94results about How to "Large electrochemical active area" patented technology

The invention discloses a composite nanostructure based on a three-dimensional porous transition metal carbide Ti3C2MXene and a general preparation method thereof, and belongs to the field of nanomaterials. The three-dimensional composite structure is composed of a three-dimensional porous Mxene-supported inorganic nanostructure, and has a honeycomb hierarchical porous structure. A precursor of atwo-dimensional transition metal carbide and a metal-organic framework compound is subjected to high-temperature pyrolysis or a chemical reaction in an inert or reactive atmosphere to prepare the composite nanostructure with a controllable size. According to the composite nanostructure, stacking of MXene itself is inhibited, an active surface area, porosity, and ion permeability of MXene are increased, and thereby a surface interface of MXene is efficiently used. At the same time, introduction of the metal-organic framework compound realizes uniform and stable compounding of the three-dimensional porous MXene and an inorganic nanomaterial, the fundamental difficult problem that plagues exerting and application of inorganic nanomaterial performance is solved, and the composite nanostructurehas wide application prospects in the fields such as catalysis, energy, photo-electricity, space technology, and military industry.

The invention discloses a preparation method of a hollow-nanostructural Co2P@C composite material obtained by direct phosphorization of a cobalt-based metal organic framework and used as a catalyst ofan oxygen evolution reaction, and belongs to the fields of nanocatalysis, nano materials and metal organic framework materials. The method comprises the following specific steps: 1) synthesizing a cobalt-containing metal organic framework precursor Co-BTC by using cobalt nitrate hexahydrate as a cobalt source and benzenetricarboxylic acid as an organic ligand; and 2) placing the precursor and sodium hypophosphite into a tube furnace, and performing direct heating to a corresponding temperature to prepare the hollow-nanostructural Co2P@C composite material. The raw materials used in the composite material provided by the invention have low costs, the preparation process is simple, and the composite material has excellent electrocatalytic performance in the oxygen evolution reaction; and inthe 1 mol/L KOH electrolyte, the overpotential is 330 mV when a current density is 10 mA/cm<2>, the corresponding Tafel slope is 44 mV/dec, and the catalytic performance can be maintained at 92.2% after the catalyst is used for the reaction for 6 h.

The invention provides a preparation method of a supported platinum-based alloy catalyst. The catalyst can be used as a low temperature fuel cell catalyst. The preparation method comprises the steps of taking ethylene glycol as a solvent and stabilizer, dispersing a carrier in the solvent, and reducing platinum and non-platinum precursors by strong reducing agents such as borohydride, hydrazine hydrate and tetrabutyl borohydride to obtain supported platinum-based alloy nanoparticles. The preparation method adopted by the invention is simple, effective and free of a problem of difficult removalof the stabilizer. The prepared alloy catalyst has a small particle size and uniform particle size distribution, and has good dispersion on the carrier at the same time. In addition, the catalyst canshow high area specific activity and unit mass Pt specific activity for oxygen reduction reaction, can effectively reduce the platinum consumption and has potential application prospects in the low temperature fuel cell.

The invention discloses an electrocatalytic material loaded with vanadium-cobalt alloy nanoparticles and a preparation method of the electrocatalytic material, and belongs to the technical field of composite material preparation. The carbon nanofiber-supported vanadium-cobalt alloy nanoparticle catalytic material for water electrolysis is prepared by loading a vanadium source and a cobalt source onto an ultrafine fiber carbon precursor by utilizing an electrospinning method, performing pre-oxidation, and performing reduction; and the catalytic material for the water electrolysis is composed ofreaction active matter and a carrier, wherein the reaction active matter is a vanadium-cobalt alloy nanoparticles, and the carrier is a carbon nanofiber material prepared by the electrospinning method. The catalytic material for the water electrolysis prepared by the method has a high specific surface area, thereby facilitating electrolyte diffusion and gas desorption; hydrogen evolution can be performed under acidic and alkaline conditions, and the hydrogen production speed under large voltage is much higher than that of a commercial Pt/C electrode; and in addition, the catalytic material for the water electrolysis prepared by the method does not need to coat an electrode, and can be directly used as an electrode for electrolyzing water.

