1008results about How to "Increase the active site" patented technology

The invention discloses magnetic submicron composite core-shell particles. In the magnetic submicron composite core-shell particles, Fe3O4 particles with the particle size of between 80 and 800nm are taken as a magnetic core, amorphous SiO2 is taken as an immediate shell layer and a substance with heavy metal absorption performance is taken as an outer shell layer. The invention also discloses a preparation method for the magnetic submicron composite core-shell particles. The preparation method comprises the following steps of: preparing the Fe3O4 particles with the particle size of between 80 and 800nm by a solvothermal method and taking the Fe3O4 particles as magnetic cores, performing alkaline hydrolysis of a silicon source reagent on Fe3O4 and dehydrating and condensing hydroxy groups so as to obtain amorphous SiO2 immediate shell layers, and coating the substance with heavy metal absorption performance on obtained submicron spheres under chemical or physical action to obtain the magnetic submicron composite core-shell particles. The submicron material has high performance of absorbing heavy metal ions in the sewage; and the material has stable characteristics, can be magnetically recovered and meets environmental protection requirements, and secondary pollution is avoided.

The invention relates to the energy storage field and discloses MOS2 (molybdenum disulfide) and TiO2 (titanium dioxide) nanocomposites and a production method thereof. The MOS2 and TiO2 nanocomposites are composite materials of nano molybdenum disulfide and titanium dioxide, namely the MOS2 and TiO2. The MOS2 and TiO2 nanocomposites are obtained through the two-step hydrothermal method which comprises, to be specific, growing titanium dioxide nanorods on a seed layer through the auxiliary hydrothermal method and coating a layer of molybdenum disulfide on the outer layer of the titanium dioxide nanorods through the direct hydrothermal method. According to the obtained MOS2 and TiO2 nanocomposites through production, the energy can be effectively stored and a good method is provided for the existing energy storage problem due to the high specific surface area of the titanium dioxide one-dimensional nanorods and the excellent super capacitance performance of the molybdenum disulfide. According to the production method, the energy consumption is low, the condition is simple, the large-scale production is easy and the like.

The invention relates to a nitrogen-doped mesoporous carbon immobilized enzyme biosensing material and a preparation method thereof, which belongs to the field of biocatalysis and biosensing. Mesoporous carbon is prepared by taking mesoporous silica as a template and ethylenediamine, acrylonitrile or tripolycyanamide as a carbon-nitrogen source, and then nitric acid is used to modify the surface of the mesoporous carbon to obtain hydrophilically modified nitrogen-doped mesoporous carbon. The material has high specific surface area, large pore volume, large aperture and good biocompatibility, and also has good water and thermal stability and electric conductivity at the same time. The activity of enzyme molecules mobilized by taking the material as a carrier is well maintained. The biosensing based on nitrogen-doped mesoporous carbon immobilized enzyme has quick response time, wide linear range, high sensitivity, and low detection limit. In addition, a preparation process for the immobilized enzyme biosensing material is simple and controllable, and has the advantages of mild conditions, easily-obtained raw materials, and conventional equipment.

The invention relates to the technical field of a sodium ion battery, in particular to a MoS2 / nitrogen-doped carbon tube composite material and preparation method and application thereof. Low-cost melamine sponge is used as a template material, a layer of MoS2 is grown on a surface of sponge fiber, high-temperature calcination is performed under argon protection, the sponge fiber contracts and iscollapsed from inside to outside, a unique three-dimensional hollow structure is grown, a layer of MoS2 nanosheet is uniformly grown at an outer layer, a nitrogen-doped carbon tube structure is arranged at an inner layer, electrolyte moving is facilitated, rapid electron transfer is also facilitated; and a nitrogen-doped carbon tube is arranged at an inner wall, many active sites are increased bya large amount of nitrogen, and the material obtains very excellent cycle property and rate performance when used as a sodium ion battery negative electrode material.

