KR101449643B1 - Fabrication Method of Metal Oxide Nanotube - Google Patents

Abstract

A method for producing a metal oxide nanotube according to the present invention comprises the steps of: a) forming a nanowire, a metal oxide precursor, a C1-C5 Preparing a mixed solution containing a lower alcohol and water; b) hydrothermally reacting the mixed solution to produce a nanowire-metal oxide nanotube composite having a metal oxide layer on the surface of the nanowire; And c) removing the nanowires of the nanowire-metal oxide nanotube composite to produce a metal oxide nanotube.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a metal oxide nanotube,

The present invention relates to a method for producing metal oxide nanotubes, and more particularly, to a method for mass-producing metal oxide nanotubes of high quality in a short time by an extremely easy method.

Nanostructured metal oxides have characteristics of high integration, high sensitivity, and high selectivity, and various studies have been attempted to utilize semiconductor metal oxides in electric and optical fields. For example, ZnO, TiO2, SnO ₂ and the like, depending on the like having a wide band gap, the light transmittance, electrical conductivity, and the piezoelectric property superior, luminous material, solar cells, gas sensors, bio / chemical sensors, UV laser, LED, electroluminescent An effect transistor, an active material of a secondary battery, and the like.

As disclosed in Korean Patent Publication No. 2005-0006635, metal oxide nanotubes are manufactured using vapor deposition or synthesis. When vapor deposition or synthesis is used, a high-quality nano structure can be obtained, but energy consumption is high, process control is difficult, and large area processing or mass production is difficult.

Korea Patent Publication No. 2005-0006635

The present invention enables the production of metal oxide nanotubes having long and short axial ratio, high quality metal oxide nanotubes with uniform tube wall thickness, and mass production of high quality metal oxide nanotubes by a simple and easy method And to provide a manufacturing method capable of improving productivity.

The method for producing a metal oxide nanotube according to the present invention comprises the steps of: a) mixing a nanowire, a metal oxide precursor, a lower alcohol of C1-C5 and water in which a magnetically-bonded monolayer of a linker compound is formed to prepare a mixed solution; b) hydrothermally reacting the mixed solution to produce a nanowire-metal oxide nanotube composite having a metal oxide layer on the surface of the nanowire; And c) removing the nanowires of the nanowire-metal oxide nanotube composite to produce a metal oxide nanotube.

In the method of manufacturing a metal oxide nanotube according to an embodiment of the present invention, the nanowire may be selenium nanowire.

A method for preparing a metal oxide nanotube according to an embodiment of the present invention includes the steps of: a) adding a linker compound containing a thiol group and containing a hydroxyl group or a carboxyl group to a nanowire- And preparing a nanowire having a self-assembled monolayer of a linker compound providing a site of chemisorption of the metal oxide precursor.

In the method of manufacturing a metal oxide nanotube according to an embodiment of the present invention, the metal of the metal oxide precursor may be at least one selected from the group consisting of Sn, Zn, and Ti, and the metal oxide precursor may include metal alkoxide, Halide, metal oxysulfate, and their hydrates.

In the method of manufacturing a metal oxide nanotube according to an embodiment of the present invention, the hydrothermal reaction may be performed at a temperature of 110 to 130 ° C.

In the method for manufacturing a metal oxide nanotube according to an embodiment of the present invention, in the step c), the nanowire is thermally sublimated

Lt; / RTI >

In the method of manufacturing a metal oxide nanotube according to an embodiment of the present invention, in the step a), a metal oxide precursor is mixed with a dispersion of a C1-C5 lower alcohol in which a nanowire having a self- Mixing a precursor body fluid dissolved in a lower alcohol, and then adding water to the mixture of the dispersion and the precursor body fluid.

In the method of manufacturing a metal oxide nanotube according to an embodiment of the present invention, when the dispersion and the precursor solution are mixed, 5 to 30 mu Mole of metal oxide precursor may be mixed with 1 g of the nanowire.

In the method for producing a metal oxide nanotube according to an embodiment of the present invention, the volume ratio of the lower alcohol to the precursor body fluid may be 1: 0.05 to 0.2.

The manufacturing method according to the present invention is advantageous in that various metal oxide nanotubes can be mass-produced by an extremely easy method, and a metal oxide nanotube having a long length and a very uniform thickness can be manufactured And there is an advantage of having excellent productivity.

