3669 results about "Noble metal" patented technology

The present application relates to the technical field of catalysts and relates to a non-noble metal cathode hydrogen evolution catalyst for PEM water electrolysis and a use thereof. The present application provides a method for preparing a cathode hydrogen evolution catalyst. A nickel-molybdenum heteropoly acid having a specific structure is generated in situ on the surface of a porous carbon material carrier, and is used as a hydrogen evolution catalyst active component precursor, and an in-situ generated nickel-containing molybdenum sulfide active component is subjected to sulfidation treatment to prepare a non-noble-metal-supported cathode hydrogen evolution catalyst, wherein the in-situ generated nickel-containing molybdenum sulfide active component has a hydrogen adsorption free energy similar to that of Pt and catalytic hydrogen evolution activity, the dispersity is good, and the number of active sites is large, thereby reducing the costs of the catalyst; in addition, during the sulfidation treatment of the nickel-molybdenum heteropoly acid, nitrogen or phosphorus atoms in the carrier can be doped into the lattice of molybdenum disulfide, thereby reducing the hydrogen evolution Gibbs free energy of sulfur atoms on an MoS2 crystal basal surface, and more active sites are formed on a sulfur edge and a molybdenum edge, facilitating a hydrogen evolution reaction.

The invention discloses a gas sensing material based on Ag / Pd-LaFeO3 and application of the gas sensing material in detection of hydrogen sulfide gas in municipal sewage, and relates to the technical field of gas sensing materials. The chemical formula of the gas sensing material based on Ag / Pd-LaFeO3 is X wt% of Ag-Y wt% of Pd-LaFeO3, wherein 0 lt; x < = 5, 0lt; y < = 5. According to the invention, on the basis of LaFeO3, the humidity interference resistance of the gas sensing material based on Ag / Pd-LaFeO3 can be improved through double noble metal surface modification of Ag and Pd. In addition, through double noble metal doping of Ag and Pd, the response sensitivity and selectivity of the prepared gas-sensitive material to H2S gas can be improved, and the working temperature of the gas-sensitive material is reduced. Specifically, at the working temperature of 110 DEG C, the response value of the prepared double noble metal modified LaFeO3 to 1ppm H2S gas is 46.16.

The invention discloses a long-life alumina crucible as well as a preparation method and application thereof. The raw material composition of the alumina crucible comprises pretreated quartz particles; the pretreated quartz particles are obtained through a pretreatment process; according to the pretreatment process, the surfaces of fused quartz particles are coated with a modifier through a granulation process, and the pretreatment process specifically comprises the steps that the fused quartz particles, the modifier and a binding agent are mixed, granulated and dried, and pretreated quartz particles are obtained. The fused quartz particle raw material is subjected to modification pretreatment, so that the crystallization behavior of fused quartz is reduced or inhibited, the stability of the fused quartz particles in the crucible firing and high-temperature service process is improved, and the binding property of the fused quartz particles and the fine powder component is enhanced, so that the mechanical properties such as breaking strength and fracture toughness of the alumina crucible are improved; therefore, the service life and the stability of the crucible are improved, and the performance of the alumina crucible can completely meet the requirement of the service life under extreme conditions in the fields of rare noble metal smelting and the like.

The invention belongs to the technical field of preparation of sensor materials, and particularly relates to a room-temperature formaldehyde sensor material based on a catalytic principle as well as preparation and application of the room-temperature formaldehyde sensor material. The polyphenol is adsorbed on the surface of the semiconductor metal oxide through chelation, then noble metal ions are introduced, and the polyphenol on the surface of the semiconductor metal oxide can capture the noble metal ions and reduce and stabilize the noble metal ions on the surface of the semiconductor metal oxide; the noble metal nanoparticles are anchored on the surfaces of the semiconductor metal oxide nanoparticles, the original morphology of the semiconductor metal oxide is maintained, and the noble metal nanoparticles are loaded on the surfaces of the semiconductor metal oxide nanoparticles. The nano composite material not only has the intrinsic electrical and thermodynamic properties of semiconductor metal oxide, but also combines the catalytic characteristics of noble metal nanoparticles, so that the lower detection limit of formaldehyde is reduced to 3ppb, and the sensitivity of the sensor is remarkably improved. The preparation method of the room-temperature formaldehyde sensing material is simple and suitable for large-scale production, the raw materials are simple and easy to obtain, the cost is low, and the materials are environment-friendly.