The invention provides a preparation method for a nitrogen-doped carbon oxygen reduction catalyst with a hierarchical porous structure, belonging to the technical field of a fuel cell. The preparation method comprises the following steps of: firstly, preparing a eutectic molten salt having a three-dimensional macro-porous structure by a freeze drying method; secondly, using the eutectic molten salt as a template, doping a nitrogen-containing precursor, and leading the nitrogen-containing precursor to be oxidized and polymerized on the surface of the eutectic molten salt by a solid-phase polymerization method, wherein ammonium persulfate serves as an oxidizing agent, and a ferric salt serves as a promoter; and finally, carrying out high-temperature pyrolysis and removing the eutectic molten salt. With the adoption of the nitrogen-doped carbon oxygen reduction catalyst with the hierarchical porous structure, the nitrogen-containing precursor can be effectively prevented from pyrolysis loss, structural collapse and sintering during the high-temperature carbonation process, the catalyst yield and the nitrogen doping efficiency are improved, moreover, a large amount of micropores, mesoporous and macropores can be generated, and the mass transfer efficiency of oxygen and water is improved. The method is simple and practical, the production cost is low, and the prepared catalyst has excellent oxygen reduction catalytic activity and can substitute the traditional commercial Pt / C catalyst.

The invention relates to a method for preparing an oxidized graphene / conductive polypyrrole nano wire composite material. The method comprises the following steps of: preparing oxidized graphene by using natural graphite according to a chemical oxidization method, uniformly dispersing the oxidized graphene into deionized water by adopting an ultrasonic method to obtain a stable oxidized graphene suspension; adding hexadecyl trimethyl ammonium bromide with the mole concentration being 0.025 to 0.038 mol / L into the oxidized graphene suspension, uniformly stirring and mixing, adding pyrrole into the suspension, and uniformly mixing and stirring; polymerizing pyrrole monomers on an oxidized graphene nano sheet in situ by taking the hexadecyl trimethyl ammonium bromide as a surface active agent and ammonium persulfate as an oxidant, and performing frequent washing, suction filtration and vacuum drying on a product to finally obtain the oxidized graphene / conductive polypyrrole nano wire composite material. According to the preparation method, the process is simple, and the cost is low; and the product is high in specific capacity and high stability. The method can be applied to fields such as lithium ion batteries, sensors, electronic devices and fuel batteries.

The invention discloses a method for preparing a graphene oxide-chitosan composite material. The method includes the steps that a chitosan solution is prepared; secondly, a graphene oxide solution is prepared, a 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) solution is added into the graphene oxide solution during stirring, stirring reaction is conducted after dropwise addition, then an N-hydroxyl succinimide (NHS) solution is dropwise added into the graphene oxide solution, stirring reaction is conducted, and an activated hydroxyl graphene oxide solution is obtained; thirdly, the activated hydroxyl graphene oxide solution is dropwise added into the chitosan solution and stirred, the mixture is poured into a mould after being cooled to room temperature, and the cross-linked graphene oxide-chitosan composite material is obtained after freezing drying. The novel graphene oxide-chitosan composite material having an interface bonding function is provided, compared with non-cross-linked composite materials, mechanical properties of the composite material are greatly improved, and use of the composite material in the aspect of the bone induction technology is achieved.

The invention discloses a manganese dioxide modified biochar composite material as well as a preparation method and an application thereof. The composite material is prepared from manganese dioxide and biochar by loading generated manganese dioxide on biochar through the neutralization reaction of permanganate and manganese in divalent manganese salt. The manganese dioxide modified composite material has the advantages of high adsorption capacity for heavy metal lead or cadmium, obvious adsorption effect, low preparation cost and the like, and is an ideal heavy metal wastewater adsorbent; thepreparation method of the composite material has the advantages of simple process, cheap raw materials, sufficiently used raw materials, low production cost and the like. The manganese dioxide modified composite material can be used for treating heavy metal wastewater, and has the advantages of high adsorption capacity for heavy metals, high adsorption efficiency, low toxicity to organisms in theenvironment and the like, and can be produced and applied on a large scale.

