1448 results about "Nitrogen doping" patented technology

The present invention relates to a nitrogen-doped porous carbon material for a lithium-air battery positive electrode, wherein the nitrogen-doped porous carbon material has an interconnected graded pore structure, N is uniformly doped in the C skeleton, N accounts for 0.2-15% of the carbon material atomic ratio, the graded pores comprise mass transfer pores and deposition holes, the deposition holes account for 40-95% of the total pore volume, and the mass transfer pores account for 4-55% of the total pore volume. According to the present invention, with application of the carbon material as the lithium-air battery electrode material, the space utilization rate of the carbon material during the charge-discharge process can be increased at a maximum, and the energy density and the power density of the lithium-air battery can be effectively increased; and the preparation process is simple, the material source is wide, the pore structure of the graded pore carbon material can be regulated, the regulation manner is diverse, and the nitrogen doping manner is easily achieved.

The invention discloses a preparation method of a nitrogen-doped porous-structure carbon material and belongs to the technical field of inorganic material preparation. The preparation method utilizes a micromolecular carbon-containing compound as a raw material and comprises the following steps of based on the weight of the raw material, adding 0-400wt% of an inorganic base, 0-400wt% of an organic nitrogen-containing compound and 0-50wt% of a metal or metal oxide or inorganic metal salt into the raw material, carrying out uniform dispersion, and carrying out a reaction process in an inert gas protective atmosphere at a temperature of 400-900 DEG C for 0.5-12h so that the nitrogen-doped porous-structure carbon material having micropores, mesopores and macropores is obtained. The preparation method has simple processes, can be controlled easily, and realizes one-step combination of porous structure, functionalization nitrogen doping and metal particle modification. The nitrogen-doped porous-structure carbon material having high nitrogen content has a large capacitance value and good cycle performances, can be used as an oxygen reduction reaction catalyst having high activity, high selectivity and high stability and has a very large application prospect.

The invention relates to a method for preparing nitrogen-doped graphene, in particular to a novel simple, convenient and scale method for preparing nitrogen-doped graphene at high temperature under the protection of inert gas by taking melamine as a nitrogen source. In the method, graphene oxide and the melamine are taken as raw materials, wherein the melamine is taken as the nitrogen source and the graphene oxide is taken as a carbon source; high temperature annealing is carried out in the atmosphere of inert gas, and the reduction of the graphene oxide and the nitrogen doping of graphene are realized; and by controlling reaction conditions such as temperature, time, the ratio of the raw materials and the like, graphene products with different nitrogen doping ratios can be prepared. The preparation method is simple and practicable; catalysts are not needed; the reaction process is easy to control; special requirements on equipment do not exist; the cost is low; and the method is easy to promote and use.

Belonging to the technical field of catalysts, the invention discloses a nitrogen doped carbon material loaded catalyst. The carbon material can realize nitrogen doping by means of nitrogen containing precursor chemical coupling and other surface modification methods, also a nitrogen source and a carbon source can be introduced simultaneously at high temperature for in situ synthesis of a nitrogen doped carbon material, and then a simple substance or compound of one or more of gold, copper, manganese, potassium or bismuth can be loaded on the nitrogen doped carbon material. The nitrogen doped carbon material loaded mercury-free catalyst involved in the invention has activity and stability obviously superior to those of ordinary carbon material loaded catalysts. Under certain reaction conditions, the activity of the nitrogen doped carbon material loaded catalyst is superior to that of ordinary carbon material loaded catalysts by over 10%. The carbon material and the catalyst disclosed in the invention are green and non-toxic, and have good environmental benefits. The process involved in the invention is simple, economical and feasible.

A method of fabricating a semiconductor uses chemical vapor deposition, or plasma-enhanced chemical vapor deposition, to deposit an amorphous silicon film on an exposed surface of a substrate, such as ASIC wafer. The amorphous silicon film is doped with nitrogen to reduce the conductivity of the film and / or to augment the breakdown voltage of the film. Nitrogen gas, N2, is activated or ionized in a reactor before it is deposited on the substrate.