1 (a) and 1 (b) are SEM micrographs of selenium nanowires produced in the production example. Fig. 1 (c) is a transmission electron microscope photograph of selenium nanowires. The results of EDX (Energy Dispersive X-ray microanalysis) analysis of nanowires.
2 is a Fourier Transform Infrared Spectroscopy (FT-IR) analysis result of the selenium nanowire produced in the production example.
FIG. 3 (a) is a scanning electron microscopic (SEM) image of a product produced by hydrothermal reaction in Example 1, and FIG. 3 (b) ray microanalysis.
4 (a) shows the result of X-ray crystallization of the titanium oxide nanotube prepared in Example 1, and FIG. 4 (b) shows the result of EDX analysis of the titanium oxide nanotube prepared in Example 1 will be.
5 is a scanning electron microscope (SEM) image of the titanium oxide nanotube prepared in Example 1. Fig.
6 is a transmission electron microscope photograph of the titanium oxide nanotube manufactured in Example 1. FIG.
7 (a) is a scanning electron microscope (SEM) image of a product produced by a hydrothermal reaction in Example 2, and FIG. 7 (b) is a scanning electron microscopic image of tin oxide nanotubes prepared in Example 2 .
8 is a graph showing the X-ray diffraction pattern (FIG. 8 (a)), the EDX analysis result (FIG. 8 (b)), and the transmission electron microscope photograph (d)).
9 (a) and 9 (b) are a scanning electron micrograph (FIG. 9 (a)) and an EDX analysis result (FIG. 9 (b)) observing the product produced by the hydrothermal reaction in Example 3, (c) and (d) are scanning electron micrographs (FIG. 9 (c)) and EDX analysis results (FIG. 9 (d)) of the zinc oxide nanotubes prepared in Example 3.

Hereinafter, a method of manufacturing the metal oxide nanotube of the present invention will be described in detail with reference to the accompanying drawings. Hereinafter, the technical and scientific terms used herein will be understood by those skilled in the art without departing from the scope of the present invention. Descriptions of known functions and configurations that may be unnecessarily blurred are omitted.

The method for producing a metal oxide nanotube according to the present invention comprises the steps of: a) preparing a mixed solution containing a nanowire having a self-bonding monolayer of a linker compound, a metal oxide precursor, a lower alcohol of C1-C5, and water; b) hydrothermally reacting the mixed solution to produce a nanowire-metal oxide nanotube composite having a metal oxide layer on the surface of the nanowire; And c) removing the nanowires of the nanowire-metal oxide nanotube composite to produce a metal oxide nanotube.

The method for preparing a metal oxide nanotube according to the present invention uses hydrothermal synthesis to produce a metal oxide nanotube. According to the present invention, metal oxide nanotubes can be synthesized using hydrothermal synthesis, and can be synthesized under relatively relaxed process conditions compared to gas phase synthesis such as atomic layer deposition (ALD) or chemical vapor deposition (CVP) Also, it is economical and economical, and it is possible to mass-produce metal oxide nanotubes through a low-temperature process in a short time and commercialize them.

In the production of metal oxide nanotubes by hydrothermal synthesis, homogeneous nucleation of the metal oxide during hydrothermal synthesis is required to uniformly form the wall (tube wall) thickness of the metal oxide nanotube and form a dense wall, And to prevent non-uniform heterogeneous nucleation of the metal oxide at the nanowire surface.

As described above, in the method for preparing a metal oxide nanotube according to the present invention, after hydrothermal reaction is performed with a mixed solution containing a nanowire having a self-bonding monolayer of a linker compound formed thereon and a metal oxide precursor, Can be produced.

The nanowire is a template for the production of metal oxide nanotubes. The metal oxide precursor is spontaneously uniform and homogeneous on the surface of the nanowire as the monolayer of the linker compound is bonded to the surface of the nanowire To enable homogeneous heterogeneous nucleation of the metal oxide.

That is, the linker compound forming the self-assembled monolayer may comprise a monovalent group that spontaneously chemically bonds with the nanowire and another monovalent group that spontaneously chemically bonds with the metal oxide precursor. The metal oxide precursor is uniformly and homogeneously chemisorbed onto the template nanowire surface by bonding with the other one end group of the linker compound bonded to the nanowire surface and is uniformly deposited on the surface of the nanowire by the hydrothermal reaction To form a dense metal oxide layer.

