15023 results about "Hydrothermal reaction" patented technology

The invention relates to a catalyst for selective hydrogenation reaction of an aromatic nitrocompound and a preparation method of the catalyst. The catalyst consists of a catalyst carrier and active metal coated with carbon, wherein the catalyst carrier includes a carbon-base carrier, SiO2, TiO2 or Al2O3; the active metal is selected from Co, Fe, Ni or Cu and other poor and noble metals. The catalyst is prepared by adopting a Pechini type sol-gel process which comprises the steps of dispersing an active metal precursor to water containing a coordination compound, adding a polyhydric alcohol solution and a macromolecule auxiliary, then adding the carrier, stirring for dispersion, carrying out hydrothermal reaction, separating out solid on the lower layer, and calcining in the inert atmosphere to obtain the catalyst in which carbon coats the active metal. Compared with the prior art, the catalyst can realize the hydrogenation reaction of a substituted aromatic nitrocompound in the mild condition; substrate conversion rate and production selectivity are high; the catalyst has recyclable economy and good application prospect.

The invention discloses a method for preparing aerogel materials by combining hydrothermal synthesis technology and sol-gel technology. The prepared aerogel comprises one or more of alumina aerogel, silica aerogel, zirconia aerogel and titania aerogel. The method comprises the following steps: mixing a reactant and a structure-directing agent according to certain proportion, and adding a pH value control agent to adjust the pH value; sealing hydrothermal reaction equipment, heating the mixture to be between 50 and 280 DEG C, making the mixture stand for 0 to 72 hours, raising the temperature to be between 60 and 300 DEG C, and continuously reacting for 0.1 to 72 hours; and cooling gel, taking out the gel, drying the gel and obtaining the aerogel. Compared with the prior art, the method has low reaction temperature and pressure, small equipment investment and simple and controllable technology, reduces potential safety hazards, greatly improves the preparation speed of the aerogel, saves the production cost, and is favorable to realize commercial mass production.

The invention relates to a preparation method of a graphene / titanium dioxide composite photocatalyst, which comprises the following steps: dissolving oxidized graphite in an organic solvent and obtaining oxidized graphene dispersion by ultrasonic processing; adding titanium salt precursor to the oxidized graphene dispersion and stirring evenly; transferring the mixed dispersion into a hydrothermal reaction kettle and reacting at 120-200 DEG C for 4-20 hours; respectively cleaning the product of the reaction by absolute ethyl alcohol and de-ionized water; and drying in vacuum at 40-80 DEG C for 8-24 hours to obtain the graphene / titanium dioxide composite photocatalyst. The invention has the advantages of common and easily obtained raw material, low cost and simple and safe preparation process, and in the obtained product, TiO2 particles can be evenly dispersed on the surface of the graphene, and stronger acting force is formed between the TiO2 particles and the surface of the graphene, thereby avoiding aggregation of the particles and effectively preventing restacking of graphene laminas. The graphene / titanium dioxide composite photocatalyst has good photocatalysis activity due to structural advantages and has potential application value in the fields of environment protection and solar cells.

A preparation method of high length-diameter ratio anhydrous calcium sulfate whisker belongs to the technical field of inorganic chemical material preparation. The method takes inorganic calcium saltand inorganic precipitant as raw materials and surfactant as dispersant, and includes the following steps: first preparing superfine calcium sulphate dihydrate precursor with good dispersion at the temperature of 10-90 DEG C; then adding the precursor into water solution containing shape control agent to conduct hydrothermal reaction for 0.5-10h at the temperature of 100-250 DEG C, and obtaining calcium sulfate hemihydrate whisker; mixing the calcium sulfate hemihydrate whisker with inorganic solvent; and roasting the mixture for 0.5-6h at the temperature 200-800 DEG C to obtain anhydrous calcium sulfate whisker with the length of 20-2000mum, the diameter of 0.5-20mum, the length-diameter ratio of 40-1000 and the main content greater than 95wt% after washing and drying. The technology is simple, the cost is low and the added value of the product is high. The prepared calcium sulfate whisker has large length-diameter ratio and regular shape and can be used as reinforcing material to beapplied in industries such as plastics, rubber, ceramics, cement, papermaking and the like.

