2189results about "Nano-carbon" patented technology

The invention discloses a lithium iron phosphate positive electrode material, a preparation method thereof and a lithium battery, and relates to the technical field of lithium ion batteries. According to the method, the pressing index of the lithium iron phosphate positive electrode material is tested by adopting a specific method, so that the pressing index meets a specific range, meanwhile, the average circularity of larger particles in a Dv50-Dv100 range meets a proper range, the lithium iron phosphate positive electrode material has better particle movement capability, and the particles can move at a higher speed to be rearranged during pressing, so that the particle size of the lithium iron phosphate positive electrode material is reduced, and the quality of the lithium iron phosphate positive electrode material is improved. Therefore, the positive pole piece with high compaction density can be obtained, the charge-discharge capacity of the battery can be improved, and meanwhile, the particles can be prevented from being broken when being pressed, so that the positive pole piece has good anti-pressure capability. By adopting the lithium iron phosphate positive electrode material provided by the invention, the lithium battery has relatively high energy density and capacity retention ratio.

The present disclosure relates to a carbon-based nanomaterial composition that may be formed from a gas mixture and a sulfur powder. The gas mixture may include a carbon based gas, an oxygen gas, and a hydrogen gas. The carbon-based nanomaterial composition may include sulfur doped nanospheres.

The invention discloses a preparation method and application of a zinc-manganese bimetal organic framework derived composite nano-enzyme, and belongs to the technical field of nano-materials. Zinc-manganese bimetal organic framework nanoparticles prepared by reacting ZIF-8 with manganese (III) acetylacetonate are used as a template, and are calcined at different temperatures in a tubular furnace to obtain zinc-manganese bimetal organic framework derivative composite nano-enzymes with different morphologies. The nano enzyme has peroxidase-like activity, glutathione peroxidase-like activity and catalase-like activity, and has a wide application prospect in anti-tumor treatment.

The invention discloses porous carbon, a silicon-carbon negative electrode material, a preparation method, a pole piece and a battery. The porous carbon comprises a carbon skeleton and calabash-shaped pores distributed in the carbon skeleton, the average pore size of the porous carbon is 0.05-15 nm, and the pore volume is 0.05-2 cm < 3 > / g. The preparation method of the porous carbon comprises the following steps: S1, carrying out melting treatment on a mixture, and filtering; the mixture comprises asphalt-based porous carbon and asphalt, the average pore size of the asphalt-based porous carbon is 0.1-20 nm, the pore volume of the asphalt-based porous carbon is 0.1-2 cm < 3 > / g, and the mass content of quinoline insoluble in the asphalt is 0.003%-3%; and S2, carrying out carbonization treatment on the solid obtained by filtering in the step S1. The porous carbon with most closed pores, small aperture and calabash-shaped pore body structure is beneficial to subsequent silane gas deposition, electrolyte isolation and silicon elementary substance expansion inhibition, and can well cooperate with high first effect and high capacity of a silicon-carbon negative electrode material.

The invention discloses a synthesis method of amphiphilic quantum dots and application of the amphiphilic quantum dots in nano oil displacement, and belongs to the field of nano oil displacement. The synthesis method comprises the following steps: heating a mixture containing a carbon source and a nitrogen source in an air atmosphere for reaction, and centrifuging, filtering and drying a reaction product to obtain the amphiphilic quantum dots, the carbon source is selected from at least one of glucose, mannose, citric acid, lignin, chitosan and starch; the nitrogen source is selected from at least one of alkylamine, and the carbon chain length of the alkylamine is C6 to C12. The synthesis method is simple, heating of a high-pressure reaction kettle is not needed, the technological process is simple, and the method is suitable for large-scale industrial production; the series of amphiphilic carbon quantum dots show better solubility and higher absolute fluorescence quantum yield in water and various organic solvents.

