1978 results about "Sodium borohydrate" patented technology

The preparation process of 2, 3, 5, 6-tetrafluoro-para-xylyl alcohol with 2, 3, 5, 6-tetrachloro-p-phenyl diformyl chloride as material includes fluorination with potassium fluoride, etc. as fluorination agent, sulfolane, etc. as solvent and calixarene, etc. as catalyst and at 40-230 deg.c; esterification of ester with fatty alcohol or aromatic alcohol as esterifying agent and at 20-120 deg.c; reduction of ester with sodium borohydride, etc. as reductant and sulfolane, etc. as solvent, and at -10 deg.c to 60 deg.c; bromination with HBr acid as brominating agent and dichloromethane as solvent and at 30-160 deg.c; and reduction of bromide with magnesium powder, etc as reductant and fatty alcohol, water, chloride, etc as solvent, and at -10 deg.c to 50 deg.c. The present invention has the advantages of simple process, low production cost, high product yield and purity, and is suitable for industrial production.

Solid self-stabilized borohydride fuel compositions, fuel cartridges, related methods of preparation and hydrogen generation are provided. The fuel compositions comprise mixtures of at least one borohydride salt with a cation selected from the group consisting of alkali metal cations, alkaline earth metal cations, aluminum cation, zinc cation, and ammonium cation, preferably sodium borohydride, and at least one hydroxide salt with a cation selected from the group consisting of alkali metal cations, alkaline earth metal cations, aluminum cation, zinc cation, and ammonium cation, preferably sodium hydroxide.

The invention relates to a method for preparing formaldehyde room temperature oxidation catalyst. The method comprises the following steps: making porous inorganic oxide as a carrier; making sodium borohydride as reducing agent; making soluble hydroxide as additive; and drying the carrier including noble metal processed by carrier impregnation noble metal precursor-room temperature reduction-deposition so as to prepare catalyst. According to the invention, sodium borohydride reducing agent is added for one time at the room temperature, thus, the aperture of generated noble metal nano particle is smaller than that of particle prepared in a high-temperature burning / hydrogen reducing method; crystal particle is within 0.1-5nm; and dispersibility is good; the loading quantity of the noble metal is within 0.05-10wt%, preferably within 0.5-2%; corresponding aperture is within 0.5-3nm; prepared loading-type noble metal catalyst has very high oxidative activity to formaldehyde in air on a room temperature condition without illumination or heat; activity is not changed basically in repeated using procedures; and the method disclosed by the invention is characterized by simple compound line, easily-acquired raw material and is suitable for industrial production.

A hydrogen generation system includes a fuel container, a spent fuel container, a catalyst system and a control system for generating hydrogen in a manner which provides for a compact and efficient construction while producing hydrogen from a reaction involving a hydride solution such as sodium borohydride.

The invention relates to a layered double hydroxide and a preparation method thereof, belonging to the technical field of metal hydroxide preparation. A chemical formula of the layered double hydroxide is as follows: (M1(1-x)M2x(OH)2)(A<n->)x / n), wherein x is larger than or equal to 0.2 and smaller than or equal to 0.33; M1 represents any one or more of divalent metal ions including Mg<2+>, Zn<2+>, Ni<2+>, Co<2+>, Ca<2+>, Cu<2+>, Fe<2+> and Mn<2+>; M2 represents any one or two of trivalent metal ions including Fe<3+> and Al<3+>; A<n-> represents any one of interlayer anions including CO3<2->,NO3<->, Cl<-> and SO4<2->; and the grain size ranges from 12 nm to 80 nm. The invention has the advantages that the preparation method is a direct method for preparing the layered double hydroxide with high crystallinity, layered structure regularity, wide application range and adjustable particle size. The preparation method comprises the following steps: obtaining highly dispersed metal nanoparticle sol by utilizing the action of colloid mill axial shear force and the sodium borohydride reducibility, and then performing slow oxydrolysis in a hydrothermal system, and the like to generate thenano layered double hydroxide with layered structure regularity and adjustable particle size. The method has the advantages of wide application range, low cost, simple operation and environmental protection.