The invention discloses a graphene nano sheet / MoS2 composite nano material and a synthesis method thereof. The method comprises the following steps of: preparing a graphite oxide nano sheet from graphite by using a chemical oxidation method, then dissolving molybdate into deionized water to form a solution of 0.02 to 0.07M, and adding thioacetamide or thiourea serving as a sulfur source and a reducer, wherein the mass ratio of the thioacetamide or the thiourea to the molybdate is 5:1-12:1; and adding the graphite oxide nano sheet into the solution, performing ultrasonic treatment for 1 to 2 hours so that the graphite oxide nano sheet is fully dispersed in a hydrothermal reaction solution, transferring the mixture into a hydrothermal reaction kettle, sealing, reacting for 20 to 36 hours at the temperature of between 220 and 260 DEG C, and obtaining the graphene nano sheet / molybdenum disulfide composite nano material by one-step hydrothermal synthesis, wherein the mass ratio of the graphene nano sheet to the molybdenum disulfide in the composite material is 1:2-4:1. The method has the characteristics of mild reaction condition and simple process. The synthesized graphene nano sheet / molybdenum disulfide composite nano material serving as an electrochemical lithium storage and electrochemical magnesium storage electrode material has wide application.

The invention relates to a sludge treatment process based on a hydrothermal modification technology. The sludge treatment process is carried out by comprising the following steps of: (1) temporarily storing the sludge which is subjected to mechanical dehydration and has the water content of 70-85% to a pretreatment unit and deodorizing the sludge; (2) introducing to a homogeneous device, fully mixing and homogenizing, introducing the homogenized sludge to a slurrying device, introducing the slurried sludge to a hydrothermal reactor for hydrothermal reaction, and introducing the hydrothermal sludge to a flash evaporator for decompression and flash evaporation; (3) cooling to 35-45 DEG C by using a cooler, then introducing to a high-pressure diaphragm pressure filter for pressure filtering and dehydration to obtain a dehydrated mud cake with the solid content of 35-45% and dehydrated filtrate; (4) introducing the dehydrated filtrate to an intermediate temperature anaerobic reactor, wherein the residence time is for 5.5-7.5d, the inlet water temperature is controlled below 40 DEG C, and the anaerobic reaction temperature is 30-40 DEG C; and (5) preparing a biomass fuel rod by using the dehydrated mud cake, and introducing the biomass fuel rod to a boiler to provide steam for the hydrothermal reactor and the flash evaporator. The sludge treatment process has the advantages of goodtreatment effect, obvious volume reduction effect, high harmless degree, recycling of methane, good economic benefit and the like.

The invention discloses a method for repair and regeneration of waste lithium iron phosphate battery cathode materials, which allows a lithium-source solution or a suspension to react with a recovered waste lithium iron phosphate battery material by a hydrothermal reaction or a solvent-thermal reaction, or allows the recovered waste lithium iron phosphate battery material to be processed by solid-phase ball-milling and calcination with the lithium source, performs liquid-phase or solid-phase direct lithium-supplementing repair of delithiated waste lithium iron phosphate, and then performs pertinent repair and regeneration by coating conductive agents or coating conductive agents and doping metal ions. The invention adopts a direct repair and regeneration method; the repaired waste lithium iron phosphate battery cathode material has excellent performance, and the specific capacity can reach above 90% of the specific capacity before discard; the method not only can effectively reduce environmental pollution of waste batteries, but also can make full use of waste resources and changes waste into valuables.

The invention discloses a nitrogen doped carbon quantum dot as well as a preparation method and an application thereof, belonging to the technical field of material science. The preparation method comprises the steps: after mixing organic acid and organic amine, directly performing a hydrothermal reaction to prepare a nitrogen doped carbon quantum dot water dispersion solution, and extracting and drying the nitrogen doped carbon quantum dot water dispersion solution to obtain a nitrogen doped carbon quantum dot solid. The size of the nitrogen doped carbon quantum dot is not more than 10 nm, the nitrogen content is not more than 50 percent, the surface of the nitrogen doped carbon quantum dot contains amino, carboxyl and hydroxyl; and the quantum efficiency is 39.8-50 percent. The preparation method is simple to operate, environment-friendly, low in equipment requirement; and the prepared nitrogen doped carbon quantum dot has excellent light emitting property, and can be widely applied to fields such as photoelectric materials, biological imaging and fluorescence probe.