The invention discloses an electrocatalyst for acidic oxygen evolution reaction as well as a preparation method and application of the electrocatalyst, and belongs to the technical field of electrolyzed water. The preparation method of the electrocatalyst for the acidic oxygen evolution reaction comprises the following steps: growing a transition metal oxide on a conductive substrate in situ to obtain a transition metal oxide carrier; the transition metal oxide carrier is subjected to plasma treatment and then placed in a precious metal salt solution for a cation exchange reaction, and the electrocatalyst is obtained. The electrocatalyst prepared by the invention has extremely low initial overpotential (187mV) when a water electrolysis reaction is carried out in a 0.5 M H2SO4 solution, has no obvious performance degradation in a continuous acidic water electrolysis process for 4500h, shows very high operation stability, and has great application potential in the aspects of replacing a commercial RuO2 / IrO2 catalyst and reducing electrode preparation cost and acidic water electrolysis.

The invention discloses a method for synthesizing GaOOH and beta-Ga2O3 materials with relatively good crystal quality and relatively uniform phase by taking gallium nitrate as a gallium source through a hydrothermal method and high-temperature calcination treatment, and characterizing the GaOOH and beta-Ga2O3 materials. The hydrothermal method adopted by the method has the advantages of simplicity in operation, low cost and the like, and has great advantages in the aspect of synthesizing gallium oxide. And compared with the traditional methods such as CVD (Chemical Vapor Deposition) and the like, which need to introduce noble metal elements as catalysts, easily cause reduction of material crystal quality and introduce unnecessary impurity elements, the method disclosed by the invention can be used for synthesizing the gallium oxide material with relatively good crystal quality and relatively uniform phase by combining a hydrothermal method and high-temperature calcination treatment. GaOOH powder is synthesized by adding an anionic surfactant sodium dodecyl benzene sulfonate (SDBS) solution with different concentrations, and then the GaOOH powder is calcined at the high temperature of 900 DEG C to obtain beta-Ga2O3 materials with different sizes.

The present invention belongs to the technical fields of nanomaterials, analytical detection, and food safety, and specifically relates to a single-atom POD-mimicking enzyme nanomaterial, a preparation method thereof, and a food safety detection application. The single-atom POD-mimicking enzyme nanomaterial comprises a noble metal Os and a defective metal oxide, wherein the defective metal oxide is an oxide of metal Cu, and the Os is anchored on the defective metal oxide in the form of single atoms. The present invention also relates to the use of the single-atom POD-mimicking enzyme nanomaterial in the preparation of a detection reagent having POD activity and in the colorimetric detection of hydrogen peroxide or nitrite.

The invention discloses a preparation method of Au (at) Au (at) Ag / Pt / M NPs and application of the Au (at) Au (at) Ag / Pt / M NPs in klebsiella pneumoniae detection, and belongs to the technical field of analysis and detection. The invention particularly relates to development of a signal probe and combination and assembly of the signal probe and lateral flow immunochromatography (LFIA) for klebsiella pneumoniae detection. Au (at) Au (at) Ag / Pt / MNPs is a multi-element noble metal nanoparticle with plasma resonance property, peroxidase-like activity and light stability, shows strong detection potential in three modes of colorimetric (CM), catalytic colorimetric (CL) and surface enhanced Raman scattering (SERS), and is loaded into LFIA to construct a multi-mode LFIA (CM / CL / SERS-LFIA). The kit is expected to be used for direct multimode detection of klebsiella pneumoniae in clinical sputum samples, and a new early detection strategy is provided for respiratory tract infection diseases such as klebsiella pneumoniae.

