KR20240013391A - Hydrogen gas sensor comprising non-noble metal catalysts and Method for manufacturing thereof - Google Patents

Abstract

The present invention relates to: A metal oxide layer located on the substrate; A first electrode and a second electrode positioned spaced apart from each other on the metal oxide layer; A palladium nanoparticle layer located between the first electrode and the second electrode; and a non-precious metal nanoparticle layer located between the first electrode and the second electrode and located on the palladium nanoparticle layer. It is economical by using a non-precious metal, and has high sensitivity and response rate to hydrogen gas by using a different kind of metal. Not only is this high, but it also provides a hydrogen gas sensor in which the hysteresis behavior of hydrogen gas is alleviated.

Description

Hydrogen gas sensor comprising non-noble metal catalysts and Method for manufacturing the same}

The present invention relates to a hydrogen gas sensor, and more specifically, to an economical hydrogen gas sensor that has high sensitivity to hydrogen gas and a fast response speed.

Hydrogen energy, which is emerging due to the depletion of fossil fuels and environmental pollution problems, is an eco-friendly technology with high potential for use in almost all fields used in energy systems, including basic industrial materials, general fuels, hydrogen cars, hydrogen airplanes, fuel cells, and nuclear fusion energy. It is in the spotlight as energy.

However, hydrogen gas has a wide explosive concentration range and small ignition energy, so it is easily ignited by even a small amount of static electricity, so even a small amount of leakage can be very dangerous. Accordingly, high-performance sensors that can quickly and accurately detect hydrogen gas are required to reduce major accidents and casualties caused by hydrogen leaks.

Accordingly, research on hydrogen sensor technology to detect hydrogen has been continuously conducted recently. These hydrogen sensors detect hydrogen by using changes in electrical signals resulting from reactions with hydrogen in metal or semiconductor materials. In this case, in order to quickly and accurately detect hydrogen in a hydrogen sensor, it is most important to have a high degree of reactivity to hydrogen. However, hydrogen generally has little reaction with metallic or semiconductor materials. To solve this problem, numerous studies have proposed a technology to maximize the reactivity with hydrogen by functionalizing metal or semiconductor materials with palladium (Pd) as a catalyst for reaction with hydrogen (Kong J, Chapline G and Dai H, Adv. Mater. 13, 2001) Additionally, precious metal catalysts including platinum (Pt), palladium (Pd), gold (Au), silver (Ag), titanium (Ti), and nickel (Ni) It is commonly used in hydrogen sensors.

However, these noble metal catalysts are expensive, and some noble metal catalysts do not provide optimal function due to low hydrogen dissociation activity at room temperature. Palladium forms palladium hybrid (PdH) during absorption/desorption of hydrogen (H ₂ ), This is problematic because it can easily cause structural instability and hysteresis of the sensor.

In addition, conventionally used hydrogen gas sensors are large in size and made of hard materials, making them difficult to install in spaces where hydrogen gas must be detected, and are having difficulties in commercialization due to the high price of using noble metal catalysts.

Accordingly, there is a need for a hydrogen gas sensor that has low location constraints, is economical, has high sensitivity to hydrogen gas, and has a fast response speed.

Republic of Korea Patent Publication No. 2016-0074291

Kong J, et al. Advanced Materials 13(18), 2001. pp. 1384-1386.

The purpose of the present invention is to provide an economical hydrogen gas sensor that has few restrictions on installation space, has high sensitivity to hydrogen gas, and can operate stably.

The hydrogen gas sensor according to the present invention includes a base material; A metal oxide layer located on the substrate; A first electrode and a second electrode positioned spaced apart from each other on the metal oxide layer; A palladium nanoparticle layer located between the first electrode and the second electrode; and a non-metallic nanoparticle layer located between the first electrode and the second electrode, but located on the palladium nanoparticle layer.

In the hydrogen gas sensor according to an embodiment of the present invention, the palladium nanoparticle layer may include a region that is in contact with the non-noble metal nanoparticle layer and a region that is not in contact.

In the hydrogen gas sensor according to an embodiment of the present invention, the molar ratio of palladium contained in the palladium nanoparticle layer and non-noble metal nanoparticles contained in the non-noble metal nanoparticle layer may satisfy 1:0.2 to 1:1.

In the hydrogen gas sensor according to an embodiment of the present invention, the non-noble metal of the non-noble metal nanoparticle layer is aluminum (Al), chromium (Cr), copper (Cu), cobalt (Co), nickel (Ni), or a combination thereof. It can be.

