JP2021003666A - Adsorbent, method for producing adsorbent, adsorber, concentrator, detector, gas sensor, and nano-wire assembly - Google Patents

Abstract

To provide an adsorbent that has an adsorption characteristic different from the original adsorption characteristic of zinc oxide.SOLUTION: An adsorbent 10 includes a zinc oxide-containing nano-wire 11. The nanowire 11 has a wire-shaped core portion 112 and an adsorption portion 111 that covers the core portion 112. The adsorption portion 111 contains zinc oxide and nitrogen atom.SELECTED DRAWING: Figure 1

Description

The present disclosure generally relates to an adsorbent, a method for producing an adsorbent, an adsorber, a concentrator, a detection device, a gas sensor, and a nanowire aggregate. The present invention relates to an adsorber including a material, a concentrator including the adsorber, a detection device including the adsorber, a gas sensor including the adsorbent, and a nanowire aggregate.

The adsorbent that adsorbs a chemical substance is applied to, for example, a concentrator that concentrates the concentration of the chemical substance, a detection device that detects the chemical substance, and the like, and the adsorbent is produced from, for example, zinc oxide (Patent Document). 1).

International Publication No. 2017/047041

The type of chemical substance that can be concentrated by a concentrator equipped with an adsorbent and the type of chemical substance that can be detected by a detector depend on the adsorption characteristics of the adsorbent. If an adsorbent having new adsorption characteristics can be obtained by modifying the adsorption characteristics of the adsorbent, it is possible to increase the variation of chemical substances that can be targeted for collection, concentration, detection, etc. using the adsorbent.

The subject of the present disclosure is an adsorbent having an adsorption characteristic different from the original adsorption characteristic of zinc oxide, a method for producing the adsorbent, an adsorbent including the adsorbent, a concentrator equipped with the adsorber, and the adsorber. The present invention provides a detection device including, a gas sensor including the adsorbent, and an aggregate of nanowires.

The adsorbent according to one aspect of the present disclosure includes nanowires containing zinc oxide. The nanowire has a wire-shaped core portion and an adsorption portion that covers the core portion, and the adsorption portion contains zinc oxide and a nitrogen atom.

The adsorbent according to another aspect of the present disclosure includes an adsorbent containing zinc oxide and a nitrogen atom. When the adsorbent is exposed to a sample gas containing 1 volume ppm each of nonanal and pyrrol for 1 minute, the ratio of the adsorbed amount of pyrrole to the adsorbed amount of nonanaal to the adsorbent is 0.4. It has the adsorption characteristic of the above.

The method for producing an adsorbent according to one aspect of the present disclosure is the method for producing an adsorbent. In this method, the nanowires are grown in an aqueous solution containing zinc ions, ammonia of 250 mmol / L or more and 750 mmol / L or less, and polyethyleneimine of 1 mmol / L or more and 3 mmol / L or less. The time for growing the nanowire is the value of the ratio of the amount of adsorbed pyrrole to the amount of adsorbed nonanal to the adsorbent when the adsorbent is exposed to a sample gas containing 1 volume ppm each of nonanal and pyrrol for 1 minute. It is specified to be 0.4 or more.

The method for producing an adsorbent according to another aspect of the present disclosure is the method for producing an adsorbent. In this method, the wire-shaped base is immersed on the surface of the base by immersing it in an aqueous solution containing zinc ions, ammonia of 250 mmol / L or more and 750 mmol / L or less, and polyethyleneimine of 1 mmol / L or more and 3 mmol / L or less. It involves growing the nanowires by precipitating the product.

The adsorbent according to one aspect of the present disclosure includes the adsorbent.

The concentrator according to one aspect of the present disclosure includes a concentrating chamber and the adsorbent arranged in the concentrating chamber.

The detection device according to one aspect of the present disclosure includes the adsorbent and a sensor unit that detects a chemical substance adsorbed by the adsorbent and outputs a signal corresponding to the chemical substance.

The gas sensor according to one aspect of the present disclosure includes the adsorbent and an electrode electrically connected to the adsorbent.

The nanowire aggregate according to one aspect of the present disclosure is an aggregate of a plurality of nanowires containing zinc oxide, and the nanowire has a wire-shaped core portion and an adsorption portion covering the core portion. The adsorbed portion contains zinc oxide and a nitrogen atom.

According to the present disclosure, an adsorbent having an adsorption characteristic different from the original adsorption characteristic of zinc oxide, a method for producing the adsorbent, an adsorber including the adsorbent, a concentrator having the adsorber, and the adsorber are provided. A detection device, a gas sensor including the adsorbent, and a nanowire assembly can be provided.

FIG. 1 is a schematic cross-sectional view showing nanowires of an adsorbent according to an embodiment of the present disclosure. FIG. 2 is a schematic perspective view showing an adsorbent according to an embodiment of the present disclosure. FIG. 3 is a schematic cross-sectional view showing a concentrator according to an embodiment of the present disclosure. FIG. 4 is a schematic perspective view showing the same concentrator. FIG. 5 is a block diagram showing a configuration for controlling the concentrator of the same. FIG. 6 is a schematic perspective view showing a detection device according to an embodiment of the present disclosure. FIG. 7 is a schematic cross-sectional view showing a gas sensor according to an embodiment of the present disclosure. FIG. 8 is a graph showing the measurement results of the adsorption amounts of Samples 1 to 6 in Examples. FIG. 9 is a graph showing the photoluminescence spectra of Samples 1 to 6 in Examples. FIG. 10 is a graph showing the measurement results of the adsorption amounts of Sample 1, Sample 4, and Comparative Sample in the Example. FIG. 11A is a transmission electron microscope image of nanowires in sample 1, and FIG. 11B is a transmission electron microscope image of nanowires in sample 1 having a higher magnification than that of FIG. 11A. FIG. 12A is a transmission electron microscope image of nanowires in sample 4, and FIG. 12B is a transmission electron microscope image of nanowires in sample 4 having a higher magnification than that of FIG. 12A.