The invention provides a self-support transition metal selenide catalyst as well as a preparation method and application thereof, belongs to the field of alkaline full electrolytic tank water decomposition, and solves the technical problems that the existing catalyst is low in catalytic activity or the catalyst activity is limited by pH value. The preparation method of the self-support transition metal selenide catalyst comprises the following steps: dissolving selenium powder in a sodium borohydride aqueous solution, or adding metal salt of a transition metal element to obtain a mixed solution; then, adding a conductive substrate of the transition metal into the obtained mixed solution for reaction to obtain the self-support transition metal selenide catalyst; or preparing transition metal selenide electrolyte from the metal salt of the transition metal element, selenium dioxide and lithium chloride; then adopting the conductive substrate of the transition metal as a working electrode for carrying out electrodeposition in the obtained transition metal selenide to obtain the self-support transition metal selenide catalyst. According to the invention, the preparation method is free of pH influence, and the prepared selenide catalyst has excellent electro-catalysis hydrogen evolution and oxygen evolution performance when applied in a battery.

The invention relates to a method for chemically plating nickel on the surface of carbon fiber. The invention aims to solve the problem that the existing method for chemically plating the nickel on the surface of the carbon fiber causes environment pollution, is unstable in activation fluid, complex in operation, and low in plating layer bonding intensity. The method comprises the following steps of: 1, firstly, removing glue and oil from the surface of the carbon fiber; 2, soaking in concentrated nitric acid for coarsening, then washing by distilled water under the help of ultrasound, and finally drying into constant weight, so that the cleaned and coarsened carbon fiber can be obtained; 3, firstly, soaking the obtained product in the activation fluid, then washing by distilled water and soaking in sodium borohydride solution to be reduced, and finally rewashing by distilled water, so that the activated carbon fiber can be obtained; and 4, soaking into chemical nickel-plating liquid, withdrawing, and washing by distilled water, and then drying into constant weight, so that the nickel can be chemically plated on the surface of the carbon fiber. The method for is mainly used for chemically plating the nickel on the surface of the carbon fiber.

The invention discloses a short length-diameter ratio gold nanometer rod preparation method. A strong reducing agent of sodium borohydride is added in a hexadecyl trimethyl ammonium bromide surface modifying agent solution to reduce gold acid chloride and obtain a gold seed solution; a mixed fluid of didodecyl dimethyl ammonium bromide, gold acid chloride and silver nitrate is prepared, and an ascorbic acid solution is added thereto for obtaining a growth solution; the seed solution of a certain amount is filled into the growth solution to react for 5 to 12 hours, so as to obtain the short length-diameter ratio gold nanometer rod. The operation of the method is simple, the gold nanometer rod production rat is high, and the size distribution is narrow.

The invention provides a method for preparing a silver / graphene antimicrobial composite material, and the method provided by the invention comprises the following steps: a) providing a reductive graphene oxide-sodium polystyrene sulfate composite solution; b) heating the composite solution obtained in the step a) to 50-70 DEG C; and c) adding a silver nitrate solution into the heated composited solution obtained in the step b) for reaction, thus obtaining the silver / graphene antimicrobial composite material. The invention provides the method for preparing the silver / graphene antimicrobial composite material; and in the method, a reductive graphene oxide tablet is taken as a reducing agent for carrying out reduction on silver ions under a neutral pH condition so as to generate silver nano particles. In the method provided by the invention, no sodium borohydride is taken as a reducing agent, and in the whole preparation process, no potassium hydroxide is adopted, therefore, when the composite material prepared by the method is subjected to later application, no large biological irritant is caused. In addition, antibacterial experiments show that the silver / graphene antimicrobial composite material provided by the invention has a better antibacterial effect.

