147 results about "Nitrogen doped graphene" patented technology

According to the cobalt-doped molybdenum disulfide lithium-sulfur battery composite positive electrode material, the preparation method and the application, a cobalt-doped stable molybdenum disulfide defect structure composite nitrogen-doped graphene material is prepared by combining a solvothermal method and an annealing technology, and the process is mature; the method is simple, and the composite positive electrode material with high sulfur content is easy to obtain. According to the lithium-sulfur battery composite sulfur positive electrode material disclosed by the invention, the strong chemical adsorption effect and catalytic conversion effect of the cobalt-doped stable molybdenum disulfide defect structure composite nitrogen-doped graphene carrier on polar lithium polysulfide are utilized, so that the diffusion of the lithium polysulfide in an ether electrolyte is inhibited, and the electrochemical reaction kinetics is improved; therefore, the shuttling effect is slowed down, and the lithium-sulfur battery has the characteristics of high capacity and long service life.

The invention relates to the technical field of capacitors, and discloses a high-energy-density capacitor which is characterized in that a positive electrode is composed of a composite active material, a conductive agent and a binder, the composite active material comprises a mixture of nitrogen-sulfur co-doped carbon foam magnetic microspheres and iron sesquioxide nanodot at nitrogen-doped graphene, and the conductive agent is a mixture of nitrogen-sulfur co-doped carbon foam magnetic microspheres and iron sesquioxide nanodot at nitrogen-doped graphene. The preparation method of the nitrogen-sulfur co-doped carbon foam magnetic microspheres comprises the following steps: by taking polyacrylonitrile as a carbon source, thiourea as a sulfur source and ferric nitrate as an iron source, carrying out hydrothermal reaction and then carrying out carbonization treatment at 800-1000 DEG C for 2-4 hours; the energy density of the high-energy-density capacitor can reach 700-800 Wh / kg, the power density is larger than or equal to 10 kW / kg, compared with a traditional super capacitor, the high-energy-density capacitor has the advantages that the energy density is remarkably improved, and the application requirements of the fields with high requirements for energy and power such as electric automobiles and intelligent power grids can be met.

The invention discloses a method for screening a high-catalytic-activity nitrogen-doped graphene-loaded single-metal-atom ammonia synthesis catalyst, and belongs to the technical field of ammonia synthesis. The method comprises the following steps: constructing an original graphene configuration; constructing a nitrogen-doped graphene configuration; a nitrogen-doped graphene loaded monometal configuration is constructed; the Eform is formed to judge the stability; constructing an adsorption configuration of reactant molecules; analyzing the relaxation configuration to judge the activation degree; the adsorption stability is judged according to the adsorption energy Eads; determining a path of N2 thermal reduction reaction; adopting NEB and Dimer methods to construct a transition state spatial configuration; reaction heat and activation energy are calculated, and activity differences of different catalyst surfaces are analyzed. Based on density functional theory calculation, catalyst screening standards with formation energy, adsorption energy and activation energy barriers as indexes are established, the high-activity catalyst is screened out theoretically, the experiment trial and error cost is reduced, and the catalyst development efficiency is improved.

The present application relates to thermal insulation coating technical field, specifically to a kind of low VOCs ultraviolet resistant thermal insulation coating composition and its performance testing device, consisting of the following mass parts components: water-based acrylic resin 30-45 parts, nitrogen-doped graphene 1-3 parts, nano composite powder 2-5 parts, low water absorption and expansion glass microsphere 8-12 parts, silane coupling agent modified sepiolite 5-10 parts, silane coupling agent KH560 0.5-1.5 parts, ultraviolet absorber UV-9 0.3-0.8 parts, hydroxyethyl cellulose thickening agent 0.2-0.5 parts;Composition meets the following conditions: (1) VOCs content≤50g / L;(2) ultraviolet absorption rate≥95%;The present application realizes the purpose that VOCs content is far lower than traditional solvent type coating through the synergistic effect of water-based acrylic resin system and low water absorption and expansion glass microsphere, while nitrogen-doped graphene and nano ITO-SiO2 Composite powder form ultraviolet-infrared dual-effect shielding layer, ultraviolet absorption rate, infrared reflectivity greatly improve, solve the problem that traditional anti-UV coating function is single, VOCs is overproof.