The adsorbent 10 according to the first embodiment of the present disclosure includes nanowires 11 containing zinc oxide. The nanowire 11 has a wire-shaped core portion 112 and a suction portion 111 that covers the core portion 112. The adsorption unit 111 contains zinc oxide and a nitrogen atom. The core portion 112 may or may not contain a nitrogen atom.

In the first embodiment, the adsorbent 10 is the ratio of the amount of pyrrol adsorbed to the amount of nonanaal adsorbed on the adsorbent 10 when the adsorbent 10 is exposed to a sample gas containing 1 volume ppm each of nonanal and pyrrol for 1 minute. It is preferable to have an adsorption characteristic in which the value of (hereinafter, also referred to as adsorption ratio) is 0.4 or more.

The adsorbent 10 according to the second embodiment of the present disclosure includes an adsorbent 111 containing zinc oxide and a nitrogen atom. The adsorbent 10 has an adsorption property having an adsorption ratio of 0.4 or more.

Although the adsorbent 10 according to the present disclosure contains zinc oxide, it can have adsorption characteristics different from those of the original zinc oxide. Specifically, zinc oxide originally has an adsorption property of easily adsorbing nonanal and hardly adsorbing pyrrole, but the adsorbent 10 according to the present disclosure adsorbs nonanal as compared with the original adsorption property of zinc oxide. It can have an adsorption characteristic that it is difficult to adsorb and easily adsorbs pyrrole.

Hereinafter, one embodiment of the present disclosure will be described.

The adsorbent 10 according to the present embodiment includes nanowires 11 as shown in FIG. The adsorbent 10 is, for example, an aggregate of a plurality of nanowires 11 (hereinafter, also referred to as a nanowire aggregate 5) as shown in FIG. More specifically, the adsorbent 10 is, for example, a bundle of nanowires 11. For example, a plurality of nanowires 11 are bundled so as to have a gap between the nanowires 11 to form an adsorbent 10 composed of the nanowire aggregate 5. In this case, a chemical substance enters the gap between the nanowires 11 and is easily adsorbed on the nanowires 11.

The wire diameter of the nanowire 11 is, for example, 1 nm or more and 1000 nm or less. The length of the nanowire 11 is, for example, 1 μm or more and 150 μm or less. When the nanowire 11 has such a dimension, the nanowire 11 can have a high adsorption performance by having a high specific surface area. Regardless of the range of the length of the nanowire 11, the length of the nanowire 11 may be 10 times or more the wire diameter of the nanowire 11. For example, when the wire diameter of the nanowire 11 is 1 nm, the length of the nanowire 11 may be 10 nm or more.

The nanowire 11 contains zinc oxide. Further, the nanowire 11 includes a wire-shaped core portion 112 and a suction portion 111 that covers the core portion 112. In the present embodiment, the suction portion 111 constitutes the outermost layer of the nanowire 11, that is, the suction portion 111 forms the surface of the nanowire 11. The adsorption unit 111 may be covered with a material that does not easily inhibit the adsorption of chemical substances by the adsorption unit 111. Further, the suction portion 111 may completely cover the core portion 112, or may partially cover the core portion 112. Further, the suction portion 111 may be in direct contact with the core portion 112, and a layer different from the core portion 112 and the suction portion 111 may be interposed between the core portion 112 and the suction portion 111.

In the present embodiment, zinc oxide is the main component of the nanowire 11, and is contained in both the core portion 112 and the adsorption portion 111. The adsorption unit 111 also contains a nitrogen atom in addition to zinc oxide. The nitrogen atom is doped into, for example, the zinc oxide crystal in the adsorption unit 111. The core portion 112 may or may not contain a nitrogen atom.

The adsorbent 10 preferably has an adsorption characteristic that the adsorption ratio is 0.4 or more. Such adsorption characteristics can be realized by the adsorbent 10 including the above-mentioned adsorption portion 111. In this case, the adsorption ratio is more preferably 0.44 or more, further preferably 0.5 or more, and particularly preferably 1 or more. In this case, an adsorbent 10 having an adsorption characteristic significantly different from the original adsorption characteristic of zinc oxide can be obtained. The conditions for measuring the adsorption amount will be described in detail in Examples described later.

It is preferable that the core portion 112 and the adsorption portion 111 have different crystal sequences from each other. Specifically, for example, in the adsorption portion 111, the orientation of the crystals is lower than that in the core portion 112, and it is preferable that the core portion 112 includes a plurality of portions in which the crystals are oriented in different directions. "Having different crystal sequences from each other" means that the adsorption portion 111 contains amorphous and microcrystals, and the microcrystals thereof have a crystal lattice direction different from that of the crystal lattice in the core portion 112. Including the case where is included. It can also be said that the adsorption portion 111 has a lower order of atomic arrangement than the core portion 112. In this case, although the reason has not been clarified, the adsorbent 10 is less likely to adsorb nonanal and is more likely to adsorb pyrrole.