The invention discloses a preparation method of a proton exchange membrane water electrolysis hydrogen production membrane electrode, and belongs to the technical field of proton exchange membranes, a catalyst carrier is prepared, S101, a polyimide membrane is inversely fixed in a magnetron sputtering vacuum coating chamber, a cavity cover of the magnetron sputtering vacuum coating chamber is closed, vacuumizing is performed, and a substrate is heated; and S102, argon is introduced into a cavity of the magnetron sputtering vacuum coating chamber, coating is started, the power of the bismuth metal target is set to be 0.2-0.5 kW, and the deposition time is 60-1800 s. In the invention, the physical vapor deposition method is utilized to load the catalyst on the surface of the metal oxide carrier with high specific surface area and ordered nanostructure, so that the exposure of active sites of the catalyst is increased, the dosage of the noble metal catalyst is reduced, and the bonding strength between the catalyst and the carrier is enhanced; the catalyst is not easy to separate from the surface of the carrier, and large-scale slurry agglomeration is avoided.

The invention discloses a preparation method for selectively oxidizing thioether into sulfoxide through photo-initiation, and belongs to the field of synthesis of medical compounds. The preparation method comprises the following steps that in the air atmosphere, a thioether compound is dissolved in an acetonitrile-water mixed solvent, inorganic metal salt catalysts such as ferric chloride and copper sulfate are added, the mixture reacts for 8-48 h at the temperature of 0-45 DEG C under illumination with the wavelength of 295-405 nm, selective oxidation is carried out, and the sulfoxide product is obtained, and the molar ratio of thioether to the catalysts is 5: 1. The method overcomes the problems of excessive oxidation risk, complicated operation, environmental pollution and the like caused by dependence of a noble metal catalyst and use of a strong oxidant in the existing thioether oxidation method, has the advantages of high catalytic efficiency, high yield and excellent selectivity, can greatly reduce the production cost, is suitable for later industrial synthesis and amplification, and has wide application prospects. The method has the advantages of no expensive metal catalyst or oxidant, simple preparation process, high efficiency, environmental protection, safety and cost saving.

The invention discloses a method for preparing a single-benzene-ring liquid chemical through solvent-free hydrogenation degradation of polystyrene waste plastics based on a bifunctional catalyst. According to the method, Nb2O5 is taken as a carrier, 1-3wt% of noble metal ruthenium is loaded to prepare a bifunctional catalyst, and high-molecular-weight polystyrene is efficiently degraded into single-benzene-ring liquid chemicals such as benzene, methylbenzene and ethylbenzene through hydrogenation reaction under a solvent-free condition. Precious metal ruthenium hydrogenates a polystyrene long chain to generate a short-chain hydrocarbon intermediate, then a carrier # imgabs0 # acid site drives beta-cracking and hydrogen transfer reaction, and a single-benzene-ring product is directionally generated through the synergistic effect of the short-chain hydrocarbon intermediate and the carrier # imgabs0 # acid site. The method has the advantages of no solvent, reduced equipment cost, high reaction efficiency, simple reaction operation, mild reaction conditions, simple catalyst preparation process, high activity, selectivity and good stability, and is suitable for industrial production, and no other solvents preempt acidic sites. The method not only can realize cyclic utilization of resources, but also can alleviate the current environmental pollution problem.

The invention discloses a carbon nitride-based composite material as well as a preparation method and application thereof. The carbon nitride-based composite material comprises a non-metal doped carbon nitride carrier and a noble metal, wherein the noble metal exists in the carrier in an element doping form and / or is loaded on the carrier in an oxide form; the precious metal is one or more of Pt, Pd, Au and Ru, and the nonmetal is one or more of P, S and I. According to the carbon nitride composite material disclosed by the invention, noble metal is utilized to modify carbon nitride, the number of surface active sites is increased, the electron and chemical structures of an active center are adjusted, and meanwhile, generation and migration of photo-generated charges are promoted. Meanwhile, the surface of the carbon nitride composite material is modified by non-metallic elements, so that adsorption and activation of reactant H2O molecules are effectively promoted. The catalyst disclosed by the invention is simple in preparation process, good in repeatability and easy for large-scale production.