The invention discloses a controllable synthesizing method of an N-doped graphitized carbon ball with hollow structures. The method comprises the following steps: (1) dissolving silicon source, soluble metal salt and a catalyst to the solvent according to the molar ratio, transferring the solvent to the thermal water kettle to conduct hydro-thermal synthesis after being stirred until being thoroughly dissolved, and cleaning, filtering and drying the sediment to obtain a primary commodity; (2) reducing the primary commodity at high temperature under the protection of gas in a high-temperature reaction furnace; and (3) soaking the product obtained by high-temperature reducing in acidic solution, and obtaining the graphitized carbon ball nitrogen doping with the hollow structure after cleaning, filtering and drying. The graphitized carbon ball with the hollow structures provided by the invention has the advantages that the carbon sphere has a uniform appearance, the carbon shell has millipore structures, a mesoporous carbon support structure is formed inside the carbon sphere and a better graphitize degree is provided, and can be used in the field of high-efficient catalyzing and transforming, energy storage and transforming, medicine releasing, substance adsorptive separation and the like. The non-template hydrothermal synthesis technique provided by the invention is simple and controllable, and can be used in large scale production.

Provided is a transparent graphene film which is prepared by maintaining the primary reduced state of a graphene oxide thin film via chemical reduction, reducing the graphene oxide thin film with chemical vapor deposition, and doping nitrogen, thereby enhancing the conductivity and enabling the control of work function and a manufacturing method thereof. According to the present disclosure, a flexible, transparent, electrical conductivity-enhanced, and work function controllable graphene film can be large area processed and produced in large quantities so that can be applied in real industrial processes by forming a graphene oxide thin film on a substrate, performing the primary chemical reduction using a reducing agent, and performing further the secondary thermal reduction and nitrogen doping by injecting hydrogen and ammonia gas through chemical vapor deposition equipment.

The invention discloses a nitrogen-doped graphene / molybdenum disulfide composite material, and a preparation method and application thereof. The nitrogen-doped graphene / molybdenum disulfide composite material is obtained by mixing a graphite oxide solution, a nitrogen-containing precursor, a sulfur-containing precursor and a molybdenum-containing precursor in a solution, removing the solvent or hetero-ion to obtain a precursor material, performing heat treatment on the precursor material under the protection of an inert gas, and performing nitrogen doping and crystallization. The nitrogen-doped graphene / molybdenum disulfide composite material is applicable to lithium ion batteries, sodium cells, magnesium cells, hydrogen generation under electrocatalysis, hydrogen generation under photocatalysis and super capacitors, and is capable of improving the capacity of an anode material and also enhancing the cycling performance and the rate performance of the anode material when being used as a lithium ion battery anode material.

The invention provides a nitrogen-doped high-luminescent carbon quantum dot and a preparation method thereof. The preparation method comprises the following steps: reacting by using a sodium citrate solution as a carbon source and ethanediamine as a source of N under a sealing condition, cooling an obtained product, then separating, and drying a solution obtained after separation so as to obtain the nitrogen-doped high-luminescent carbon quantum dot. The preparation method is simple in process, short in preparation period, low in manufacturing cost and good in repeatability; obtained raw materials are simple and easily available. The nitrogen-doped high-luminescent carbon quantum dot prepared by using the method is uniform in size distribution and high in luminescent density; the luminescent density of the nitrogen-doped high-luminescent carbon quantum dot is about 20 times of that of a general quantum dot, so that the application of the nitrogen-doped high-luminescent carbon quantum dot in the field of cell marking can be expanded. As the improvement of the luminescent density is caused by nitrogen doping, the nitrogen-doped high-luminescent carbon quantum dot prepared by the method has unique application when being used for detecting whether N exists in environments.