Further, the crystals constituting each of the core portion 112 and the adsorption portion 111 may have atomic vacancies. In this case, since the electrical conductivity of the nanowire 11 is increased, it becomes easy to heat the adsorbent 10 by an electric current.

The thickness of the suction portion 111 along the radial direction of the nanowire 11 is preferably 10 nm or more and 30 nm or less. In this case, the adsorbent 10 tends to realize adsorption characteristics different from those of the original zinc oxide. This thickness is an average value of the results of measuring the thickness of the adsorption portion 111 appearing in the transmission electron microscope image of one nanowire 11 at 10 points.

The adsorption unit 111 preferably has a photoluminescence property that the maximum peak top in the wavelength range of 300 nm to 750 nm in the photoluminescence spectrum is 550 nm or less. In this case as well, although the reason has not been clarified, the adsorbent 10 is less likely to adsorb nonanal and more easily to adsorb pyrrole, and this tendency becomes more remarkable as the intensity of the peak top is higher. This makes it easier to realize the adsorption characteristic that the adsorption ratio is 1 or more. Since the maximum peak top of the zinc oxide crystal is originally above 550 nm, the adsorption portion 111 has a photoluminescence property that is significantly different from the original photoluminescence property of the zinc oxide crystal. The conditions for measuring the photoluminescence spectrum will be described in detail in Examples described later.

The content of nitrogen atoms in the adsorption unit 111 is preferably 5 at% or more and 13 at% or less. In this case as well, although the reason has not been clarified, the adsorbent 10 is less likely to adsorb nonanal and more easily to adsorb pyrrole, and this tendency becomes more remarkable as the content of nitrogen atoms increases. The nitrogen atom content is measured by XPS (X-ray photoelectron spectroscopy), and the detailed conditions thereof will be described in detail in Examples described later.

The adsorbent 10 preferably includes a plurality of nanowires 11. The adsorbent 10 is also preferably a nanowire aggregate 5. In the nanowire assembly 5, for example, a plurality of nanowires 11 are bundled so that their length directions are the same as each other.

The adsorber 1 including the adsorbent 10 will be described. The adsorber 1 shown in FIG. 2 includes a base 13 and an adsorbent 10 supported by the base 13. The shape and material of the substrate 13 are not limited as long as the substrate 13 can support the nanowires 11. One end of each of the plurality of nanowires 11 in the adsorbent 10 is fixed to the substrate 13, and the other end faces the side opposite to the substrate 13. That is, for example, a plurality of nanowires 11 project from the substrate 13 in the same direction and are bundled on the substrate 13.

The manufacturing method of the adsorbent 10 and the adsorber 1 will be described.

First, a first example of the manufacturing method will be described.

In the first example, the nanowire 11 is grown in an aqueous solution containing zinc ions, ammonia of 250 mmol / L or more and 750 mmol / L or less, and polyethyleneimine of 1 mmol / L or more and 3 mmol / L or less. The time for growing the nanowire 11 is the value of the ratio of the amount of adsorbed pyrrole to the amount of adsorbed nonanal on the adsorbent 10 when the adsorbent 10 is exposed to a sample gas containing 1 volume ppm each of nonanal and pyrrole for 1 minute. It is preferably specified to be 0.4 or more.

Specifically, for example, first, a base 113 containing zinc oxide is prepared. The base 113 is, for example, a zinc oxide film formed on the substrate 13 (see FIG. 2). As described above, the shape and material of the substrate 13 are not limited, but for example, the substrate 13 is a substrate made of a material such as silicon, metal, SiO ₂ , or a synthetic resin having electrical insulation. When the base 113 is a zinc oxide film, the base 113 is formed by an appropriate method such as a vapor deposition method, a sputtering method, or a CVD method.

Prepare an aqueous solution containing zinc ions, ammonia and polyethyleneimine. As described above, the concentration of ammonia in the aqueous solution is 250 mmol / L or more and 750 mmol / L or less. When this concentration is 250 mmol / L or more, zinc ions are complex-ionized, and the ionic state becomes more stable in terms of energy, which has an advantage that the precipitation rate of zinc oxide crystals can be suppressed, and is 750 mmol / L or less. This has the advantage that zinc oxide crystals can be prevented from precipitating at all. The concentration of polyethyleneimine in the aqueous solution is 1 mmol / L or more and 3 mmol / L or less. When this concentration is 1 mmol / L or more, there is an advantage that the growth of the nanowire 11 in the radial direction is suppressed, and the adsorption portion 111 distinct from the core portion 112 is easily formed on the nanowire 11, and this concentration is 3 mmol. When it is less than / L, there is an advantage that zinc oxide crystals can be prevented from being precipitated at all. The concentration of zinc ions in the aqueous solution is not particularly limited, but is preferably 10 mmol / L or more and 50 mmol / L or less in order to obtain nanowires 11 having a large aspect ratio (length / diameter). The aqueous solution contains at least one compound selected from the group consisting of, for example, zinc nitrate, zinc sulfate, zinc acetate, and zinc phosphate as a zinc ion source.

In growing the nanowires 11 in an aqueous solution, for example, the base 113 is immersed in the aqueous solution. The temperature of the aqueous solution at this time is, for example, 80 ° C. or higher and 110 ° C. or lower. Then, the nanowires 11 grow from the base 113 to obtain an adsorbent 10 having the nanowires 11 and the base 113, and an adsorbent 1 having the adsorbent 10 and the substrate 13.