The invention discloses an atom manipulation construction method of an artificial quantum structure on a two-dimensional layered material substrate, which comprises the following steps of: under an ultrahigh vacuum condition, evaporating and depositing noble metal atoms and non-metal atoms on the surface of a two-dimensional layered material by a molecular beam epitaxy method, and applying a voltage pulse through a tip of a scanning tunneling microscope to construct the artificial quantum structure on the two-dimensional layered material substrate. The method comprises the following steps: accurately lifting and placing monodisperse noble metal atoms, applying a voltage pulse through a tip of a scanning tunneling microscope, accurately placing a single non-metal atom near the noble metal atoms, accurately lifting and placing the single noble metal atom and the non-metal atom for multiple times, and carrying out N-type and P-type doping. And construction of an atomic-scale precise artificial quantum structure is realized. According to the method, accurate positioning, lifting, carrying, placing and other operations of the monatomic on the surface of the two-dimensional layered material are carried out, the problems of controllable control and structure construction of the monatomic on the surface of the two-dimensional layered material are solved, preparation of the diatomic PN junction is achieved, and a feasible scheme is provided for accurate design of quantum devices with atomic scales.

The invention discloses preparation of a high-performance carbon matrix embedded iron-based catalyst based on a metal organic framework precursor and application of the high-performance carbon matrix embedded iron-based catalyst in reverse water-gas shift reaction. In the preparation process, commercially available 1, 3, 5-trimesic acid iron (the chemical formula is C9H3FeO6, abbreviated as Fe-BTC) is selected as a raw material, pyrolysis treatment is carried out in an argon atmosphere, then air passivation is carried out, and finally the high-performance carbon matrix embedded iron-based catalyst based on the metal organic framework precursor is successfully prepared. The MOF-600 has excellent performance in many catalysts, the carbon dioxide production rate reaches 24.0 mmol CO.gcat <-1 >. S <-1 > at the temperature of 400 DEG C in a reverse water gas shift reaction, the performance is remarkably superior to that of an existing non-noble metal catalyst, and extremely high catalytic efficiency and application potential are shown.

Composite materials with noble metal coated silver nanowires loaded into polymer are described. The composite materials may have resistivities of no more than about 100 Ohm-cm, or from about 100 Ohm-cm to about 1×1011 Ohm-cm depending on the amount of noble metal coated silver nanowires loaded into the polymer. The noble metal coated silver nanowires may be platinum coated silver nanowires. Metal particulates such as silver flakes or silver particles may be added to the composite materials in order to obtain desired properties. Composite precursor compositions and methods for preparing the composite materials are described.

Provided are: a negative electrode composite material for a negative electrode for a solid-state battery, the negative electrode composite material being capable of being used even when a high-capacity negative electrode active material having a large volume change rate and a sulfide-based solid electrolyte that is reactive with an ionic liquid are used in the negative electrode composite material; and a solid-state battery using the negative electrode composite material. As a result, it is possible to achieve a solid-state battery in which loss of an ion conduction path during charging and discharging of the solid-state battery is suppressed, and a decrease in capacity during a charging and discharging cycle is suppressed. The negative electrode composite material contains a specific ionic liquid. Specifically, in a negative electrode composite material containing a negative electrode active material, a solid electrolyte, and an ionic liquid, the negative electrode active material is a silicon-based negative electrode active material, the solid electrolyte is a sulfide-based solid electrolyte, and the ionic liquid contains an anion having a donor number of 9 or less as determined from the half-wave potential of a noble metal.

The invention discloses a method for preparing furfuryl amine by reductive amination of biomass-based furfural, which comprises the following steps: adding furfural, a catalyst, ammonia water and a solvent into a closed reaction kettle in proportion, replacing air in the reaction kettle with high-purity hydrogen, and reacting in an oil bath pan for a period of time to obtain a target product furfuryl amine, the nano-catalyst provided by the invention is a nitrogen-doped porous hollow carbon sphere loaded nano bimetallic catalyst, takes noble metal and non-noble metal as a metal active center together, and has adjustability of macroscopic size and microstructure at the same time; the method has the advantages of simple reaction system, mild conditions, no pollution to the environment, high efficiency, energy conservation, low cost, few byproducts, high yield, high selectivity and the like, the furfural is efficiently converted into furfuryl amine at low temperature and low pressure within a short time, the used heterogeneous catalyst is stable and easy to recover, a new thought and direction are provided for enterprise production and scientific research, and the method is suitable for industrial production. The method has great significance on development and utilization of biomass-based furfural.

