyst layers to the interiors of the catalyst layers, and react with hydrogen protons moved from anodes. According to characteristics of the reaction of the fuel cells, oxygen diffuses from diffusion layers to the interiors of the catalyst layers and reacts with the hydrogen protons transmitted from the anodes to produce water. In the design of the catalyst layer structure, the Pt concentration and the ion conductor concentration of a catalyst layer close to the membrane side are improved in an emphasis mode so that reaction efficiency under intermediate and low current density is improved.

The invention relates to a guiding device and a guiding method for a diesel engine selective catalytic reduction (SCR) system for an automobile. The guiding device comprises an expansion pipe and at least two guiding plates arranged in a mutually embedding mode. The end where gas flows to the expansion pipe is a gas inlet end and the end where the gas flows out of the expansion pipe is a gas output end. The guiding plates at fixedly arranged on the gas inlet end of the expansion pipe and each guiding plate is in a trumpet shape without a front end face and a rear end face. A fluid channel is formed among the guiding plates. The guiding device is simple in structure, low in manufacturing cost and easy to install. According to the guiding device and the guiding method, due to backflow generated in the portion of an elbow pipe, exhaust of the automobile and urea sprayed from a nozzle can mix well so that generation of crystal on a wall is reduced. Due to the guiding device in the expansion pipe portion, mixed gas is converted from turbulent flow to laminar flow so that velocity distribution is even, radial pressure difference and temperature difference inside a catalytic agent are reduced, conversion efficiency of nitric oxides is improved, through capacity of a catalytic agent carrier is improved and service life of a catalyst is prolonged.

The invention discloses a method for preparing a platinum gradient-distribution catalyst layer structure of a proton exchange membrane fuel cell. The method comprises the following steps of 1, uniformly spraying a layer of a low-platinum load capacity carbon-supported platinum catalyst as a matrix on a polymer electrolyte membrane, 2, dipping the polymer electrolyte membrane with the matrix layer into a platinum precursor-containing solution so that platinum is reduced by a weak reductant and platinum nano-wires form on the matrix layer, 3, uniformly spray-coating a layer of an electrolyte resin solution on the platinum nano-wires to obtain a three-phase interface, and 4, carrying out hot-pressing with a diffusion layer to obtain a membrane electrode.

The invention describes the preparation and application of an ordered gas diffusion electrode based on a nanotube array, including the formation of an ordered microstructure, the preparation of the nanotube array, and the assembly of the ordered gas diffusion electrode. Co‑OH‑CO with regular orientation is first grown on the substrate 3 nanorod arrays; then in Co‑OH‑CO 3 The catalyst film is deposited on the surface of the nanorod array, and the Co‑OH‑CO loaded with the catalyst film can be 3 Nanorod arrays were directly transferred onto the gas diffusion layer, or the catalyst-loaded Co‑OH‑CO 3 After the nanorod array is annealed, it is transferred onto the gas diffusion layer, and the prepared gas diffusion electrode can be directly applied to the fuel cell, and can also be applied to the fuel cell after the catalyst is loaded on the surface of the nanotube array. The gas diffusion electrode constructed by the invention has the advantages of low catalyst loading, high catalyst utilization and the like.

A fuel cell membrane-electrode assembly having a fuel electrode and an oxidant electrode has a non-supported-catalyst containing catalyst layer that contains a metal catalyst nanoparticle of 0.3 nm to 100 nm in primary particle diameter that is not supported on a support, and an electrochemically active surface area of the metal catalyst nanoparticle is 10 m2 / g to 150 m2 / g, and a layer thickness of the non-supported-catalyst containing catalyst layer is less than or equal to 10 μm.

The invention discloses a method for directly synthesizing hydrogen peroxide in a fixed bed under the condition of high hydrogen-oxygen ratio. The method provided by the present invention is that the raw material hydrogen and oxygen are independently dissolved and liquefied outside the reactor without direct mixing, and then fed into the fixed bed reactor, and hydrogen and oxygen are catalyzed to prepare hydrogen peroxide in the presence of a supported noble metal catalyst. After the reaction, it is separated, the unreacted liquefied hydrogen is recycled, and the hydrogen peroxide is separated and refined. In the case of safe operation, the present invention adopts a higher hydrogen-oxygen ratio, increases the selectivity and conversion rate of hydrogen peroxide, and realizes the continuous production under the circulation system. The present invention has the advantages of simple operation process, low investment cost, continuous stability Good sex and other characteristics.

The invention discloses a preparation method of an alloy hydrogen evolution electrode loaded on foam transition metal. The preparation method includes: subjecting the three-dimensional foam transitionmetal to deoiling, pickling and drying; taking the three-dimensional foam transition metal as a base material placed in a glow plasma metallizing furnace and using a molybdenum plate with the purityof 99.99% as a sputter target material; cleaning and cooling to room temperature, and generating a molybdenum-molybdenum transition metal alloy hydrogen evolution electrode on the surface of the foamtransition metal. The obtained hydrogen evolution electrode is high in catalytic activity, large in specific area and good in electrical conductivity can can maintain stable structure and chemical activity under acidic, neutral and alkaline conditions, and most importantly, the preparation method is simple in process, low in cost, easy to control and suitable for large-scale industrial production.

The preparation method for electric catalyst of fuel cell comprises: selecting 3-50nm nano Ni as core and thin Pt or PtRu as shell, wherein the rate between Ni and Pt or PtRu is 10:10~100; selecting the load capacity of Pt or PtRu on C carrier as 10-60%; preparing the glycol solution of NiSO4, NiCl2 or Ni(NO3)2; adding C carrier and N2H4, adjusting pH value by KOH or NaOH; adding glycol solution of HPtCl6 or mixture of HPtCl6 and RuCl3; adjusting pH value; separating, cleaning, and drying. This invention can improve noble metal utility and reduces cell cost.