When the nanowires 11 are grown, the adsorption characteristics of the adsorbent 10 are adjusted by controlling the time for immersing the base 113 in the aqueous solution, that is, the time for growing the nanowires 11, that is, the adsorption of nonanal and pyrrole of the adsorbent 10. Ease of use is controlled. The longer the time for growing the nanowires 11, the more difficult it is for the adsorbent 10 to adsorb nonanal and the easier it is for pyrrole to be adsorbed. This is because the longer the time for growing the nanowire 11, the easier it is for the adsorption portion 111 to be formed on the nanowire 11 so as to be distinguished from the core portion 112, and the adsorption portion 111 has a crystal arrangement and photoluminescence different from the original zinc oxide. It is presumed that this is because it becomes easier to have characteristics.

The time for growing the nanowires 11 is defined so that the adsorbent 10 has the desired adsorption properties. This time is preferably defined so that the adsorption ratio is 0.4 or more as described above. This time is more preferably defined so that the adsorption ratio is 0.44 or more, and further preferably 1 or more.

The upper limit of the time for growing the nanowires 11 is not particularly specified. However, if the time is too long, the nanowires 11 may become brittle. In that respect, the upper limit of the time for growing the nanowires 11 is preferably 120 hours or less, and more preferably 80 hours or less.

The time for growing the nanowires 11 is preferably 10 hours or more. In this case, it is easy to realize that the adsorption ratio is 0.4 or more. The time for growing the nanowires 11 is preferably 20 hours or more, and preferably 40 hours or more. If this time is 20 hours or more, it is easy to realize that the adsorption ratio is 1 or more, and if it is 40 hours or more, the adsorption characteristic that nonanal is hardly adsorbed and pyrrole is very easily adsorbed is realized. Cheap.

In the above description, the base 113 is a zinc oxide film. In this case, for example, if the zinc oxide film which is the base 113 is provided on the substrate 13, a plurality of nanowires 11 as shown in FIG. 1 are fixed to the substrate 13 and bundled. The obtained nanowire assembly 5 can be obtained. However, the base 113 may be any material as long as it serves as a starting point for the growth of the nanowire 11. Further, the nanowire assembly 5 is not limited to the structure shown in FIG. 1 as long as it is configured by assembling a plurality of nanowires 11.

For example, the base 113 may be zinc oxide particles. In this case, the nanowires 11 can grow from a plurality of zinc oxide particles in the aqueous solution. In this case, the plurality of nanowires 11 are generated in a dispersed state in the aqueous solution. Further, the nanowires 11 may be grown in the aqueous solution by adjusting conditions such as the composition and temperature of the aqueous solution without using the base 113. In this case, the plurality of nanowires 11 are generated in a dispersed state in the aqueous solution. By assembling the plurality of nanowires 11 without bundling, for example, the nanowire assembly 5 can be formed. In this case, for example, the nanowire assembly 5 can be applied to the adsorbent 10 shown in FIG. 7, which will be described later.

Next, a second example of the manufacturing method will be described.

Prepare the base. In the second example, the base is wire-like and is supported, for example, by the substrate 13. The base contains, for example, zinc oxide, specifically a wire made of, for example, zinc oxide.

Prepare an aqueous solution containing zinc ions, ammonia and polyethyleneimine. The composition of the aqueous solution may be the same as in the first example.

Immerse the base in aqueous solution. The temperature of the aqueous solution at this time is, for example, the same as in the case of the first example. Then, the product is deposited on the surface of the base portion, so that the nanowire 11 having the core portion 112 derived from the base portion and the adsorption portion 111 formed from the precipitate is formed, and the adsorbent 10 including the nanowire 11 is formed. Is obtained. The adsorption unit 111 may be composed of a part of the precipitate. Further, an adsorber 1 including the adsorbent 10 and the substrate 13 can be obtained. In the case of the second example as well, as in the case of the first example, when the nanowires 11 are grown, the adsorption characteristics of the adsorbent 10 are adjusted by controlling the time for immersing the base 113 in the aqueous solution.

The configuration of the adsorbent 10 is not limited to the above. For example, in the above description, the adsorbent 10 is a nanowire assembly 5 composed of a plurality of nanowires 11, but the adsorbent 10 does not have to be the nanowires 11. For example, the adsorbent 10 may be in the form of a net, a non-woven fabric, or the like. In that case, the adsorbent 10 may include a core portion 112 having an appropriate shape such as a net shape or a non-woven fabric shape, and a suction portion 111 that covers the core portion 112. Further, the adsorbent 10 does not have to include the core portion 112, and in that case, the adsorbent 10 may include only the adsorption portion 111, or may include a member other than the core portion 112 that supports the adsorption portion 111. ..

The concentrator 2 including the adsorbent 10 will be described. The concentrator 2 includes a concentrating chamber 21 and an adsorbent 10 arranged in the concentrating chamber 21. When the concentrator 2 is used, for example, while supplying a gas containing a chemical substance (hereinafter, also referred to as a sample gas) into the concentrating chamber 21, the adsorbent 10 adsorbs the chemical substance in the sample gas. Subsequently, the chemical substance is desorbed from the adsorbent 10 and released into the concentration chamber 21. As a result, a gas having a higher concentration of the chemical substance than the sample gas (hereinafter, also referred to as a adjusting gas) can be generated in the concentration chamber 21. Examples of sample gases are human and animal exhalations, as well as car and factory exhausts. Examples of chemicals include ketones, amines, alcohols, aromatic hydrocarbons, aldehydes, esters, organic acids, methyl mercaptans, disulfides and other volatile organic compounds, as well as hydrogen sulfide, sulfur dioxide and carbon disulfide. Inorganic compounds such as.