The invention belongs to the field of synthesis of nano materials, relates to the preparation of graphene / mesoporous oxide series of nano composite material, and particularly relates to a preparation method and application of graphene / cellulose / titanium dioxide composite material. The graphene / cellulose / titanium dioxide composite material is prepared by preparing graphite oxide by utilizing an improved Hummers method, carrying out ultrasound to obtain graphene oxide, reducing graphene oxide into graphene by using sodium borohydride; and finally uniformly mixing cellulose, titanium dioxide, a surface active agent (hexadecyl trimethyl ammonium bromide) and grephene. According to the invention, the synthesis method is simple, the prepared graphene / cellulose / titanium dioxide composite material is taken as an adsorbent, and a malachite green dye solution is taken as an adsorption object, the experiment shows that the composite material has an excellent adsorption removal effect. The composite material is applied to the treatment of dyes in sewage water, has the advantages of simplicity in operation, convenience, easiness in availability, high adsorption rate and the like, and has good industrially practical value.

The invention discloses a preparation method of butylphthalide, which comprises the following steps: taking phthalic anhydride as a raw material; enabling the phthalic anhydride to carry out addition reaction with the Grignard reagent of butyl halide to obtain an intermediate of o-valeryl benzoic acid; and then, reducing by sodium borohydride, and carrying out acidic cyclization to obtain the butylphthalide. The phthalic anhydride and the butyl halide which are used as raw materials in the preparation method of the butylphthalide of the invention are commercial products, and the reaction raw materials can be obtained easily. Because the Grignard reaction, the sodium borohydride reduction and the acidic cyclization are classical reactions, the operation is simple, the industrialized production can be realized easily, the yield of the butylphthalide reaches 50-60%, and the purity of the butylphthalide reaches 97-98%.

The invention relates to a MoSe2 / Co0.85Se composite material for electrocatalytic water decomposition. The microtopography of the composite material is that a micron / nano rod of a MoSe2 / Co0.85Se compound is loaded with a nano sheet of a molybdenum selenide / cobaltous selenide compound; the micron / nano rod has the length of is 1.5 to 3.5 microns and a diameter of 0.2 to 0.5 micron. A composite-material precursor CoMoO4 is firstly prepared and obtained through a hydrothermal reaction by using cobalt nitrate and sodium molybdate as reactive raw materials; afterwards, the composite material is made through the hydrothermal reaction by using sodium borohydride, selenium powder and the prepared composite-material precursor as raw materials. A preparation method of the MoSe2 / Co0.85Se composite material is simple; the raw materials are easily obtained; the cost is low; the industrialized production is easily realized; the prepared and obtained composite material is good in electrocatalytic effect, and further, has favorable stability.

The invention discloses a preparation method of a nitrogen-doped graphene loaded platinum nano-particle catalyst. The preparation method comprises the following steps of: firstly, preparing graphene oxide (GO); secondly, preparing polyaniline / graphene oxide (PANI / GO) through a liquid-liquid interface polymerization method; thirdly, drying the PANI / GO, transferring the dried PANI / GO into a tubular furnace, and performing high-temperature treatment for 2 hours at 800 DEG C to prepare NGs (nitrogen-doped graphenes); and finally, ultrasonically dispersing the NGs into an aqueous solution, uniformly mixing the NGs with chloroplatinic acid according to a certain mass ratio, slowly adding sodium borohydride (NaBH4) into the mixed solution, and performing magnetic stirring for 8 hours to prepare the NGs loaded platinum nano-particle catalyst (Pt / NGs) which takes the NGs as a catalyst carrier to uniformly load platinum nano-particles to the surfaces of the NGs without any chemical modification. The nitrogen atoms which are doped into molecular structures of GNs not only provide a large amount of active sites for PtNPs loading, but also enhance the interaction between the PtNPs and an NGs carrier and improve the catalytic stability and catalytic activity of a nano composite material.