The invention discloses an MOF / nitrogen-doped graphene-based electrocatalyst and a preparation method thereof, nitrogen-doped graphene has a single nitrogen configuration, and the nitrogen-doped graphene is pyridine nitrogen or pyrrole nitrogen; the MOF is ZIF-67, and the MOF is connected with a nitrogen atom of the nitrogen-doped graphene through a coordinate bond. Carrying out covalent functionalization on the surface of the graphene by using a specific pyridine nitrogen configuration polymer; then growing MOF in situ by taking the nitrogen-doped graphene as a precursor, and then calcining to realize the compounding of the nitrogen-doped graphene with the single nitrogen configuration and the MOF. According to the prepared MOF / nitrogen-doped graphene composite electrocatalyst, the stability and the electrocatalytic activity (such as OER, HER and ORR) of MOF can be remarkably improved. Meanwhile, the preparation method is simple in process, low in cost and remarkable in industrial application potential.

The invention discloses conductive silver paste doped with graphene powder and a preparation method of the conductive silver paste, and relates to the technical field of conductive silver paste. The method comprises the following steps: performing nitrogen doping on graphene by using plasma, introducing nitrogen atoms into graphene crystal lattices to form nitrogen-doped graphene, and introducing oxygen-containing functional groups on the surface of the graphene through a plasma surface modification technology to further improve the conductivity. The preparation method comprises the following steps: mixing an aniline monomer and an aminobenzoic acid monomer, carrying out in-situ polymerization on the surface of nitrogen-doped graphene to generate a polyaniline-aminobenzoic acid copolymer, and compounding a graphene-polyaniline material obtained by in-situ polymerization with carbon nanotubes to construct a three-dimensional conductive network. Secondly, the prepared three-dimensional filler is added into conductive silver paste, carboxyl in aminobenzoic acid is adsorbed and combined with silver particles through Van der Waals force, a stable interface structure is formed, the interface resistance is reduced, and the connectivity of a conductive network is enhanced. The prepared conductive silver paste has the effect of high conductivity.

The invention discloses an iron-carbon composite material for heavy metal contaminated soil remediation and a preparation method of the iron-carbon composite material, and belongs to the field of heavy metal contaminated soil remediation. The iron-carbon composite material comprises rape straw, hydroxyapatite, zero-valent iron, sulfydryl functionalized magnetic cerium oxide and nitrogen-doped graphene quantum dot-sodium alginate. The sulfydryl-functionalized magnetic cerium oxide is prepared from cerium nitrate and ferric nitrate through precipitation, calcination and sulfhydrylation, and the nitrogen-doped graphene quantum dot-sodium alginate is prepared from citric acid and urea through microwave reaction, dialysis, mixing and freeze drying; the preparation method comprises the following steps: treating straws and hydroxyapatite to obtain ball-milled phosphorus-containing biochar, mixing the ball-milled phosphorus-containing biochar with zero-valent iron and two modifiers, and carrying out molding and high-temperature calcination to obtain the phosphorus-containing biochar-based composite material. The material has a remarkable remediation effect on the heavy metal contaminated soil, can effectively reduce the activity of heavy metals in the soil, has the characteristics of environmental friendliness and high stability, and is suitable for treating the soil compositely contaminated by the heavy metals such as cadmium and lead.

The invention provides an Mxene quantum dot modified nitrogen-doped graphene material, a preparation method and an isolating membrane. The Mxene quantum dot modified nitrogen-doped graphene material comprises Mxene quantum dots and nitrogen-doped graphene, and based on the mass of the Mxene quantum dot modified nitrogen-doped graphene material, the mass percentage content of the Mxene quantum dots is 30%-60%. According to the Mxene quantum dot modified nitrogen-doped graphene material provided by the invention, a conductive-adsorption-catalysis interface can be constructed, the shuttle effect of polysulfide is effectively inhibited, rapid conversion of the polysulfide is promoted, and the cycle performance and rate capability of a lithium-sulfur battery are improved.