The invention discloses a molybdenum disulfide (MoS2) nano-sheet film material and its preparation methods. The film material is characterized in that MoS2 nano-sheets vertically and sequentially grow on a conductive substrate, and the diameters and the thicknesses of the MoS2 nano-sheets are 0.05-2mum and 2-30nm respectively. There are two preparation methods of the film material. One preparation method comprises the following steps: a substrate which can be a copper sheet, a silver sheet, a titanium sheet, a tungsten sheet, a molybdenum sheet or carbon is placed in a solution comprising a molybdate and sulfur-containing compounds (comprising thiourea, thioacetamide and L-cysteine); and the sulfur-containing compounds undergo a hydrothermal reaction to grow the compactly-grown and uniformly-sequential MoS2 nano-sheet films on the substrate. Another method comprises the following steps: the molybdenum sheet is directly placed in a solution of the sulfur-containing compounds (comprising thiourea, thioacetamide and L-cysteine); and the sulfur-containing compounds undergo a sulfuration reaction under a hydrothermal condition to form the compact and uniform MoS2 nano-sheet ordered films. The film has a low hydrogen evolution overpotential (-30mv), a small Tafel slope (52mV / dec) and a high electrochemical stability, and is a hydrogen evolution electrode material extremely having an application prospect.

The invention discloses a high-efficiency graphene / silver phosphate composite visible light photocatalyst and a preparation method thereof, belonging to the technical field of composite materials and environmental management photocatalysis. The preparation method comprises the following steps: dissolving graphene oxide in water, and carrying out ultrasonic treatment to obtain a graphene oxide dispersed liquid; dissolving silver nitrate in deionized water, gradually and dropwisely adding into the graphene oxide dispersed liquid while stirring to obtain a mixed solution, uniformly stirring, and aging; dropwisely adding a prepared disodium hydrogen phosphate or sodium dihydrogen phosphate solution into the graphene oxide-silver nitrate mixed solution, continuing stirring, transferring into a hydrothermal reaction kettle, carrying out hydrothermal reaction, and cooling to room temperature; and washing the reaction product, and carrying out vacuum drying to obtain the visible light photocatalyst. The invention has the advantages of wide material sources and simple preparation process; and the obtained composite material has the advantages of controllable structure and regular pattern, and has high-efficiency degradation effect on organic dyes rhodamine B and methylene blue with certain concentration under the visible light irradiation.

The invention relates to a graphene nanometer sheet-cobaltous oxide composite negative electrode material of a lithium ion battery and a preparation method thereof, and belongs to the technical field of batteries. The negative electrode material consists of graphene nanometer sheets and cobaltous oxide, wherein the graphene nanometer sheets are distributed on cobaltous oxide particles in a staggering way; the mass fraction of the graphene nanometer sheets is 5 to 90 percent; the thickness of the graphene nanometer sheets is 1 to 50 nanometers; and the particle size of the cobaltous oxide is 10 to 500 nanometers. The preparation method comprises the following steps: dispersing graphite oxide in alcohol-water solution or aqueous solution with ultrasound or stirring; adding cobalt salt, alkali and a reducing agent into the mixture and pouring the mixture into a hydrothermal kettle after stirring; performing further sealing and synchronous hydrothermal reaction, washing, filtering and drying to obtain a graphene nanometer sheet-cobaltous oxide composite; and processing the graphene nanometer sheet-cobaltous oxide composite in the protective atmosphere to obtain the graphene nanometer sheet-cobaltous oxide composite negative electrode material. In the invention, when the material is charged or discharged by a current of 200mA / g, the reversible specific capacity of the material can be stabilized in a range of over 900mAh / g.

