KR101551539B1 - Metal oxide materials with raspberry hollow structure decorated by transfer method of metal catalysts, and method for fabricating the same and ultra-sensitive sensors comprising the same - Google Patents

Abstract

Disclosed is a metal oxide material of a raspberry hollow structure bound by a metal catalyst transfer method, a production method thereof, and a high sensitivity sensor using the same. The high sensitivity sensor sensing material for diagnosing harmful environmental gas and disease according to the embodiments of the present invention includes a raspberry-shaped hollow structure metal oxide material including a metal catalyst, a hemispherical structure metal oxide material including a metal catalyst, And at least one metal oxide material among the metal oxide materials of the spherical structure. More particularly, embodiments of the present invention provide a nano-sized metal catalyst capable of exhibiting chemical and electronic sensitization when it is bound to metal oxide, and uniformly transferring the nano-sized metal catalyst into the hollow metal oxide, Of hollow metal oxide sensor material. These metal oxides can provide a high sensitivity sensing material by allowing the gas to react both internally and externally by the open structure and the binding of the uniform nanocatalyst. Further, by using such a material, it becomes possible to apply a highly sensitive hazardous environmental gas and an exhalation sensor for diagnosing disease, which can improve the sensitivity characteristic, the quick reaction rate, the recovery speed and the selectivity.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal oxide material having a raspberry hollow structure bounded by a metal catalyst transfer method, a method for producing the metal oxide material, and a high sensitivity sensor using the metal oxide material with a raspberry hollow structure. sensitive sensors comprising the same}

Embodiments of the present invention relate to a method for manufacturing a metal oxide material in which a metal nanoparticle catalyst is bound in a raspberry-shaped hollow hemisphere or a hollow ball structure, and a high-sensitivity gas sensor including the same. More specifically, in the manufacturing method, a polymer bead in which a metal catalyst is uniformly contained on a surface is used as a template, a metal catalyst is deposited on the template and heat-treated to transfer the metal catalyst to the metal oxide . The metal oxide inner surface of the hollow structure applied through such a manufacturing method can bond the nanoparticle catalyst uniformly and raspberry shaped protrusions can be formed on the outer surface.

In the 21st century, the average life expectancy of humans is rapidly increasing due to the development of science technology and medical technology. The average life expectancy at age 50, 50 years ago, is expected to extend to about 80 years in 2011 and to 150 years in 2050. Therefore, the paradigm of medical care has changed from treatment to prevention and early diagnosis of diseases, and research and development has been actively carried out to apply biosensor and IT convergence technology to medical field centered on developed countries. In Korea, government-led ubiquitous-health (u-health) industry is designated as a next-generation growth engine, and mid- to long-term vision and step-by-step action plans are established at the national level.

It is important to try to diagnose and prevent diseases and harmful factors affecting our health in this period.

Externally, the factors affecting our health are the harmful factors in the working environment exposed daily, the pollution in the city or the complex, and even the air quality in the home. Harmful factors in the daily air, which had not been known before, are now being detected as the science develops, and medicines have been reported as to what dysfunctions the detected factors have on the human body. It is very important to monitor continuously because the air quality exposed in daily life has a great influence on our human body.

In addition, attempts have been made to diagnose the health condition of our body internally. As a part of this, it is the diagnosis method using the exhalation (expiration) of the person that is recently spotlighted. Analysis of volatile organic compounds (VOCs), a gaseous chemical component that is mixed with a person's exhalation, reveals the abnormality of the body or the contents of the disease. This method is noninvasive and can be easily applied to infants and elderly people because it does not cause pain and infection like blood sampling. It has a relatively short diagnostic time and has a great advantage of being able to monitor our health condition from time to time in everyday life . This diagnosis is based on the fact that a specific gas among the various volatile organic compound gas components contained in a person's exhalation serves as a biomarker that can indicate the onset of a specific disease. For example, toluene, which is present at the level of ppb (parts per billion) in exhalation, is known as a biomarker that can diagnose lung cancer. In the diagnosis of diabetes, acetone in parts per million (ppm) A diagnosis is made. Ammonia is used to diagnose kidney disease and H ₂ S gas is also used as an indicator of bad breath diagnosis. To diagnose diseases, it is necessary to be able to detect quickly and accurately the concentration of trace amounts of gases coming from human mouth.