The invention discloses a preparation method and application of a potassium-doped carbon nitride photocatalyst. The method comprises steps as follows: ammonium chloride, dicyandiamide and potassium nitrate are mixed, and the mixture is heated to 500-600 DEG C and then kept at the constant temperature for 3-6 h; the mixture is naturally cooled to the room temperature after calcination ends, and thepotassium-doped carbon nitride photocatalyst can be obtained. The potassium-doped carbon nitride photocatalyst is used for photocatalytic decomposition of organic matter. The prepared photocatalyst has larger interlayer spacing and specific surface area and excellent photocatalytic activity, the degradation efficiency is two times or more that of pure carbon nitride in the degradation experimentof the organic matter, and the preparation method is simple and feasible, has lower requirements for experiment facilities and can save the preparation cost to the greatest extent.

The invention discloses a transition-metal doped lead dioxide electrode for wastewater treatment and a preparation method thereof. The transition-metal doped lead dioxide electrode is prepared through the steps of performing thermal decomposition on a titanium material which serves as a substrate so as to prepare a tin-antimony oxide underlayer, then electroplating an alpha-PbO2 interlayer by use of an alkaline solution and finally preparing a transition-metal doped fluorine-containing beta-PbO2 surface active layer by use of acidic composite electroplating bath. The transition-metal doped lead dioxide electrode prepared by the method has the characteristics of low price, high oxygen evolution potential, high catalytic activity, long service life and the like; the electrode can be used for realizing effective removal of organic pollutants in wastewater through an electrochemical oxidation method, is simple to operate and convenient to manage and has wide social and economic benefits.

The invention discloses a preparation method of a nitrogen-doped graphene / nitrogen-doped carbon nanotube / zinc cobaltite composite material. The method comprises the following specific steps: (a) adding potassium permanganate, hydrochloric acid and hydrogen peroxide to graphene oxide, and carrying out a stirring reaction to obtain porous graphene; (b) dialyzing the porous graphene for 8-12 days, carrying out ultrasonic dispersion, then adding a carbon nanotube, carrying out ultrasonic mixing and carrying out suction filtration to form a film; (c) drying the film, and then adding ammonium hydroxide for reaction for 24 hours; (d) adding zinc nitrate, cobalt nitrate, urea, ammonium fluoride, absolute ethyl alcohol and distilled water for reaction for 4 hours; and (e) transferring a mixture to a tube furnace, and sintering the mixture in a nitrogen atmosphere for 2 hours, so as to obtain the composite material. The composite material has relatively good flexibility; the electrochemical properties are barely changed after the composite material is bent into various angles; the specific capacitance value of the composite material can be up to 1802F / g; compared with relatively simple graphene, the carbon nanotube and most of composite materials of the graphene and the carbon nanotube, the composite material provided in the invention are significantly improved.

The invention belongs to the technical field of high-performance / high-energy-density lithium ion battery negative electrodes, and particularly relates to an MXene / metal sulfide composite material, ananode material and preparation and application. The preparation method comprises the following steps: mixing and stirring a metal salt of a transition metal element and an MXene material, and carryingout solid-liquid separation and drying to obtain an MXene / metal salt mixture; and under a protective atmosphere, mixing the MXene / metal salt mixture with a sulfur source, and carrying out heat treatment to obtain the MXene / metal sulfide composite material. The invention also provides a sulfur-doped MXene / metal sulfide-based composite battery anode material. The anode material comprises the MXene / metal sulfide composite material. The anode material provided by the invention has good long-cycle stability, high energy density and excellent rate capability, and can be applied to various fields.

The invention discloses a composite material with hollow graphene spheres loaded with nanometer tin disulfide. The composite material is characterized in that the hollow graphene spheres with sub-micron sizes are used as carriers, tin disulfide nanometer particles are loaded on the inner walls and the outer walls of the hollow graphene spheres, and the sizes of the tin disulfide nanometer particles grown on the surfaces of the hollow graphene spheres range from 10 nm to 40 nm. A method for preparing the composite material includes steps of a, synthesizing cationic polystyrene spheres; b, synthesizing the hollow graphene spheres; c, loading the tin disulfide to obtain the composite material with the hollow graphene spheres loaded with the nanometer tin disulfide. The composite material and the method have the advantages that the composite material is a carbon material with a two-dimensional structure, the tin disulfide with an expanded volume can be accommodated in charging and discharging procedures, and the electric conductivity and the structural stability of electrode materials can be improved; the electric conductivity and the ion transport performance of the materials can be improved by porous graphene structures, and the composite material is favorable for embedding lithium ions in the materials and releasing the lithium ions from the materials.