The invention provides a preparation method of a nano porous metal oxide / carbon lithium ion battery cathode material. The preparation method comprises the following steps: firstly, weighting ferric salt or manganese salt and carboxylate organic ligands, and putting into a high-pressure reaction kettle; and after a polar solvent is added and dissolved, carrying out a hydrothermal reaction for 10-72h at 100-180 DEG C to generate a transition metal coordination polymer precursor; and after the transition metal coordination polymer precursor is washed and dried, decomposing the precursor for 0.5-6h at a temperature of 300-600 DEG C in an inert atmosphere in a tube furnace, thus obtaining a nano porous metal oxide / carbon lithium ion battery cathode material containing iron oxides or manganese oxides. According to the preparation method, since the transition metal coordination polymer precursor which is structurally designable and controllable is used as a template-type precursor, a nano porous metal oxide / carbon lithium ion battery cathode material is obtained by using an in-situ thermal decomposition method. The method is simple in process, and the obtained products have the advantages of high electrical conductivity, high specific capacity, good cycle stability, excellent high-ratio discharge performance and high energy density.

The invention discloses a compound nano material of graphene and molybdenum disulfide (MoS2) and a preparation method thereof. The compound material is formed by mixing graphene and a MoS2 nano material in a mass ratio of (1 to 1)-(4 to 1). The preparation method comprises the following steps of: preparing an oxidized graphite nano slice from graphite by a chemical oxidization method; then dissolving molybdate into deionized water so as to form 0.02 to 0.07M of solution; adding L-cysteine serving as a sulfur source and a reduction agent, wherein the mass ratio of the L-cysteine to the molybdate is (5 to 1)-(12 to 1); adding the oxidized graphite nano slice into the solution, and ultrasonically treating so that the oxidized graphite nano slice can be fully dispersed in the hydrothermal reaction solution; transferring the mixture into a hydrothermal reaction kettle and sealing; and synthesizing by a one-step hydrothermal method to obtain the compound nano material of graphene and MoS2, wherein the mass ratio of the graphene nano slice to the MoS2 is (1 to 1)-(4 to 1). The method has the characteristics of mild reaction condition and simple process. The compound nano material of graphene and MoS2 synthesized by the method can be widely used as electrode materials of new energy batteries, high-performance national lubricants, catalyst carriers and the like.

The invention provides a controllable synthetic method of graphitized carbon spheres with a hollow structure. The controllable synthetic method comprises the following steps of: (1) dissolving a carbon source, soluble metal salts and a catalyst in deionized water according to proportioning, stirring till completely dissolving, transferring to a hydrothermal reaction kettle for hydro-thermal synthesis, and washing, filtering and drying precipitates to obtain primary products; (2) reducing the primary products at a high temperature in a high-temperature reaction furnace under the production of gas; and (3) placing the products obtained through reduction in an acid solution for soaking, and washing, filtering and drying to obtain the graphitizing carbon spheres with the hollow structure. The graphitizing carbon spheres with the hollow structure have the advantages that the morphology is uniform, the carbon shells are of microcellular structures, the interiors of the carbon spheres are of mesoporous support structures, the graphitization degree is good, and the like. The graphitizing carbon spheres can be used in numerous fields of high-efficiency catalytic conversion, energy source storage and transition, medicine release control, matter adsorption and separation and the like. An invented formwork-free hydrothermal synthesis technology is simple and controlled and can be used for large-scale production.

The present invention relates to the preparation of nano material. One-dimensional monocrystalline nano manganese dioxide wire of different crystal form is synthesized selectively via controlling thetemperature, period and material control of the hydrothermal reaction of two-valent manganese salt and ammohnium persulfate as raw material and ammonium sulfate as additive at 100-220 deg.c inside one sealed reactor. The process may be widely used in basic theory research in lithium ion cell, molecular sieve and relevant fields.