The invention relates to the elimination of the arsenic in drinking water, in particular to a preparation method of a supported type nano-adsorbent for removing arsenic from drinking water; the method includes the following steps: (1) activated carbon material with pore volume of 0.100-0.500cm<3> / g is selected for pretreatment; (2) soluble ferric salt solution is firstly used for soaking the activated carbon for 10-120 min; (3) alcoholic solution is taken as a dispersant to be added into the ferric salt solution; (4) under the protection of inert gases at room temperature, a strong reductant, potassium borohydride or sodium borohydride, is used for titrating the ferric salt, and agitation is carried out under the protection of inert gases; after the titration of potassium borohydride or sodium borohydride solution, agitation lasts for 10-120 min; (5) after agitation, centrifugation is carried out; oxygen-free water is firstly used for washing for 1-3 times, then organic solvent is adopted for washing for 1-3 times, and vacuum drying is done at 40-100 DEG C for 12-48h to obtain the product. The adsorbent of the invention has large adsorption capacity and small volume and is safe, stable and easy to store and transport.

The present invention relates to a method for preparing a CdX (X= Se or Te) quantum dot nano material with high quantum yield in an aqueous phase by using simple operation conditions, and belongs to the field of nano material preparation. The preparation method does not require nitrogen as a protective gas, or a buffer solution, or a particular ligand, or a large amount of hydrazine hydrate as a reducing agent, or a special post-treatment. In the aqueous phase, a thiol compound is used as a ligand; cadmium salt and potassium tellurite (selenite) are selected respectively as a cadmium source and a tellurium (selenium) source; and sodium borohydride is used as a reducing agent. The water-soluble CdTe (CdSe) quantum dot with quantum yield up to 83% can be prepared from a one-pot reaction.

The invention relates to a preparation method of nanometer silver antibacterial agent, which belongs to the technical field of the antibacterial agent preparation. The invention is characterized in that distilled water or deionized water is taken, nanometer silicon dioxide carrier is added, dispersing protective agent adopts polyvinyl pyrrolidon which is evenly mixed; then silver salt silver nitrate and reducing agent sodium borohydride are added, mixed and dispersed, and the nanometer silver antibacterial agent colorless transparent solution is obtained through sufficient reaction, being bottled and packaged in a sealing way. The invention extends the application scope of nanometer silver greatly; the particle diameter is small, and the particle diameter distribution is even; the smaller particle diameter has higher specific surface area, higher antibiotic activity and lower dosage; the dispersivity of the nanometer silver collosol system is good, and aggregation is not easy to occur; the environment is friendly, and the nontoxic and the nuisance-free raw materials are adopted for the preparation; the invention has quite excellent environment affinity, and pollution can be caused to the environment.

The invention relates to a dual-emission ratio-type quantum dot fluorescence probe for visual detection of aspirin, a preparation method and an application thereof and belongs to the technical field of preparation of material and detection of content of medicines. The preparation method of the probe includes following steps: preparing a precursor NaHTe solution from sodium borohydride, tellurium powder and water under an ultrasonic environment; adding the precursor to an aqueous solution of CdCl2.2.5H2O in the presence of thioglycollic acid; carrying out a reflux reaction with a nitrogen protecting condition to obtain required green fluorescence quantum dot and red fluorescence quantum dot; by means of a sol-gel method, wrapping the red fluorescence quantum dot with silicon spheres with amino group being connected; dispersing a green fluorescence quantum dot solution and the red fluorescence quantum dot wrapped with the silicon spheres in an MES buffer solution with addition of an EDC / NHS solution; and carrying out a reaction at room temperature in a dark place to obtain the dual-emission ratio-type quantum dot fluorescence probe. The dual-emission ratio-type quantum dot fluorescence probe is used in detection of the content of the aspirin through fluorescence quantitation and visualized analysis. The quantum dot fluorescence probe is quite good in optical performance and stability and has a capability of visualizedly detecting the aspirin.