The invention belongs to the technical field of catalytic conversion materials, and particularly relates to nitrogen-doped graphene aerogel for H2S removal and a preparation method of the nitrogen-doped graphene aerogel. The preparation method of the nitrogen-doped graphene aerogel for H2S removal comprises the following steps: (1) uniformly mixing a graphene oxide aqueous solution with a nitrogen source to obtain a mixed solution; (2) carrying out a hydrothermal reaction on the mixed solution, and after the hydrothermal reaction is finished, freeze-drying the obtained hydrogel to obtain aerogel; and (3) carrying out carbonization treatment on the aerogel, so as to obtain the nitrogen-doped graphene aerogel for removing H2S. According to the nitrogen-doped graphene aerogel for H2S removal disclosed by the invention, large-size graphene sheet layers are mutually connected to form a macroporous and mesoporous mass transfer passage inside the nitrogen-doped graphene aerogel, and the surface of the material has a rich microporous structure and a high-content nitrogen doping characteristic, so that efficient adsorption and removal of H2S molecules can be realized.

The invention relates to the technical field of palladium recovery, in particular to a method for recovering palladium. According to the technical scheme, the method comprises a precipitant pre-synthesis stage, a targeted palladium precipitation stage and a multi-stage reduction purification stage, and the precipitant pre-synthesis stage comprises the step of adding 10-15 parts by mass of butanedione, 18-30 parts by mass of hydroxylamine hydrochloride and 0.1-0.3 part by mass of iron phthalocyanine into a reaction kettle. Through a composite precipitator system and a multi-stage reduction process, the method has safety and high efficiency: flammable and explosive solvents such as ethanol and highly toxic reducing agents such as hydrazine hydrate are not needed, so that the potential safety hazard of production and the environment-friendly treatment cost are remarkably reduced; high-selectivity capture and efficient reduction of palladium are achieved through magnetic separation of magnetic nano-microspheres, induced precipitation of nitrogen-doped graphene quantum dots and a staged temperature-control and pressure-control reduction technology, the palladium recovery rate and purity are high, the process period is short, operation is controllable, and the method is suitable for industrial continuous production.

The invention belongs to the technical field of electrode materials, and particularly relates to an electrode composite material of a flexible supercapacitor and a preparation method and application of the electrode composite material. According to the method, the nitrogen-doped graphene quantum dots are deposited on the 1T-phase molybdenum disulfide nanosheets growing on the carbon cloth through an electrophoretic deposition method, the method is carried out at normal temperature and normal pressure, N-GQDs aggregation can be avoided, the process is simple, the controllability is high, the applicable material range is wide, and batch production is easy. The prepared flexible composite electrode has excellent electrochemical performance, compared with an original electrode, the specific capacitance value is remarkably improved, the cycling stability is enhanced, the flexible composite electrode can serve as a supercapacitor electrode material, and an assembled flexible all-solid-state symmetrical supercapacitor has good flexibility and electrochemical performance and has wide application prospects.

The invention discloses a nitrogen-doped graphene composite material and a preparation method thereof, and belongs to the technical field of composite materials. The preparation method comprises the following steps: S1, preparing a nitrogen-doped graphene material; s2, dissolving indium nitrate, 2-amino-benzothiazole and the nitrogen-doped graphene material in a DMF (Dimethyl Formamide) aqueous solution, carrying out hydrothermal reaction, cooling to room temperature, washing and freeze-drying to obtain a nitrogen-doped graphene / indium-based MOF (Metal Organic Framework) material; and S3, adding the nitrogen-doped graphene / indium-based MOF material into the lead acetate dispersion liquid, carrying out ultrasonic treatment, stirring and uniformly mixing, dropwise adding a 2g / L sodium hydroxide solution into the mixed liquid in a stirring state until the solution Ph is 8, then carrying out freeze drying, putting a dried sample into a tubular furnace, and calcining in an inert atmosphere to obtain the nitrogen-doped graphene composite material. When the prepared composite material is applied to the negative electrode of the lead-acid battery, the hydrogen evolution side reaction in the charging process of the negative electrode plate can be remarkably reduced, and the electrochemical performance of the battery is improved.