The invention provides a tungsten disulfide/niobium disulfide heterojunction nanosheet. The tungsten disulfide/niobium disulfide heterojunction nanosheet grows on the surface of a substrate, wherein afirst upward layer on the substrate is a single-layer tungsten disulfide layer; the surface of the tungsten disulfide layer is at least partially covered with the niobium disulfide layer; and the thickness of the niobium disulfide layer is 4 to 6 nm. The invention also provides preparation and application of the tungsten disulfide/niobium disulfide heterojunction nanosheet. The NbS2/WS2 heterojunction nanosheet has the advantages stable chemical properties, good crystallinity, great electrochemical active area and the like, presents good electrochemical hydrogen evolution performance and goodstability, and can be applied to hydrogen production by electrolysis of water and related fields.

The invention discloses a preparation method of a titanium dioxide nanotube-ruthenium-titanium oxide coating titanium electrode. The preparation method comprises the following steps: carrying out pre-treatment on a titanium substrate, namely putting a pre-treated titanium sheet as a positive electrode and a large-area platinum mesh as a negative electrode into an electrolyte solution; then applying a direct current constant voltage to the two electrodes to anodize; in the anodizing process, keeping the temperature of the electrolyte solution constant and stirring the electrolyte solution; after anodizing, taking out the oxidized titanium sheet, namely a TiO2 nanotube/Ti electrode; ultrasonically cleaning with ethanol and water and annealing, and cooling to room temperature for later use; and coating the surface of the TiO2 nanotube/Ti electrode with coating liquid by means of a brush coating method, and drying, thermally oxidizing and cooling the TiO2 nanotube/Ti electrode to obtain the titanium dioxide nanotube-ruthenium-titanium oxide coating titanium electrode. According to the preparation method disclosed by the invention, the TiO2 nanotube can directly grow on a Ti substrate and has a very good bonding force with the titanium substrate, so that the TiO2.RuO2/TiO2 naotube/Ti electrode is longer in fortified life, and the electrochemical active area is large.

The invention discloses a supported palladium-ultrathin CoNi-LDH (Layered Double Hydroxide) nanosheet composite material as well as a preparation method and application thereof. The preparation methodcomprises the following steps: firstly, preparing ultrathin CoNi-LDH nanosheets by using a one-step hydro-alcohol thermal-solvent method, and supporting noble metal Pd nanoparticles by the ultrathinCoNi-LDH nanosheets as a carrier so as to obtain the supported palladium-ultrathin CoNi-LDH nanosheet composite material. The composite material can be applied to an electrocatalytic ethanol oxidationreaction, and has the advantages of high mass activity, good stability, good anti-poisoning ability and the like. The advantages can be attributed to the following aspects: (1), the ultrathin carriercan provide a larger electrochemical activity area, good electrical conductivity, and good CO poisoning resisting ability; and (2), the Ni-based LDH carrier can remove carbonaceous intermediates nearPdNPs sites, the Co element which is highly dispersed in laminates can achieve uniform and solid loading of PdNPs and is beneficial to sufficient utilization of PdNPs, and thus catalytic activity andstability can be synergistically improved.

The invention discloses a direct methanol fuel cell capable of improving utilization rates of catalysts and a preparation method thereof, and relates to the technical field of fuel cells. In a fuel cell membrane electrode prepared through the method, a microporous layer is of a double-layer structure, and comprises an outer microporous layer which contains a hydrophobic polymer and an inner microporous layer which contains a polymer having a proton conduction ability. The double-microporous layer structure has a high three-phase reaction interface and a high electrochemical reaction area and is capable of effectively reducing the material transfer resistance in the electrode and powerfully improving the utilization rates of the catalysts, so as to improve the discharge performance of the electrode and prolong the life of the cell. Through single-cell performance test, the membrane electrode prepared by the preparation method has the advantage that the monomer performance is remarkablyenhanced when being compared with the membrane electrodes prepared by the traditional method.