The invention relates to a composite material of a nitrogen-doped porous carbon-wrapped carbon nano tube as well as a preparation method and an application of the composite material. The preparation method comprises the following steps: dispersing the carbon nano tube in water, adding a carbon source to obtain a reaction system, subsequently performing hydrothermal reaction, performing thermal treatment on the carbon nano tube wrapped with a carbon layer on the surface, and a nitrogen source at the high temperature so as to obtain the composite material of the nitrogen-doped porous carbon-wrapped carbon nano tube. According to the preparation method, the carbon source is polymerized under a hydrothermal reaction condition so as to obtain the carbon layer, the outer surface of the carbon nano tube is wrapped with the carbon layer, subsequently the carbon layer is carbonized and decomposed to generate a porous structure under high temperature treatment, and at the same time, the gasified nitrogen source is diffused to the carbon layer through ducts to be subjected to in-situ doping. The composite material provided by the invention can be used as a cathode oxidation reduction catalyst of a fuel battery, is excellent in catalysis, and is high in oxidation activity when being compared with other nitrogen-doped materials reported in documents. The preparation method provided by the invention is simple and economic in process, convenient to operate and easy to achieve the large-scale production.

The invention discloses a graphene-based nano iron oxide composite material and a preparation method thereof. By the method, iron oxide nano granules with uniform diameter and controllable shape and components can be loaded on graphene. The method comprises the following steps of: uniformly dispersing graphite oxide into deionized water by adopting an ultrasonic method to obtain graphene oxide solution; adding an iron salt precursor into the obtained solution and mixing the precursor and the solution uniformly, adjusting the pH of the solution, and hydrolyzing the iron salt; putting the mixed solution into a reaction kettle and performing hydrothermal reaction; and finally, cleaning and freeze-drying the obtained product to obtain the graphene-based nano iron oxide composite material. The raw materials are common and easily obtained, the cost is low, and the preparation process is simple, safe and environmentally-friendly; the prepared graphene-based nano iron oxide composite material has good structural stability and monodispersity; when the composite material is used as a lithium iron battery electrode material, the charge / discharge capacity can reach over 1,000mAh / g; and the composite material has good multiplying power performance and cycle life.

The invention relates to a graphene / rare earth oxide nanometer composite material and a preparation method and application thereof. The preparation method comprises the following steps of: uniformly mixing oxidized graphene dispersion liquid and a soluble rare earth compound at the weight ratio of (1:1)-(1:10), regulating a pH value to alkalescence, and carrying out hydrothermal reaction to obtain the graphene-rare earth oxide nanometer composite material; and uniformly mixing the oxidized graphene dispersion liquid and the soluble rare earth compound at the weight ratio of (1:1)-(1:10), adding a reducer, and carrying out reflux reaction at certain temperature to obtain the graphene-rare earth oxide nanometer composite material. According to the invention, rare earth oxides are successfully loaded to the surface of graphene, the rare earth oxides can be connected in a physical loading or chemical bonding way because of the electrostatic action of the surface of the oxidized graphene and uniformly dispersed to the surface of a nanometer graphene sheet by being formed into nanometer level particles, the particle size is 5-50 nanometers, and the sheet thickness is 1-5 layers, so that the agglomeration phenomena of the graphene is obviously improved, and the electrochemical property of the graphene nanometer composite material as a cathode material and the circulation stability of the graphene nanometer composite material in the charge-discharge process are effectively enhanced and superior to those the cathode of the traditional commercial lithium ion battery. The preparation method disclosed by the invention has the advantages of simple process, low cost, short period, and the like.

A process for preparing the nanometre tubes of hydrated sodium titanate and titanate series includes such steps as hydrothermal reaction of TiO2 or metatitanic acid to obtain the nanometre tubes of hydrated sodium titanate, mixing them with the solution containing one or two kinds of metal ions to convert them to the nanometre tubes of hydrated titanate or composite hydrated titanates of the saidmetal ions, and thermal dewatering to obtain the nanometre tubes of corresponding titanate or composite titanates. Its advantages are uniform shape, large specific surface area, high thermal stability and regulatable catalytic performance.