The concentrator 2 may include an adsorber 1 including an adsorbent 10. The adsorber 1 may include a heater that heats the adsorbent 10. The adsorber 1 may further include a cooler 25 for cooling the adsorbent 10. When the adsorber 1 is provided with a heater, the chemical substance can be easily desorbed from the adsorbent 10 by heating the adsorbent 10 that has adsorbed the chemical substance with the heater. The adsorbent 10 may not be provided with a heater, and the adsorbent 10 may be heated by Joule heat by passing an electric current through the adsorbent 10 to desorb the chemical substance from the adsorbent 10. Further, when the adsorber 1 is provided with the cooler 25, the heated adsorbent 10 can be cooled by the cooler 25, so that the adsorbent 10 can be quickly returned to a state in which chemical substances can be adsorbed. Further, by cooling the adsorbent 10 with the cooler 25 when the chemical substance is adsorbed on the adsorbent 10, the total amount of the chemical substance adsorbed on the adsorbent 10 can be increased.

Hereinafter, an example of a specific configuration of the concentrator 2 when the adsorber 1 includes the first electrode 221 and the second electrode 222 and the cooler 25 will be described with reference to FIGS. 3 and 4.

The concentrator 2 has a housing 23 and a concentrating chamber 21 in the housing 23. The housing 23 includes an arrangement surface 24 facing the concentration chamber 21. The adsorbent 10 is arranged on the arrangement surface 24 in the concentration chamber 21. The housing 23 is provided with a first electrode 221 and a second electrode 222 that are separated from each other. Each of the first electrode 221 and the second electrode 222 is electrically connected to the adsorbent 10 by being in contact with the adsorbent 10. A cooler 25 is provided in the vicinity of the arrangement surface 24 of the housing 23.

More specifically, the housing 23 is made of, for example, resin. The housing 23 is composed of a first substrate 231 and a second substrate 232. The second substrate 232 has a groove. Since the first substrate 231 is overlapped on the grooved surface of the second substrate 232, the space in the groove constitutes the concentration chamber 21. The housing 23 includes an intake 26 that allows the inside of the concentration chamber 21 and the outside of the concentration chamber 21 to pass through, and an outlet 27 that allows the inside of the concentration chamber 21 and the outside of the concentration chamber 21 to pass through and is different from the intake port 26. The intake port 26 and the intake port 27 face each other with the concentration chamber 21 interposed therebetween. The arrangement surface 24 is composed of the bottom surface of the groove in the second substrate 232.

The concentration chamber 21 is configured to be supplied with gas. The concentration chamber 21 is, for example, a flow path through which gas can pass. The gas can flow from the outside of the concentration chamber 21 into the concentration chamber 21 through the intake port 26, pass through the concentration chamber 21, and then flow out of the concentration chamber 21 through the outlet 27. The direction in which the gas flows in the concentrating chamber 21, that is, the direction from the intake port 26 to the outlet 27 is also referred to as a distribution direction.

At least a part of each of the first electrode 221 and the second electrode 222 is interposed between the arrangement surface 24 and the adsorber 1. The material of each of the first electrode 221 and the second electrode 222 is, for example, gold, copper, platinum or carbon.

The adsorbent 10 is arranged on the arrangement surface 24 in the concentration chamber 21. Therefore, the second substrate 232 corresponds to the substrate 13 in the adsorber 1. A part of the adsorbent 10 in the adsorber 1 is in contact with the first electrode 221 and another part of the adsorbent 10 is in contact with the second electrode 222. Therefore, the adsorbent 10 is electrically connected to the first electrode 221 and the second electrode 222.

The configuration of the adsorber 1 described here is an example, and the adsorber 1 may have various configurations.

As shown in FIG. 5, a current supply circuit 29 that supplies a current to the adsorbent 10 by applying a voltage between the first electrode 221 and the second electrode 222 to the first electrode 221 and the second electrode 222. Is connected. Further, a controller 28 that controls the current flowing through the adsorbent 10 by controlling the current supply circuit 29 is connected to the current supply circuit 29.

The controller 28 is composed of, for example, a microcomputer having one or more processors and memories. In other words, the controller 28 is implemented in a computer system having one or more processors and memory, and the computer system functions as the controller 28 by executing a program in which one or more processors are stored in the memory. .. The program may be recorded in advance in each memory of the controller 28, may be recorded through an electronic communication line such as the Internet, or may be recorded and provided on a non-temporary recording medium such as a memory card.

The cooler 25 is provided so as to overlap the outer surface of the second substrate 232 facing the side opposite to the arrangement surface 24. The cooler 25 is composed of, for example, a Peltier element. As shown in FIG. 5, the controller 28 is also connected to the cooler 25. The controller 28 also controls the operation of the cooler 25 to control the cooling of the adsorbent 10.

The position of the cooler 25 may be anywhere as long as the adsorbent 10 can be cooled. For example, the cooler 25 may be provided on the first electrode 221 or the second electrode 222.