A process for the preparation of (R)—N-propargyl-1-aminoindane, or a salt thereof, comprising reacting 1-indanone with propargylamine, in presence of a mixture of sodium borohydride and acetic acid, to obtain N-propargyl-1-aminoindane; and its conversion into (R)—N-propargyl-1-aminoindane or a salt thereof.

The invention provides a gold nanocluster preparation method and an application thereof, and belongs to the technical field of nano materials. The problem of high cost of gold nanoparticle compositing in the prior art is solved. The gold nanocluster preparation method includes the steps: a, mixing polypeptide water solution with HAuCl4 solution in a reaction vessel to prepare solution A; and b, adding NaBH4 solution into the solution A for reduction, and reacting for a certain time to obtain fluorescent gold nanocluster products. A series of gold nanoclusters with different maximum emission wavelengths are composited successfully by means of taking different polypeptides as templates and sodium borohydride as a reducer. The composited gold nanoclusters have the advantages of large Stokes shift, long fluorescence lifetime, good stability and the like, can be used for detecting mercury ions (Hg2+) in water samples, and is high in detection sensitivity.

The invention discloses a nano-silver loaded graphene antibacterial agent, a graphene in-situ reduction nano-silver loaded water-based antibacterial coating, and a preparation method of coating. The nano-silver loaded graphene antibacterial agent is prepared from the following components: graphene oxide, silver nitrate, polyvinylpyrrolidone and sodium borohydride. The graphene in-situ reduction nano-silver loaded water-based antibacterial coating o is prepared from the following raw materials in parts by weight: 25-35 parts of water, 30-40 parts of acrylic resin, 20-30 parts of polyurethane resin, 2-3 parts of the nano-silver loaded graphene antibacterial agent, 1.5-2.5 parts of a dispersant, 1-1.5 parts of a curing agent, 0.8-1 part of a defoamer, 0.5-0.8 part of film formation aid and 0.5-0.8 part of levelling agent. Under the combined action of graphene and nano-silver, the antibacterial efficiency, the antibacterial time and the antibacterial property of the coating can be greatlyimproved; the coating is excellent in antibacterial effect, long in antibacterial time, free of toxicity, free of pollution, high in water resistance and weather resistance, and high in adhesion; thenano-silver is loaded in graphene in situ, is incapable of settling, and can be uniformly dispersed in emulsion.

The invention discloses a platinum nano-material with the activity of four mimic enzymes and a preparation method thereof. The preparation method comprises the following steps: using citrate ions as a modifier, reducing chloroplatinic acid by utilizing sodium borohydride, and preparing the platinum nano-material modified by citric acid. The platinum nano-material is simply and quickly prepared, the particle size is small, and the dispersibility and stability of a water solution are high. The obtained platinum nano-material has the activity of four mimic enzymes at the same time, and comprises peroxidase, oxidase, catalase and superoxide dismutase. The activity of the four mimic enzymes of the platinum nano-material can be adjusted and controlled through the concentration of the citrate ions used in the preparation process.

Trace amount levels of heavy metals such as mercury in crude oil are reduced by contacting the crude oil with a sufficient amount of a reducing agent to convert at least a portion of the non-volatile mercury into a volatile form of mercury, which can be subsequently removed by any of stripping, scrubbing, adsorption, and combinations thereof. In one embodiment, at least 50% of the mercury is removed. In another embodiment, the removal rate is at least 99%. In one embodiment, the reducing agent is selected from sulfur compounds containing at least one sulfur atom having an oxidation state less than +6; ferrous compounds; stannous compounds; oxalates; cuprous compounds; organic acids which decompose to form CO2 and / or H2 upon heating; hydroxylamine compounds; hydrazine compounds; sodium borohydride; diisobutylaluminium hydride; thiourea; transition metal halides; and mixtures thereof.