As we have seen, the detection technology of VOCs in exhalation that can diagnose our health internally and the technology to detect harmful gas externally close to health are becoming important, and many devices are being used for this purpose .

The gas detection system for diagnosis of exhalation and detection of harmful factors can be roughly divided into gas chromatograph / mass spectrometer (GC / MS) method, optical method and electric resistance type sensor method. However, in order to diagnose individual health condition through frequent daily exhalation, or to detect individual harmful factor coverage in real time, portability of gas detection system should be emphasized, and it should be cheap and easy to use in real time. In this context, electrical resistive sensors using metal oxide using semiconductor characteristics are widely used because of their high utilization, simple structure, low cost, and applicability to various gases.

In recent years, in order to secure a reaction site with more gas, the development of sensors that detect minute amounts of gas quickly and accurately using metal oxide semiconductor nanomaterials having a wide specific surface area is predominant. At this time, nanomaterials are being studied in a structure having a wide surface area such as a nano-wire, a nano-tube, or a sphere in a conventional thin film structure. In the case of a hollow structure, a nanostructure having a specific open structure and high specific surface area is attracting attention.

In addition to this specific surface area improvement, researches to improve the characteristics of the sensor using a catalyst are also actively conducted. When a catalyst is used, a chemical sensitization method which exhibits an effect of increasing the concentration of adsorbing ions participating in the surface reaction by using a metal catalyst such as platinum or the oxidation of a metal catalyst by using a metal catalyst such as palladium or silver And the electronic sensitization that exhibits the sensitivity effect through the sensor can greatly improve the characteristics of the sensor. An important part of the binding of these catalysts is that the catalyst must be uniformly distributed throughout the metal oxide sensing material at the nanoscale. Research is under way to synthesize nano-sized metal catalysts uniformly using synthetic methods such as polyol processes and various chemical dispersion techniques. However, when a nanoparticle catalyst is bound to a sensing material for a sensor, clustering between the nanoparticles is observed in most cases. In order to realize better sensor characteristics, it is most important that the nanoparticle-sized catalyst is adhered to the metal oxide sensor material in a uniformly arranged form.

In the transfer method of the metal catalyst, the open hollow structure in the raspberry-like hollow structure which can be easily synthesized provides a larger surface area in which the gas can react due to the raspberry-like projections formed on the inside and the outside as well as on the outside But also the sensitivity and selectivity of the gas can be greatly improved due to the even binding of the inside of the metal catalyst, which is an excellent technique to be applied to the metal oxide material of the electric resistance sensor. Therefore, it is required to develop a process technology capable of easily binding a catalyst to such a hollow structure.

Embodiments of the present invention provide a method for producing a metal oxide in which a metal nanoparticle catalyst is bound in a raspberry-shaped hollow hemisphere or a hollow ball structure, and the metal oxide material is used for the diagnosis of harmful environmental gases and diseases The purpose is to manufacture a high sensitivity sensor.

It is an object of the present invention to provide a method of transferring a metal catalyst into a metal oxide for a raspberry shaped metal oxide hollow structure in which a metal catalyst is bound inside.

The embodiments of the present invention are capable of securing a high surface area with an open structure of a metal oxide and capable of obtaining a high sensitivity and selectivity of gas detection through chemical or electronic sensitization of an even catalyst inside, It is an object of the present invention to provide a sensing material for a sensor and to manufacture an excellent high sensitivity gas sensor using such sensing material.

It is an object of the present invention to provide a platform of a sensor array that accurately identifies a sensing gas with a selective crossing property by using a metal oxide semiconductor sensor material having at least two Raspberry hollow structures.

A sensor-sensing material comprising at least one metal oxide material selected from the group consisting of a metal oxide material having a hollow structure in the form of a raspberry, a metal oxide material having a semispherical structure including the metal catalyst, and a metal oxide material having a crushed spherical structure, Is provided.