The hydrogen gas sensor according to an embodiment of the present invention may further include a polymer layer formed on the non-noble metal nanoparticle layer.

In the hydrogen gas sensor according to an embodiment of the present invention, the polymer of the polymer layer may be an acrylate-based polymer or a vinyl-based polymer.

In the hydrogen gas sensor according to an embodiment of the present invention, the polymer of the polymer layer may be polymethyl methacrylate.

In the hydrogen gas sensor according to an embodiment of the present invention, the polymer layer may be a non-porous polymer layer.

In the hydrogen gas sensor according to an embodiment of the present invention, the substrate may be a flexible substrate or a shrink film.

In the hydrogen gas sensor according to an embodiment of the present invention, the metal of the metal oxide layer may be one selected from the group consisting of gallium (Ge), indium (In), tin (Sn), and alloys thereof.

A method for detecting hydrogen gas using the above-described hydrogen gas sensor according to the present invention is provided.

The present invention provides a method for manufacturing the above-described hydrogen gas sensor, which method includes the steps of (a) forming a metal oxide layer on one surface of a substrate; (b) forming a first electrode and a second electrode spaced apart from each other on one side of the metal oxide layer that is not in contact with the substrate; (c) forming a palladium nanoparticle layer in the area where the first electrode and the second electrode are spaced apart; and (d) forming a non-precious metal nanoparticle layer on the palladium nanoparticle layer.

In the method of manufacturing a hydrogen gas sensor according to an embodiment of the present invention, in step (c), a palladium nanoparticle layer may be formed by depositing on a partial area of the surface of the metal oxide layer.

In the method of manufacturing a hydrogen gas sensor according to an embodiment of the present invention, in step (d), a non-noble metal nanoparticle layer may be formed by depositing on a partial area of the surface of the palladium nanoparticle layer and the metal oxide layer.

In the method of manufacturing a hydrogen gas sensor according to an embodiment of the present invention, after step (d), (e) heat treating the palladium nanoparticle layer and the non-noble metal nanoparticle layer may be further included.

In the method for manufacturing a hydrogen gas sensor according to an embodiment of the present invention, the heat treatment in step (e) may be performed at a temperature lower than the melting point of palladium or non-precious metal nanoparticles.

In the method for manufacturing a hydrogen gas sensor according to an embodiment of the present invention, the heat treatment temperature may be 80 to 500 °C.

In the method of manufacturing a hydrogen gas sensor according to an embodiment of the present invention, after step (e), (f) further forming a polymer layer on the non-noble metal nanoparticle layer may be further included.

In the method for manufacturing a hydrogen gas sensor according to an embodiment of the present invention, step (f) may be performed by applying and drying polymethyl methacrylate dissolved in a solvent on the non-noble metal nanoparticle layer.

In the method for manufacturing a hydrogen gas sensor according to an embodiment of the present invention, the solvent in step (f) may be a halogenated alkoxy benzene compound.

The hydrogen sensor according to the present invention can operate at room temperature, has high sensitivity and response speed to hydrogen gas, and has an economical advantage over hydrogen sensors using only existing noble metal nanoparticles by using non-precious metal nanoparticles.

The hydrogen sensor according to the present invention can contribute to the commercialization of hydrogen gas by providing a hydrogen gas sensor that is stable and usable for a long period of time by alleviating the hysterical behavior of the hydrogen sensor due to the presence of a gap between catalysts.

Figure 1 is a schematic diagram of a hydrogen gas sensor according to an embodiment of the present invention.
Figure 2 is a schematic diagram of a palladium metal nanoparticle layer and a non-precious metal nanoparticle layer according to an embodiment of the present invention.
Figure 3 is a scanning micrograph of a polymer layer according to an embodiment of the present invention.
Figure 4 is a graph of the detection test results for each hydrogen gas concentration of the hydrogen gas sensor when Al is used as the non-precious metal of the present invention.
Figure 5 is a graph of the detection test results for each hydrogen gas concentration of the hydrogen gas sensor when Cr is used as the non-precious metal of the present invention.

Hereinafter, the present invention will be described in detail so that those skilled in the art can easily implement it. However, the present invention may be implemented in various different forms and is not limited to the implementation examples described herein. Additionally, it is not intended to limit the scope of protection limited by the scope of the patent claims.

In addition, if there is no other definition in the technical and scientific terms used in the description of the present invention, they have the meaning commonly understood by those skilled in the art in the technical field to which this invention pertains, and in the following description, the present invention Descriptions of known functions and configurations that may unnecessarily obscure the point are omitted.