The invention provides a preparation method of a porous structural elastic composite material for extracting uranium from seawater. The preparation method comprises preparing an amidoximated polyacrylonitrile solution, mixing the amidoximated polyacrylonitrile solution and a strong alkali aqueous solution, maintaining heating and stirring until dissolved, adding the stirred solution into an aqueous solution of a polymer material capable of cross-linking gelation, mixing uniformly the solution, immersing a porous structure elastic material into the mixed solution, carrying out vacuum defoaming,carrying out drying, immersing the dried porous structure elastic material in a cross-linking agent solution, carrying out cross-linking gelation and carrying out rinsing with water. The aqueous solution of the polymer material which can be cross-linked and gelled is cross-linked and gelled so that the coating strength of amidoximated polyacrylonitrile on the porous structure elastic material skeleton is improved, the material flexibility, mechanical stability and hydrophily are improved and the high adsorptive porous structural elastic composite material for extracting uranium ions from seawater is obtained.

The invention relates to a preparation method for a petal-shaped molybdenum disulfide hollow mesoporous carbon sphere by in-situ growth, and belongs to the technical field of nanometer material production. The preparation method comprises the steps of mixing ethanol, deionized water, ammonia water, tetraethyl orthosilicate, resorcinol and formaldehyde for reaction; drying a solid phase and performing calcination in argon; etching the solid phase with a sodium hydroxide solution to obtain the solid phase, and drying the solid phase to obtain the hollow mesoporous carbon nanometer sphere; mixingsodium molybdate dihydrate, thiourea and the hollow mesoporous carbon nanometer sphere for hydrothermal reaction, performing centrifugal washing after hydrothermal reaction, drying the solid phase, and performing high-temperature calcination under protection of argon atmosphere to obtain the petal-shaped molybdenum disulfide hollow mesoporous carbon sphere by in-situ growth. The preparation method has the advantages that the raw material is low in cost, the process is environmental-friendly, high yield is achieved, and the prepared petal-shaped molybdenum disulfide hollow mesoporous carbon sphere by in-situ growth can be used as a lithium ion battery electrode material, a photocatalytic material or an electrocatalytic material.

The invention provides a porous silver micro-nano structure and a shape and size controllable preparation method of the porous silver micro-nano structure, and belongs to the technical field of precious metal porous nano-crystalline structures. The overall appearance shape of the porous silver micro-nano structure is a hexagonal sandwich shape or a quadrilateral shape or a strip shape and is formed by stacking 30-50-nanometer silver basic composition units, and multiple pores are formed by stacking silver basic composition units. The preparation method includes the steps that sodium citrate, sodium carbonate and citric acid are dissolved in deionized water, a silver nitrate solution and a D-glucose solution are added in sequence, the mixture is stirred and sinks, and a precursor is obtained after centrifugal drying; the porous silver micro-nano structure is obtained after heat treatment is conducted on the precursor. The method is simple, environmentally friendly and controllable in shape and size; the prepared porous silver micro-nano structure is uniform in size distribution, large in specific surface area, good in permeability and higher in catalytic rate for p-nitrophenol, and has potential application in the precious metal catalytic aspect.

The invention relates to a sulfurated modified Fe-Cu bimetallic material, a preparation method and a method for removing chromium-containing wastewater. In the sulfurated modified Fe-Cu bimetallic material, the molar ratio of sulfur to iron is (0.05-0.06): 1, and the mass ratio of iron to copper is 10: (0.1-4). The preparation method comprises the following steps: in a buffer solution with an acidic environment, performing a reaction on zero-valent iron and soluble sulfate to obtain sulfurated modified zero-valent iron; performing a replacement reaction on the sulfurated modified zero-valent iron and bivalent copper salt to obtain the sulfurated modified Fe-Cu bimetallic material. The heavy metal chromium removing efficiency of the sulfurated modified Fe-Cu bimetallic material is much higher than that of the zero-valent iron, and the reactivity of the sulfurated modified Fe-Cu bimetallic material is also higher than those of a sulfurated modified zero-valent iron material and a Fe-Cu bimetallic material, so that removal of pollutants is effectively accelerated; in addition, the sulfurated modified Fe-Cu bimetallic material has the advantages of small chemical dosage, high reaction speed rate, relatively wide pH adaptability, and the like, and has a wide application prospect in heavy metal-containing wastewater treatment.