The invention discloses a preparation method and application of an iridium oxide nanoparticle catalyst. A mixed solution containing a polymer and an iridium-containing compound is uniformly applied toa treated conductive substrate; calcining in an air atmosphere is carried out to convert the iridium-containing compound into iridium oxide and the polymer is decomposed at the same time; the iridiumoxide nanoparticle material which is small in particle size, amorphous and of a porous structure is obtained, polymers remaining on the iridium oxide nanoparticle material are removed through a plasma generator, and the surfaces of iridium oxide nanoparticles are rich in hydroxyl. The film formed by the polymer in the mixed solution is utilized to solve the problem that the iridium-containing compound is agglomerated to form large particles when being calcined to generate the iridium oxide nanoparticles, thereby obtaining the small-particle-size iridium oxide nanoparticles. Besides, the plasma generator is used for removing residual polymers in the calcining process, the contact area of the iridium oxide nano particles is increased, and therefore the catalytic efficiency of the iridium oxide nano particles is improved.

The invention relates to the field of nanometer materials, and provides a preparation method of a MoS2-modified three-dimensional porous carbon-based composite material for electro-catalytic hydrogenevolution. The method specifically comprises the following steps: using a three-dimensional porous carbon-based material as a carrier, using ammonium tetrathiomolybdate as a sulfur source and a molybdenum source, transferring into a reaction kettle, and preparing the MoS2-modified three-dimensional porous carbon-based composite material by using a one-step solvothermal method. According to the invention, the method is simple and convenient to operate and low in cost; the synthesized composite material has an open three-dimensional porous structure, and easily achieves the migration of electrolyte and the release of hydrogen; and ultrathin MoS2 nano-sheets are uniformly and vertically arranged on a framework, so that the material shows excellent hydrogen evolution catalytic activity and excellent conductivity in an acidic electrolytic solution, still keeps efficient hydrogen evolution performance after cyclic polarization 2000 times, is good in stability and high in reusability, can beused for large-scale production, is expected to replace precious metals such as platinum and the like, and is widely applied to electrocatalytic hydrogen production.

The invention discloses a preparation method of a metal-doped bismuth layered oxide. The method comprises the steps of soaking a conductive substrate in a bismuth precursor solution and drying to obtain a conductive substrate modified with a bismuth oxide seed layer; and soaking the conductive substrate modified with the bismuth oxide seed layer in a bismuth precursor solution containing heteroatoms, and and synthesizing the metal-doped bismuth layered oxide with a nanosheet array structure on the conductive substrate through a hydrothermal method. The invention also discloses application of the metal-doped bismuth layered oxide in electrocatalytic reduction of CO2. The metal-doped bismuth layered oxide prepared by the invention is more stable in structure and performance, has a honeycomb nanosheet array structure, can provide a large electrochemical active area, and can promote enrichment and reduction of CO2 on the surface of an electrode and improve the current density when being used as a cathode catalyst in a reaction of electrocatalytic reduction of CO2.

The invention belongs to a method for synthesizing a nanometer material from top to bottom by a physical mode, and discloses a method for synthesizing a cobalt oxide and ferrocobalt layered bimetal hydroxide compound. The method comprises the steps of taking a block-shaped ferrocobalt alloy target as a raw material, and polishing and cleaning to remove an oxide layer on a surface; placing the block-shaped ferrocobalt alloy target in a container, and adding a sodium chloride solution to a position above the alloy target by 3-4 centimeters; performing ablation on the alloy target for 20-30 minutes by employing a nanosecond pulse laser liquid phase with a wavelength being 1,064 nanometers; and finally, taking out a brown solution in the container, performing freezing and drying to obtain a powder compound product after centrifugation. The ferrocobalt alloy target in the sodium chloride solution is ablated by a nanosecond laser liquid phase ablation technology to obtain the cobalt oxide and ferrocobalt layered bimetal hydroxide compound, the defect of poor conductivity of the material is effectively overcome by a synergistic effect of the cobalt oxide and ferrocobalt layered bimetal hydroxide, and meanwhile, the catalytic activity of water electrolysis to generate oxygen is also greatly improved; and the method is simple in process, ingenious in design and low in cost, and is safe and controllable.