The invention discloses a preparation method of a nitrogen-doped graphene carbon nanotube high-power composite electrode material. The material is prepared by taking graphene oxide and carboxylated multi-walled carbon nanotubes as precursors and urea as a nitrogen source through synergism of chemical reduction and a hydrothermal method. A three-dimensional porous network structure is constructed through solvent dispersion, ultrasonic compounding, high-temperature reduction and hydrothermal doping processes, and the nitrogen-doped graphene carbon nanotube composite hydrogel is obtained. The electronic structure of the carbon material is regulated and controlled through nitrogen atom doping, active sites such as pyridine nitrogen, pyrrole nitrogen and graphite nitrogen are introduced, and the surface wettability and the pseudocapacitance performance are improved. The prepared NGM5 electrode has a high specific surface area (197.91 m < 2 > / g) and a multilevel mesoporous structure. 37.0 wt% H2SO4 is used as an electrolyte to assemble a symmetric supercapacitor, the surface capacity of 498 mF cm <-2 > and the energy density of 69.03 mu Wh cm <-2 > are realized at room temperature of 1 mA cm <-2 >, the energy density of 57.51 mu Wh cm <-2 > is still kept at the extreme low temperature of-60 DEG C, and the capacitance retention rate exceeds 70% after 8000 times of charge and discharge cycles. The preparation process is simple, the cost is low, graphene stacking and carbon nanotube agglomeration are effectively inhibited, the problem of low-temperature performance degradation of a traditional carbon-based material is solved, and the method is suitable for industrial production of a high-power and wide-temperature-range supercapacitor electrode material.

The invention relates to the technical field of electrochemical luminescence sensing, and discloses an electrochemical luminescence immunosensor for detecting interleukin-1 beta, a preparation method and application thereof, the electrochemical luminescence immunosensor comprises a working electrode, a reference electrode and a counter electrode; the working electrode comprises a substrate electrode and an ordered mesoporous silica film (SNF) modified on the surface of the substrate electrode; a composite nano-enzyme containing cobaltosic oxide nanoparticles and nitrogen-doped graphene quantum dots is loaded in a nano-pore channel of the SNF, the outer surface of the SNF is modified with an epoxy group, and an anti-interleukin-1beta antibody is covalently immobilized through the epoxy group; a detection system of the electrochemical luminescence immunosensor is a luminol / dissolved oxygen system. According to the electrochemical luminescence immunosensor, a luminol / dissolved oxygen system signal can be remarkably enhanced, and high-sensitivity and accurate quantitative detection of interleukin-1 beta is realized under a neutral condition.

The invention discloses a master batch, a preparation method thereof, a light diffusion plate and a refrigerator, and belongs to the technical field of refrigerator materials. In the preparation method of the master batch, the nitrogen-doped graphene is prepared by the following steps: preparing a graphene oxide dispersion liquid with the mass fraction of 1-3%; taking ammonia water as a nitrogen source, uniformly mixing the graphene oxide dispersion liquid and the ammonia water according to a volume fraction ratio of the ammonia water to the graphene oxide dispersion liquid of (1-2): 1, carrying out heating reaction in a closed container, taking out the mixed liquid, cooling to room temperature, and carrying out freeze drying to obtain powder; and heating the tubular furnace to 450-500 DEG C, putting the powder from one side of the tubular furnace, and pushing out the powder from the other side to obtain the nitrogen-doped graphene. The coating is applied to a refrigerator back surface light source light diffusion plate, solves the problems that an existing antibacterial coating cannot meet the requirements of high visible photocatalytic effect and food contact at the same time, and the manufacturing process is complex due to a spraying process, has the characteristics of wide spectrum and visible light response, and is high in catalytic activity, good in antibacterial performance and suitable for large-scale popularization and application. And a spraying process is omitted.

The invention belongs to the technical field of electro-catalytic materials, and particularly discloses a preparation method of a nitrogen-doped graphene nanosheet loaded nickel monatomic catalyst, which comprises the following steps: preparing a Ni / Zn-ZIF-L precursor, preparing a nickel monatomic catalyst by a molten salt method, and preparing a post-impregnated nickel monatomic catalyst. The specific surface area of the substrate is remarkably increased by adopting a molten salt method, so that a metal center site is fully exposed; the loading capacity of metal nickel atoms is effectively improved through a post-impregnation strategy; the nickel monatomic catalyst loaded by the nitrogen-doped graphene nanosheet with high specific surface area and low defect degree is synthesized, and the nickel monatomic catalyst has high selectivity from CO2 to CO in a wide potential interval, high catalytic current density and good catalytic stability in the field of electro-catalysis CO2RR.