A method of concentrating a chemical substance using the concentrator 2 will be described. The sample gas is sent into the concentration chamber 21. For that purpose, for example, the sample gas flows from the outside of the concentration chamber 21 into the concentration chamber 21 through the intake port 26, and further flows out from the inside of the concentration chamber 21 through the outlet 27 to the outside of the concentration chamber 21. Creates an air flow inside. The airflow can be generated by using an appropriate airflow generator 36 such as a pump or a fan. When an air flow is generated, the adsorber 1 is exposed to the sample gas, and the adsorbent 10 in the adsorber 1 adsorbs the chemical substances in the sample gas. Since the sample gas in the concentration chamber 21 is sequentially updated by the air flow, the adsorbent 10 can adsorb an amount of chemical substances according to the time of exposure to the sample gas. That is, the adsorbent 10 can adsorb more chemical substances than the amount of chemical substances in the sample gas having the same volume as the volume of the concentration chamber 21. Subsequently, the adsorbent 10 is heated. For example, the current supply circuit 29 applies a voltage between the first electrode 221 and the second electrode 222 to generate heat in the adsorbent 10. When the concentrator 2 is provided with a heater, the heater may heat the adsorbent 10. When the adsorbent 10 is heated, the chemical substance adsorbed on the adsorbent 10 is desorbed from the adsorbent 10 and released into the concentration chamber 21. As a result, the concentration of the chemical substance in the concentration chamber 21 can be higher than the concentration in the sample gas. As a result, a adjusting gas having a concentration of a chemical substance higher than that of the sample gas can be generated in the concentration chamber 21. This adjusting gas is sent out of the concentration chamber 21. If the air flow is still generated in the concentrating chamber 21, the adjusting gas can be sent to the outside of the concentrating chamber 21 through the outlet 27 by the air flow. After the adjusting gas is sent to the outside of the concentration chamber 21, the adsorbent 10 is cooled by the cooler 25 as needed, so that the adsorbent 10 can be quickly returned to a state in which the chemical substance can be adsorbed.

The concentrator 2 may include a plurality of concentrating chambers 21 and an adsorber 1 arranged in each concentrating chamber 21. In this case, the concentrator 2 may include one housing 23 including a plurality of concentrating chambers 21, or may include a plurality of housings 23 each including one concentrating chamber 21. When the concentrator 2 includes a plurality of adsorbers 1, the concentrator 2 includes a first electrode 221 and a second electrode 222 corresponding to each of the plurality of adsorbers 1, or corresponds to each of the plurality of adsorbers 1. A heater can be provided. Further, the concentrator 2 may be provided with a cooler 25 corresponding to each of the plurality of adsorbers 1.

The detection device 4 including the adsorbent 10 will be described.

The detection device 4 includes an adsorbent 10 and a sensor unit 31 that detects the chemical substance adsorbed by the adsorbent 1 and outputs a signal corresponding to the chemical substance. The detection device 4 may include the adsorbent 10 by providing the above-mentioned concentrator 2. When the detection device 4 includes the concentrator 2, the sensor unit 31 can detect the chemical substance in the adjusting gas having an increased concentration of the chemical substance. In this case, the detection accuracy of the chemical substance by the detection device 4 can be improved, and for example, it is possible to accurately detect the chemical substance contained in the sample gas in a very small amount.

FIG. 6 shows an example of the detection device 4. The detection device 4 includes a detector 3 and a concentrator 2. The detector 3 includes a sensor unit 31. The concentrator 2 includes an adsorber 1. The configuration of the concentrator 2 is the same as that in FIGS. 3 and 4. The same reference numerals are given to FIGS. 6 and the description thereof will be omitted as appropriate for the configurations common to those in FIGS. 3 and 4.

The detector 3 has a housing 33 and a detection chamber 32 in the housing 33. The housing 33 is made of, for example, resin. The housing 33 includes a passage 34 that allows the inside of the detection chamber 32 and the outside of the detection chamber 32 to pass through. The housing 33 of the detector 3 and the housing 23 of the concentrator 2 are connected so that the through port 34 in the housing 33 of the detector 3 leads to the outlet 27 in the housing 23 of the concentrator 2. There is. That is, the concentrating chamber 21 and the detection chamber 32 communicate with each other through the outlet 27 of the concentrator 2 and the through port 34 of the detector 3. In the present embodiment, the housing 33 of the detector 3 and the housing 23 of the concentrator 2 are separate members, but the housing 23 of the detector 3 and the housing 23 of the concentrator 2 are integrated. One member may be composed.

The detector 3 preferably includes a discharge port 35 for discharging the gas in the detection chamber 32 from the detection chamber 32. In the present embodiment, the pump, which is the airflow generator 36, is connected to the discharge port 35. The pump operates so as to suck the gas in the detection chamber 32 through the discharge port 35. Therefore, the airflow generator 36 can generate an airflow. This air flow flows from the outside of the concentrating chamber 21 into the concentrating chamber 21 through the inlet 26 of the concentrator 2, and from the inside of the concentrating chamber 21 through the outlet 27 of the concentrator 2 and the through port 34 of the detector 3, the detection chamber 32. It flows into the inside and further flows out of the detection chamber 32 through the discharge port 35. The airflow generator 36 is not limited to the pump as long as it can generate an airflow, and may be, for example, a blower fan.

When detecting a chemical substance in a gas using the detection device 4, for example, the intake 26 of the concentrator 2 is first arranged in the sample gas outside the concentrating chamber 21. By operating the airflow generator 36 in this state, an airflow is generated in the detection device 4. Due to this air flow, the sample gas flows from the outside of the concentrating chamber 21 into the concentrating chamber 21 through the inlet 26 of the concentrator 2, and from the inside of the concentrating chamber 21, the outlet 27 of the concentrator 2 and the inlet 34 of the detector 3 It flows into the detection chamber 32 through the detection chamber 32, and is further discharged to the outside of the detection chamber 32 through the discharge port 35.