The invention discloses a three-dimensional porous nickel oxide and nitrogen doped graphene quantum dot composition which is prepared from foamed nickel as a matrix, a great number of micron-order pores in the surface of the foamed nickel in an oxidation etching manner, meanwhile a three-dimensional porous structure of the foamed nickel is maintained, and the nickel oxide and nitrogen doped graphene quantum dot composition is formed on the surface of the foamed nickel. The composition has excellent electric catalysis upon oxygen evolution reactions in alkali systems, and overpotential of electrolysis water oxygen evolution reactions can be effectively reduced. The invention further discloses a preparation method of the composition.

The invention relates to a preparation and application of a NiWP electric catalyst material with a three-dimensional structure, which belongs to the technical field of clean energy materials. The preparation comprises the following steps: preprocessing foam metal (cathode matrix material) and a pure nickel sheet (anode material) to remove oxides and impurities on the surface; respectively adding a nickel salt and tungsten salt into distilled water according to a ratio, uniformly dissolving in a magnetic stirrer, adding a complexing agent, stirring and dissolving the complexing agent in a tungsten salt-containing solution, mixing the two solutions, then adding a phosphorus salt, uniformly stirring, and finally adjusting a pH value of plating solution by utilizing sulfuric acid and ammonia water; and performing the electric precipitation under a given current density and temperature by adopting a direct-current voltage stabilizing power supply, after a given time of precipitation, cleaning the surface of a test sample by utilizing deionized water, and drying at a room temperature to obtain the NiWP electric catalyst with the three-dimensional structure. The electric catalyst prepared by using the method can effectively reduce overpotential of water electrolysis hydrogen evolution reaction and oxygen evolution reaction by virtue of electrochemical test, and has good circulating stability. The preparation method is simple in process procedures, easy in operation and good in application prospect.

The invention relates to a preparation method of supported photocatalyst Bi2WO6-TiO2 / foam metal. Bi(NO3)3.5H2O and Na2WO4.2H2O are used as a Bi source and a W source, ethylene glycol and absolute ethyl alcohol are used as a mixed solvent, TiO2 powder is added and mixed uniformly, the mixture reacts for 15h at 180 DEG C and then is washed and dried; Bi2WO6-TiO2 precursors are dispersed in an absolute ethyl alcohol solution, a foam metal carrier is soaked and washed with acetone, diluted hydrochloric acid and deionized water, then a silica gel layer with the solid content of 25% is coated on the surface of the foam metal carrier and is dried in the air for 20min in a leveling manner for standby use; dispersion liquid is uniformly sprayed to the foam metal carrier coated with the silica gel, and the foam metal carrier is dried in the air for 20min in a leveling manner and is roasted for 2h at 400 DEG C to obtain the supported photocatalyst Bi2WO6-TiO2 / foam metal. The preparation process is simple, can be amplified easily, and is suitable for large-scale practical application.

The invention belongs to the technical field of material preparation and photocatalysis, and discloses a high-activity graphite-phase carbon nitride material and a preparation method thereof. The preparation method comprises the following steps: forming a self-generated gas atmosphere a gas generated from a precursor by pyrolysis in the high-temperature calcining process under the control on an inert gas, and guiding synthesis of a carbon nitride material, thereby obtaining a flaky porous graphite-phase carbon nitride material. According to the preparation method, after the inert gas is not introduced any longer, a self-generated gas generated from the precursor is relatively uniform at different parts, and the carbon nitride material prepared with the preparation method is uniform in morphology and relatively good in crystal form; due to the escape of the self-generated gas, the material is effectively pored, and thus the specific surface area and the active sites of the material are increased; due to the self-generated gas atmosphere, the polymerization degree of the precursor is reduced, and the obtained carbon nitride material has a relatively large amount of unpolymerized amino or imino groups. The preparation method disclosed by the invention is simple, efficient and low in cost, and the carbon nitride material prepared with the preparation method is excellent in photocatalysis activity and very good in practicability.