The application relates to application of iron-nitrogen doped graphene in preparation of anti-radioactive enteritis drugs and belongs to the technical field of biological medicines. ZIF-8 powder, 1,10-phenanthroline powder, iron (II) acetate powder and a grinding medium are placed in a closed container to perform mechanical ball milling treatment to obtain a mixed powder; under the protection of inert gas, the mixed powder is placed in a preheated tube furnace to perform pyrolysis treatment, and is cooled to room temperature to obtain iron-nitrogen doped graphene. The iron-nitrogen doped graphene has NADH oxidase-like activity, can directly catalyze the conversion of NADH into NAD + , can rapidly supplement NAD + depletion caused by radiation, can enhance PARP-dependent DNA damage repair, can reduce the generation of active oxygen (ROS), can reduce intestinal cell death and can protect the integrity of intestinal structure, and can realize efficient protection of radioactive enteritis. Moreover, the problem of low-efficiency biosynthesis of NAD + supplementation in existing radioactive intestinal injury protection technologies is solved.

The present invention provides a transition metal-free electrocatalyst (AlOOH / NGr), comprising of monodispersed aluminium oxyhydroxide (AlOOH) sheets anchored over the electronically conducting nitrogen-doped graphene (NGr), for ORR (Oxygen reduction reaction). The AlOOH / NGr possesses good catalytic durability in alkaline medium. The invention further provides synthesis of AlOOH / NGr and its applications in an air electrode for fabricating a primary Zn-air battery.

The present invention relates to the field of graphene materials, and specifically provides a wave-absorbing material containing graphene and a preparation method thereof. Magnetic metal salts are used to prepare FeCoNi Prussian blue nano-precursor particles (FeCoNi PBAs). An organic carbon coating layer is coated on the surface of FeCoNi PBAs through a self-polymerization coating strategy. After carbonization, FeCoNi-C with a magnetic FeCoNi core and nano-carbon cages is obtained. Utilizing the catalytic characteristics of the magnetic core metal elements, pyridine is used as a carbon source for the catalytic growth of nitrogen-doped graphene, and a graphene-based carbon cage composite material with a FeCoNi-N-Gr@C magnetic core is obtained. A wave-absorbing material and a preparation method thereof provided by the present invention are broadband electromagnetic absorption materials with both magnetism and high conductivity, which can absorb low-frequency and high-frequency electromagnetic waves simultaneously. By using the catalytic action of the magnetic alloy core, flocculent nitrogen-doped graphene rich in pyridine N is grown inside the carbon cage, greatly improving the conductivity of the composite material.

A method for rapidly detecting and identifying food-borne pathogens by using a two-dimensional / zero-dimensional MXene / GQDs Schottky heterojunction fluorescence sensor array based on machine learning comprises the following steps: synthesizing three nitrogen-doped graphene quantum dots through a hydrothermal method, determining the optimal excitation wavelength, concentration, reaction temperature and pH value of the nitrogen-doped graphene quantum dots, and further determining the fluorescence intensity of the nitrogen-doped graphene quantum dots under the optimal condition; constructing a fluorescence sensor array, mixing the three graphene quantum dots with target heavy metal ions, incubating, then measuring fluorescence intensity to obtain fluorescence response data, and normalizing the data to obtain the fluorescence response data. And analyzing by using machine learning methods of a decision tree, a support vector machine, K nearest neighbor, linear discriminant analysis, naive Bayes and a neural network. The prepared fluorescence sensor array can rapidly identify heavy metal ions, is excellent in accuracy, sensitivity and stability, provides an economical and efficient solution for heavy metal ion detection, and has remarkable application potential in environmental monitoring.

The invention discloses dual-application nitrogen-doped graphene / dopamine grafted carboxymethyl cellulose aerogel as well as a preparation method and application thereof, and relates to the technical field of graphene aerogel preparation. The preparation method comprises the following steps: dispersing graphene oxide in water to obtain a graphene oxide dispersion liquid; mixing the graphene oxide dispersion liquid with ethidene diamine and dopamine grafted carboxymethyl cellulose, and performing heating reaction to obtain composite graphene hydrogel; the composite graphene hydrogel is sequentially subjected to washing, liquid nitrogen quick freezing, freeze drying and calcination, and the dual-application nitrogen-doped graphene / dopamine grafted carboxymethyl cellulose aerogel is obtained. The nitrogen-doped graphene / dopamine grafted carboxymethyl cellulose aerogel has the advantages of ultralight weight, hyperelasticity, rapid shape recovery, strong adsorption capacity, good electrochemical performance and the like, and can be used as an adsorption material for adsorption of oil, heavy metal Cr and the like and as an electrode material for preparation of a supercapacitor.