Provided in the present application are a biomass-based hard carbon material, and a preparation method therefor and the use thereof. The preparation method comprises: sequentially performing anaerobic baking, impurity removal, oxidative modification and high-temperature carbonization on a biomass raw material to obtain a biomass-based hard carbon material. In the present application, by means of first sequentially performing anaerobic baking and impurity removal, lignin, cellulose, etc., in the biomass raw material are destroyed, and pores and defects are left inside the biomass raw material, such that the material is in a metastable-state structure to expose impurities; thus, impurity removal can be selected at a normal temperature, and an impurity removal effect is good; and the impurity content of the obtained biomass-based hard carbon is low, the ash content thereof can be reduced to 0.5 wt% or below, and the obtained biomass-based hard carbon has a disordered interlayer structure, thereby facilitating the intercalation / deintercalation of sodium ions, such that the material can show relatively high reversible capacity and initial efficiency performance.

The invention discloses a high-entropy nanoparticle catalytic material with a metal atom shell structure and a preparation method of the high-entropy nanoparticle catalytic material, and belongs to the technical field of preparation of catalytic materials. The preparation method comprises the following steps: dispersing a metal salt and a nanofiber precursor in an organic solvent, and carrying out electrostatic spinning to obtain a nanofiber membrane; and then calcining and pre-oxidizing the nanofiber membrane, and then carbonizing and calcining to obtain the nanofiber membrane. Wherein the selection principle of the metal salt is as follows: (n-1)-(n-2) metals are selected as an alloy substrate, and the sum of the mixing enthalpy of elements of the alloy substrate is not greater than-5kJ mol <-1 >; one or two metal elements serve as a precipitated phase, and the sum of the mixing enthalpy of the metal elements of the precipitated phase and the elements of the alloy substrate is larger than 20 kJ mol <-1 >; the high-entropy nanoparticle catalytic material obtained by the method shows relatively high catalytic activity and stability, and the method has wide universality.

The invention provides carbon-coated lithium iron phosphate and a preparation method thereof, a positive plate and a lithium ion battery. The preparation method comprises the following steps: S1, mixing raw materials including a lithium source, a phosphorus source, an iron source and a first solvent to obtain slurry; s2, sequentially carrying out spray drying and crushing treatment on the slurry to obtain a lithium iron phosphate precursor; s3, carrying out polymerization reaction on raw materials of the lithium iron phosphate precursor, styrene, an initiator and a second solvent in an inert atmosphere, and adding a cationic monomer in the polymerization reaction process to obtain a cationic polystyrene coated lithium iron phosphate precursor; and S4, calcining the cationic polystyrene coated lithium iron phosphate precursor in an inert atmosphere to obtain the carbon coated lithium iron phosphate. According to the preparation method disclosed by the invention, lithium iron phosphate is coated with a layer of porous carbon while being controlled to be nano-sized, so that the electrochemical impedance of the lithium iron phosphate material is reduced, and the rate capability of the lithium iron phosphate material is improved.

The invention relates to a sodium ion battery, and belongs to sodium ion batteries. The battery cell of the sodium-ion battery comprises a positive plate, a negative plate and an electrolyte, the active material of the positive plate is carbon-coated aluminum-doped sodium ferric sulfate; the chemical formula of the aluminum-doped sodium ferric sulfate is Na < 2 + 2y > Fe < 2-x-y > Al < x > (SO4) 3, x is more than or equal to 0.01 and less than or equal to 0.05, and y is more than or equal to 0.1 and less than or equal to The particle size of the carbon-coated aluminum-doped sodium ferric sulfate ranges from 50 nm to 100 nm; the weight ratio of a carbon coating layer in the carbon-coated aluminum-doped sodium ferric sulfate is 1%-5%; the active material of the negative plate is carbon-coated sodium titanate; the specific surface area of the carbon-coated sodium titanate is 20 m < 2 > / g to 25 m < 2 > / g; the weight ratio of a carbon coating layer in the carbon-coated sodium titanate is 0.5%-3%. Volume expansion is jointly inhibited through structural stability of positive and negative electrode materials, and the cycle life is prolonged.