The invention discloses a graphene-based nitrogen-doped hierachical-pore carbon nanosheet / sulfur composite material for a cathode of a lithium sulfur battery, as well as a preparation method and application of the graphene-based nitrogen-doped hierachical-pore carbon nanosheet / sulfur composite material. The carbon nanosheet is a graphene-based nitrogen-doped hierachical-pore carbon nanosheet, and is prepared by the steps of growing poly-pyrrole on graphene oxide in situ, performing carbonization at high temperature, activating by using potassium hydroxide and forming pores, wherein the graphene oxide and nano-silicon dioxide serve as double templates; the thickness of the carbon nanosheet is 10 to 25 nm; the specific surface area is 800 to 1,600 m<2> / g; the pore diameter of the carbon nanosheet is distributed into the range of 0.8 to 6 nm in a concentrated way; the structure of the carbon nanosheet is a sandwich-like type which adopts graphene as the interlayer of the carbon nanosheet. The carbon nanosheet with abundant micro-pores, meso-pores and large specific surface area can load more sulfur active substances and can effectively inhibit dissolution of polysulfide. The ultrathin nanosheet, and the micro-pores and meso-pores guarantee diffusion of electrolyte and transmission of ions. According to the structure, the capacity, the cycling stability, the coulombic efficiency and the rate performance of the carbon nanosheet / sulfur composition material applied to the lithium sulfur battery are improved synergistically.

The invention discloses a porous nano composite material for a fuel cell oxygen reduction catalyst, and is an M-N-C porous nano composite material, wherein M in M-N-C refers to base metal ferrum, cobalt or nickel, N refers to nitrogen, and C refers to carbon; small-particle-size metal nano particles are uniformly dispersed and embedded in a nitrogen-doped porous carbon carrier material; the base metal nano particles have the particle size range being 5-100nm; the mass percentage of nitrogen contained in the porous carbon carrier is 3-7%. The porous nano composite material for the fuel cell oxygen reduction catalyst, which is provided by the invention, has the advantages that because of the in-situ nitrogen doping of a carbon substrate, the implant of base metal nano particles in uniform distribution and the formation of the porous structure with high specific area, the catalytic oxygen reduction capability of the porous nano composite material is improved obviously, and the cycle stability of the material is improved; a precursor prepared by the composite material is low in cost, is easy to prepare, is controlled easily in the preparation process, is simple to operate, and facilitates industrial large-scale production.

The invention discloses a method for preparing nitrogen-doped graphene with high nitrogen doping amount. The method comprises the following steps: (1) dispersing of graphene; (2) ultrasonic dispersion; (3) microwave heating; and (4) filtering and drying. The nitrogen doping amount of the nitrogen-doped graphene prepared by the method disclosed by the invention is 10%-15.0%, the density of free carriers in graphene is greatly increased by the high nitrogen doping amount, the interaction of graphene and metal is enhanced, no oxidation pretreatment is carried out, no toxic solvent is used in the reaction process, reactants are simple in component, reaction conditions are mild, and the prepared nitrogen-doped graphene has excellent electrochemical property and can be used for preparation of new energy materials such as lithium ion battery, lithium-air battery, super capacitor electrode material and fuel cell oxygen reduction catalysts. According to the method disclosed by the invention, a high-pressure kettle is heated by using microwaves without high temperature; the method is low in energy consumption, is carried out in an airtight environment and therefore hardly causes environment pollution; in addition, the method is simple in process and convenient to operate and needs less production equipment, thus, the cost is further reduced.

The invention relates to the technical field of zinc oxide preparation, and in particular relates to a preparation method of a nitrogen-doped zinc oxide film. The preparation method comprises: placing a silicon substrate in the reaction cavity of atomic layer deposition (ALD) equipment; introducing gas containing a zinc source into the reaction cavity of the ALD equipment, wherein the zinc atoms in the gas containing the zinc source are adsorbed to the silicon substrate; conveying hydrogen to the reaction cavity of the ALD equipment based on nitrogen as a carrier gas, and simultaneously carrying out plasma discharge; introducing an oxygen-containing source to the reaction cavity of the ALD equipment, wherein the zinc atoms which do not react with nitrogen atoms form zinc-oxygen bonds withthe oxygen atoms in the oxygen-containing source; and repeating the steps, so as to grow the zinc oxide film containing the nitrogen atoms layer by layer. In the preparation method provided by the invention, nitrogen doping is carried out on the zinc oxide film by utilizing the ALD equipment; the method is simple and practicable; by utilizing the characteristic of atomic layer deposition and single-layer cycle growth, the uniform nitrogen doping in the whole film structure can be achieved in the process of zinc oxide film growth so that the doped film is complete in structure and excellent inproperty.