Numerical ranges as used herein include lower and upper limits and all values within that range, increments logically derived from the shape and width of the range being defined, all doubly defined values, and upper and lower limits of numerical ranges defined in different forms. Includes all possible combinations of Unless otherwise specified in the specification of the present invention, values outside the numerical range that may occur due to experimental error or rounding of values are also included in the defined numerical range.

In the present invention, unless otherwise specified, the fact that a part "includes" a certain component means that it may further include other components rather than excluding other components unless specifically stated to the contrary. Additionally, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly dictates otherwise.

Units used in this specification without special mention are based on weight. For example, the unit of % or ratio means weight % or weight ratio, and weight % refers to the amount of any one component of the entire composition in the composition, unless otherwise defined. It means the weight % occupied by .

Conventional hydrogen gas sensors use sensors using catalytic fuel or heat wire, metal oxide (nitride) semiconductors such as SiO2 and AlN, and bulk Pd and Pt using SiC and GaN, etc., and wall-wall Schottky barrier diodes with a two-pole structure. Sensors, etc. are being used. However, conventional sensors are large in size, have a complex structure, and are made of hard materials, which limits the installation location. They are expensive because they use noble metal catalysts such as Pt, Au, and Ag, and have low sensitivity to hydrogen. There is a breaking point.

Accordingly, there is a need to develop a hydrogen gas sensor that is economical, not limited by installation location, has high space efficiency, and is highly sensitive to hydrogen.

The hydrogen gas sensor according to the present invention can use a flexible or shrinkable material as a substrate, and as the hydrogen gas sensor has high flexibility, it can be used in areas that require hydrogen gas sensing, such as gas cylinders and gas pipes. It can be transformed into shapes and takes up very little space, allowing for high space efficiency.

In addition, the hydrogen gas sensor of the present invention includes a palladium nanoparticle layer as a catalyst and a non-noble metal nanoparticle layer present on the palladium nanoparticle layer, and has high sensitivity and fast response speed to hydrogen gas while using non-noble metal nanoparticles. Because it is included, it has the advantage of providing an economical hydrogen gas sensor.

Hereinafter, a hydrogen gas sensor according to an embodiment of the present invention will be described in detail with reference to the attached drawings. The attached drawings are provided as examples in order to sufficiently convey the technical idea of the present invention to technicians, and the present invention is not limited to the drawings presented below and may be embodied in many other forms.

Figure 1 shows a schematic diagram of a hydrogen gas sensor according to an embodiment of the present invention.

Referring to Figure 1, the hydrogen gas sensor of the present invention includes a substrate 100; A metal oxide layer 310 located on the substrate 100; A first electrode 321 and a second electrode 322 spaced apart from each other on the metal oxide layer 310; A palladium nanoparticle layer 350 located between the first electrode 321 and the second electrode 322; and a non-precious metal nanoparticle layer 370 located between the first electrode and the second electrode and present on the palladium nanoparticle layer 350.

Specifically, the substrate 100 is not particularly limited as long as it is made of an insulating material, and may be glass, ceramic, alumina, silicon wafer, or polymer.

In one example of the present invention, the substrate 100 may be a flexible substrate. As a specific example, the flexible substrate may be flexible polyimide or flexible polyethylene terephthalate, but is not limited thereto.

In one example of the present invention, the substrate 100 may be a shrink film. Shrink film can be a material that is flexible and can be contracted by external forces such as heat. Specifically, a material composed of one or more polymers selected from the group consisting of polyester (PET), oriented polystyrene (OPS), polyvinyl chloride (PVC), and polypropylene (PP). It can be.

_The metal _oxide layer ₃₁₀ is made of metal _{oxide ( MO} . The metal of the metal oxide layer 310 is not limited as long as it has the ability to absorb hydrogen. Specifically, the metal of the metal oxide layer 310 is tin (Sn), zinc (Zn), aluminum (Al), silicon (Si), indium (In), titanium (Ti), chromium (Cr), and iron (Fe). and nickel (Ni). Preferably, the metal of the metal oxide layer 310 may be tin (Sn), and the metal oxide layer 310 may be a tin oxide (SnO ₂ ) layer. The tin oxide layer has a higher hydrogen adsorption rate compared to other metal oxide layers 310, making it possible to sense even low-concentration hydrogen gas.

The thickness of the metal oxide layer 310 may be 5 to 300 nm, specifically 30 to 200 nm, but is not limited thereto. However, within the above range, it can exhibit high hydrogen sensitivity compared to the thickness.