The invention relates to the field of battery materials, in particular to a preparation method and application of a modified porous carbon material for nano silicon CVD (chemical vapor deposition). According to the invention, the non-porous two-dimensional lamellar material is self-assembled on the porous carbon material, so that the modified porous carbon material for CVD deposition of nano-silicon is obtained, when high-speed carrier gas passes through the surface of the porous carbon material, the two-dimensional lamellar material on the surface of the porous carbon material is stressed intensively, and is not dispersed due to a pore channel structure on the surface of the porous carbon material; therefore, under the same fluidization condition, the modified porous carbon material shows better fluidization characteristics, deposition of nano silicon is more uniform after silane or organic gas is subsequently introduced, the content of floating silicon on the surface is extremely low, silicon enrichment can be reduced while the capacity of the negative electrode material is ensured, and the service life of the negative electrode material is prolonged. Furthermore, the electrochemical performance of the obtained nano silicon-carbon composite negative electrode material is more prominent, and the performance stability of negative electrode materials produced in different batches is also good.

The invention relates to a carbon quantum dot for strengthening and promoting growth of microalgae and application thereof. In the process of preparing the carbon quantum dots by a conventional hydrothermal method, a precursor mixture is subjected to acidification modification in advance, the pH value is adjusted to 2 by using nitric acid, and then a hydrothermal reaction is performed, so that the prepared carbon quantum dots have the capability of promoting the growth of microalgae. However, if other acids are adopted or pH adjustment is not in place, the effect cannot be achieved, and even the inhibition effect can be achieved. The obtained product is good in effect and stable in performance, no special reaction device needs to be additionally arranged in the acidification modification process, and the method has the advantages that operation is easy and convenient, raw materials are easy to obtain, and the process can be quantified; the method is simple and convenient in process operation, has universality and is easy for industrial production.

The invention provides a lithium manganese iron phosphate material and a preparation method and application thereof.The preparation method comprises the steps that firstly, an iron source, a manganese source, a phosphorus source and a fluorine source are mixed and react to prepare a manganese iron phosphate precursor; and then preparing the lithium manganese iron phosphate material through double-step compounding of a carbon source and operations such as multiple times of grinding and sintering of an intermediate mixed material in the preparation process. According to the preparation method, firstly, a fluorine source is added into a ferromanganese phosphate precursor, and then substances such as a lithium source are added into the prepared ferromanganese phosphate precursor, so that the obtained lithium ferromanganese phosphate material can give full play to the current transmission effect of lithium in the material on the basis of inheriting the performance of the ferromanganese phosphate precursor material. The compaction performance and the cycle performance of the lithium manganese iron phosphate material are further improved through double-step carbon source compounding and repeated grinding, sintering and other operations of an intermediate mixture in the preparation process. In addition, the preparation method is simple in process and convenient to operate, and the obtained composite material is stable in performance and high in repeatability.

The invention provides a nitrogen-doped biomass-based fluorescent carbon quantum dot, a preparation method and application, and relates to the technical field of carbon nanomaterials, the method comprises the following steps: mixing a biomass material and deionized water under an ultrasonic condition, adding a nitrogen source, and carrying out ultrasonic dispersion to obtain a uniformly dispersed to-be-reacted solution; reacting the to-be-reacted solution at a preset temperature for a preset time to obtain a mixed product solution; and filtering and dialyzing the mixed product solution to obtain the nitrogen-doped biomass-based fluorescent carbon quantum dot solution. The nitrogen-doped biomass-based fluorescent carbon quantum dot prepared by the method shows a stable fluorescent effect and good water solubility, the free radical clearance rate can reach 90% or above, and the antibacterial rate can reach 99% or above. The method can be used in the fields of drug sustained release, bioimaging and the like.

The invention discloses a preparation method of a coal-based yellow fluorescent carbon dot aqueous solution, which comprises the following steps: drying lignite to constant weight, grinding, sieving to obtain a primary coal sample, and weighing the primary coal sample; adding the weighed primary coal sample into a mixed solution of peracetic acid and hydrogen peroxide, stirring, and filtering to obtain a pretreated coal sample; the method comprises the following steps: mixing a coal sample with water, stirring to obtain a lignite solution, transferring the lignite solution into a cavitation device, starting a cavitation program, and adjusting and maintaining the flow; collecting circulating liquid in the cavitation device, and filtering to remove residual large particles to obtain an aqueous solution of the coal-based carbon dots; the method comprises the following steps: pretreating a coal sample by using a mixed solution of peracetic acid and hydrogen peroxide, and stripping the coal sample by combining a hydrodynamic cavitation method to prepare a carbon dot with yellow fluorescence; the method is low in cost, environmentally friendly, simple in equipment and huge in large-scale production potential, and a new method and thought are provided for enriching polychromaticity of the coal-based carbon dots.