(A) preparing a raspberry-type polymer containing a metal catalyst; (B) uniformly coating the polymer; (C) depositing a metal oxide on the resulting polymer template by uniformly coating the polymer; The polymer template is removed by heat treatment to remove the metal oxide of the raspberry hollow structure transferred with the metal catalyst, the hemispherical structure metal oxide to which the metal catalyst is transferred, and the metal oxide of the crushed spherical structure to which the metal catalyst is transferred (D) obtaining one metal oxide material; (E) dispersing the at least one metal oxide material in a solvent to prepare a coating solution; (F) coating the at least one metal oxide material on a sensor substrate; And (g) heat treating the at least one metal oxide material coated on the sensor substrate.

According to the embodiments of the present invention, there is provided a method for producing a raspberry hollow structure metal oxide sensing material in which a metal catalyst is uniformly bound to an inner surface using a raspberry-type polymer containing a metal catalyst as a template, And a highly sensitive gas sensor for detecting a harmful factor having excellent selectivity and reaction speed and a volatile organic compound in exhalation.

According to embodiments of the present invention, in addition to maximizing the change in electrical resistance in a surface depletion layer that can be obtained from the open structure and the thin shell structure of the raspberry hollow structure metal oxide in the gas adsorption / desorption process, Since gas adsorption can be done simultaneously on the surface and inside of the structure, the sensing material can have excellent sensing properties. In addition, unlike the previously reported drop coating of dispersed metal catalyst solutions or the binding method using metal salts, the nano-sized metal catalysts that are united with one another are uniformly bound to the inner surface of the metal oxide, Or by maximizing the electronic sensitization process, excellent sensitivity and reaction rate / recovery rate characteristics can be obtained.

1 is a conceptual diagram illustrating an example of a sensing material according to an embodiment of the present invention.
FIG. 2 is a flowchart schematically showing a method of manufacturing a raspberry hollow structure metal oxide material bound by a metal catalyst transfer method and a method of manufacturing a sensor using the manufactured material according to an embodiment of the present invention.
3 is a scanning electron micrograph of a raspberry polymer template comprising a gold (Au) catalyst in one embodiment of the present invention.
4 is a scanning electron microscope (SEM) image of a raspberry polymer template containing gold (Au) catalyst after depositing tin oxide (SnO ₂ ) in an embodiment of the present invention.
5 is a scanning electron microscope (SEM) image of a raspberry hollow structure tin oxide (SnO ₂ ) formed after heat treatment of a polymer template deposited with tin oxide (SnO ₂ ) at a high temperature in an embodiment of the present invention.
6 is a scanning electron micrograph of a sensor substrate coated with a raspberry hollow structure tin oxide (SnO ₂ ) containing gold (Au) catalyst, according to an embodiment of the present invention.
7 is a scanning electron micrograph of a raspberry hollow structure tin oxide not containing a gold (Au) catalyst.
FIG. 8 shows the reactivity results of acetone gas of an exhalation sensor using raspberry hollow structure tin oxide (SnO ₂ ) produced through one embodiment of the present invention as a sensing material.

In embodiments of the present invention, a metal oxide semiconductor material having a raspberry hollow structure containing a metal catalyst may be prepared and used as a sensor for a sensor for sensing an exhalation environment gas and a volatile organic compound. In addition, a variety of n-type or p-type semiconductor sensing materials including catalysts may be fabricated to provide a material platform for manufacturing a variety of sensor arrays. In particular, a sensing material having excellent gas reaction characteristics can be provided through a high specific surface area of a hollow structure and a sensitization process by a catalyst.

1 is a conceptual diagram illustrating an example of a sensing material according to an embodiment of the present invention. 1 shows a spherical polymer (001) and a metal catalyst (002) used as a template of a raspberry hollow structure, and a raspberry hollow structure metal oxide (003) and a transferred metal catalyst (004).

2 is a flowchart schematically showing an example of a method of manufacturing a raspberry hollow structure metal oxide material bound by a method of transferring a metal catalyst and a method of manufacturing a sensor using the manufactured material according to an embodiment of the present invention. Hereinafter, the metal oxide material of the raspberry hollow structure will be described, but the raspberry hollow structure described below may include a hemispherical structure or a crushed spherical structure.