The invention relates to a method for preparing graphene, a method for carrying out graphene surface modification by taking one or more than two of pyrene, pyrene derivatives, naphthalene and naphthalene derivatives as a modifying agent as well as a method for manufacturing TiO2-graphene nano-composite material by utilizing the reaction of the surface-modified graphene and a titanium-containing compound and a product thereof. The method for preparing graphene comprises the steps of (a1) reducing dispersive graphite oxide in inert solvent by using a reducing agent to form a graphene-containing reaction mixture, wherein the reducing agent comprises sodium borohydride, vitamin C or combination thereof; and (a2) isolating graphene from the reaction mixture. The obtained graphene is flocculent and the TiO2-graphene nano-composite material has efficient photocatalytic performance.

The invention relates to a preparation method of an ultrafine platinum nano-wire. The method mainly comprises that an insulin fiber suspension is obtained by dissolving bovine insulin powders into a hydrochloric acid solution with the concentration of 10-25 mM to prepare an insulin hydrochloric acid solution, blending the insulin hydrochloric acid solution with vortexes, and heating the blended insulin hydrochloric acid solution for 5-20 h in a constant-temperature metal bath at the temperature of 65-70 DEG C; and that the ultrafine platinum nano-wire is obtained by adding a chloroplatinic acid solution into the above insulin fiber suspension, fully blending the mixture, incubating the mixture for 10-20 h in a shaking table at the temperature of 4-10 DEG C and with the rotating speed of 50-100 r / min, dropwise adding a sodium borohydride reductant solution with a concentration of 5-10 mM into the mixture, and vibrating the mixture for 8-24 h in a shaking table at the temperature of 4-10 DEG C and with the rotating speed of 50-100 r / min to make the mixture fully reacted. The method of the invention has the advantages of a simple process, mild reaction conditions, and good repeatability, and is environment protective and highly efficient. With the method, appearance of the platinum nano-wire has no obvious changes while output of the nano-wire increases substantially. Thus, the nano-wire is provided with higher aspect ratio and simpler regulation and control method of output, thereby being easier to realize large-scale production.

The invention discloses a preparation method of nanometer low-silver-content back silver conductor paste for crystalline silicon solar application. The method comprises the following steps of silver powder preparation, organic carrier preparation and nanometer silver conductor paste preparation. In silver powder preparation, a saturated silver nitrate and PVA mixed solution is added dropwise into a sodium borohydride solution, then water bath stirring is conducted, centrifugation, alcohol washing and low-temperature negative-pressure drying are conducted, and then silver powder with the grain size being 1 nm-100 nm can be obtained. According to the preparation method, the self-made nanometer silver powder is used for replacing micro-sized silver powder in existing back silver conductor paste, so that the conductive performance, the printing performance and the crystalline silicon substrate adhesion performance of the paste are changed, and application of the back silver conductor paste in crystalline silicon solar energy is greatly expanded; in addition, according to the method, the adding amount of the silver powder is greatly reduced, existing paste production equipment is used in the preparation process, extra new investment is not needed, environment protection is facilitated, and use of the precious metal silver is reduced.

The invention belongs to the technical field of medicament synthesis, and in particular relates to a chemical synthetic method of hydroxytyrosol. The chemical synthetic method comprises the steps of (1) protecting two phenolic hydroxyl groups of catechol by using dichloromethane, and enabling catechol to react with dichloromethane to prepare 1,2-methylenedioxybenzene; (2) enabling 1,2-methylenedioxybenzene to react with various monoesters of oxalyl chloride to prepare 3,4-methylenedioxy phenylglyoxylic acid ester; (3) preparing 3,4-methylenedioxy phenylacetic acid by using 3,4-methylenedioxy phenylglyoxylic acid ester through a Wollff-kishner-Huang Minglong reduction reaction; and (4) reducing the 3,4-methylenedioxy phenylacetic acid by using lithium aluminum hydride, lithium borohydride or sodium borohydride to prepare 3,4-methylenedioxy phenethyl alcohol, and then removing methylene protection of the 3,4-methylenedioxy phenethyl alcohol by using boron tribromide or palladium on activated carbon to prepare hydroxytyrosol. A reactive reagent used in the synthetic method disclosed by the invention is easy to obtain and low in price, the reaction condition is mild, and the final yield of the whole reaction is 23%.