The invention discloses an extraction head for detecting malathion residues in agricultural products and a detection method applying the extraction head, the extraction head is a composite material of poly (5-amino indole pyrrole)-ionic liquid-porous nitrogen-doped graphene, and the ionic liquid is 1-butyl-3-methylimidazolium hexafluorophosphate. The extraction head has the beneficial effects that the extraction head made of the composite material has relatively good stability and repeatability, and can be used for rapidly detecting the residue of malafos sulfur in agricultural products.

According to the graphene exothermic coating and the preparation method thereof, nitrogen-doped graphene and graphene oxide are used as heat conduction materials, the heat resistance of the exothermic coating can be remarkably improved through the synergistic effect, and meanwhile the heat resistance, adhesive force and durability of a coating can be remarkably improved through an in-situ polymerization process.

The invention discloses a high-thermal-conductivity pouring sealant based on modified nitrogen-doped graphene as well as a preparation method and application of the high-thermal-conductivity pouring sealant, and belongs to the technical field of pouring sealants. The pouring sealant comprises a pouring sealant matrix and modified nitrogen-doped graphene, wherein the pouring sealant matrix comprises 50-85 parts of matrix resin, 1-10 parts of a filler, 1-5 parts of a flexibilizer and 10-30 parts of a solvent; the modified nitrogen-doped graphene is prepared by the following steps: uniformly adsorbing manganese carbonate in nitrogen-doped graphene, treating in a high-temperature reducing atmosphere, uniformly distributing lithium fluosilicate in the nitrogen-doped graphene, and finally sintering. The nitrogen-doped graphene is pretreated by adopting manganese carbonate and lithium fluosilicate, so that the dispersity and the compatibility with a resin matrix of the nitrogen-doped graphene are effectively improved, the heat-conducting property, the tensile strength, the hardness and the heat stability of the pouring sealant are improved, the construction performance is good, the nitrogen-doped graphene can stably work in a high-temperature and high-power environment, and the service life of the pouring sealant is prolonged. And the packaging method can be widely applied to packaging of the vehicle-mounted charger transformer of the electric vehicle.

The invention discloses a preparation method of an in-situ nitrogen-doped graphene reinforced copper-based composite material based on external pyrolysis, and relates to the technical field of metal-based composite material preparation. The method specifically comprises the following steps that copper powder is placed in a heating device, and a solid nitrogen-containing carbon source is placed in an external pyrolysis device; after the system is vacuumized and cleaned, inert gas and hydrogen are introduced, and the heating device is heated to a specific temperature and is subjected to heat preservation. An external pyrolysis device is started, the temperature is increased to the pyrolysis temperature, a nitrogen-carbon-containing small molecule precursor is generated and conveyed into a heating device, in-situ growth is conducted on the surface of the copper powder, and high-dispersion composite powder is prepared; and sintering the powder to obtain the densified high-dispersion nitrogen-doped graphene / copper composite block material. According to the method, the in-situ uniform growth of the nitrogen-doped graphene on the surface of the copper powder is realized through a solid nitrogen-containing carbon source external pyrolysis technology in combination with a synergistic mechanism of copper powder regulation and control, precursor directional transportation and in-situ doping growth, and a new way is provided for controllable synthesis of the copper-based composite material.

The application discloses a kind of adsorbents for noble metal recovery and preparation method thereof, further provide a kind to be used in the noble metal recovery method of the catalyst, wherein the adsorbents for noble metal recovery includes nitrogen-doped graphene-SiO2 Hybrid Material, the nitrogen-doped graphene-SiO2 Hybrid Material includes graphene-SiO2 Hybrid Material and nitrogen doped therein, wherein the molar amount of nitrogen in the nitrogen-doped graphene-SiO2 Hybrid Material and the total molar amount of C and Si are 1: (55-10050) ratio. The noble metal recovery adsorbent of the application can effectively recover noble metal Au in wastewater, has strong noble metal recovery adsorption capacity, high recovery rate, especially for the catalyst washing produced in the preparation process of vinyl acetate catalyst containing lower content of noble metal element Au has higher noble metal recovery adsorption capacity.