As shown in FIG. 2, a method for manufacturing a metal oxide semiconductor material having a raspberry hollow structure including a metal catalyst and applying the metal oxide semiconductor material to a sensor includes the steps of: i) the production of a raspberry- (Ii) depositing a metal oxide thin film on the polymer template layer, (iii) depositing a metal oxide thin film on the surface of the polymer bead by heat treatment, and (iii) a metal catalyst having a raspberry- Oxide manufacturing step S30 and iv) fabricating a sensor for coating a metal oxide having a raspberry-like hollow structure on the sensor substrate and increasing electrical and mechanical stability (S40). In addition to the above-described steps S10 to S40, the method may further include other steps necessary for manufacturing.

First, Step S10 may include a coating process for forming a template layer on a substrate with a coating solution in which a polymer bead containing a metal catalyst is prepared and dispersed in a solvent.

The polymer may include poly (vinylpyridine) and may not be limited as long as it is a micelle-type block copolymer having poly (vinylpyridine) as a core. Also, in the case of a metal catalyst, it may not be limited as long as it is a metal capable of interacting with poly (vinylpyridine). As a typical example, gold (Au), platinum (Pt), iron oxide (Fe _x O _y ) and the like may be used as the polymer.

As a method of coating a spherical polymer used as a template bead layer for the hollow structure production, a method of coating a polymer by a spin coating method, a method of coating a polymer by dip coating, a method of drop coating drop coating method, a method of coating a polymer using a Doctor Blade, a method of coating a polymer using a dip-drawing method, and the like. The embodiments of the present invention do not limit the specific polymer coating method.

Step S20 may be a process of depositing a metal oxide on a raspberry-type polymer template containing the metal catalyst prepared in step S10. Metal oxide semiconductors can be deposited on spherical polymer templates using thin film vacuum process equipment. The thickness of the thin film deposited at this time can be determined according to the purpose of use, and can be preferably deposited to have a thickness ranging from 10 nm to 200 nm.

The metal oxide to be deposited may be selected from the group consisting of ZnO, SnO ₂ , WO ₃ , Fe ₂ O ₃ , Fe ₃ O ₄ , NiO, TiO ₂ , CuO, In ₂ O ₃ , Zn ₂ SnO ₄ , Co ₃ O ₄ , PdO, LaCoO ₃ , NiCo ₂ O ₄ , Ca ₂ Mn ₃ O ₈ , V ₂ O ₅ , Ag ₂ V ₄ O ₁₁ , Ag ₂ O, MnO ₂ , InTaO ₄ , InTaO ₄ , CaCu ₃ Ti ₄ O ₁₂ , Ag ₃ PO ₄ , BaTiO _{3, NiTiO 3, SrTiO 3,} Sr 2 Nb 2 O 7, Sr 2 Ta 2 O 7, Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3 , but may be at least one or more composite selected from the group consisting of, but not limited thereto.

The metal oxide may be coated on the polymer template using a variety of thin film coating methods. For example, there can be used an RF sputtering method, a pulsed laser deposition (PLD) method, a thermal evaporation method, an E-beam evaporation method, a chemical vapor deposition method (CVD) At least one of the thin film coating methods such as ALD (Atomic Layer Deposition) may be used, and there is no restriction on the specific equipment for the deposition.

The shape and thickness of the hollow structure vary greatly depending on the method of coating the spherical polymer surface and the coating time. When a metal oxide thin film is coated on a spherical polymer template using a physical vapor deposition sputtering method, a hollow structure with an open bottom can be obtained. Since the sputtering deposition process deposits on the surface of the spherical polymer template as the ions separated from the ceramic target undergo scattering process, the upper layer of the spherical polymer is thickest, the thin film coated on the side is somewhat thin, The deposited thin film may be very thin or in some cases not coated. Particularly, when the sputtering thickness is as thin as 50 nm or less, the bottom portion of the spherical polymer template is not coated, and a hemi-sphere having a hemispherical shape is obtained. When a metal oxide is deposited using chemical vapor deposition (CVD) or atomic layer deposition (ALD), a relatively uniform shape of a sphere can be obtained.

