KR100721814B1 - Pd-doped silica nanotube and a manufacturing method thereof - Google Patents

Abstract

The present invention relates to a double layered silica nanotube doped with palladium by reacting silica and palladium after preparing a template using an organic compound, and more specifically, hydrogen and other gas molecules such as nitrogen, argon, carbon dioxide, and methane are stored. In order to prepare nanotubes useful for the preparation of palladium-doped silica nanotubes, the organic compound used as a gel-forming agent is added to an organic solvent or a mixture of an organic solvent and an aqueous solution to prepare a mold, and then doped with palladium and silica. It is about a method.

Palladium (Pd), Silica Nanotubes

Description

Pd-doped silica nanotube and a manufacturing method thereof

1a and 1b are SEM images of palladium doped double layer silica nanotubes of the present invention.

FIG. 2 shows the results of element mapping of the nanotubes of Example 2 using electron energy-loss spectroscopy (EELS). FIG. A is the measurement of the whole nanotube, B is the result of mapping Si, C for oxygen, and D for Pd.

Figure 3 is a graph measuring the hydrogen storage capacity of the nanotubes of Examples 1 to 3.

The present invention relates to a silica nanotube doped with palladium by reacting silica and palladium after preparing a mold using an organic compound. More specifically, an organic compound used as a gel-forming agent may be added to an organic solvent or a mixture of an organic solvent and an aqueous solution. The present invention relates to a method for producing a palladium-doped silica nanotube which is prepared by adding a mold and doping the palladium and silica thereto.

Nanometer-sized functional materials are widely studied in the field of nanotechnology because of their potential use. Smart tubes capable of recognizing specific complementary molecules are increasingly being recognized for their application to electronics, optics and sensors. In particular, there has been a great deal of interest in nanotube fabrication over the last decade, because of the potential to provide basic principles for representing nanometer-sized wires and devices.

Inorganic porous bodies have molecular selectivity depending on the surface area and pore size, etc., and are used as catalysts, support material adsorbents, chromatography materials, and the like, and new improvements have been attempted. In the production of such porous materials, a method using a mold is mainly used. In other words, an inorganic porous body was synthesized using a fibrous or hollow inorganic material or a molecular association of tartaric acid, carbon fiber, or carbon nanotube as a template. In addition, there has been an attempt to manufacture various types of inorganic materials by using biological materials as a template (Japanese Patent Laid-Open No. 2000-220036), and use a cylindrical organic inorganic composite using a self-organized fat tube. Prepared.

Japanese Laid-Open Patent Publication No. 11-319070 relates to a method for producing a spiral metal oxide and a structure in which a metal of a different type from the metal is fixed by using a cholesterol derivative gel having an azacrown ring substituted with a specific functional group as a template. . In addition, Japanese Patent Laid-Open No. 2001-335594 relates to a technique for producing an organic-inorganic composite and a metal oxide using a cholesterol derivative having a hydrogen bonding site as a template, and a metal oxide in a cylindrical or roll paper shape. Was prepared.

As described above, the present invention relates to a technique for forming a metal oxide by forming a metal oxide polymer while polymerizing and crosslinking a sol such as an organic molecule and a metal alkoxide by a catalyst. The composite or metal oxide is manufactured in a fiber shape or a spiral in which a hollow is formed and has a difficulty in controlling to a uniform shape.

In recent years, attempts have been made to various applications such as fuel cells and portable electronic products by electrochemical, magnetic, and chemical properties of precious metal elements such as gold, platinum, luteolin, rhodium, and palladium. Particularly, since palladium among these precious metals has excellent hydrogen adsorption capacity, studies are actively underway to apply them to fuel cells.

Hydrogen has attracted attention as a new energy source to replace fossil fuels in fuel cells and portable electronics because of its clean combustion and high thermal efficiency. Fuel cells and portable electronics must be able to store large amounts of hydrogen at room temperature or at low pressures, and must be small in size, light in weight, and fast in charging for recharging.

However, despite these advantages of hydrogen, practical means for the storage and transportation of hydrogen have not yet been developed. Various materials have been used for hydrogen storage, including metal hydrides, chemical hydrides, carbon nanotube structures and metal-organic structures (MOFs).

Among these, carbon nanostructures are the most widely used to date, but carbon nanostructures have been reported to be unable to store a large amount of hydrogen at room temperature and under proper pressure. Although the hydrogen storage capacity of the carbon nanotubes is about 4 to 8% by weight, the reaction is irreversible, and is possible only under abnormal temperature and pressure, and thus practical application is very low and thus not useful. For example, the adsorption of 8% by weight of hydrogen on carbon nanotubes was observed at 80K, the temperature of liquid nitrogen, but this was measured at very low temperature conditions, so the cost of maintaining the temperature of the storage system was increased. Application is not realistic.

Therefore, in recent years, as a new approach for the production of porous materials, metal-organic structures have attracted much attention because they allow for a more flexible and reasonable design. However, a serious problem of these materials is that they have instability such as deformation or collapse of the structure upon removal of guest such as organic matter.