The invention relates to an elementary substance / alloy-metal oxyhydroxide anchored noble metal single atom / cluster heterojunction catalyst. A preparation method comprises the following steps: 1) dissolving a metal salt A, urea and ammonium fluoride in deionized water to obtain a mixed solution B; 2) performing hydrothermal reaction on the mixed solution B and a carrier to obtain a primary sample 1; 3) performing high-temperature calcination on the primary sample 1 in a mixed atmosphere of hydrogen and argon to obtain a primary sample 2; and 4) putting the preliminary sample 2 into a noble metal compound C solution for vacuum impregnation, taking out the sample after impregnation, and drying to obtain the catalyst. According to the scheme, the metal salt A is used as a metal source of a simple substance / alloy, the metal salt A is subjected to hydro-thermal synthesis to form a metal hydroxide and then subjected to high-temperature calcination reduction, the metal salt A is calcined to form the simple substance / alloy, then the simple substance / alloy is soaked in the precious metal compound solution C to form a metal oxyhydroxide, and meanwhile precious metal single atoms / clusters are anchored; the prepared catalyst is high in activity, and the preparation method is simple.

The invention relates to the technical field of chemical catalysts, in particular to a cerium-based solid solution loaded iron-based oxygen vacancy enhanced low-temperature ammonia synthesis catalyst. The heterovalent ions are doped in CeO2 crystal lattices to introduce strain and defects, so that the oxygen vacancy formation energy and concentration are greatly improved. Experiments show that the oxygen vacancy concentration (delta) of the Ce0. 8Zr0. 2O2-delta carrier disclosed by the invention can reach 0.12, which is 3-5 times that of pure CeO2. Under the conditions of 250 DEG C and 5 MPa, the ammonia synthesis rate reaches 120 [mu] mol / g / h, which is more than 20 times that of a traditional molten iron catalyst; under the conditions of 350 DEG C and 10 MPa, the ammonia synthesis rate exceeds 1000 [mu] mol / g / h and is close to the level of a noble metal ruthenium-based catalyst. As the working temperature is reduced by 100-150 DEG C, the reaction heat consumption is reduced by more than 30%, and the overall energy consumption is reduced by 25-40%.

The invention discloses a graphite diacetylene / copper oxide composite material cocatalyst and a co-production preparation process and application thereof. Graphite diyne has a two-dimensional layered structure and is composed of sp and sp hybridized carbon atoms, a periodically distributed structure is formed, and excellent electron transmission performance and pore structure are shown. An existing graphite diacetylene synthesis method is complex and high in cost, large-scale application of the graphite diacetylene in the industrial field is seriously restricted, the potential value of a copper catalyst cannot be fully exerted, and resource waste is caused. According to the invention, through a simple and efficient co-production process, co-production of graphite diyne and copper oxide nanoparticles is realized for the first time, and the graphite diyne / copper oxide composite material is successfully prepared. The novel composite material can be used as a cocatalyst to effectively improve photocatalytic hydrogen production, and the hydrogen production performance can be comparable with that of noble metal photocatalysts such as Pt. The problems of tedious steps, high energy consumption, low yield and the like in a traditional preparation method are solved, and the preparation method has important application value in the field of high-performance photocatalysis.

The invention discloses a shape-selective isomerization catalyst as well as a preparation method and application thereof. The catalyst comprises a ten-membered ring aluminum phosphate molecular sieve, a noble metal active component and a metal oxide auxiliary active component. The ten-membered ring aluminum phosphate molecule is selected from at least one of SAPO-11, MeAPO-11, SAPO-41 and MeAPO-41, and the ten-membered ring aluminum phosphate molecule is selected from at least one of SAPO-11, the noble metal active component is selected from at least one of Pt and Pd; the metal oxide auxiliary agent is selected from at least one of CeO2, Nb2O5 and Ta2O5. Compared with the catalyst prepared in the prior art, the catalyst prepared by the method provided by the invention has higher activity and isomer yield in the isomerization reaction of long-chain n-alkanes.

The present invention relates to the nanoparticles (NP) of the invention, compositions thereof and their use as therapeutic agents, in particular in the field of oncology and / or as imaging agents. The NPs consist of first nanoparticles of at least one high-Z metal oxide material, to which smaller second nanoparticles are covalently bonded at the surface of the first nanoparticles. The second nanoparticles consist of a) at least one noble metal or at least one metal oxide, metal sulfide, metal selenide or metal sulfide / selenide as a Fenton or Fenton-like reaction catalyst. The NPs of the invention produce a surprising therapeutic effect when exposed to ionizing radiation such as X-rays, gamma-rays, protons, neutrons, radioisotopes and / or electron beams. Therefore, these NPs can be used as radiosensitizers in the field of oncology. These nanoparticles can also be used as contrast agents.