In Figure 2, the palladium nanoparticle layer 350 and the non-precious metal nanoparticle layer 370 located in the area where the first electrode 21 and the second electrode 23 are spaced apart on the metal oxide layer 310 are shown in an enlarged form. there is. The palladium nanoparticle layer 350 can be divided into a lower surface in contact with the metal oxide layer 310 and an upper surface in contact with the non-precious metal nanoparticle layer 370.

Referring to FIG. 2, the structure of the particle layer is shown in which both the palladium nanoparticle layer 350 and the non-noble metal nanoparticle layer 370 located on the palladium nanoparticle layer 350 are discontinuously dispersed. The location of the non-noble metal nanoparticle layer 370 on the palladium nanoparticle layer 350 may mean that the non-precious metal nanoparticles are in discontinuous contact with the upper surface of the discontinuously dispersed palladium nanoparticle layer, and the palladium With respect to the surface of the nanoparticle, this may mean that all or part of the surface area of the palladium nanoparticle, excluding the surface area in contact with the metal oxide layer 310, is coated with a non-precious metal.

In addition, as the palladium nanoparticle layer has a discontinuously dispersed structure on the metal oxide layer 310, the non-precious metal nanoparticle layer 370 is formed on the metal oxide layer 310 where the palladium nanoparticles are not located. It may be formed in whole or in part.

The palladium nanoparticle layer 350 may be formed to have a thickness of 1 to 5 nm, specifically 2 to 4 nm. The palladium nanoparticle layer 350 may be made of palladium nanoparticles in the form of clusters or dispersed particles. As a specific example, it may be made of cluster-type palladium nanoparticles with an average particle diameter of 0.5 to 1 nm. This palladium nanoparticle layer 350 has both conductivity and excellent hydrogen adsorption capacity, so it can adsorb a large amount of hydrogen gas and enable high-sensitivity sensing.

Specifically, hydrogen gas sensing is possible with high sensitivity as the palladium nanoparticle layer is located in a specific area, that is, an area where the first electrode 321 and the second electrode 322 on the metal oxide layer 310 are spaced apart. Palladium nanoparticles may be uniformly or non-uniformly distributed in the area. Preferably, the palladium nanoparticle layer 350 is formed on the metal oxide layer 310 in the area where the first electrode 321 and the second electrode 322 are spaced apart. ) It is distributed only in some areas on the surface, and the surface of the metal oxide layer 310 in the area where the first electrode 321 and the second electrode 322 are spaced apart is the first area where the palladium nanoparticle layer 350 is located, and the palladium It may include a second area where the nanoparticle layer 350 is not located.

In detail, the area of the second region is 50% to 90%, preferably 60% to 80%, of the total area of the surface of the metal oxide layer 310 partitioned by the first electrode 321 and the second electrode 322. It may be %. The non-noble metal nanoparticles of the non-noble metal nanoparticle layer 370 may exist as zero-dimensional particles or aggregates. The average size of the non-noble metal nanoparticles may be similar to the size of the palladium nanoparticles, and specifically, the average particle diameter may be 0.5 to 3 nm. The non-noble metal nanoparticle layer 370 may be formed to have a thickness of 1 to 5 nm, specifically 2 to 4 nm.

The non-precious metal may be aluminum (Al), chromium (Cr), copper (Cu), cobalt (Co), nickel (Ni), or a combination thereof, and is not limited to non-precious metals commonly used in hydrogen gas sensors. . Conventional hydrogen gas used only noble metals such as platinum (Pt), gold (Au), and silver (Ag) as catalysts, but the present invention uses a palladium nanoparticle layer 350 and a non-precious metal nanoparticle layer located on the palladium nanoparticle layer ( 370), it has the effect of providing an economical hydrogen sensor with high sensitivity to hydrogen gas and a fast response speed.

According to an example of the present invention, the molar ratio of palladium to non-noble metal contained in the palladium nanoparticle layer and the non-noble metal nanoparticle layer may be 1:0.1 to 1:1, specifically 1:0.2 to 1:1. It could be 0.5. In the above range, more sensitive sensing of hydrogen gas is possible. Additionally, the thickness of the palladium nanoparticle layer and the non-noble metal nanoparticle layer may be 1:0.1 to 1:1, specifically 1:0.2 to 1:0.5.

As the palladium nanoparticle layer 350 and the non-precious metal nanoparticle layer 370 include the structural features described above, the hydrogen gas sensor of the present invention shows high sensitivity and fast response rate despite the low palladium content, and has hysteresis behavior. By being relaxed, both performance and stability can be improved compared to conventional hydrogen gas sensors.