The invention discloses an oxygen-sulfur double-vacancy modified SnO2 / SnS2 / C nano material as well as a preparation method and application thereof, and belongs to the technical field of electrode materials. The preparation method comprises the following steps: mixing a structure regulating agent with tin salt, dropwise adding alkali liquor, stirring, and carrying out suction filtration to obtain Sn6O4 (OH) 4; the preparation method comprises the following steps: adding glucose and polyvinylpyrrolidone into distilled water, stirring to form a uniform solution, adding Sn6O4 (OH) 4 into the uniform solution, stirring, and carrying out ultrasonic and hydrothermal reaction to obtain SnO2 / glucose; and calcining the SnO2 / glucose and a sulfur source in an inert atmosphere to obtain the SnO2 / SnS2 / C nano material modified by oxygen and sulfur double vacancies. The SnO2 / SnS2 / C disclosed by the invention is used for a lithium / sodium ion battery negative electrode, can effectively relieve volume expansion of tin-based oxysulfide and improve the conductivity of an electrode material, and shows high charge-discharge specific capacity, excellent rate capability and high-rate long-cycle stability.

The invention discloses a solid-state capacitor and a preparation method thereof, and the preparation method comprises the following steps: (1) core package winding: interposing electrolytic paper between an anode foil and a cathode foil, and winding to form a core package; (2) a repairing step: immersing the core package into a formation liquid for repairing treatment; (3) a drying step: carrying out drying treatment on the core package in the step (2); (4) an impregnation step: immersing the core package in the step (3) into a first impregnation liquid for impregnation treatment; performing drying; immersing into a second impregnation liquid for impregnation treatment, and drying; (5) a polymerization step: immersing the core cladding in the step (4) into an oxidation liquid for polymerization; and (6) assembling, girdling and aging treatment.

The invention discloses a carbon dioxide hydrogenation methanation-cracking carbon preparation series method, which comprises the following steps: generating CH4 through a reaction of # imgabs0 # imgabs1 #, and realizing the production of a carbon material by adopting the technologies of condensation separation of CH4 and water vapor, CH4 cracking reaction of # imgabs2 #, cyclic utilization of hydrogen and the like. The process is composed of a carbon dioxide hydrogenation methanation reactor and a methane cracking reactor. In the methanation reactor, CO2 and H2 react under a low-temperature condition to generate CH4 and water vapor; cH4 and water vapor are separated by adopting a compressor condensation separation technology, and the separated CH4 is conveyed to a cracking reactor. In the methane cracking reactor, CH4 is cracked at a high temperature to generate H2 and a carbon nanomaterial, and then H2 is returned to the methanation reactor again. The separation of CH4 and water vapor at a relatively low temperature is realized in the tandem carbonization process through a low-temperature condensation technology; through low-temperature CO2 methanation and CH4 catalytic cracking, the content of CO2 is reduced, a high-quality carbon nanomaterial is obtained, and cyclic utilization of CO2 and H2 is realized.

The invention relates to the technical field of lithium ion batteries, in particular to a carbon source mixed gas CVD coated silicon-carbon negative electrode material, a preparation method and a lithium ion battery. The preparation method comprises the following steps: 1) preparation of a silicon-carbon material: placing porous carbon in equipment, regulating and controlling the gas speed and the dynamic rotation speed of the equipment to uniformly disperse the porous carbon, heating to 380-650 DEG C, and introducing silane mixed gas with the concentration of 5-50% to form the silicon-carbon material; and 2) coating the silicon-carbon material with mixed gas carbon: introducing mixed gas sources with different proportions into equipment, regulating and controlling the gas speed and the dynamic rotation speed of the equipment to uniformly disperse the mixed gas sources, and heating to 450-700 DEG C to realize uniform carbon coating on the surface of the silicon-carbon material. According to the invention, the problem of explosion caused by self-polymerization reaction of single acetylene is solved; and moreover, the uniform carbon coating isolates the side reaction problem caused by direct contact between the electrolyte and the nano silicon, and the stability of the silicon-carbon material is improved.