Among the above-described deposition methods, metal oxide materials having a raspberry-shaped hollow structure prepared by using a spherical polymer as a template do not limit the specific coating method. It is possible to obtain a laminated structure of a core-shell structure in which a raspberry-like polymer and a metal oxide thin film are composed of a core (polymer bead) and a shell (metal oxide thin film), respectively, through metal oxide deposition.

In step S30, the raspberry-type polymer template containing the metal oxide-coated metal oxide prepared in step S20 may be heat-treated to remove the polymer used as the template. The heat treatment temperature is a temperature at which the polymer is completely removed, but it is not limited, but it may be carried out under an atmosphere of air or oxygen at a temperature of 400 ° C or higher, preferably 450-600 ° C. From this, a hollow structure metal oxide having a hemispherical or spherical structure can be produced. At this time, the metal catalysts attached to the spherical polymer surface undergo heat treatment and transition to the metal oxide deposited on the surface of the polymer, and a metal oxide having a raspberry hollow structure including a metal catalyst can be obtained. Raspberry Hollow Structure The metal oxide is not limited to the spherical shape having one opening, and the hemispherical structure and the hollow structure may be broken according to the manufacturing method and may show a two-dimensional planar structure. Metal oxides forming the hollow metal oxide is _{ZnO, SnO 2, WO 3,} Fe 2 O 3, Fe 3 O 4, NiO, TiO 2, CuO, In 2 O 3, Zn 2 SnO 4, Co 3 O 4, _{PdO, LaCoO 3, NiCo 2 O} 4, Ca 2 Mn 3 O 8, V 2 O 5, Ag 2 V 4 O 11, Ag 2 O, MnO 2, InTaO 4, InTaO 4, CaCu 3 Ti 4 O 12, Ag _{3 PO 4, BaTiO 3, NiTiO} 3, SrTiO 3, Sr 2 Nb 2 O 7, Sr 2 Ta 2 O 7, can be a _{Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2} O 3 at least one or more composite selected from the group consisting of, But is not limited thereto. The fracture profile of the hollow structure metal oxide may be spherical or non-spherical

In the raspberry hollow structure metal oxide to which the metal catalyst is transferred, the outer surface and the inner surface of the hollow structure can participate in the gas reaction. The average diameter of the hollow structure metal oxide may be several tens of nanometers to several tens of micrometers. This can be determined by the size of the polymeric beads. The diameter of the beads is preferably a polymer bead containing a metal catalyst having a size of 50 nm to 5000 nm. Depending on the size of the spherical polymer used as a template, the diameter can be varied. Shell or wall thickness of the hollow metal oxide may range from 5 nm to 200 nm. When the thickness of the shell is as thin as 5 nm or less, it can be easily broken in the handling process, and when broken, the hemispherical structure can have a two-dimensional surface structure. When the shell thickness of the hollow structure metal oxide is thicker than 200 nm, the resistance changes due to the adsorption and desorption of the gas in the surface depletion layer (usually having a thickness of 5 to 25 nm), and the effect becomes deteriorated .

When the metal oxide material of the raspberry hollow structure including the metal catalyst prepared by the above method is applied to a gas sensor, excellent response to gas can be obtained by forming open pores, a thin shell structure and an electron depletion layer of the hollow structure metal oxide . ≪ / RTI > In addition, it is possible to increase the concentration of the adsorbed ions participating in the reaction or actively transfer electrons by the effect of sensitization by the metal catalyst evenly transferred inside, so that a good reaction rate / recovery speed and sensitivity to the reaction gas can be expected.

Hereinafter, the present invention will be described in more detail by way of examples. However, it should be understood that the present invention is not limited thereto.