The first electrode 321 and the second electrode 322 are used to measure changes in current or resistance, and are positioned spaced apart from each other on the metal oxide layer 310. Examples include copper (Cu), aluminum (Al), nickel (Ni), titanium (Ti), silver (Ag), gold (Au), platinum (Pt), and palladium (Pd), but are limited to these. This does not mean that all materials commonly used as electrodes can be used. The thickness of the first electrode 321 and the second electrode 322 may be 10 to 200 nm, respectively, and specifically 50 to 150 nm, but is not limited thereto.

In one example of the present invention, as shown in FIG. 1, the hydrogen gas sensor of the present invention includes a first electrode 321, a second electrode 322, a metal oxide layer 310, and a palladium nanoparticle layer 350. , and may further include a polymer layer 500 formed on the non-precious metal nanoparticle layer 370. The polymer layer 500 plays a role in preventing the separation of palladium nanoparticles and precious metal nanoparticles from external environments such as moisture and air, and prevents sensitivity to hydrogen gas from decreasing due to moisture, etc. when exposed to the outside for a long period of time. That is, the polymer layer 500 can significantly improve the sensitivity, hydrogen selectivity, and physical and chemical stability of the hydrogen sensor.

In one example of the present invention, when the polymer layer 500 is formed, the externally exposed metal oxide layer 310, palladium nanoparticle layer 350, and non-noble metal nanoparticle layer 370 are combined with the polymer layer 500. Can be contacted directly. Such a hydrogen gas sensor has the advantage of further increasing the selectivity of hydrogen.

The polymer of the polymer layer 500 may be an acrylate-based polymer, a polyimide-based polymer, or a vinyl-based polymer. Specifically, it may be one or more selected from polymethacrylate, polymethylacrylate, polyethylmethacrylate, polyimide, polystyrene, or mixtures thereof.

Preferably, the polymer of the polymer layer may be non-porous polymethylmethacrylate (PMMA). This polymer layer 500 greatly increases hydrogen selectivity, enabling more reliable hydrogen gas sensing. Specifically, the polymer layer 500 made of non-porous polymethyl methacrylate can have higher hydrogen selectivity than porous polymethyl methacrylate, thereby improving sensitivity and reliability in a hydrogen gas sensor.

The method of detecting hydrogen gas of the present invention through the hydrogen gas sensor of the present invention described above can be accomplished by measuring current or resistance before and after exposing the gas to be detected to the hydrogen gas sensor 1. As a non-limiting specific example, setting a standard by measuring the drain current (lds(ref)) of the hydrogen gas sensor; Introducing a gas to be detected into a sensing unit located between the first electrode and the second electrode; A detection step of measuring the drain current when the detection target gas is introduced; and analyzing the concentration of the detection gas using the measured drain current value. The detection gas may be detected based on the drain current value changed before and after introduction of the detection target gas. In contrast, of course, the detection gas can be detected with a changed resistance value rather than a drain current value that changes before and after the introduction of the detection target gas.

At this time, the operating temperature of the hydrogen gas sensor may be -50 to 300 °C, specifically -10 to 200 °C, and more specifically 4 to 150 °C.

Additionally, the concentration range of hydrogen gas may be 0.1 to 100,000 ppm, specifically 1 to 8,000 ppm.

Hereinafter, the manufacturing method of the hydrogen gas sensor of the present invention will be described in detail.

The method for producing hydrogen gas of the present invention includes the steps of a) forming a metal oxide layer on one side of a substrate; b) forming a first electrode and a second electrode spaced apart from each other on one side of the metal oxide layer that is not in contact with the substrate; and c) forming a palladium nanoparticle layer in an area where the first electrode and the second electrode are spaced apart; and d) forming a non-precious metal nanoparticle layer on the palladium nanoparticle layer. This manufacturing method has the advantage of being able to manufacture a hydrogen gas sensor with high sensitivity even at room temperature, that is, the hydrogen gas sensor of the present invention described above, and has the advantage of being commercializable because the process is easy and simple.

In detail, the step of forming a metal oxide layer on one side of the substrate (hereinafter referred to as step a) may be performed by coating the insulating layer with a precursor solution containing a metal oxide precursor material. Specifically, the metal oxide may be tin oxide, and the precursor material may be any type as long as it is soluble in the solvent used, and may be used without limitation to specific precursors such as chloride series, acetate series, and halide. The solvent is a group consisting of 2-methoxyethanol, isopropanol, dimethylformamide, ethanol, methanol, acetylacetone, and dimethylamineborane. may include at least one. The molar concentration of the precursor material in the precursor solution may be 0.01M to 3M, specifically 0.025M to 0.2M, and more specifically 0.05 to 0.15M, but is not limited thereto.