Korean Patent Laid-Open Publication No. 2005-24430 relates to a noble metal nanotube and a method for manufacturing the same, and to a noble metal nanotube prepared by preparing a reaction mixture with a surfactant, water, and the like and adding light or reducing agent.

In addition, Korean Patent Application Publication No. 2005-4377 relates to a microporous thin film composed of nanoparticles and a method for manufacturing the same, and is formed of nanoparticles of uniform size and maintains high porosity, thereby providing fuel cells, primary or secondary batteries, adsorbents, and the like. The present invention relates to a microporous thin film that can be usefully used in various devices such as a hydrogen storage alloy and a method for manufacturing the same. That is, nanoparticle thin films were prepared by depositing gold, palladium, iridium, ruthenium, tin, molybdenum, and the like as metal sources on a carbon substrate by sputtering. However, since the deposition by sputtering is most efficient when the plane of application is flat, there is a limit in applying it to structures such as nanotubes.

In addition, Korean Patent No. 454820 describes a method for producing alumina nanotubes and uses as a hydrogen storage body, and describes a method for producing alumina nanotubes by hydrothermal synthesis using a surfactant, an alumina precursor, and water as a reactant.

In addition to the prior art, various metal nanostructures have been manufactured by hydrogen storage, but there is no practical use for fuel cells.

Accordingly, the present invention is to provide a method for producing palladium nanotubes having high storage capacity for hydrogen and other gas molecules such as nitrogen, argon, methane or carbon dioxide by using a novel organic compound as a template.

In addition, an object of the present invention is to variously apply the palladium-doped double-wall layer silica nanotubes to the fuel cell catalyst and portable electronic products.

In order to achieve the above object, the present inventors prepared a porous palladium-silica nanotube having a double-wall layer structure using palladium, which is well known for storing hydrogen and other gas components, as a template. It was.

The present invention

Iii) preparing a tubular mold by adding an organic solvent represented by the following Chemical Formula 1 to an organic solvent, an aqueous solution, or a mixed solution of the organic solvent and an aqueous solution;

Ii) doping palladium into the tubular mold by adding Pd (Ac) ₂ solution to the solution prepared in step iii);

And iii) adding colloidal silica to the solution after the step of doping the palladium, followed by calcination, and calcining the palladium-doped silica nanotubes.

In addition, the present invention relates to a method for producing palladium-doped silica nanotubes, characterized in that 1 to 15% by weight of the organic compound of Formula 1 is mixed with respect to the solvent.

Acetonitrile, hexaol, heptanol, heptane or octanol may be used as the organic solvent, and an aqueous solution of acetic acid is preferable.

The present invention also relates to a method for producing palladium-doped silica nanotubes, which comprises adding 1 to 50% by weight of palladium in step ii).

In addition, the present invention relates to a method for producing palladium-doped silica nanotubes, characterized in that 1 to 50% by weight of colloidal silica is added in step iii).

Examples of the colloidal silica include tetraethoxysilane, 1,4-bis (triethoxysilyl) benzene, and 1,3-bis (triethoxysilyl) benzene. (1,3-bis (triethoxysilyl) benzene), (1-naphthyl) triethoxysilane ((1-Naphthyl) triethoxy silane) or triethoxyphenylsilane (triethoxyphenylsilane) and the like can be used.

In addition, the present invention has a unidirectional arrangement having a pore size of 2.0 to 10 nm, doped palladium particles of 1.8 to 6.0 nm, an inner diameter of 160 to 300 nm, and an outer diameter of 200 to 400 nm. Palladium doped silica nanotubes.

The present invention also relates to palladium-doped silica nanotubes, wherein the nanotubes have a double-wall structure.

That is, palladium and silica are adsorbed on the inner surface and the outer surface of the tube mold to form a tube.

Furthermore, the present invention relates to a gas molecule storage body obtained by adsorbing one kind of gas selected from hydrogen, nitrogen, argon, methane or carbon dioxide to palladium-doped silica nanotubes.

Hereinafter, the configuration of the present invention through the embodiment in detail. However, the scope of the present invention is not limited to the examples.

Example  1: palladium is Doped  Silica nanotube manufacturing

As a gel-generator, 30 mg of the organic material of Chemical Formula 1 was added to 900 mg of acetic acid and warmed until the solution became clear. After standing at room temperature for 1 hour at static condition, 13 mg of Pd (Ac) ₂ dissolved in 60 mg of acetic acid was added, which was left at room temperature and static condition overnight. 240 mg of TEOS (tetraethoxysilane) and 120 mg of water were added sequentially, and the mixture was stirred to mix well, and then stored at room temperature and static condition for 5 days.

Palladium (Pd) -doped silica nanoparticles were calcined at 600 ° C. under nitrogen and air conditions to remove the organic material of Formula 1 from the mixture containing the silane compound, and then reduced with Pd ions in an aqueous solution of 30 mg of ascorbic acid. A tube (silica nanotube) was prepared.