The invention provides an amphiphilic carbon dot, a carbon nanofluid and application of the amphiphilic carbon dot and the carbon nanofluid, and belongs to the technical field of nanomaterial oil displacement, and the amphiphilic carbon dot is prepared by taking alkylphenol polyoxyethylene ether and glucose as raw materials to perform solvothermal reaction; the alkylphenol polyoxyethylene ether comprises octylphenol polyoxyethylene ether and / or nonylphenol polyoxyethylene ether; the mass ratio of the alkylphenol polyoxyethylene ether to the glucose is 1: (0.1-2). According to the invention, alkylphenol polyoxyethylene ether and glucose are taken as raw materials, and simple preparation of the amphiphilic carbon dots with high surface and interface activity is realized. The amphiphilic carbon dots provided by the invention show good surface and interface activity at high temperature and high salinity. According to the carbon nanofluid provided by the invention, the amphiphilic carbon dots and the zwitterionic surfactant are compounded, so that the stability of a carbon nanofluid oil displacement system at high temperature and high salt can be further improved, the crude oil recovery rate is increased, and efficient yield-increasing development of high-temperature and high-salt deep oil reservoirs is realized.

The invention provides a silicon carbon material with a multilayer coating structure and a preparation method and application thereof, and relates to the technical field of battery materials. The silicon-carbon material with the multi-layer coating structure comprises a porous carbon core body, and a first carbon layer and a second carbon layer which sequentially coat the porous carbon core body from inside to outside, and the porous carbon core body comprises porous carbon and nano silicon particles deposited on the surface and in pore channels of the porous carbon; and a conductive nano carbon filler is dispersed in the second carbon layer. The silicon carbon material with the multilayer coating structure provided by the invention is used as a lithium ion battery negative electrode material, and has excellent specific capacity, coulombic efficiency and cycle performance. The result of the embodiment shows that when the silicon carbon material with the multi-layer coating structure is applied to the lithium ion battery, the first reversible capacity is 1882-2071 mAh / g, the first coulombic efficiency is 92.6-94.1%, and the capacity retention ratio of 100 cycles is 95.3-97.7%.

The invention relates to the technical field of sodium ion battery positive electrode materials, and discloses a preparation method and application of a carbon-coated sodium ferric sulfate positive electrode material, and the preparation method comprises the following steps: (1) adding an iron source into an aqueous solution containing an organic acid, and stirring, the organic acid being ascorbic acid and / or citric acid; adding a sodium source or the sodium source and a sulfuric acid source, and stirring; (2) finally adding a carbon source, dropwise adding absolute ethyl alcohol while stirring, vacuumizing after dropwise adding, and continuously stirring for 2-4 hours to obtain a mixed solution; and (3) carrying out closed spray drying on the mixed solution, and calcining in an inert atmosphere to obtain the carbon-coated sodium ferric sulfate positive electrode material. According to the preparation method, coating of the carbon material is achieved in a closed spray drying mode, the conductivity of sodium ferric sulfate is greatly improved, in the whole preparation process, contact with oxygen is avoided, organic acid with an anti-oxidation effect is avoided, ferrous iron is prevented from being oxidized, and then the electrochemical performance can be further improved.

The invention relates to the technical field of hydrogen energy, and provides a vanadium oxide catalytic magnesium-based hydrogen storage material based on alkali metal enhancement and a preparation method. The material is prepared from spherical MgH2 powder and lamellar XV6O15 (at) C powder through a high-energy ball milling method, wherein X is one of alkali metals Li, Na and K. The material has a nanoscale composite structure, and the hydrogen storage performance can be remarkably improved. The preparation method comprises the following steps: 1) preparing XV6O15 (at) C nano powder through acid etching, alkali metal modification and heat treatment; and 2) mixing the powder with MgH2 in a protective atmosphere, and preparing the composite material by adopting high-energy ball milling. Results show that the catalyst improves the hydrogen absorption and desorption rate of MgH2, the hydrogen storage temperature is reduced to 50 DEG C for hydrogen absorption, and the hydrogen is rapidly desorbed at 200-225 DEG C. The hydrogen storage dynamics and temperature performance are remarkably optimized, an effective strategy is provided for design and application of a novel magnesium-based composite hydrogen storage material, and the method is suitable for hydrogen energy industrial application.