The precursor solution may further include a solution stabilizer used in the art.

In step a), the precursor solution is applied onto the insulating substrate described above to form a precursor thin film. The precursor solution can be applied by coating methods known in the art, such as spin coating, inkjet printing, and dip coating. Afterwards, heat treatment is performed on the precursor thin film of the substrate to form a metal oxide layer.

The heat treatment may be performed at 200°C to 500°C, specifically 280°C to 400°C, but is not limited thereto, and may be performed in 1st and 2nd stages at different temperatures.

Alternatively, step a) can be performed via deposition. Specifically, a metal layer can be deposited on a substrate and then oxidized to form a metal oxide layer on the substrate, or the metal oxide layer can be formed by directly depositing the metal oxide. Deposition may use physical or chemical methods, and specifically, may be performed through ALD (Atomic layer deposition), CVD (Chemical Vapor deposition), or PVD (Physical Vapor Deposition). As a more specific example, deposition may be performed through sputtering, thermal evaporation, electron beam evaporation, or electroplating.

Thereafter, a step (hereinafter referred to as step b) of forming a first electrode and a second electrode spaced apart from each other on the metal oxide layer is performed.

Specifically, first, a shadow mask having openings in the shape of the first electrode and the second electrode is placed on the substrate on which the metal oxide layer is formed through step a). The shadow mask is a mask designed to selectively deposit deposition materials through the openings, making it possible to manufacture electrode parts with precise shapes. The shadow mask can be a metal shadow mask, a polymer shadow mask such as PDMS or PMMA, etc.

Next, metal is deposited using an electron beam on the substrate on which the shadow mask is placed, thereby forming a first electrode and a second electrode on the metal oxide layer. Metals include, but are not limited to, copper, aluminum, nickel, titanium, silver, gold, platinum, and palladium.

Next, the step (hereinafter, step c) of forming a palladium nanoparticle layer in the area where the first electrode and the second electrode are spaced apart is performed.

In step c), the palladium nanoparticle layer may be formed by depositing palladium nanoparticles in the form of clusters and dispersed particles. Palladium nanoparticles can be deposited using physical or chemical methods. Specific examples include sputtering, thermal evaporation, electron beam evaporation, electroplating, and spraying an aqueous metal solution on the sample surface, but are not necessarily limited to these. That is not the case.

In one aspect of the present invention, in step c), the palladium nanoparticle layer may be formed by depositing only on a partial area of the surface of the metal oxide layer.*?* Accordingly, the metal in the area where the first electrode and the second electrode are spaced apart The surface of the oxide layer can be divided into a first region in contact with the palladium nanoparticle layer and a second region exposed to the outside because it does not contact the palladium nanoparticle layer.

Next, the step of forming a non-precious metal nanoparticle layer on the palladium nanoparticle layer (hereinafter referred to as step d)) is performed.

In step d), the non-noble metal nanoparticle layer may be formed by depositing non-noble metal nanoparticles on the palladium nanoparticle layer. Non-noble metal nanoparticles can be deposited using physical or chemical methods, preferably by sputtering, thermal evaporation, electron beam evaporation, electroplating, or spraying an aqueous metal solution on the sample surface, but are limited to these. It doesn't work.

In one aspect of the present invention, in step d), the non-noble metal nanoparticle layer may be formed by depositing non-noble metal nanoparticles also in the above-described second region. Accordingly, in addition to the first and second regions described above, the surface of the metal oxide layer may further include any one of a third region in contact with the non-noble metal nanoparticle layer and a fourth region not in contact with any particles. That is, through step d), the third to fourth regions in addition to the first to second regions can be selectively formed on the metal oxide layer, and this manufacturing method enables the production of a hydrogen gas sensor with even better sensitivity. possible.

In an example of the present invention, after step d), e) heat treating the palladium nanoparticle layer and the non-noble metal nanoparticle layer (hereinafter referred to as step e)) may be further included. A manufacturing method that further includes such a heat treatment step increases thermal stability and may enable very stable hydrogen gas sensing with little noise even at high temperatures.

The heat treatment step in step e) is not limited as long as it is a method that can apply a temperature higher than room temperature (20 ± 5°C) to the manufactured hydrogen gas sensor. Specifically, it can be performed by storing it in a heating device such as an oven or hot plate that maintains a constant temperature.