The invention provides an iron-nitrogen co-doped carbon and MXene compound as well as a preparation method and application thereof. The preparation method comprises the following steps: preparing an iron-doped imidazolinate framework; preparing Fe-N-C; mixing Fe-N-C and Ti3C2Tx, dispersing the mixture into N,N-dimethylformamide, and carrying out ultrasonic treatment; carrying out suction filtration, washing and drying, heating to 300 DEG C and 400 DEG C in a nitrogen atmosphere, and carrying out heat preservation for 0.5 hour to 2 hours so as to obtain the iron-nitrogen co-doped carbon and MXene compound FeNC@Ti3C2Tx. The iron-nitrogen co-doped carbon and MXene compound prepared by the preparation method can effectively catalyze an oxygen reduction reaction.

The invention relates to a technology for directly growing a three-dimensional platinum nanowire array on a substrate through strong ligand control at room temperature. According to the invention, theobtained platinum nanowire array is uniform in distribution, high in repeatability and controllable in length, density and surface roughness, the conductive substrate with platinum wires grown can bedirectly used as a working electrode for methanol fuel cell testing, and compared with commercial platinum carbon, the platinum nanowire array has high activity and stability; and the method has theadvantages of simple and accessible raw materials, simple and safe operation process, low cost, high catalytic activity and high stability, can be suitable for industrial large-scale production, and has high practicability.

The invention belongs to the field of material preparation and particularly discloses a preparation method of an N-doped microporous carbon sphere ORR catalytic material. The preparation method comprises the following steps: (1) reacting a raw material solution containing pyrrole, formaldehyde and a structure regulator to obtain gel, wherein the structure regulator is water-soluble salt of zinc, and the concentration of Zn<2+> in the raw material solution is 1 to 5 mol/L; and (2), dehydrating the gel and then pyrolyzing the gel at a temperature not lower than 700 DEG C, so as to obtain the N-doped microporous carbon sphere ORR catalytic material. The invention also discloses the material prepared by the preparation method an application of the material in air batteries. The method disclosed by the invention can be used to prepare the ORR catalytic material with uniform spherical morphology, rich microporous structure and rich pyridine nitrogen-doped morphology, and the material has better ORR catalytic performance and anti-catalytic poisoning effect.

The invention discloses a preparation method of a long-cycle-life aqueous zinc secondary battery negative electrode, and belongs to the technical field of zinc secondary batteries. The preparation method comprises the following steps: firstly, carrying out chemical replacement reaction on zinc and metal salt to deposit a metal simple substance on the zinc metal surface and further to obtain a zincmetal surface covered solid electrolyte precursor; covering a solid electrolyte precursor on the surface of zinc metal to serve as a negative electrode to assemble a battery; and after the solid electrolyte precursor material is subjected to in-situ electrochemical cycle activation, generating solid electrolyteon the surface of zinc metal in situ, and obtaining the zinc secondary battery negativeelectrode material. The obtained zinc/solid electrolyte electrode has a large actual electrochemical active area and high mechanical stability, and meanwhile, the solid electrolyte isolates zinc metal from liquid electrolyte, so that the defects of active metal corrosion, surface passivation, dendritic crystal growth and the like of a traditional zinc metal electrode are inhibited, and the cycling stability of an electrode material is improved.

The invention discloses a palladium-nickel-cobalt-sulfur composite nanotube array electrocatalyst grown on a conductive substrate and a preparation method and the application of the electrocatalyst. The preparation method comprises the following steps: firstly, soaking a conductive substrate which is cleaned into a nickel-cobalt growth liquid, carrying out a primary kettle thermal reaction, soaking into a sulfur-containing compound solution, carrying out a secondary kettle thermal reaction, finally soaking into a palladium source solution, and carrying out a third kettle thermal reaction, so as to obtain the palladium-nickel-cobalt-sulfur composite nanotube array electrocatalyst grown on the conductive substrate. The palladium-nickel-cobalt-sulfur composite nanotube array electrocatalyst is grown on the surface of the conductive substrate, and palladium is distributed on the surface of palladium-nickel-cobalt-sulfur nano sodium. The invention further discloses the application of the palladium-nickel-cobalt-sulfur composite nanotube array electrocatalyst in water decomposition hydrogen production. The electrocatalyst has the characteristics of being simple in preparation process, low in cost and good in reproducibility, a palladium-nickel-cobalt-sulfur composite nanotube array is grown on the surface of the conductive substrate in situ, palladium-nickel-cobalt-sulfur has a goodbinding capability with the conductive substrate, and the electrocatalyst has a unique nanotube array structure and is excellent in electro-catalytic property.