The invention discloses a method for preparing cyclohexylamine based on reductive amination of cyclohexanone, and belongs to the technical field of fine chemical engineering. The preparation method comprises the following steps: adding a reactant cyclohexanone into a reaction kettle containing a certain amount of solvent, ammonia water and hydrogen atmosphere, and carrying out reductive amination reaction in the presence of a catalyst to obtain cyclohexylamine. The catalyst is CoyAl-LDHs loaded with metal active components, the CoyAl-LDHs are layered cobalt-aluminum bimetal hydroxides, and cobalt ions and precious metal ions in laminates are subjected to spontaneous oxidation-reduction reaction, so that the precious metal ions can be efficiently reduced into active metal nanoparticles. The layered cobalt-aluminum double-metal hydroxide not only has abundant surface acid-base sites, but also has high dispersity of loaded metal nanoparticles. The catalyst preparation and reductive amination reaction conditions are mild, the yield is high, the reaction system is simple and easy to separate, and the method is suitable for industrial production of cyclohexylamine.

The invention discloses a gas-sensitive material based on double noble metal doped holmium iron oxide and application of the gas-sensitive material to detection of hydrogen sulfide in a sulfur-containing ore body exploration environment, and relates to the technical field of gas-sensitive materials. HoFeO3 is used as a substrate material, and two elements of Au and Pt are used for doping modification of the HoFeO3 to prepare the gas sensitive material based on double noble metal doped holmium iron oxide. Au and Pt are combined to perform doping modification on HoFeO3, a synergistic effect is achieved on improving the temperature stability of the gas-sensitive material, the sensitivity of the gas-sensitive material in a high-humidity environment can be improved, in addition, due to the synergistic catalysis effect of Au and Pt, an energy barrier of H2S adsorption reaction can be remarkably reduced, surface electron transfer and reaction activity are promoted, and the sensitivity of the gas-sensitive material in a high-humidity environment is improved. Therefore, the working temperature is reduced, the response value is improved, and the method is suitable for detecting hydrogen sulfide gas in a sulfur ore body exploration environment.

The invention provides a CoCe-SNC catalyst and a preparation method and application thereof, and belongs to the technical field of hydrogen fuel cell / metal air cell cathode catalysts. The preparation method comprises the following steps: mixing and grinding a metal organic framework ZIF-8 and KSCN, carrying out first pyrolysis, compounding the obtained nitrogen and sulfur-containing co-doped carbon with two metal complexes Co-PM and Ce-PM, and carrying out second pyrolysis to obtain the CoCe-SNC diatomic catalyst. According to the invention, the two-dimensional lamellar structure carbon material and the asymmetric coordination diatomic metal are compounded, so that the catalytic performance of the whole catalyst is improved, and meanwhile, the yield of hydrogen peroxide generated by side reaction is reduced. The catalyst is applied to a hydrogen fuel cell / metal air cell, and the defects that in the prior art, a noble metal catalyst is high in cost, and a non-noble metal catalyst is low in catalytic activity, high in hydrogen peroxide yield, poor in catalyst stability and the like are overcome.

The invention discloses a Ti / IrO2-SnO2-SbO2 gradient active coating anode with low cost and high stability and a preparation process of the Ti / IrO2-SnO2-SbO2 gradient active coating anode. The gradient active coating is characterized in that the gradient active coating is composed of 3-5 layers, the total thickness is 5-15 microns, the thickness of each layer is 1-5 microns, the molar percentage content of iridium in a bottom layer is 0-5%, the sum of the molar percentage content of tin and antimony is 95-100%, the molar percentage content of iridium in a surface layer is 10-20%, the sum of the molar percentage content of tin and antimony is 80-90%, and the thickness of each layer is 1-5 microns. The molar percentage content of iridium from the bottom layer to the surface layer is sequentially increased from 2% to 10%, the molar percentage content of tin and antimony is sequentially reduced from 2% to 10%, and the total iridium loading amount in the gradient active coating is 0.05-0.2 mg / cm < 2 >. The preparation method comprises the three steps of titanium substrate pretreatment, precursor salt alcohol solution preparation and gradient active coating preparation. By adopting a gradient coating mode, the thermal stress between the coating and the titanium substrate in the preparation process is remarkably reduced, the consumption of noble metal is reduced, the oxygen evolution activity of the anode is improved, and the service life of the anode is prolonged. The method is simple to operate and low in cost, and has remarkable industrialization advantages.