In addition, in the case of preparing metal oxide nanotubes by hydrothermal synthesis of the nanowires and metal oxide precursors formed with the self-bonding monolayer of the linker compound, the metal oxide precursor can be bonded to the surface of the nanowire by the linker compound, The amount of the metal oxide precursor can be reduced and the amount of the metal oxide precursor can be controlled by adjusting the amount of the metal oxide precursor to form the metal oxide nanotube The tube wall thickness can be easily controlled. That is, since the metal oxide precursor is bonded to the surface of the nanowire by the self-bonding monolayer of the linker compound, nucleation of the metal oxide is generated uniformly and homogeneously on the surface of the nanowire by the hydrothermal reaction, According to the amount of the precursor, the degree of growth of the generated nuclei can be controlled, and the thickness of the tube wall of the metal oxide nanotube can be easily controlled.

 In the method of manufacturing a metal oxide nanotube according to an embodiment of the present invention, the nanowire is characterized by being selenium nanowire.

Specifically, a method for producing a metal oxide nanotube according to an embodiment of the present invention includes the steps of: a1) mixing a selenium nanowire, a metal oxide precursor, a lower alcohol of C1-C5, and water, in which a magnetically bonded monolayer of a linker compound is formed, Producing; b1) preparing a selenium nanowire-metal oxide nanotube composite having a metal oxide layer on the surface of the selenium nanowire by hydrothermal reaction of the mixed solution; And c1) removing the selenium nanowire of the selenium nanowire-metal oxide nanotube composite to produce a metal oxide nanotube.

When metal oxide nanotubes are produced in the form of nanotubes which are hollow one-dimensional nanostructures due to the brittle characteristic inherent to metal oxides, the physical strength thereof is weak and the risk of breakage in the manufacturing process is very high. Due to the inherent properties of the metal oxide, the productivity is inevitably reduced. By using selenium nanowires as a template, it is possible to prevent such metal oxide nanotubes from being damaged by a physical impact during the manufacturing process. Since selenium of the selenium nanowire can spontaneously bind to sulfur, a self-bonding monolayer having a thiol group as a terminal group can be easily and stably formed. In addition, it has an excellent strength in comparison with an organic material such as a polymer, has a very low Young's modulus and hardness, and is not easily broken by physical impact, and can be removed by thermal sublimation at an extremely low temperature.

In particular, by using the selenium nanowire as a template, the productivity and quality of the metal oxide nanotube can be improved by being able to be removed by thermal sublimation at an extremely low temperature, specifically at a temperature of 150 ° C or higher.

Specifically, when a selenium nanowire core and a metal oxide sheath core-sheath composite (corresponding to the nanowire-metal oxide nanotube composite described above) are formed by hydrothermal synthesis, crystals of a metal oxide forming a sheath For the production of metal oxide nanotubes with poor properties, no desired crystal phase, or higher strength, subsequent heat treatment for crystallization of metal oxide particles, crystal growth of metal oxide particles and / or densification may be performed .

In a manufacturing method according to an embodiment of the present invention, when the template is a selenium nanowire, the selenium nanowire can be thermally sublimated and removed in this subsequent heat treatment step. That is, in one embodiment of the present invention, by using the selenium nanowire as a template, metal oxide nanotubes can be produced without performing a separate step for removing the template.

That is, the step of removing nanowires in step c) may be a step of removing by thermal sublimation, and crystallization, crystal growth and / or densification of the metal oxide may be performed at the same time during the heat treatment for removing the selenium nanowire.