The invention discloses a carbon coated sodium manganese pyrophosphate@graphene oxide composite material with a sandwich structure, as well as a preparation method and application thereof. The composite material is formed by stacking graphene oxide sheets, wherein carbon coated sodium manganese pyrophosphate particles are uniformly distributed on the surfaces of the graphene oxide sheets. The preparation method comprises the following steps: adding the graphene oxide into an aqueous solution in which a phosphorus source, a sodium source, a manganese source and a complexing agent are dissolved, and performing ultrasonic treatment, liquid nitrogen freezing and freeze drying sequentially to obtain a precursor; putting the precursor under protective atmosphere and performing heat treatment to obtain the carbon coated sodium manganese pyrophosphate@graphene oxide composite material with the sandwich structure. The carbon coated sodium manganese pyrophosphate@graphene oxide composite material serving as a sodium ion battery positive electrode material has excellent electrochemical property; the 'Na-Mn-P-O' system resource is rich, and the cost is low; the preparation method is simple to operate, and the commercial application prospect is wide.

The invention discloses a gas-sensitive material for detecting NO2 and a method for manufacturing a gas-sensitive element made of the gas-sensitive material. The gas-sensitive material is prepared into a SnO2 nano-fiber with a rough surface and a hollow tubular structure by adopting an electrospinning method and high-temperature processing, the hollow SnO2 nano-fiber is of a rutile structure, the SnO2 nano-fiber diameter is about 250-300nm, and the thickness of a particle layer is about 40nm. Au particle modification is performed on the surface of SnO2 in an in-situ reduction manner without changing the crystal structure of SnO2. The specific surface area of the material is increased by the one-dimensional hollow nano-structure characteristic of the gas-sensitive material, the gas-sensitive performance of SnO2 is obviously improved by precious metal modification, and higher sensitivity to NO2 and a larger measurement range are presented. The obtained material is applied to the surface of a ceramic tube, annealing is performed, and a calcined ceramic tube core and a nickel-chromium heating wire are welded to a base, accordingly, the gas-sensitive element is manufactured.

The present invention belongs to the technical field of industrial catalysis, and provides a method for synthesizing cyclic carbonate through a polyionic liquid nanometer catalysis cycloaddition reaction. According to the method, phosphine functionalized polymer nanoparticles are adopted as a carrier, and is subjected to quaternary phosphorization with a carboxylic acid halide including a carboxylic acid bromide or carboxylic acid chloride so as to obtain a quaternary phosphonium polyionic liquid catalyst, and the cycloaddition reaction is characterized in that CO2 and an epoxide are adopted as reaction substrates to carry out a cycloaddition reaction at a high temperature under a high pressure in the absence of a solvent so as to generate the cyclic carbonate compound. According to the present invention, the separation of the product and the catalyst can be achieved through the simple method, the catalyst can present the high catalysis activity and the high selectivity, and the stability and the reproducibility of the catalysis activity can be easily improved through the regular structure morphology; and the green approach for cyclic carbonate synthesis through the nano-scale polyionic liquid catalysis is provided.

The invention specifically relates to a CoP / graphene aerogel composite material for high-efficiency hydrogen evolution and a preparation method thereof, and research on the hydrogen evolution performance of the CoP / graphene aerogel composite material. According to the method, hydrogel is prepared by using a simple sol-gel process, and then the CoP / graphene aerogel composite material for high-efficiency hydrogen evolution is prepared by using high-temperature phosphatization process. The CoP / graphene aerogel composite material prepared in the invention has excellent electrocatalytic hydrogen evolution performance.

The invention belongs to the technical field of preparation of environment materials, and concretely relates to a preparation method and an application of a metallic Ag nano-particle deposited NiCo-LDH composite photocatalyst. The preparation method of the metallic Ag nano-particle deposited NiCo-LDH composite photocatalyst mainly comprises the following steps: heating nickel nitrate, cobalt nitrate, ammonium chloride, sodium hydroxide and deionized water used as raw materials in a water bath to obtain a NiCo-LDH material; and radiating the NiCo-LDH material, silver nitrate and water which areused as raw materials under an ultraviolet lamp for a certain time to prepare the metallic Ag nano-particle modified NiCo-LDH composite photocatalyst used for photocatalytic degradation of tetracycline. A low-temperature water bath process is adopted, so the energy consumption in the synthesis process is low; and the synthesized NiCo-LDH composite material has a ball flower-shaped structure, anddeposition of silver makes the obtained metallic Ag nano-particle deposited NiCo-LDH composite photocatalyst have a greatly improved electron-hole pair separation efficiency and an excellent tetracycline photocatalytic degradation performance.