The invention discloses an in-situ carbon-coated positive electrode lithium supplement agent, a preparation method and application, and belongs to the field of lithium ion batteries. The preparation method of the positive electrode lithium supplement agent comprises the following steps: S1, mixing lithium oxalate with a carbon source, and grinding to prepare mixed powder; s2, the mixed powder is placed in a reaction kettle, sealing and vacuumizing are conducted, carbon dioxide gas is introduced, and the pressure is controlled to be 10-20 Mpa; keeping the temperature at 30-60 DEG C and reacting for 10-24 hours; and S3, exhausting, washing with alcohol, centrifuging and drying to obtain the in-situ carbon-coated positive electrode lithium supplement agent. The invention provides a preparation method of an in-situ carbon-coated positive electrode lithium supplement agent, which comprises the following steps: placing lithium oxalate and a carbon source in a supercritical carbon dioxide fluid, stirring and dissolving, controlling the reaction temperature and pressure to promote the polymerization reaction of carbon source micromolecules, and depositing a layer of compact and uniform carbon material on the surface of lithium oxalate particles in situ, thereby obtaining the in-situ carbon-coated positive electrode lithium supplement agent. The conductivity and the ion mobility of the material are improved, so that the electrochemical activity of lithium oxalate is improved.

The invention relates to an external composition for hair growth regulation and a preparation method thereof, and belongs to the technical field of cosmetics and medicines. The composition disclosed by the invention comprises nano mesoporous carbon for enhancing permeation, various surface functional modifications on the nano mesoporous carbon, minoxidil, protein fragments, polypeptides, oligopeptides, amino acids, dutasteride, bimatoprost, traditional Chinese medicine extracts, vitamins, caffeine, nucleosides, growth factors and various auxiliary functional components. Wherein the pore diameter of mesopores of the nano mesoporous carbon for enhancing permeation is 2-30 nm, the total pore volume of the mesopores is 1.5-3.5 cm < 3 > / g, and the particle size of the nano mesoporous carbon is 50-200 nm. The prepared nano mesoporous carbon is granular, controllable in size, stable in structure, free of irritation to skin, capable of keeping inert to various active ingredients in the composition, capable of enhancing absorption and permeation of other ingredients on the skin, wide in application range, capable of compounding various types of active ingredients and high in biological safety.

The invention is applicable to the technical field of electrode materials, and relates to a two-dimensional mesoporous nanosheet compound and a preparation method and application thereof, the compound comprises single-layer uniform spherical mesoporous structures which are regularly arranged on the two sides of an MXene nanosheet respectively, and the method comprises the following steps: (1) preparing a single micelle solution; (2) preparing an MXene-coated micro single micelle superstructure alcohol solution with the concentration of 2 to 5 mg / mL; (3) preparing a compound of the MXene coated micelle single micelle wrapped by the polydopamine; (4) preparing a two-dimensional mesoporous nanosheet compound constructed by a spherical mesoporous element; the invention also discloses an application of the two-dimensional mesoporous nanosheet compound in a battery. The two-dimensional mesoporous nanosheet compound and the preparation method thereof disclosed by the invention have the beneficial effects that the specific surface area of the two-dimensional mesoporous nanosheet compound is greatly increased, active sites of chemical reaction are increased, a better substance transmission channel can be provided, and the two-dimensional mesoporous nanosheet compound has rapid mass transfer kinetics; and the assembled aqueous zinc ion battery has relatively high specific discharge capacity and relatively stable long cycle performance.

The invention belongs to the technical field of lithium battery materials, and particularly relates to a lithium trifluoromethanesulfonate in-situ doped graphdiyne composite material and a preparation method and application thereof. The preparation method of the lithium trifluoromethanesulfonate in-situ doped graphdiyne composite material adopts a one-step in-situ synthesis method, and specifically comprises the following steps: adding hexaacetylene benzene and lithium trifluoromethanesulfonate into a solvent, mixing, adding a catalyst, carrying out a heating reaction, and carrying out post-treatment on the obtained reactant to obtain the lithium trifluoromethanesulfonate in-situ doped graphdiyne composite material. Finally, the lithium trifluoromethanesulfonate in-situ doped graphdiyne composite material is obtained. The preparation method of the lithium trifluoromethanesulfonate in-situ doped graphdiyne composite material provided by the invention is simple in process, the prepared composite material is good in interface stability, and when the composite material is applied to a negative electrode of a lithium ion battery, the electrochemical performance of the battery can be improved, and the service life of the battery can be prolonged.