The invention relates to a method for preparing nitrogen doping hollow carbon nanocages, which comprises the following steps that: (1) basic magnesium carbonate or magnesium carbonate is taken to be added into a reaction tube and is uniformly dispersed, then the reaction tube is placed in a tube furnace, air in the tube furnace is extracted, inert gases are filled into the tube furnace, under the condition of 10-500sccm of inert gases, the temperature of the tube furnace is increased to 650-1,100 DEG C, then the inert gas flow is guided into steam which contains carbon (C) and nitrogen (N), and after reacting for 5-240min, the temperature of the tube furnace is reduced to a room temperature; and (2) powder in the reaction tube is collected, put into hydrochloric acid or sulfuric acid solution to be soaked for 5-720min, filtered, cleaned by deionized water and dried, so a nitrogen doping hollow carbon nanocage is obtained. The nitrogen doping hollow carbon nanocage which is produced by the method has the advantages of high specific surface area, large pore volume, high mesoporous ratio, good graphitization degree and the like, and is a metal-free oxygen reduction reaction catalyst with excellent performance.

The invention discloses a method for preparing a nitrogen-doped carbonaceous material by modifying polymer, which can be used for preparing the nitrogen-doped carbonaceous material with the nitrogen doping amount of 5 to 26 at%. The method disclosed by the invention is characterized by comprising the following steps of: selecting a nitrogen-containing organic compound as a nitrogen precursor and utilizing the nitrogen-containing organic compound to perform polymerization reaction on a carbonaceous material to form a compound of the nitrogen-containing polymer and carbonaceous material; and then carrying out heat treatment on the polymer / carbonaceous material compound in the inert atmosphere to carbonize nitrogen-containing polymer in the compound so as to implement the nitrogen doping on the carbonaceous material and prepare the nitrogen-doped carbonaceous material. According to the invention, when the carbonaceous material is subjected to effective nitrogen doping, the original intrinsic structure of the carbonaceous material can be ensured; moreover, the nitrogen-doped carbonaceous material with the nitrogen content of 5 to 26 at% can be prepared; the specific capacity of using a carbon material as an electrode material of a supercapacitor is obviously improved; and the method has the characteristics of simple technical process and wide applicability.

The invention relates to a method for preparing nitrogen-doped graphene. The method comprises the steps: (1) with foam nickel as a substrate, making dopamine monomers undergo a polymerization reaction on the surface of the substrate to form polydopamine, and thus obtaining PDA-Ni; (2) with the generated PDA-Ni as a solid precursor and the foam nickel as a catalyst and a template, carrying out high temperature annealing in closed inert gas, finally cooling to the room temperature in the closed inert gas, and thus obtaining a foam nickel block NG-Ni coated with the nitrogen-doped graphene product; and (3) etching away the foam nickel template by hydrochloric acid, and thus obtaining a three-dimensional porous nitrogen-doped graphene material without support. By controlling the annealing temperature, a nitrogen doping type can be regulated and controlled. The preparation method is simple and easy to implement, allows the reaction process to be easy to control, has no special requirements on equipment, is low in cost, and is easy to popularize and use.