The invention discloses a method for preparing a coated straw fiber-based water-retaining slow-release fertilizer. According to the method, a straw cellulose polysaccharide chain is used as a framework; acrylic acid and acrylamide substances generated by a reaction of acrylic acid and urea are grafted to a cellulose main chain; then crosslinking is carried out by a cross-linking agent to form a polymer with a three-dimensional network structure; meanwhile, the polymer with the three-dimensional network structure and polyvinyl alcohol interpenetrate through each other to form high-water-absorbing resin with a semi-interpenetrating network structure; then the high-water-absorbing resin with the semi-interpenetrating network structure coats fertilizer particles; and a mixed solution of polyvinyl alcohol, sodium alginate and carboxymethyl cellulose forms a membrane by crosslinking to coat the outermost layer of the fertilizer particles to obtain the coated straw fiber-based water-retaining slow-release fertilizer. The fertilizer disclosed by the invention has good mechanical properties and water absorption performance, has excellent slow release effects on the fertilizer, reduces nutrient loss, improves the utilization rate of the fertilizer, reduces maintenance cost of farmland in the later period, and improves the yield and quality of crops. The method provided by the invention has the advantages that the operation method is simple and convenient, cost is low, the additional value of straw application is improved, and the new idea of straw resourceful utilization is further expanded.

The invention discloses nitrogen phosphorus co-doped porous carbon-coated copper phosphide composite catalyst and its preparation method, and relates to the technical field of composite catalyst and electro-catalysis. The of composite catalyst prepares the composite nitrogen phosphorus co-doped porous carbon-coated copper phosphide hydrogen-producing catalyst by taking a nitrogen phosphorus double-heteroatom mixing type copper based metal-organic framework material (Cu-NPMOF for short) as a precursor, and is used for producing hydrogen efficiently by brine electrolysis. In the .05 mol-L-1 sulfate electrolyte, the overpotential of hydrogen evolution is 0-89mV when the current density is 10mAcm-2, and the nitrogen phosphorus co-doped porous carbon-coated copper phosphide composite catalyst has low hydrogen overvoltage. Through circular tests for many times, the catalyst keeps good catalytic activity, and has strong stability, and high actual application value.

The invention discloses a two-dimensional nickel and cobalt MOFs (metal organic frameworks) nano-sheet and an application of the nano-sheet to glucose detection. The two-dimensional nickel and cobalt MOFs nano-sheet is synthesized on substrates such as nano-porous gold needles, carbon paper and gold sheets by a one-step hydrothermal method from bottom to top, serves as an electrode and is applied to a non-enzyme electrochemical glucose sensor. A two-dimensional nickel and cobalt MOFs nano-sheet material has the advantages that more active sites are exposed, nickel and cobalt are cooperated, charge transfer capacity is high and the like relative to a traditional spherical polyhedral MOFs material, so that glucose sensing properties of the nano-sheet material is effectively improved.

The invention discloses graphene oxide modified biochar composite as well as a preparation method and an application thereof. The graphene oxide modified biochar composite comprises graphene oxide, biochar and chitosan, wherein graphene oxide is bonded on the biochar through chitosan to form a support structure. The preparation method comprises steps as follows: the biochar is prepared; the chitosan is dissolved in an acetic acid solution to form a chitosan and acetic acid mixed solution; the chitosan and acetic acid mixed solution and the graphene oxide are mixed to form a chitosan / graphene oxide mixed solution; the biochar is added to the chitosan / graphene oxide mixed solution and mixed, and the graphene oxide modified biochar composite is obtained. The graphene oxide modified biochar composite has the characteristics of high adsorption capacity, high adsorption efficiency and the like and can be applied to removal of Pb<2+> in water on a large scale.