The invention discloses a carbon based bimetallic composite material. The composite material includes a carbon based shell, the inner surface of the carbon based shell is compounded with a sulfide ofa transition metal A, and the outer surface is compounded with an oxide of a transition metal B. The transition metal A and the transition metal B are selected from different metals. The invention also discloses a preparation method of the carbon based bimetallic composite material, and the method includes: subjecting a mixed solution salt containing a salt of the transition metal A, a salt of thetransition metal B, an organic ligand and alcohol to hydrothermal reaction at 60-180DEG C so as to obtain bimetallic MOF; and mixing the obtained bimetallic MOF with sublimed sulfur, then conductingroasting in a protective atmosphere at 300-800DEG C, thus obtaining the carbon based bimetallic composite material. In addition, the invention also includes application of the composite material as anOER electrocatalyst. The invention provides an electrocatalyst with a brand-new structure. The material has excellent OER catalytic performance. Under an electric current density of 10mA / cm<2>, the oxygen evolution potential is close to 0.55V, and under an overpotential of 320mV, the TOF can reach 34.7s<-1>.

The invention provides a method of partial vulcanization to improve oxygen evolution electrode performance of metal hydroxide and belongs to the field of oxygen evolution catalyzation of electrolysis of water. The method comprises the following steps: firstly, pretreatment is carried out on nickel foam, then, special nano floriform metal hydroxide is formed on the surface of the nickel base after the pretreatment in an in-situ growth manner through the hydrothermal synthesis method, and finally, the prepared metal hydroxide and a sulphur source have hydrothermal reaction to prepare a hydroxyl metal sulfide oxygen evolution electrode. According to the invention, the method is novel, the demanded technology is simple, the production cost is low, requirements to equipment are lower, and industrial production is suitable; in addition, the prepared electrode has excellent oxygen evolution activity and stability, is large in specific surface area, firmly combines with a base, and can be applied to the field of oxygen evolution through industrial electrolysis of water.

The invention discloses chitosan-functionalized metal organic framework materials. The chitosan-functionalized metal organic framework materials comprise at least one metal ion and an organic ligand. A preparation method of the chitosan-functionalized metal organic framework materials comprises the following step of: carrying out hydrothermal reaction on the metal ion and the organic ligand in a certain proportion at high temperature in a reaction kettle or reacting by adopting a microwave process, an ultrasonic process, and the like by taking a surfactant as a template to synthesize the metal organic framework materials in different shapes, and modifying the metal organic framework materials by a biocompatible material chitosan and a derivative thereof, and the like, to functionalize the organic framework materials. In a process of synthesizing nano-scale metal organic frameworks and modifying by using chitosan and the derivative thereof, different drug molecules can be loaded to the internal frameworks of the metal organic frames and external chitosan macromolecular structures. The chitosan-functionalized nano-scale metal organic framework materials disclosed by the invention can be applied to targeted transportation of various drugs and controlled release of drugs in a living body.

The invention relates to a preparation method and application method of a titanium dioxide nanosheet supported MIL-100 (Fe) composite photocatalysis material, belongs to the field of titanium dioxide photocatalysis, and especially relates to the field of titanium dioxide nanosheet supported porous metal organic skeleton (MOFs) composite materials. The preparation method comprises the following steps: 1, uniformly stirring tetrabutyl titanate and hydrofluoric acid at normal temperature, putting the obtained mixture in a hydrothermal reaction kettle, carrying out a reaction, separating the obtained material, washing the separated material, and drying the washed material to obtain titanium dioxide nanosheets; and 2, uniformly dispersing the titanium dioxide nanosheets in an anhydrous ethanol solution of iron trichloride, carrying out magnetic stirring at normal temperature for 15 min, carrying out suction filtration separation to obtain a product, dispersing the product in an anhydrous ethanol solution of trimesic acid, carrying out a 50-80 DEG C water bath reaction for 20-50 min, carrying out suction filtration separation to obtain a product, and repeating above processes in step 2 2-50 times to obtain the titanium dioxide nanosheet supported MIL-100 (Fe) composite photocatalysis material. The catalyst prepared through the method is especially suitable for catalytic degradation of high-concentration organic dyes (such as methylene blue) under visible light irritation) to reach a very high degradation rate.