The heat treatment may be performed at a temperature lower than the inherent melting point of the palladium of the palladium nanoparticle layer or the non-noble metal of the non-noble metal nanoparticle layer. Specifically, the heat treatment may be carried out at a temperature below 1000°C, advantageously between 80 and 500°C, more advantageously between 100 and 300°C. Within the above range, it may be possible to manufacture a hydrogen gas sensor with high thermal stability within a relatively short time.

The heat treatment time is not particularly limited, but may be performed for 1 to 100 hours, specifically 10 to 50 hours.

In an example of the present invention, after step e), f) forming a polymer layer on the non-noble metal nanoparticle layer may be further included.

In step f), the polymer layer may be formed by coating the above-described sensing unit with a liquid polymer resin. Specifically, the polymer resin may be an acrylate-based polymer resin or a vinyl-based polymer resin, but it is advantageous for it to be a polymethacrylate resin.

The thickness of the polymer layer may be 50 to 500 nm, specifically 100 to 300 nm. As the polymer layer has a corresponding thickness, the sensitivity of hydrogen gas sensing increases.

Preferably, the polymer resin can be applied through spin coating, spray coating, knife coating, or roll coating, but is not limited to this and can be coated by various methods known in the art. Polymer resin can be hardened in various ways depending on the type of resin. As a non-limiting example, polymethyl methacrylate (PMMA) resin can be cured by applying a solution dissolved in a solvent and then evaporating the solvent. Specifically, step d) may be performed including applying and drying polymethyl methacrylate dissolved in a solvent on the metal nanoparticle layer. At this time, the solvent may be a halogenated alkoxy benzene compound. Halogens can be chlorine, fluorine, and bromine. For example, the halogenated alkoxy benzene compound may be anisole (CH3OC6H5). The polymer layer produced using such a solvent is non-porous polymethyl methacrylate, and as described above, the selectivity of hydrogen gas can be greatly increased.

Hereinafter, the present application will be described in more detail using examples. However, the following examples are merely illustrative to aid understanding of the present application, and the content of the present application is not limited to the following examples.

(Example 1)

The hydrogen gas sensor shown in Figure 1 was manufactured. After spin coating (1000 rpm, 30 seconds) liquid polyimide (PI) resin on the cleaned silicon wafer substrate (thickness: 500-550um, resistivity: <0.005 ohm, SiO2 thickness: 3000A (Dry)), A flexible substrate was manufactured by baking while increasing the temperature. Each step was performed at temperatures of 60, 80, 150, 230, and 300°C, and each step lasted 30 minutes, with the final temperature of 300°C lasting 1 hour.

A 0.1M SnCl2 solution using 2-methoxyethanol as a solvent was spin coated on the manufactured flexible substrate (3,000 rpm, 60 seconds) and then annealed at 280°C for 4 hours to form a SnO2 layer. Next, Al was deposited to a thickness of 90 nm and a width of 1000 μm through a shadow mask to form the first and second electrodes. At this time, the separation distance between the first and second electrodes was 200㎛. Next, Pd was deposited at a rate of 0.1 Å/s using a thermal evaporator, and then Al was deposited at a rate of 0.1 Å/s using a thermal evaporator. The Pd atom:Al atom ratio was 7:3.

Next, 40 mg/ml polymethyl methacrylate (PMMA) was first spin-coated (500 rpm, 5 seconds), followed by second spin-coating (4000 rpm, 30 seconds), followed by heat treatment at 175°C for 10 minutes. A hydrogen gas sensor was manufactured by forming a PMMA layer.

(Example 2)

A hydrogen gas sensor was manufactured in the same manner as Example 1, except that Cr was used as the non-noble metal nanoparticle.

Referring to Figure 3, a scanning micrograph (SEM) of the surface of polymethyl methacrylate (PMMA) of Example 1 is shown. As shown, it was confirmed that the surface of the PMMA polymer layer was non-porous and had a flat surface. However, the surface of the PMMA polymer layer manufactured using acetone, tetrahydrofuran, and dimethylformamide as solvents was found to be porous or not flat (not shown), and the detection test of the hydrogen gas sensor showed poor performance. Sensitivity was shown. On the other hand, Example 1 showed the best sensitivity, so a subsequent hydrogen gas detection test was performed using the hydrogen gas sensors of Examples 1 and 2, which had a polymer layer with a non-porous and flat surface.