Example 1: Preparation of raspberry-type tin oxide containing gold (Au) catalyst

(1) Production of a raspberry-type polymer template containing a gold (Au) catalyst

(PD Mn) = 292 kg / mol (PS Mn = 213 kg / mol, P4VP Mn = 79 kg / mol) and polydispersity (PDI) = 1.14 to prepare a raspberry- PS-b-P4VP (polymer Sources Inc.) having the characteristics of < RTI ID = 0.0 > A 1 wt% solution of PS-b-P4VP in chloroform was added to 4.5 mL of distilled water containing 1 wt% of a surfactant (pluronic F108 (PEO-b-PPO-b-PEO, 14,600 g / mol, Sigma Aldrich) Treated with an ultrasonic mill for 10 minutes to emulsify. Distilled water was added to the obtained aqueous emulsion to dilute the organic solvent, and the organic solvent was reduced in pressure and evaporated using a rotary evaporator at 50 占 폚. The resultant was annealed at 95 DEG C for 24 hours to form an internal structure. The dispersion was washed with deionized water and then centrifuged (13,000 rpm, 30 minutes) to remove remaining surfactant to prepare fine particles of polymer.

In order to prepare fine particles decorated with gold nanoparticles using the fine particles, a gold precursor (HAuCl ₄ .3H ₂ O, Aldrich) solution was added to the fine particle dispersion at a 1: 1 molar ratio based on P4VP units. The mixture was stirred for 24 hours, washed with deionized water, and centrifuged (13,000 rpm, 30 minutes) repeatedly to purify the polymer microparticles in the form of raspberry polymer containing gold catalyst.

(2) Production of raspberry hollow structure tin oxide containing gold (Au) catalyst

A raspberry-type polymer coating solution containing the above-prepared gold (Au) catalyst was filled on a 3X3 Si / SiO ₂ wafer and uniformly coated by a spin coating machine at 1200 RPM for 30 seconds. After coating, the substrate is dried at room temperature to complete a template for depositing tin oxide.

Scanning electron micrographs of the Raspberry polymer template containing the gold catalyst obtained by the spin coating method can be observed in FIG. 3 is a scanning electron micrograph of a raspberry polymer template comprising a gold (Au) catalyst in one embodiment of the present invention. As can be seen from FIG. 3, it can be seen that gold (Au) catalysts are distributed in the form of islands on the surface, and that the polymer having a raspberry structure has a diameter of 400 nm to 2 μm and is well formed.

Tin oxide having a hollow structure was prepared using the raspberry polymer containing the gold catalyst prepared above as a template layer. Tin oxide thin films were deposited by RF sputtering method. A 2 inch tin oxide target was used. RF power was 50 W, base pressure (initial high vacuum) was 1.8 x 10 ^-6 Torr, and working pressure was 1.0 x 10 ^-2 Torr. The gas used was Ar, and Ar gas was injected at a flow rate of 5 sccm. The deposition time was fixed to 3 minutes and 30 seconds, and the deposition time of 3 minutes and 30 seconds was 90 nm on the flat substrate. The tin oxide thin film deposition proceeded at room temperature. In order to prevent deformation of the polymer template during the deposition process, the polymer template was removed by heat treatment at 500 ^° C. for 1 hour, and the deposited tin oxide thin film was crystallized thereon.

FIG. 4 is a scanning electron micrograph of a raspberry polymer template containing gold (Au) catalyst after depositing tin oxide (SnO.sub.2) in an embodiment of the present invention. FIG. 4 shows a scanning electron micrograph of the raspberry hollow structure tin oxide prepared by depositing tin oxide on the raspberry polymer template by sputtering. It can be seen that the tin oxide was uniformly deposited while maintaining the raspberry-shaped polymer template structure in a form similar to that of the Raspberry polymer template scanning electron micrograph including the gold catalyst of FIG.

FIG. 5 is a scanning electron micrograph of a raspberry hollow structure tin oxide (SnO.sub.2) formed after heat treatment of a polymer template deposited with tin oxide (SnO.sub.2) at a high temperature in an embodiment of the present invention. FIG. 5 is a scanning electron microscope (SEM) image of a tin oxide thin film deposited by heat treatment of tin oxide deposited on a Raspberry polymer template prepared in FIG. 4 by heating at 500 ^° C. for 1 hour to remove the polymer template. It can be confirmed that the inner polymer template is removed and the tin oxide hollow structure is stably formed.