More specifically, by heat treating the selenium nanowire core and the metal oxide sheath core-sheath composite, the selenium nanowire is removed by thermal sublimation and the crystallinity and / or strength of the metal oxide is enhanced . Accordingly, a method for preparing a metal oxide nanotube according to an embodiment of the present invention includes: a1) mixing a selenium nanowire, a metal oxide precursor, a lower alcohol of C1-C5, and water, in which a self-bonding monolayer of a linker compound is formed, Producing; b1) preparing a selenium nanowire-metal oxide nanotube composite having a metal oxide layer on the surface of the selenium nanowire by hydrothermal reaction of the mixed solution; And c1) heat treatment of the selenium nanowire of the selenium nanowire-metal oxide nanotube composite to remove selenium nanowire by thermal sublimation, and simultaneously crystallization, crystal growth and densification of the metal oxide nanotube are performed; . ≪ / RTI >

Further, according to one embodiment of the present invention, by using selenium nanowire as a template, the diameter and length of a desired metal oxide nanotube can be extremely easily controlled. Specifically, the selenium nanowire comprises i) a selenium nanowire comprising: adding a reducing agent to a selenium precursor solution containing a selenium oxide compound; ii) recovering and washing the product of step i); And iii) aging the washed product by dispersing it in a C1-C5 lower alcohol.

That is, the selenium nanowire can be prepared by an extremely simple method of dissolving selenium oxide compound only, adding a reducing agent to obtain a primary product, and dispersing and mulling the obtained primary product into a lower alcohol, and i) To (iii) can all be carried out at room temperature.

As described above, the selenium nanowire can be manufactured through an extremely simple room temperature process. The diameter of the nanowire can be controlled by controlling the reaction temperature, and the length of the nanowire can be controlled by controlling the reaction time have. As the diameter and length of the selenium nanowires can be controlled very easily, the size (tube diameter and length) of the desired metal oxide nanotubes can also be very easily controlled when the selenium nanowires are used as templates.

A specific method of producing the selenium nanowire may be a conventional method based on the manufacturing steps of i) to iii). As a non-limiting, specific example, the selenium oxide compound may be one or more selected from selenium dioxide, selenic acid, aselenic acid, and sodium selenite, and the solvent of the selenium precursor solution may be water. The reducing agent may be an ascorbic acid which is soluble in water and provides a high reducing power. Stirring may be carried out in step i), and the washing of the product may be carried out using water, a lower alcohol of C1-C5 or a mixture thereof, and the temperature at the time of washing may also be room temperature. The C1-C5 lower alcohol used in the washing and iii) dispersion of the step may comprise ethanol, and the aging step may be carried out in a dark room for 0.5 to 2 days.

Metal oxide nanotubes are easily crushed, making the nanotubes a blended paste and shortening the length of the paste. Se nanowire templates increase the hardness of the material, making it easy to form and paste nanowires with desired lengths. It is very advantageous to construct a device of a long metal oxide material since the Se mold can be easily removed in a simple heat treatment process after application. In the case of the organic mold, the electrical properties of the material can be lowered by the residual carbon due to the high temperature heat treatment in order to remove the mold. However, since the Se mold is sublimated at a low temperature, it is easily removed without leaving residue.

As described above, when the template is a selenium nanowire, the nanowire having the self-bonding monolayer of the linker compound may be prepared by adding a linker compound containing a thiol group and containing a hydroxyl group or a carboxy group into a dispersion in which nanowires are dispersed, And preparing a nanowire having a self-assembled monolayer of a linker compound to provide a place for chemisorption of the metal oxide precursor.

As described above, the linker compound contains a thiol group so as to uniformly form a monomolecular film by self-assembly on the surface of the selenium nanowire, and a compound containing a hydroxyl group or a carboxyl group so as to chemically bond with the metal oxide precursor by chemical reaction . ≪ / RTI >

More specifically, the linker compound may be an organic compound whose one terminal group is a thiol group and the other terminal group is a hydroxyl group or a carboxyl group. For example, a thiol group is formed at one end of an aromatic or aliphatic organic chain, and a hydroxyl group Or an organic compound having a carboxyl group formed thereon. As a more specific example, the linker compound may be a carboxylic acid containing a thiol group. As a practical example, the linker compound may be one or both of 2-mercaptoethanol, thioglycolic acid, mercaptopropionic acid and mercaptobenzoic acid. The above selected materials can be used.