A preparation method for a water phase of nitrogen-doped graphene (NG) is characterized in that the preparation method comprises the following steps: mixing 0.5-5mg / mL oxidized graphene water suspension and solid urea as raw materials and dissolving, wherein the mass ratio of the oxidized graphene to the urea is 1 to 0.01; transferring the mixture into a stainless steel reaction kettle; feeding the stainless steel reaction kettle in a drying oven and carrying out constant temperature hydrothermal reaction at the reaction temperature of 150-200DEG C for 5-20 hours; naturally reducing the temperature to room temperature; taking out a sample and soaking or dialyzing with secondary deionized water; and removing the un-reacted urea; freezing and drying to obtain the nitrogen-doped graphene, wherein the nitrogen doping amount is 2.05-8.47 percent and the specific surface area is 450-550m<2> / g. According to the preparation method disclosed by the invention, the control over effective reduction of the nitrogen-doped graphene and the nitrogen doping ratio in the product can be realized by regulating and controlling the conditions such as the reaction temperature, the time, the ratio of a reactant and the like according to the requirement on the properties of products.

The invention belongs to the technical field of lithium sulfur batteries, specifically relates to a sulfur-carbon composite material with a nitrogen-doped porous carbon nanofiber net-shaped structure, as well as a preparation method and an application of the composite material. By taking a polypyrrole net-shaped structure which is synthesized by virtue of a soft template method as a raw material, taking the potassium hydroxide as a pore forming agent, and taking the nitrogen-doped carbon nanofiber net-shaped structure which is synthesized through high-temperature carbonization under nitrogen atmosphere and is in a porous structure as a precursor, the sulphur-carbon composite material which can be used as the anode of the lithium sulfur battery can be prepared through heat treatment with elemental sulfur. The preparation method provided by the invention is simple, and good in reproducibility, and the prepared composite material is uniform in structure distribution, and can be used as the anode of the lithium sulfur battery. Due to the nitrogen doping and the tridimensional net-shaped structure, for the material, the conductivity can be improved, a transmission path of lithium ions is shortened, meanwhile, the dissolving of the sulfur and intermediate product in an electrolyte can be prevented, the electrochemistry performance of a positive material of the lithium sulfur battery is improved, good specific discharge capacity, cycle performance and rate performance can be achieved.

The invention provides a research of a surface-modified nitrogen-doped porous carbon-sulfur composite material in a positive electrode of a lithium-sulfur battery. The nitrogen-doped porous carbon material is prepared by a hard template method and an ammonia activation method; the carbon material is mixed with sublimed sulfur powder evenly; the mixture is heated to synthesize the carbon-sulfur composite material in an airtight condition; and a film is formed by polymerizing dopamine on the porous carbon surface and then is chemically crosslinked with graphene oxide to obtain the surface-modified nitrogen-doped porous carbon-sulfur composite material. The surface of the composite material is evenly coated with polydopamine and the graphene oxide; and a nitrogen-containing functional group in the polydopamine and an oxygen-containing functional group in the graphene oxide can well fix sulfur and inhibit shuttling of polysulphide. Furthermore, a similar shell structure is formed on the surface of the carbon material through the chemical crosslinking action of the polydopamine and the graphene oxide to stabilize the material structure, so that the composite material with good performance for the positive electrode of the lithium-sulfur battery is obtained.

The invention discloses a nitrogen-doped carbon nanometer particle as well as a preparation method and application thereof, belongs to the field of nanometer material science and is used for solving the technical problems that fluorescence quenching is easily caused to the aggregative state of the carbon nanometer particle due to surface passivation modifier which is added for the preparation of existing carbon nanometer particles. The nitrogen-doped carbon nanometer particle is prepared through a microwave method by using organic compounds containing polycarboxyl or polyhydroxy as materials and using ammonia water as a solvent and a nitrogen doping source. The invention further provides the application of the nitrogen-doped carbon nanometer particle as fluorescent ink and fluorescent glue. The preparation method disclosed by the invention is simple, low in cost, and convenient to realize large-scale production; the maximal fluorescent quantum efficiency of the solid film formed by the prepared fluorescent glue is as high as 84%; the prepared fluorescent ink is non-toxic, generates no precipitates after being placed for a long time, is strong in fluorescence characteristic and can be applied to various fields such as bio-imaging, biological product identification, information storage, information encryption, counterfeiting prevention, illumination and display, sensing and photovoltaic devices.