Example  2: palladium is Doped  Silica nanotube manufacturing

As a gel-generator, 30 mg of the organic material of Chemical Formula 1 was added to 900 mg of acetic acid and warmed until the solution became clear. This was allowed to stand for 1 hour at room temperature and static conditions, and then 13 mg of Pd (Ac) ₂ dissolved in 60 mg of acetic acid was added, which was then left overnight at room temperature and static conditions. 120 mg of tetraethoxysilane (TEOS) and 60 mg of water were added in this order and stirred to mix well, and then stored at room temperature and static condition for 5 days.

The prepared mixture was calcined at 600 ° C., nitrogen and air conditions to remove compound 1, and then palladium-doped silica nanotubes were prepared by reducing Pd ions with an aqueous solution of 30 mg of ascorbic acid. .

Example  3: palladium is Doped  Silica nanotube manufacturing

As a gel forming agent, 30 mg of the organic material of Chemical Formula 1 was added to 900 mg of acetic acid and warmed until the solution became clear. This was allowed to stand for 1 hour at room temperature and static conditions, and then 13 mg of Pd (Ac) ₂ dissolved in 60 mg of acetic acid was added, which was then left overnight at room temperature and static conditions. 80 mg of tetraethoxysilane (TEOS) and 40 mg of water were added sequentially, and the mixture was stirred to mix well, and then stored at room temperature and static condition for 5 days.

The prepared mixture was calcined at 600 ° C., nitrogen and air conditions to remove compound 1, and then palladium-doped silica nanotubes were prepared by reducing Pd ions with an aqueous solution of 30 mg of ascorbic acid. .

Experimental Example  1: Measure physical properties

Using the nanotubes and the palladium-doped silica nanotubes of Examples 1 to 3 as a control, pore diameter, BET surface area, Langmuir surface area, and pore volume were measured and shown in Table 1 below.

As can be seen in Table 1, the palladium-doped double-layer silica nanotubes of the present invention can be seen that the surface area and the volume of pores are significantly higher than the control. This shows that the nanotubes of the present invention have a high hydrogen storage capacity.

BET surface area (㎡ / g) langmuir surface area (㎡ / g) Pore volume (cm3 / g) Pore size (nm) Control 45.9 62.6 0.15 13.8 Example 1 160.6 218.9 0.36 1.8 Example 2 264.3 440.2 0.40 3.0 ~ 6.2 Example 3 190.3 314.7 0.34 3.0 ~ 6.2

Experimental Example  2: ingredients Mapping (elemental mapping)

The silica nanotubes prepared in Example 2 were measured for elemental and chemical information using electron energy-loss spectroscopy (EELS), and the results are shown in FIG. 2. A is the measurement of the whole nanotube, B is the result of mapping Si, C for oxygen, and D for Pd.

Experimental Example  3: Hydrogen adsorption rate  Measure

The nanotubes of Examples 1 to 3 and pure silica nanotubes not doped with palladium were prepared, and their respective hydrogen adsorption capacities were measured.

It was confirmed that the nanotubes of Examples 1 to 3 gradually increase the hydrogen adsorption capacity as the pressure of hydrogen increases, and also, the nanotubes of Examples 1 to 3 were effective as a hydrogen storage material even at room temperature.

The nanotubes of Example 2 showed the highest adsorption performance, and it was confirmed that the nanotubes of Example 2 bind one palladium atom to 10 or more molecules of H ₂ .

The palladium-doped silica nanotubes of the present invention can be applied in various fields such as hydrogen storage means of fuel cells and cell engineering, biomaterial production, catalysts or membranes.

In addition, the nanotubes of the present invention have high adsorptivity to gas molecules such as nitrogen, argon, carbon dioxide, and methane as well as hydrogen, and thus may be used as their storage means.

Claims (7)

Iii) preparing a tubular mold by adding an organic solvent represented by the following general formula (I) to an organic solvent, an aqueous solution, or a mixed solution of the organic solvent and an aqueous solution; Ii) doping palladium into the tubular mold by adding Pd (Ac) ₂ solution to the solution prepared in step iii); Iii) adding colloidal silica to the solution after the step of doping the palladium, reacting and calcining; palladium-doped silica nanotubes.

(Ⅰ) The method of claim 1, wherein the organic material of the general formula (I) is added 1 to 15% by weight based on the total weight of the solvent. The method of claim 1, wherein the palladium in step ii) is added to 1 to 50% by weight, characterized in that the manufacturing method of the silica nanotubes doped with palladium. The method of claim 1, wherein 1 to 50% by weight of colloidal silica is added in step iii). Prepared by the method of any one of claims 1 to 4, the pore size is 2.0 ~ 10nm, the size of the doped palladium particles is 1.8 ~ 6.0nm, the inner diameter is 160 ~ 300nm, the outer diameter 200 Silica nanotubes doped with palladium having a unidirectional arrangement of ˜400 nm and the nanotubes are double-walled structures. delete A gas molecule storage body obtained by adsorbing at least one gas selected from hydrogen, nitrogen, argon, methane or carbon dioxide to a palladium-doped silica nanotube.

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