In the production of nanowires with a self-assembled monolayer of linker compounds, the amount of linker compound that is incorporated into the dispersion of nanowires, characteristically, the selenium nanowires, may be such that a self-assembled monolayer of linker compound It is enough if there is. That is, the amount of the linker compound to be added to the dispersion may be at least the amount of the linker compound required when the monolayer of the linker compound is formed in the entire area of the surface of the nanowire. The linker compound-containing solution may contain a linker compound at a concentration of 1 to 50 mM, and 0.1 to 10 mmole of the linker compound per 1 g of the selenium nanowire may be mixed So that the linker compound-containing solution and the selenium nanowire dispersion can be mixed. Linker compound and a selenium nanowire dispersion, followed by stirring, and stirring may be performed by ultrasonic application. At this time, the solvent of the linker compound-containing solution can be used as long as it dissolves the linker compound and has compatibility with the dispersion medium of the selenium nanowire dispersion. As an example, the solvent of the linker compound-containing solution may include C1 to C5 lower alcohol, and C1 to C5 lower alcohol may include ethanol.

Further separation and recovery of the nanowires with the self-bonding monolayer of the linker compound through mixing with the linker compound and application of ultrasonic waves and / or washing of the remaining linker compound not associated with the nanowire may be performed .

The separation of selenium nanowires having a self-assembled monolayer can be performed by centrifugation, and the washing step may be performed by mixing C1 to C5 with a lower alcohol and repeating separation of the nanowires.

 Thereafter, step (a) of producing a mixed solution containing a nanowire having a self-bonding monolayer of a linker compound, a metal oxide precursor, a lower alcohol of C1-C5 and water can be carried out.

Specifically, a mixed solution may be prepared by mixing a metal oxide precursor-containing solution and a nanowire dispersion solution having a magnetic-binding monolayer formed thereon, bonding the metal oxide precursor to a magnetic-binding monolayer bonded to the nanowire, and then introducing water. More specifically, a precursor solution in which a metal oxide precursor is dissolved in a lower alcohol of C1-C5 (hereinafter, referred to as a precursor solution of a metal oxide precursor) in which a nanowire having a self-assembled monolayer is dispersed in a C1-C5 lower alcohol Body fluid), and then adding water to the mixture of the dispersion and the precursor body fluid to prepare a mixed solution.

The metal oxide precursor may be a precursor of a metal oxide capable of bonding with a hydroxy group or a carboxyl group of the linker compound. Specifically, when the metal oxide nanotube to be produced is a composite oxide nanotube of a metal selected from two or more of tin oxide nanotubes, titanium oxide nanotubes, zinc oxide nanotubes, lead wires, titanium and zinc, May be one or more selected from tin (Sn), zinc (Zn) and titanium (Ti), and the metal oxide precursor may be one or more selected from alkoxides, acetates, halides, oxysulphates and their hydrates of these metals .

More specifically, the metal oxide precursor can be selected from the group consisting of tin alkoxide, tin acetate, tin halide, tin oxysulfate, zinc alkoxide, zinc acetate, zinc halide, zinc oxysulfate, titanium alkoxide, titanium acetate, titanium halide, titanium oxysulfate, It may be one or more selected from water (hydrate).

The alkoxide of the metal may include butoxide, t-butoxide, methoxide, ethoxide, propoxide, isopropoxide or a mixture thereof, and the halide of the metal may include chloride have.

In one embodiment of the manufacturing method according to the present invention, the mixed solution may contain 5 to 30 mu Moles of metal oxide precursor per 1 g of nanowire. That is, in preparing the mixed solution, 5 to 30 mu Mole of the metal oxide precursor may be added to 1 g of the nanowire of the nanowire dispersion liquid. The number of moles of the metal oxide precursor added to 1 g of the nanowire can be chemically homogeneously and uniformly bound to the nanowire by the linker compound and the tube wall of several to several tens of nanometers can be formed by hydrothermal synthesis At the same time, homogeneous heterogeneous nucleation and growth occurs, which is the number of moles in which homogeneous nucleation of the metal oxide, which causes a partial change in the tube wall thickness, is suppressed. That is, as described above, by forming a linker compound on the nanowire and bonding the metal oxide precursor to the linker compound, metal oxide nanotubes can be prepared by injecting a very small amount of a metal oxide precursor of 5 to 30 mu Mole relative to 1 g of the nanowire Such a very small amount of the metal oxide precursor prevents the homogeneous nucleation of the metal oxide during hydrothermal synthesis and makes it possible to produce metal oxide nanotubes having a uniform and thin wall thickness in the longitudinal direction of the tube.