The invention discloses a dental implant and a surface treatment method thereof. The surface treatment method for the dental implant comprises the following steps of dental implant cleaning, sandblasting, surface acid etching, surface nanocrystallization processing, soaking, calcinating, and cleaning and the like, so that the dental implant adopting a micron and nanometer mixed structure and having the visible-light catalytic activity through nitrogen doping is obtained. The dental implant achieves preferable hydrophilia, protein adsorption capacity and good biological activity.

The invention discloses a nitrogen-doped graphene-metal oxide nanocomposite material as well as a preparation method and application thereof. The nitrogen-doped graphene-metal oxide nanocomposite material is obtained by performing reaction on nitrogen-doped graphene and a metal salt in an organic solvent in a solvothermal way, wherein the nitrogen-doped graphene is obtained by performing reaction on oxidized graphene or partially-reduced graphene and a nitrogen-enriched substance in a water solution. The nitrogen-doped graphene-metal oxide nanocomposite material is simple in process, relatively low in cost, and good in operability and repeatability; by the preparation method, the problems that the nitrogen doping content of a carrier in the composite material is not high, in-situ growth of metal oxide particles on the surface of the graphene is not uniform and the particle size is large are solved; the nitrogen-doped graphene-metal oxide nanocomposite material can be applied to lithium ion batteries and supercapacitors on a large scale.

The invention provides a preparation method of nitrogen-doping ordered mesoporous carbon materials. According to the method, rich-hydroxyl saccharide carbohydrate is used as carbon sources, ammonia water is used as nitrogen sources, amination reaction under the hydrothermal condition is adopted for preparing rich-nitrogen precursors, mesoporous silica molecular sieves SBA-15 (space group P6mm) are used as templates, and the nitrogen-doping ordered mesoporous carbon materials in two-dimensional orthohexagonal ordered mesostructures are prepared through multi-time wetting combined with the high-temperature themolysis technology.

The invention provides a method for preparing nitrogen-doped graphene with a combustion synthesis method. The method comprises steps as follows: (1) weighed magnesium powder, a solid carbon source and a nitrogen source are evenly mixed, mixed powder is obtained, and the mass ratio of the magnesium powder, the solid carbon source and the nitrogen source in the mixed power is (19.95-99):(40-79.95):(1-39.5); (2) the mixed powder obtained in Step (1) has a combustion synthesis reaction in a specific atmosphere, a reaction product is purified, and the nitrogen-doped graphene is obtained. With the adoption of the method, raw materials are wide in source, the prepared nitrogen-doped graphene is complete in sheet-like structure, good in dispersity in a solvent and large in effective specific surface area, and the nitrogen-doped graphene has the ferromagnetism through nitrogen doping.

The invention discloses a photocatalyst of loaded nonmetal nitrogen doping one-dimensional TiO2 for exciting visible light and a preparation method thereof. In the method, a metal Ti plate and concentrated alkaline solution is taken as the main raw materials, visible light photocatalyst of the loaded nonmetal nitrogen one-dimensionally doping TiO2 is prepared by acidification, ion exchange and following heat treatment and by hydrothermal technology. The photocatalyst prepared by the invention is characterized in that the doping of nitrogen leads the catalysis to absorb the visible light and the absorption wavelength red shift is 600nm; the catalyst self is a in loaded style, which solves the defect that granulated catalyst is easy to fall off; the catalyst has a one-dimensional structure, large specific surface and abundant active points, which is favorable for strengthening reaction and mass transport process, thus realizing the degradation of typical indoor air contamination, compared with granulated nitrogen doping TiO2, the activity is higher to 1.2-3.0 times.

The invention discloses a sulfur-doped carbon material or a sulfur-nitrogen-doped carbon material. The sulfur-doped carbon material is formed by doping sulfur into a carbon material, or the sulfur-nitrogen-doped carbon material is formed by doping the sulfur and nitrogen into the carbon material, wherein the carbon material is carbon black. The material can be used as or in an electrode material for manufacturing a battery and has excellent electrochemical performance. The invention further discloses a preparation method of the sulfur-doped carbon material or the sulfur-nitrogen-doped carbon material, and the preparation method comprises the following steps of: evenly mixing a sulfur doping raw material or the sulfur doping raw material and a nitrogen doping raw material with the carbon material, to form a mixture, then, pouring the mixture into water to form a uniformly-dispersed suspension; and drying the suspension to obtain a substance, grinding the substance, and then, calcining the substance in an inert gas atmosphere to obtain the sulfur-doped carbon material or the sulfur-nitrogen-doped carbon material. The preparation method is simple in operation and easy in mass production.