The invention relates to a preparation method of a Ni3S2/NiV-LDH heterogeneous nanocone electrocatalyst, which adopts a hydrothermal-solvothermal method to prepare the electrocatalyst, and comprises the following steps: soaking foamed nickel in an aqueous solution containing a nickel source, a vanadium source and an alkali source, and carrying out hydrothermal reaction to obtain a precursor with ananosheet array structure; preparing a Ni3S2/NiV-LDH heterogeneous nanocone electrocatalyst through immersing the precursor in an isopropanol solution containing an organic sulfur source and carryingout a solvothermal reaction, wherein the Ni3S2/NiV-LDH heterogeneous nanocone electrocatalyst is formed by covering a foamed nickel substrate with a nanoscale morphology formed by embedding a large amount of Ni3S2 nanoparticles into the surface of NiV-LDH pyramids. The method provided by the invention is mild in condition; produced products are uniform in morphology, the pyramidal structure can significantly increase the electrochemical active area, nickel sulfide has low overpotential, the embedding of the nanoparticles can effectively increase the length of the edge state to increase the number of active sites, and the interlacing of the nanocones facilitates the improvement of the stability of the material and greatly improves the electro-catalytic hydrogen production and oxygen production activity of the material.

The invention belongs to the field of fuel cell cathode materials, and particularly discloses a platinum-based intermetallic nanocrystalline oxygen reduction catalyst and a preparation method thereof.The preparation method comprises the following steps: S1 mixing a platinum salt solution and a reducing agent solution to obtain a mixed solution, reacting the platinum salt in the mixed solution with the reducing agent to obtain platinum nanoparticles and separating the platinum nanoparticles from the mixed solution; and S2 coating a metal oxide on the surface of the platinum nanoparticles to obtain a platinum and metal oxide composite and performing annealing treatment on the platinum and metal oxide composite to obtain the platinum-based intermetallic nanocrystalline oxygen reduction catalyst. The platinum-based intermetallic nanocrystalline oxygen reduction catalyst is used for accelerating the cathode oxygen reduction reaction rate of the fuel cell and has good activity and durability and has simple synthesis process and can effectively regulate and control the size of nanoparticles and is easy to produce in mass.

The invention discloses a preparation method of an electrocatalyst with a PdCu alloy particle loaded NiFe-LDH (layered double hydroxide) metal nanosheet material. The nickel nitrate hexahydrate-urea-triethylene glycol-ferric chloride hexahydrate composite catalyst is prepared by compounding nickel nitrate hexahydrate, urea, triethylene glycol, ferric trichloride hexahydrate, NaBH4, copper chloride dihydrate and potassium chloropalladate. The preparation method comprises the following steps: firstly, dissolving nickel nitrate hexahydrate in a mixed solution of deionized water and triethylene glycol, then adding ferric trichloride hexahydrate, and adding urea after ultrasonic dispersion; the preparation method comprises the following steps: adding NiFe-LDH into a reaction kettle, heating, reacting, washing and drying the reaction solution, dissolving the obtained NiFe-LDH powder in deionized water, adding K2PdCl4 and CuCl2. 2H2O, adding a NaBH4 solution, stirring, carrying out centrifugal treatment, washing and drying a centrifugal product to obtain a final product, adding deionized water, isopropanol and naphthol, and uniformly mixing to obtain a catalyst solution. The method is simple in process, low in energy consumption, mild in condition, good in product morphology and suitable for large-scale production.