The invention provides a preparation method of a carbon sphere loaded nanoscale zero valent iron composite material. The method comprises: (1) preparing carbon spheres containing hydrophilic functional groups (-OH, -COOH) by a hydrothermal method; (2) chelating iron ions and the functional groups by soaking; (3) finally, dropping potassium borohydride or sodium borohydride solution into carbon sphere mixed solution with the iron ions, and forming the carbon sphere loaded nanoscale zero valent iron composite material by a strong reducing effect. The material prepared by the preparation method provided by the invention not only simultaneously has an adsorption effect of the carbon spheres and the strong reducing effect of nanoscale zero valent iron, but also can form a micro primary cell between the iron and carbon; not only are the problems of clustering and the like of nanoscale zero valent iron particles solved, but also electron transfer is reinforced and a degrading effect on polluted waste water is promoted; the method provided by the invention is low in cost and simple to operate, and the nano particles have high dispersity and stability.

The present invention is a preparation method of gold nanorods whose length-to-diameter ratio can be adjusted in a large range. The strong reducing agent sodium borohydride reduces tetrachloroauric acid to obtain gold seed solution; the preparation of growth solution: prepare the mixed solution of hexadecyltrimethylammonium bromide, tetrachloroauric acid and silver nitrate, and the mol ratio of the three is 20:1:0.1~20:1:5, add crotonic acid solution to obtain a growth solution; growth of gold nanorods: inject gold seed solution into the growth solution, react for 6-12 hours, and obtain gold nanorods. The invention adopts crotonic acid as growth solution modifier, and solves the biological toxicity and biological modification problems caused by CTAB. The yield of the short-length-diameter ratio gold nanorods prepared can be as high as about 90%, the size distribution is narrow, and the length-diameter ratio is about 1.92. The aspect ratio of the prepared gold nanorods can be adjusted in a wide range from 1.9 to 7.5.

A preparation method of graphene coated silica nanotube composite negative electrode material for lithium ion batteries is as follows: (1) dispersing zinc oxide nanorods to an ethanol solution, sequentially adding water, ammonia water and a TEOS solution to obtain zinc oxide / silica core-shell nanorods; (2) dispersing the products from the step (1) in to an aqueous solution of sodium chloride, and adding PDDA for modification; (3) dispersing the products from the step (2) and the graphene oxide into an aqueous solution, dropwise adding sodium borohydride to obtain graphene coated zinc oxide / silica core-shell nanorods; and (4) dispersing the products obtained from the step (3) in an excessive amount of acid solution to dissolve zinc oxide nanorods, so as to obtain the composite negative electrode material. According to the invention, zinc oxide nanorods are used as templates, and coated by silicon dioxide and graphene, and then the template is removed, so as to prepare the graphene coated silica nanotube composite material. The prepared composite material has the performances of high discharge capacity, long cycle life and high rate capability.

Provided is preparation of a water-soluble luminous silver nano cluster with double-stranded DNA as a template. Firstly, single-stranded DNA rich in cytosine base group is used, 6 cytosine base group loops are reserved in the single-stranded DNA, the total number of the cytosine base groups is 29, single-stranded DNA rich in guanine base group complements the single-stranded DNA and is added, the total number of the guanine base groups is 23, the double-stranded DNA with the 6 cytosine base group loops is formed through the annealing function and is used as the template, and synthesis is achieved through the method of adding sodium borohydride to restore silver nitrate. The preparation process is simple, easy to implement and environmentally friendly, and the preparation can be applied to the preparation of other luminous nano materials. In addition, new nano materials synthesized through the method have water solubility, a high quantum yield, light stability, good biocompatibility and other performance, and have potential wide application to the fields of biosensors, cell imaging, clinical medicine and the like.