The gold catalysts attached to the surface of the raspberry polymer template can be transferred into the deposited tin oxide by heat treatment.

The formed tin oxide hollow structure can be formed by sputtering as a result of sputtering as a result of thin deposition of the upper layer of the polymer template, which does not sufficiently cover the lower layer, thereby forming a hollow structure with the lower layer open.

A coating solution was prepared by dispersing 5 mg of the raspberry hollow structure tin oxide transferred with the gold (Au) catalyst prepared above in 50 μl of an ethanol solvent. After coating the coating solution with a drop coating method on the sensor substrate, the raspberry hollow structure tin oxide containing the gold (Au) catalyst coated on the sensor substrate was heat treated to improve the electrical and mechanical stability.

6 is a scanning electron microscope (SEM) image of a sensor substrate coated with a raspberry hollow structure tin oxide (SnO2) containing a gold (Au) catalyst according to an embodiment of the present invention.

Comparative Example 1: A raspberry-type tin oxide not containing a gold (Au) catalyst Produce

A raspberry hollow structure tin oxide containing gold (Au) catalyst In order to more clearly observe the excellent gas sensor effect of the material, a raspberry hollow structure tin oxide film without a gold (Au) catalyst was prepared.

FIG. 7 is a scanning electron microscope (SEM) image of a raspberry polymer template not containing a gold (Au) catalyst applied with a tin oxide by a sputtering method followed by heat treatment.

A tin oxide thin film was deposited on a raspberry - type polymer containing no gold catalyst, and a tin oxide raspberry hollow structure metal oxide was prepared by heat treatment at 500 ^° C for 1 hour. Here, the tin oxide having a raspberry hollow structure not containing a gold catalyst can be prepared in the same manner as the above-mentioned method, so that the effect of forming a tin oxide of a raspberry hollow structure containing a gold catalyst can be clearly compared Respectively.

Similar to the shape of a raspberry polymer template containing a gold catalyst, but without a metal catalyst on its surface, it has a tin oxide hollow structure.

The method of manufacturing the tin oxide material of the raspberry hollow structure without the gold catalyst is described above and the sensing material is applied to the gas sensor.

FIG. 8 shows the reactivity results of acetone gas of an exhalation sensor using raspberry hollow structure tin oxide (SnO2) as a sensing material produced through an embodiment of the present invention. FIG. 8 is a graph showing a reaction result of acetone gas with a raspberry hollow structure tin oxide sensing material containing a gold catalyst prepared according to an embodiment of the present invention. For the test of the reaction to acetone gas (Response: change of R _air / R _gas resistance, R _air : resistance in air, resistance of R _gas : acetone gas) ppm, 2 ppm, and 1 ppm, respectively. As shown in FIG. 8, it was confirmed that the raspberry hollow structure tin oxide containing the gold catalyst prepared under the same conditions significantly improved the reaction to the acetone gas compared to the case where the gold catalyst was not included. In this case, the reaction (R _air / R _gas ) value of the raspberry hollow structure tin oxide containing the gold catalyst at 5 ppm is 3.49, which is about 3 times higher than the reaction value 1.25 of the raspberry hollow structure tin oxide not including the gold catalyst Respectively.