The invention discloses a preparation method for synthesizing coal-based carbon quantum dots through microbial catalysis, which comprises the following specific preparation steps: (1) pretreating coal, specifically comprising crushing and sterilizing treatment; (2) combining the pretreated coal sample with selected microorganisms or biological factors, and carrying out fermentation treatment on the coal; (3) after fermentation is completed, dialyzing the coal fermentation liquid to prepare a carbon quantum dot solution; (4) separating and purifying the dialyzed carbon quantum dot solution to remove impurities; and (5) carrying out quick freeze-drying on the separated and purified carbon quantum dot solution to obtain the carbon quantum dots with fluorescent properties. According to the method, microorganisms serve as a core, an aerobic or anaerobic fermentation process is combined, coal resources are fully utilized, and efficient preparation of the coal-based carbon quantum dots is achieved. The method not only has good environmental protection property, but also can provide a new technology for industrial production of the carbon quantum dots, and has important significance for efficient conversion and green chemical synthesis of coal.

The invention discloses a carbon quantum dot loaded diatom electrocatalyst and a preparation method and application thereof. The preparation method comprises the following steps: dissolving and mixing diethylene triamine pentaacetic acid and salt of metal M1 in water, and performing reflux reaction to obtain a complex solution of the metal M1; adding salt of metal M2 for reflux reaction, filtering after the reaction is finished, and removing a solvent from filtrate to obtain a solid complex of bimetals M1 and M2; drying and calcining to obtain a diatomic electrocatalyst precursor; and carrying out post-treatment and freeze-drying to obtain the diatomic electrocatalyst. The carbon quantum dot loaded bimetallic atom site catalyst is obtained by a preparation strategy of coupling molecular design and quantum dot confinement, and is used for research on deep reduction of carbon dioxide into methane through electro-catalysis. The obtained catalyst has excellent methane production activity on an electro-catalysis carbon dioxide reduction reaction under an alkaline condition and a flow cell configuration, and still has relatively good stability under long-term work.

The present invention belongs to the technical field of batteries. Disclosed are an iron(III) phosphate material, a preparation method therefor, and a use thereof. The iron(III) phosphate material comprises a carbon quantum dot core located internally and an iron(III) phosphate shell formed on the surface of the carbon quantum dot core, and the surface of the iron(III) phosphate shell is provided with a carbon coating layer formed from a carbon-containing dispersing agent. The iron(III) phosphate material is nanoscale iron(III) phosphate and has a uniform crystal size. The preparation method therefor comprises the following steps: mixing a first mixed solution containing a divalent iron salt and carbon quantum dots, a second mixed solution containing a phosphate and a dispersing agent, and an oxidizing agent to undergo a reaction to obtain iron(III) phosphate dihydrate; and annealing and calcining the iron(III) phosphate dihydrate. The iron(III) phosphate material can be further used for preparing a lithium iron phosphate positive electrode material and a battery.

The invention belongs to the field of carbon nanomaterials, and provides a method for preparing a carbon quantum dot material doped with elements such as silicon and aluminum by oxidative depolymerization and stripping of coal gangue. Comprising the steps of screening and matching of coal gangue, oxidative depolymerization stripping, centrifugal dialysis membrane filtration and modification, drying and the like, raw materials and all the steps are specifically set, and the particle size or fluorescence performance of fluorescent carbon dots can be specifically selected and set according to selective oxidative depolymerization stripping conditions. The main particle size of the prepared multi-inorganic-element doped carbon quantum dot material is kept within the range of 1.5-2.0 nm, the structure is stable, the optical performance also meets the requirements, and the material can be further modified and is expected to be applied to the fields of photovoltaic equipment, biological imaging, photocatalytic degradation of organic pollutants or sensing and the like.