In order for the metal oxide precursor to be homogeneously and rapidly combined with the nanowire through the linker compound, the metal oxide precursor can be introduced into the nanowire dispersion in a solution state, and a mixed solution can be prepared by dropping the metal oxide precursor solution in the nanowire dispersion have. When the metal oxide precursor body fluid is dispensed, at this time, stirring may be performed when the metal oxide precursor fluid is dispensed into the nanowire dispersion.

The molar concentration of the metal oxide precursor in the metal oxide precursor body fluid may be 1 mM to 10 mM, but it is needless to say that the molarity of such metal oxide precursor can be adjusted in consideration of the production scale. The solvent of the metal oxide precursor body fluid can be used as long as it is a solvent having miscibility with the dispersion medium of the nanowire dispersion. As an example, the solvent of the metal oxide precursor fluid may be a C1 to C5 lower alcohol comprising ethanol, and the dispersion medium of the nanowire dispersion may be a C1 to C5 lower alcohol having ethanol independently of the solvent of the metal oxide precursor fluid .

After the metal oxide precursor and the nanowire are mixed, water for hydrothermal synthesis may be introduced. At this time, a mixture of the lower alcohol of the mixture of the nanowire dispersion and the metal oxide precursor body fluid (the lower alcohol of the dispersion and the lower Total volume of alcohol): The volume ratio of added water may be 1: 0.05 to 0.2. The amount of water added is an amount that can control the pressure during the hydrothermal synthesis in the closed reactor and cause a hydrolysis reaction of the metal oxide precursor.

Thereafter, the nanotube-metal oxide nanotube composite having the metal oxide layer formed on the surface of the nanowire may be subjected to a hydrothermal reaction. The mixed solution may be charged into a closed reactor such as an autoclave, and the hydrothermal reaction may be carried out at 110 to 130 ° C for 5 to 20 hours.

After the hydrothermal reaction is completed, the nanowire-metal oxide nanotube composite can be washed and dried, and the complex can be washed by mixing the complex with the C1-C5 lower alcohol containing ethanol, Method. ≪ / RTI >

After the nanowire-metal oxide nanotube composite is prepared by hydrothermal synthesis, the nanowire of the composite may be removed to produce the metal oxide nanotube. At this time, as described above, the selenium nanowire By use, the nanowire can be removed by thermal sublimation.

 According to an embodiment of the present invention in which the nanowire is a selenium nanowire, the step (c) of removing the nanowire may be a step of heat treating the complex. By this single heat treatment, the sublimation of the selenium nanowire With the removal, the crystallization, crystal growth and / or densification of the metal oxide constituting the nanotube can be performed at the same time.

 The heat treatment of the composite may be carried out at a temperature of from 150 DEG C to 600 DEG C in an oxygen-containing atmosphere, specifically atmospheric pressure in air. When selenium is thermally sublimed in the gaseous phase and the selenium nanowire can be easily removed, if the heat treatment temperature is more than 150 ° C, in view of improving the crystallinity and / or increasing the physical strength (densification) of the metal oxide nanotube, The heat treatment temperature may be performed at a temperature of 300 ° C to 600 ° C. At this time, when the heat treatment of the composite is performed at a high temperature exceeding 600 ° C, there is a risk that the metal oxide nanotubes are damaged by partial pressure generated by the selenium gas. When a plurality of composites are heat- There is a risk of binding metal oxide nanotubes to each other.

Hereinafter, the present invention will be described in more detail based on practical production examples, but the present invention is not limited to these production examples.

(Production example)

Manufacture of selenium nanowires

Sodium ascelenate (0.5 g) was added to distilled water (50 ml) and stirred for 10 minutes to prepare an aqueous solution of sodium ascelenate. To the aqueous solution of sodium ascelenate, ascorbic acid (50 ml, 0.025 M) was added and stirred continuously for 30 minutes. The product was then recovered by centrifugation and washed with distilled water and ethanol. The washed product was redispersed in ethanol and then aged in a dark room for one day in a non-crosslinked state to prepare selenium nanowires.