In this state, when the concentrator 2 operates as described above, the adjusting gas is generated in the concentrating chamber 21, and the adjusting gas flows into the detection chamber 32 by the air flow. The sensor unit 31 can detect a chemical substance in the adjusting gas that has flowed into the detection chamber 32 and output a signal corresponding to the chemical substance. In this case, since the concentration of the chemical substance in the adjusting gas can be made higher than that in the sample gas, the detection accuracy of the chemical substance is improved by detecting the chemical substance in the sample gas by the sensor unit 31.

The application of the adsorbent 10 is not limited to the above-mentioned application to the adsorber 1, the concentrator 2, and the detection device 4. Further, the use of the adsorbent 10 is not limited to the collection of chemical substances. For example, the adsorbent 10 can be used as a sensor element for detecting a chemical substance.

A gas sensor 6 including the adsorbent 10 when the adsorbent 10 is used as a sensor element will be described. The gas sensor 6 includes an adsorbent 10 and an electrode 7 that is electrically connected to the adsorbent 10. When the gas sensor 6 is used, when the adsorbent 10 is exposed to a gas containing a chemical substance, the adsorbent 10 adsorbs the chemical substance, so that the electric resistance of the adsorbent 10 changes. Chemical substances can be detected based on this change in electrical resistance.

In the present embodiment, the adsorbent 10 has an adsorption characteristic different from the original adsorption characteristic of zinc oxide. Therefore, when the adsorbent 10 is exposed to a gas containing a chemical substance, for example, when the adsorbent 10 is exposed to a gas containing pyrrole, the electric resistance of the adsorbent 10 changes differently from that of the original zinc oxide. sell. Therefore, the gas sensor 6 having unique detection characteristics can be realized. For example, a gas sensor 6 that selectively detects pyrrole can be realized.

A specific example of the gas sensor 6 will be described with reference to FIG. The gas sensor 6 includes an adsorbent 10 and an electrode 7. The electrode 7 includes a first electrode 71 and a second electrode 72. The gas sensor 6 further includes a base material 8.

The base material 8 has electrical insulation. The base material 8 has one surface (hereinafter referred to as a support surface 81), and the first electrode 71, the second electrode 72, and the adsorbent 10 are arranged on the support surface 81. The base material 8 has, for example, the shape of a plate having a thickness in a direction orthogonal to the support surface 81. The first electrode 71 and the second electrode 72 are arranged at intervals in one direction orthogonal to the direction in which the support surface 81 faces.

The adsorbent 10 is arranged on the support surface 81 of the base material 8 and covers the first electrode 71 and the second electrode 72. As a result, the adsorbent 10 is in contact with each of the first electrode 71 and the second electrode 72. The electrical connection between the adsorbent 10 and each of the first electrode 71 and the second electrode 72 may be achieved by any structure. For example, the adsorbent 10 may be in contact with the entire first electrode 71, or may be in contact with a part of the first electrode 71. Further, the adsorbent 10 may be in contact with the entire second electrode 72, or may be in contact with a part of the second electrode 72.

The adsorbent 10 is, for example, a nanowire aggregate 5. The nanowire assembly 5 is configured by assembling a plurality of nanowires 11 without being bundled and electrically connecting them to each other.

The nanowire assembly 5 may contain a conductive material. The conductive material contains at least one material selected from the group consisting of, for example, carbon particles, carbon nanotubes, metal oxides, conductive polymers and the like. In this case, in the nanowire assembly 5, for example, a plurality of nanowires 11 and a conductive material are assembled without being bundled, and the nanowires 11 are electrically connected to each other directly or via a conductive material. ,It is configured.

The nanowire assembly 5 may contain an appropriate binder made of resin or the like. In this case, the nanowire 11 is fixed by the binder. When the nanowire assembly 5 further contains a conductive material, the nanowire 11 and the conductive material are fixed by a binder.

When producing the adsorbent 10 which is the nanowire assembly 5, for example, a composition containing a plurality of nanowires 11 and a solvent is prepared. When the adsorbent 10 contains a conductive material, the above-mentioned composition also contains the conductive material. When the adsorbent 10 contains a binder, the binder is also contained in the above-mentioned composition. The nanowire aggregate 5 can be produced by molding this composition by an inkjet method to produce a coating film and volatilizing a solvent from the coating film.

The method for producing the adsorbent 10 in the gas sensor 6 is not limited to the above. Further, the adsorbent 10 in the gas sensor 6 may have a structure as shown in FIG.

When a voltage is applied between the first electrode 71 and the second electrode 72 of the gas sensor 6, a current corresponding to the voltage and the electric resistance of the adsorbent 10 flows through the adsorbent 10. Therefore, the electrical resistance of the adsorbent 10 can be measured. Chemical substances can be detected from this value of electrical resistance. A chemical substance may be detected from the value of the current flowing between the first electrode 71 and the second electrode 72 when a constant voltage is applied between the first electrode 71 and the second electrode 72. A chemical substance may be detected from the amount of voltage change between the first electrode 71 and the second electrode 72 when a constant current is passed through the adsorbent 10. That is, the chemical substance may be detected based on an index that changes according to the change in the electrical resistance of the adsorbent 10.

1. 1. Preparation of adsorbent (1) Sample 1
A silicon wafer having an oxide film having a diameter of 10.16 cm (4 inches) was prepared as the substrate 13. The thickness of the oxide film was 300 nm. A radio frequency (RF) sputtering apparatus was used to form a base 113 (zinc oxide film) having a thickness of 30 nm on the surface of the substrate 13.