The invention discloses a monatomic catalyst modified diaphragm for a lithium-sulfur battery as well as a preparation method and application of the monatomic catalyst modified diaphragm. According to the composite material, nitrogen-doped graphene composite defect cerium hydroxide (NA (at) Ce (OH) 4) is taken as a carrier, high-dispersion cobalt single atoms (SACo) are anchored through oxygen deficiency, and the NC (at) Ce (OH) 4 (at) SACo composite material is formed. A commercial diaphragm is coated with the composite membrane to prepare a functional diaphragm, and the functional diaphragm is applied to a lithium-sulfur battery. Cobalt single atoms and defect cerium hydroxide in the diaphragm can achieve a synergistic effect, on one hand, rapid conversion of lithium polysulfide is catalyzed, and the shuttle effect is inhibited; on the other hand, uniform deposition of lithium is guided, and dendritic crystal growth is inhibited. The lithium-sulfur battery adopting the diaphragm shows high specific capacity and excellent cycle life. The preparation process is simple, and a new thought is provided for development of the high-performance lithium-sulfur battery.

The application discloses a kind of methods for constructing electrochemical immunosensor for detecting apolipoprotein A4, comprising: (1) nitrogen-doped graphene and polyethyleneimine are fully stirred in solvent Composite, then add bipyridine functionalized covalent organic framework material and fully stir Composite, obtain NG-PEI-COF composite material;With bipyridine functionalized covalent organic framework material as carrier, gold nanoparticles, apolipoprotein A4 antibody and toluidine blue are loaded in sequence, to obtain tracer probe;(2) on electrode NG-PEI-COF composite material, gold nanoparticles, apolipoprotein A4 and tracer probe are modified in sequence, to obtain the electrochemical immunosensor of the application.The electrochemical immunosensor constructed by the method shows excellent detection performance for apolipoprotein A4, the marker of depression, good reproducibility and stability, and shows good anti-interference performance for a variety of other markers of depression, can be accurately determined in 0.01~300 ng / mL linear range, detection limit is as low as 2.16 pg / mL, and can be applied to serum sample.

The present invention provides a nitrogen-doped graphene acid that is present in a sample and contains 3 at.% to 10 at.% (preferably 4 at.% to 6 at.%) of nitrogen and 25 at.% to 45 at.% (preferably 30 to 38 at.%) of oxygen for all atoms determined by X-ray photoelectron spectroscopy (XPS) using an Al-Kα X-ray source. In some embodiments, the nitrogen-doped graphene acid is in the form of dots. The nitrogen-doped graphene acid is produced by a method comprising the following steps: supplying nitrogen-doped graphene, oxidizing the nitrogen-doped graphene by reaction with an oxidizing inorganic acid, preferably nitric acid, and washing the resulting mixture with water. The nitrogen-doped graphene acid is for the isolation of Pb 2+ and / or Cd 2+ , or for the detection of Pb 2+ and / or Cd 2+ and is particularly useful.

The present invention provides a preparation method for a nickel-iron battery, which specifically includes the following steps: S1, designing a three-dimensional structure, stirring a 3D printing slurry evenly, and then sequentially performing digital light processing printing, degreasing sintering, and high-temperature reduction to obtain a 3D porous nickel template; S2, depositing graphene on the surface of the 3D porous nickel template obtained in step S1, and obtaining nitrogen-doped graphene foam after acid etching and freeze-drying; S3, preparing a positive electrode; S4, preparing a negative electrode; S5, preparing a nickel-iron battery: the positive electrode of the nickel-iron battery obtained in step S3 and the negative electrode of the nickel-iron battery obtained in step S4 are respectively placed in a gel electrolyte for immersion, then taken out, and laminated to each other to obtain a nickel-iron battery. The present invention also provides a nickel-iron battery prepared by the above preparation method. Compared with the prior art, the present invention utilizes the technical advantages of 3D printing and the microscopic porous structure to give the electrode structure flexibility while also giving the nickel-iron battery good flexibility, thereby meeting more application scenarios and actual needs.