The invention discloses a method for one-step activation synthesis of a nitrogen-doped porous carbon material for a high-performance supercapacitor from biomass such as peanut shells as raw materials, a nitrogen source and an activation reagent. The method comprises crushing biomass such as peanut shells, mixing the crushed peanut shells, the activation reagent and the nitrogen source according to a ratio, adding a certain amount of distilled water into the mixture, carrying out immersion for a period of time, drying the mixture for a certain time, activating the mixture in a tubular furnace at a high temperature for a period of time, filtering the solids, and washing and drying the solids to obtain a high performance nitrogen-doped hierarchical pore carbon material for a supercapacitor. The synthesis route of the method is simple. Through control of use amounts of the activation reagent and nitrogen source, a nitrogen doping amount and a pore development degree of the porous carbon material are controlled so that the nitrogen-doped porous carbon material for a high specific capacity supercapacitor is prepared.

A method of introducing nitrogen into a melt for use in producing a nitrogen-doped silicon single crystal by the Czochralski method includes adding a silicon material to a vessel, such as a quartz crucible, adding a nitrogen-containing powder, preferably silicon nitride powder, to the vessel, and heating the vessel for a time sufficient to melt the silicon material and to dissolve the nitrogen-containing in the silicon material in order to form the melt. A nitrogen-doped silicon single crystal is then produced from the melt by the Czochralski method by pulling the silicon single crystal from the melt with a seed crystal.

The invention discloses a nitrogen-doped three-dimensional nano porous carbon / porous graphene composite material and a preparation method thereof on the basis of a hydrothermal method. The preparation method includes: adsorbing a ZIF (zeolitic imidazolate framework) material onto GO (graphene oxide) to form GO / ZIF; adding an etching agent into a GO / ZIF ethanol solution to realize hydrothermal reaction, and enabling GO reduction in the reaction process along with GO etching and assembly of a three-dimensional network structure to obtain a ZIF / porous graphene three-dimensional structure; performing carbonation reaction to enable ZIF carbonation to form porous carbon loaded on the surface of a graphene lamella in the three-dimensional structure, and allowing nitrogen in ZIF to be doped in a graphene network to obtain the nitrogen-doped three-dimensional nano porous carbon / porous graphene composite material. The nitrogen-doped three-dimensional nano porous carbon / porous graphene composite material is high in specific surface area and catalytic activity, and the preparation process based on the hydrothermal method is simple in operation and high in repeatability.

The invention provides a novel three-dimensional anode material for hydrogen production by water electrolysis. The novel three-dimensional anode material comprises nickel foam loaded N-doped carbon / transition metal oxide prepared in situ according to a liquid-solid synthesis method as well as a three-dimensional anode piece used for hydrogen production through water electrolysis. A preparation method of the three-dimensional anode material particularly comprises the following steps: (1) immersing clean nickel foam into a mixed solution, containing transition metal salt, a silicon source and a nitrogen source, of water and ethanol, taking out the nickel foam for airing, and repeating for three times; (2) calcining the nickel foam piece obtained in the step (1) for 1-6 h at 600-800 DEG C under the protection of inert gas, and then heating for 1-1.5 h at 200-250 DEG C in the atmosphere of O2, so as to obtain a nickel foam loaded N-doped carbon / transition metal oxide three-dimensional electrode. The three-dimensional electrode produced according to the preparation method has relatively low oxygen evolution overvoltage, has relatively high structural stability and oxygen evolution catalytic activity under long-term alkaline electrolysis condition, is simple in production process and adjustable in electrode component and variety, and has wide application prospects.