The preparation method comprises the following steps: mixing a catalyst, a pore forming agent, an ionomer and a solvent, carrying out ultrasonic treatment in an ice-water bath until the mixture is uniformly dispersed, then coating a polytetrafluoroethylene membrane with the mixture to obtain a catalytic layer, and then carrying out hot pressing and transferring the catalytic layer to two sides of a proton exchange membrane to obtain the membrane electrode. The catalyst layer of the prepared membrane electrode has a cross-linked porous network structure formed in situ when the pore forming agent is pyrolyzed and separated in the hot-pressing transfer printing process, so that the specific surface area of a three-phase interface and the utilization rate of a noble metal catalyst are increased, the gas and liquid mass transfer resistance of the membrane electrode is reduced, and the material transmission capability is improved; the performance of the membrane electrode is improved, and the membrane electrode has more excellent stability.

The invention relates to the technical field of analysis and detection, in particular to a surface enhanced Raman spectroscopy (SERS)-based nano material detection method, which is characterized in that a heterojunction composite structure consisting of noble metal nano stars and semiconductor oxide nano particles is used as an SERS active substrate; and a specific recognition molecule carrying a Raman reporter molecule is used as a detection probe. During detection, the recognition molecules are firstly combined with the to-be-detected nano material, and then the compound is adsorbed on the surface of the substrate. The tip structure of the noble metal nanostar and a heterojunction interface jointly generate a synergistic effect of electromagnetic enhancement and chemical enhancement, and a reporter molecule signal is doubly amplified, so that high-sensitivity and high-selectivity detection on a to-be-detected nano material is realized. The method solves the problems of weak signal and poor selectivity of the traditional method, and is suitable for rapid and quantitative analysis of trace nano materials in the environment.

The present invention relates to the field of catalyst technology, discloses a supported noble metal catalyst and its preparation method and application, the catalyst includes a first carrier and a coating loaded on the first carrier, the raw material composition for preparing the coating includes a second carrier, an active component precursor, an auxiliary agent precursor, a binder and a dispersant; the first carrier is cordierite, mullite or cordierite-mullite; the second carrier is titanium dioxide and / or aluminum oxide; the active component precursor is selected from at least one of a platinum precursor, a palladium precursor and a rhodium precursor; the auxiliary agent precursor is a combination of a cerium precursor, a zirconium precursor and a neodymium precursor; the binder is a mixture of an organic binder, an inorganic binder and a coupling agent. The supported noble metal catalyst has low production cost, high catalytic activity, strong anti-poisoning ability and long service life, can be used for the removal of volatile organic compounds, and is particularly suitable for the removal of flue gases such as ethylene and propane with large air volume and low concentration of organic small molecule hydrocarbons.

The invention relates to the technical field of heterogeneous catalysis and fine chemical engineering, and discloses a rhodium-tungsten para-site MOF-based catalyst as well as preparation and application thereof. The invention relates to a rhodium-tungsten para-site MOF-based catalyst, which is composed of a catalytic active component, a metal additive and a carrier. The rhodium-tungsten para-site MOF-based catalyst provided by the invention takes a metal organic framework material as a carrier, an active component Rh and a metal additive W are stably anchored on the surface of the carrier, and an Rh-WOx para-site is successfully constructed; the rhodium-tungsten para-site MOF-based catalyst provided by the invention shows excellent catalytic activity and excellent cycle stability in olefin hydroformylation reaction, and overcomes the technical bottlenecks that noble metals in a homogeneous catalysis system are easy to lose and energy consumption is high in a product separation process; an efficient and stable catalyst design thought is provided for olefin hydroformylation reaction, and the catalyst has a good industrial application prospect.