This invention relates to a continuous microwave synthesis process of inorganic materials and its apparatus and more particularly, to the process of synthesizing inorganic materials prepared in a manner such that after preparing a mixed solution of precursor materials for various inorganic materials such as porous molecular sieve, layered compounds and ceramics, this mixed solution is continuously added to a tube-type microwave reactor using a slurry pump for the synthesis and crystallization of inorganic materials. Thus the manufacturing process of this invention has the following advantages: (1) the reaction time is further shortened by several to tens of minutes for crystallization, compared to the conventional hydrothermal reaction requiring a prolonged time, (2) the continuous manufacturing and collection processes of this invention can give access to mass-scale production of inorganic materials with relatively small facility, compared to the conventional batch hydrothermal or microwave synthesis, and (3) less amount of organic templating agent can be required during the manufacture of porous molecular sieve.

The invention discloses electrocatalyst of MOFs (Metal-organic Frameworks) / graphene composite carrier and a preparation method of the electrocatalyst. The electrocatalyst is composed of the MOFs / graphene composite carrier and an active component. The preparation method of the MOFs / graphene composite carrier comprises the following steps of: preparing MOFs / graphene composite carrier through a hydrothermal reaction method; and loading the active component on the composite carrier by adopting a microwave synthesis method. The preparation method disclosed by the invention is simple in preparation steps, short in time and small in product loss; and the prepared catalyst is small in grain size, unlikely to cluster, uniformly distributed and high in electrochemical catalytic activity.

The invention relates to a catalyst for loading cobalt phosphide on activated carbon as well as preparation and application of the catalyst. The catalyst is prepared by taking multilayer nanoporous activated carbon (HNC) as a carrier and loading cobalt phosphide (CoP) on the surface of the activated carbon. The preparation method comprises the following steps: mixing cobalt nitrate hexahydrate (Co(NO3)2.6H2O), urea (CO(NH3)2), ammonium fluoride (NH4F) and deionized water to obtain a reaction mixture raw material; mixing a certain quantity of HNC with the reaction mixture raw material under an ultrasonic condition for hydrothermal reaction; carrying out suction filtration drying to obtain a precursor; conducting annealing on the precursor and sodium hypophosphite under the protecting atmosphere of argon; carrying out cooling. The catalyst prepared according to the preparation method can be used for electrochemical hydrogen evolution, and is excellent in catalytic activity for hydrogen evolution.

The invention discloses a composite visible-light catalyst for TiO2 microsphere and g-C3N4, as well as a preparation method and an application of the catalyst. The preparation method comprises the following steps of: putting a cleaned titanium sheet to a mixed aqueous solution of melamine and ammonium fluoride to carry out a hydrothermal reaction; and collecting precipitate in a reaction solution after the reaction solution is cooled, cleaning the precipitate, drying and burning the cleaned precipitate to acquire the composite visible-light catalyst for TiO2 microsphere and g-C3N4. The composite visible-light catalyst overcomes the defects of low photo-transformation efficiency and low activity of a single material, has the advantages of an extensive photo-response range, high visible light catalytic activity and the like, and can be applied to the environment-friendly field, in particular an occasion that visible light catalyzes and degrades organic pollutants in water and kills pathogenic microorganisms in the water, thus the application prospect is extensive.

The invention discloses a hydrothermal method for preparing water-soluble graphene quantum dots. The invention relates to the preparation method of graphene quantum dots, and especially relates to a hydrothermal method for preparing water-soluble graphene quantum dots. The method provided by the present invention is characterized in that: 0.01 to 1.0M of an aqueous solution of polyhydroxyl carbohydrate is added to a hydrothermal reaction vessel; the aqueous solution is heated for 10 to 600 minutes under a temperature of 120 to 220 DEG C; sugar molecules are polymerized into graphene quantum dots with sizes of 1 to 10nm, such that target products are obtained. The graphene quantum dots prepared with the method provided by the present invention has characteristics of water-solubility, monodispersity and special photoelectrical characteristics. The raw materials are cheap, and the sources of the raw materials are wide. With environmental-protective technology, the method is suitable for volume production.