FIG. 1 (a) and FIG. 1 (b) are SEM micrographs of the selenium nanowires, and FIG. 1 (c) is a transmission electron micrograph of the selenium nanowires. As can be seen from FIG. 1, it can be seen that a selenium nanowire having a length of several tens of micrometers is produced, and a selenium nanowire having a diameter of 80 ± 10 nm is produced.

FIG. 1 (d) shows that pure selenium was detected except for copper and coated carbon components used as a grid, as a result of EDX (Energy Dispersive X-ray microanalysis) analysis of the selenium nanowire.

(Example 1)

10 ml of an ethanol solution in which 3-mercaptopropionic acid was dissolved at a concentration of 10 mM was added to a dispersion in which 0.02 g of selenium nanowire prepared in Preparation Example was dispersed in 15 ml of ethanol, and then ultrasonic waves were applied for 5 minutes. Selenium nanowires were recovered by centrifugation (3300 rpm, 10 minutes) after standing at room temperature for 12 hours after the application of ultrasonic waves, and washed three times with ethanol.

FIG. 2 shows FT-IR (Fourier Transform Infrared Spectroscopy) analysis results of recovered and washed selenium nanowires. As can be seen in FIG. 2, the selenium nanowires were surface-functionalized with 3-mercaptopropionic acid it can be seen that in more detail, by the OH stretching of carboxyl group may be light absorbing to know seen in 3100 and 3500cm ^-1, 3- mercapto-propionic the absorption at 2927cm ^-1 by the stretching of the CH acid can be seen to appear The absorption peaks appear at 1400 and 1550 cm ^{-1 due} to the stretching vibration of the carboxy group. The absorption peaks (2550 to 2670 cm ^-1 ) due to SH are not shown, and the surface Se of the thiol and selenium nanowires It can be seen that an interatomic bond is formed.

0.02 g of the selenium nanowire having the self-assembled monolayer of 3-mercaptopropionic acid prepared above was dispersed in 15 ml of ethanol to prepare a dispersion (nanowire dispersion). To the nanowire dispersion was added 4 ml of a metal oxide precursor solution in which titanium (IV) butoxide was dissolved in ethanol at a molar concentration of 4 mM, while agitating the nanowire dispersion. After stirring for 30 minutes, 2 ml of deionized water was mixed with the dispersion of the nanowire into which the metal oxide precursor fluid was added to prepare a mixed solution. The prepared mixed solution was charged into an autoclave, and subjected to a hydrothermal reaction at a temperature of 120 ° C for 12 hours.

After the reaction was completed, the reaction product was washed with ethanol four times, and then dried in vacuum. The dried product was heat-treated at a temperature of 500 ° C in normal pressure air for 3 hours to prepare a titanium oxide nanotube.

FIG. 3 (a) is a scanning electron microscopic (SEM) image of the product produced by the hydrothermal reaction, and FIG. 3 (B) is the result of EDX (Energy Dispersive X-ray microanalysis) analysis of the hydrothermal reaction product. From FIG. 3 (a), it was confirmed that a nanowire-shaped product having a diameter of 100 nm was obtained. As a result of the analysis of FIG. 3 (b), Ti and O were detected together with Se. From this, it can be seen that a composite of selenium nanowire core-titanium oxide sheath is produced by hydrothermal synthesis.

Fig. 4 (a) shows the result of X-ray crystallization of the titanium oxide nanotube obtained by the heat treatment, and Fig. 4 (b) shows the result of EDX analysis of the titanium oxide nanotube obtained by the heat treatment. 4 (a), it was confirmed that titanium oxide (TiO ₂ ) nanotubes having an anatase phase of tetragonal was produced. From FIGS. 4 (a) and 4 (b), it was found that selenium nanowires were completely removed by heat treatment Respectively.

FIG. 5 is a scanning electron microscope (SEM) image of the titanium oxide nanotube. It can be seen that the nanotube has a length of several to several tens of micrometers and the thickness of the tube is kept very uniform.

6 is a transmission electron micrograph ((a) and (b)) and a high magnification transmission electron micrograph (HR-TEM, (c) and (d)) of the produced titanium oxide nanotube, ± 10 nm. The HR-TEM image shows that the tube walls of the nanotubes are densely and uniformly formed with the titanium oxide crystal grains of about 6 nm, and the titanium oxide grains are formed in the tetragonal It can be seen that it has an anatase phase.