In the above embodiment, tin oxide (SnO ₂ ) is used as an example. However, any metal oxide semiconductor which can be coated by a deposition method may be used. ZnO, SnO ₂ , WO ₃ , Fe ₂ O ₃ , Fe ₃ O ₄ , _{NiO, TiO 2, CuO, In} 2 O 3, Zn 2 SnO 4, Co 3 O 4, PdO, LaCoO 3, NiCo 2 O 4, Ca 2 Mn 3 O 8, V 2 O 5, Ag 2 V 4 O 11 , Ag ₂ O, MnO ₂ , InTaO ₄ , InTaO ₄ , CaCu ₃ Ti ₄ O ₁₂ , Ag ₃ PO ₄ , BaTiO ₃ , NiTiO ₃ , SrTiO ₃ , Sr ₂ Nb ₂ O ₇ , Sr ₂ Ta ₂ O _7, Ba _0.5 may be a Sr _0.5 Co _0.8 Fe _0.2 O ₃ at least one or more composite selected from the group consisting of. A high sensitivity sensor using a metal oxide of a raspberry hollow structure including a gold catalyst is not only applied to the acetone gas shown in the concrete results of the above embodiment but also to the exhaust gas (H ₂ S, acetone, NH ₃ , toluene , pentane, isoprene, NO, etc.) and harmful environmental gas (NH ₃ , HCHO, CO, etc.). It is possible to improve not only the reaction value but also various characteristics such as the reaction rate / recovery rate from the specific gas sensor results shown in the above embodiments.

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 exemplary embodiments. Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

Claims (11)

The polymer template is formed by coating a raspberry-type spherical polymer having a metal catalyst uniformly on a substrate, a metal oxide is deposited on the polymer template, and the polymer template is removed through heat treatment to form the raspberry- Wherein the metal template has at least one structure selected from the group consisting of a hollow structure, a raspberry-shaped hemispherical structure and a raspberry-shaped crushed spherical structure,
Sensor sensing material. The method according to claim 1,
The structure of the metal oxide material is determined to have at least one of the hollow structure, the hemispherical structure and the crushed spherical structure depending on the coating method for depositing the metal oxide on the surface of the polymer template and the coating time Features a sensor-sensing material. The method according to claim 1,
The metal oxide material,
_{ZnO, SnO 2, WO 3,} Fe 2 O 3, Fe 3 O 4, NiO, TiO 2, CuO, In 2 O 3, Zn 2 SnO 4, Co 3 O 4, PdO, LaCoO 3, NiCo 2 O 4, Ca ₂ Mn ₃ O ₈ , V ₂ O ₅ , Ag ₂ V ₄ O ₁₁ , Ag ₂ O, MnO ₂ , InTaO ₄ , InTaO ₄ , CaCu ₃ Ti ₄ O ₁₂ , Ag ₃ PO ₄ , BaTiO ₃ , NiTiO ₃ , SrTiO ₃ , Sr ₂ Nb ₂ O ₇ , Sr ₂ Ta ₂ O _{7, and} Ba _0.5 Sr _0.5 Co _0.8 Fe _0.2 O ₃ . The method according to claim 1,
Wherein the polymer comprises a block copolymer having a poly (vinylpyridine) -containing poly-core as a core,
Wherein the metal catalyst comprises a metal material capable of interacting with the poly. The method according to claim 1,
Wherein the metal oxide material is a composite material having a diameter ranging from 100 nanometers to 2.5 micrometers. The method according to claim 1,
Wherein the metal oxide material is a composite material in which the thickness of the constituting shell is within a range of 5 nanometers to 200 nanometers. The method according to claim 1,
Wherein the metal catalyst is a material having a diameter ranging from 1 nm to 100 nm. 7. A method of detecting a sensor for detecting a sensor according to any one of claims 1 to 7, wherein the volatile organic compound (H ₂ S, acetone, toluene, isoprene, NH ₃ , pentane, And at least one of an ambient gas (NH ₃ , HCHO, CO, etc.). (A) preparing a raspberry-shaped polymer having a spherical structure containing a metal catalyst;
(B) uniformly coating the polymer on a substrate to produce a polymer template;
(C) depositing a metal oxide on the generated polymer template;
And removing the polymer template through heat treatment to have at least one structure out of the raspberry-shaped hollow structure, the raspberry-shaped hemispherical structure and the raspberry-shaped crushed spherical structure, (D) obtaining a catalyst-transferred metal oxide material;
(E) dispersing the metal oxide material in a solvent to prepare a coating solution;
(F) coating the metal oxide material on a sensor substrate; And
(G) heat-treating the metal oxide material coated on the sensor substrate
≪ / RTI > 10. The method of claim 9,
Wherein the coating solution of step (e) comprises the metal oxide material dispersed in an ethanol solvent. delete

Images