(Experimental Example 1) Detection test

Gas detection characteristics were measured using a semiconductor parameter analyzer (B15000A, Agilent) of the MSTECH Prostation with MFC system. The hydrogen gas sensor was placed approximately 1 cm below the gas tube and directly exposed to the required concentration of gas. The hydrogen gas detection test was conducted at room temperature. Using MFC, H2 gas (100 ppm, 1%, 10% in N2) and dry air were mixed to produce hydrogen gas of the desired concentration. Detection characteristics were expressed through comparison of the current of the hydrogen gas sensor before and after exposure to hydrogen gas.

Referring to Figures 4 and 5, it was confirmed that the sensitivity of the hydrogen gas sensor of the example increases relatively linearly in proportion to the hydrogen concentration.

As described above, the present invention has been described with specific details, limited embodiments, and drawings, but these are provided only to facilitate a more general understanding of the present invention, and the present invention is not limited to the above embodiments, and the present invention Anyone skilled in the art can make various modifications and variations from this description.

Accordingly, the spirit of the present invention should not be limited to the described embodiments, and the scope of the patent claims described below as well as all modifications that are equivalent or equivalent to the scope of this patent claim shall fall within the scope of the spirit of the present invention. .

1: Hydrogen gas sensor 100: Base material
310: metal oxide layer 321: first electrode
322: Second electrode 350: Palladium nanoparticles
370: Non-precious metal nanoparticle layer 500: Polymer layer

Claims (20)

write;
A metal oxide layer located on the substrate;
A first electrode and a second electrode positioned spaced apart from each other on the metal oxide layer;
A palladium nanoparticle layer located between the first electrode and the second electrode; and
A non-metallic nanoparticle layer located between the first electrode and the second electrode, and located on the palladium nanoparticle layer;
A hydrogen gas sensor containing a.
According to paragraph 1,
The palladium nanoparticle layer is a hydrogen gas sensor including a region that is in contact with the non-noble metal nanoparticle layer and a region that is not in contact.
According to paragraph 1,
A hydrogen gas sensor in which the molar ratio of palladium contained in the palladium nanoparticle layer to the non-noble metal nanoparticle contained in the non-noble metal nanoparticle layer is 1:0.2 to 1:1.

According to paragraph 1,
The non-noble metal of the non-noble metal nanoparticle layer is aluminum (Al), chromium (Cr), copper (Cu), cobalt (Co), nickel (Ni), or a combination thereof.
According to paragraph 1,
A hydrogen gas sensor further comprising a polymer layer formed on the non-noble metal nanoparticle layer.
According to clause 5,
A hydrogen gas sensor in which the polymer of the polymer layer is an acrylate-based polymer or a vinyl-based polymer.
According to clause 6,
A hydrogen gas sensor in which the polymer of the polymer layer is polymethyl methacrylate.
According to clause 5,
A hydrogen gas sensor wherein the polymer layer is a non-porous polymer layer.
According to paragraph 1,
A hydrogen gas sensor where the substrate is a flexible substrate or shrink film.
According to paragraph 1,
The metal of the metal oxide layer is a hydrogen gas sensor selected from the group consisting of gallium (Ge), indium (In), tin (Sn), and alloys thereof.
A method for detecting hydrogen gas using the hydrogen gas sensor according to any one of claims 1 to 10.
(a) forming a metal oxide layer on one side of the substrate;
(b) forming a first electrode and a second electrode spaced apart from each other on one surface of the metal oxide layer that is not in contact with the substrate;
(c) forming a palladium nanoparticle layer in an area where the first electrode and the second electrode are spaced apart;
(d) forming a non-noble metal nanoparticle layer on the palladium nanoparticle layer.
According to clause 12,
In step (c), the palladium nanoparticle layer is formed by depositing on a partial area of the surface of the metal oxide layer.
According to clause 12,
In step (d), the non-noble metal nanoparticle layer is deposited on a partial area of the surface of the palladium nanoparticle layer and the metal oxide layer to form a hydrogen gas sensor.
According to clause 12,
After step (d), (e) heat treating the palladium nanoparticle layer and the non-noble metal nanoparticle layer.
According to clause 13,
In step (e), the heat treatment is performed at a temperature lower than the melting point of the palladium or the non-noble metal nanoparticles.
According to clause 15,
A method of manufacturing a hydrogen gas sensor wherein the heat treatment temperature is 80 to 500 °C.
According to clause 15,
After step (e), (f) further forming a polymer layer on the non-noble metal nanoparticle layer.
According to clause 18,
Step (f) is a method of manufacturing a hydrogen gas sensor comprising applying and drying polymethyl methacrylate dissolved in a solvent on the non-noble metal nanoparticle layer.
According to clause 18,
In step (f), the solvent is a halogenated alkoxy benzene compound.