(Example 2)

Conducted in Example 1 except that the input to SnCl ₄ · 5H ₂ O in a molar concentration of 4mM in the nanowire dispersion is added dropwise to the metal oxide bulb body fluid 4ml dissolved in ethanol, and that of Example 1, Method A be the same, tin oxide Nanotubes were prepared.

7 (a) is a scanning electron microscope (SEM) image of a complex of a product selenium nanowire core-tin oxide sheath produced by hydrothermal reaction, and Fig. 7 (b) A scanning electron micrograph of the tube.

8 shows the X-ray diffraction pattern (FIG. 8 (a)), the EDX analysis result (FIG. 8 (b)), and the transmission electron microscope photograph (FIG. 8 (c) As a result of X-ray analysis, it was confirmed that SnO ₂ having a tetragonal structure was produced. As a result of EDX analysis, it was confirmed that pure tin oxide was detected. Transmission electron microscopic observation revealed that tin oxide nanotubes having a diameter of 100 nm and a thickness of several to several tens of micrometers were produced.

(Example 3)

The same procedure as in Example 1 was carried out except that 4 ml of the metal oxide precursor solution in which Zn (CH ₃ COO) ₂ .2H ₂ O was dissolved in ethanol at a molar concentration of 4 mM was added to the nanowire dispersion in Example 1 Zinc oxide nanotubes were prepared.

9 (a) and 9 (b) are scanning electron micrographs and EDX analysis results of a composite of a selenium nanowire core-zinc oxide sheath, which is a product produced by a hydrothermal reaction, Shows scanning electron micrographs and EDX analysis of zinc oxide nanotubes from which selenium nanowires have been removed by heat treatment. 9 (a) and 9 (b), it can be seen that the entire surface of the selenium nanowire is surrounded by a uniform thickness of the zinc oxide, and through 9 (c) and (d), the diameter is about 100 nm, It can be seen that pure zinc oxide nanotubes having a length of several tens of micrometers are produced.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Those skilled in the art will recognize that many modifications and variations are possible in light of the above teachings.

Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

Claims (9)

a) a self-assembled monolayer of a linker compound providing a site for chemisorption of a metal oxide precursor by applying a linker compound containing a thiol group and containing a hydroxyl group or a carboxy group to a dispersion in which selenium nanowires are dispersed, Preparing a mixed solution containing a selenium nanowire, a metal oxide precursor, a C1-C5 lower alcohol, and water, wherein the self-bonding monolayer of the linker compound is formed, after the selenium nanowire is formed;
b) hydrothermally reacting the mixed solution to produce a nanowire-metal oxide nanotube composite having a metal oxide layer on the surface of the selenium nanowire; And
c) removing the selenium nanowire of the nanowire-metal oxide nanotube composite to produce a metal oxide nanotube;
Wherein the metal oxide nanotube is a metal oxide nanotube. delete delete The method according to claim 1,
Wherein the metal of the metal oxide precursor is at least one selected from the group consisting of Sn, Zn and Ti, and the metal oxide precursor is at least one metal oxide nanotube selected from metal alkoxides, metal acetates, metal halides, metal oxysulfates, ≪ / RTI & The method according to claim 1,
Wherein the hydrothermal reaction is performed at a temperature of 110 to 130 ° C. The method according to claim 1,
Wherein the selenium nanowire is removed by thermal sublimation in the step c). 6. The method of claim 5,
The mixed solution of step a) may be prepared by mixing a selenium nanowire dispersion in which a magnetically bonded monolayer having selenium nanowires in which the magnetic bond monolayer of the linker compound is formed is dispersed in a lower alcohol of C1-C5, And then adding water to the mixture of the selenium nanowire dispersion having the magnetically bonded monolayer formed thereon and the precursor body fluid. 8. The method of claim 7,
Wherein the metal oxide precursor is mixed with 5 to 30 mu Mole of metal oxide precursor per gram of selenium nanowire when the selenium nanowire dispersion having the self-assembled monolayer is formed and the precursor body fluid are mixed. 9. The method of claim 8,
Wherein the volume ratio of the lower alcohol: water to be added to the mixture of the selenium nanowire dispersion in which the magnetically bonded monolayer is formed and the precursor fluid is 1: 0.05 to 0.2.

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