_{Also, Zn (NO 3) 2 ·} 6H 2 O concentration of 25 mmol / L, hexamethylenetetramine concentration 25 mmol / L, polyethyleneimine concentration of 2.5 mmol / L, ammonia (ammonium hydroxide: NH ₄ OH) concentration 500mmol An aqueous solution of / L was prepared. The molecular weight of polyethyleneimine used was 1800.

The adsorbent 10 was produced by immersing the base 113 in the aqueous solution for 5 hours while maintaining the temperature of the aqueous solution at 95 ° C. to grow the nanowires 11 from the base 113. After producing the adsorbent 10, a silicon wafer having a diameter of 10.16 cm (4 inches) was cut into a strip of 2 mm × 20 mm. As a result, an adsorber 1 including the substrate 13 and the adsorbent 10 was obtained.

(2) Samples 2-6
The time for immersing the base 113 in the aqueous solution is 10 hours when the sample 2 is prepared, 20 hours when the sample 3 is prepared, 40 hours when the sample 4 is prepared, 60 hours when the sample 5 is prepared, and 80 hours when the sample 6 is prepared. And said. Other than that, the adsorbent 10 was prepared by the same method and conditions as in the case of sample 1, and cut into strips of 2 mm × 20 mm to obtain an adsorbent 1 including the substrate 13 and the adsorbent 10.

2. 2. Adsorption test Each of the samples 1 to 6 was heated at 400 ° C. for 30 minutes to remove impurities, and then cooled to room temperature. Subsequently, with each sample placed in a housing formed of polyetheretherketone (PEEK) resin, a sample gas containing 1 volume ppm of nonanal, benzaldehyde, and pyrrole was placed in the housing at a flow rate of 100 mL / min. Then, it was circulated for 1 minute.

Subsequently, a sample was placed at the injection port of GCMS-TQ8040, which is a gas chromatograph mass spectrometer manufactured by Shimadzu Corporation. For the injection port, OPTIC-4, which is a multifunctional injection port manufactured by Shimadzu Corporation, was used. The temperature inside the inlet is raised from 40 ° C to 250 ° C at a rate of 20 ° C / sec, and the sample is heated at 250 ° C for 5 minutes to desorb the chemical substance from the sample, and further analyze the chemical substance by gas chromatograph mass spectrometry. It was injected into a meter to obtain a chromatogram.

In the measurement, SLB-IL60 manufactured by Sigma-Aldrich was used as the column. The temperature rising condition of the column was to first hold at 40 ° C. for 5 minutes, then raise the temperature to 240 ° C. at a heating rate of 10 ° C./min, and then maintain at 240 ° C. for 5 minutes.

From the above results, the amounts (adsorbed amount) of nonanal, benzaldehyde, and pyrrole adsorbed by each sample were derived. The result is shown in FIG. It should be noted that this result is an average value when each sample is tested 10 times. A, B and C in the figure indicate the adsorption amounts of nonanal, benzaldehyde and pyrrole, respectively.

As shown in this result, in Sample 1 where the immersion time is 5 hours, the adsorption amount of pyrrole is very small with respect to the adsorption amount of nonanal, but in Samples 2 to 6 where the immersion time is 10 hours or more, pyrrole As the adsorption amount increased, the value of the adsorption amount ratio was 1 or more in Sample 3, and in Samples 4 to 6, the adsorption amount of nonanaal was a very low value with respect to the adsorption amount of pyrrole. The change in the amount of benzaldehyde adsorbed was small.

The details of the results of 10 tests for Sample 2 are shown in the table below. As shown in this, in Sample 2 in which the immersion time was 10 hours, the value of the ratio of the adsorption amount was 0.44 or more, and the average value of the ratio of the adsorption amount was 0.573.

3. 3. Photoluminescence Properties Each of Samples 1 to 6 was heated at 400 ° C. for 30 minutes to remove impurities and then cooled to room temperature. Subsequently, the photoluminescence spectrum of each sample from a wavelength of 300 nm to 750 nm was measured. In the measurement, two 2 mm × 20 mm samples were prepared, and the measurement was performed using an FP-8500 manufactured by JASCO Corporation at an excitation light wavelength of 256 nm and a scanning speed of 10 nm / min. The result is shown in FIG. A, B, C, D, E and F in FIG. 9 show the results for samples 1, 2, 3, 4, 5 and 6, respectively.

According to FIG. 9, no large peak was observed in the samples 1 to 3 having an immersion time of 5 to 20 hours during production, and the wavelength with the maximum peak top was larger than 550 nm. On the other hand, in the samples 4 to 6 having an immersion time of 40 to 80 hours, the wavelength with the maximum peak top was 550 nm or less, and the longer the immersion time, the higher the intensity of the peak top. When this result and the result of the adsorption characteristic are combined, it was confirmed that the peak in the photoluminescence spectrum from 300 nm to 550 nm correlates with the adsorption characteristic.

4. Confirmation of Examples of Relationship between Nitrogen Content and Adsorption Properties The zinc and nitrogen contents of the nanowires 11 in each of Samples 1 to 4 in the surface layer portion were determined from the results of X-ray photoelectron spectroscopy (XPS) measurement. For XPS measurement, AXIS-165 manufactured by Shimadzu Corporation / KRATOS was used. The measurement conditions are as follows.
Monochromatic X-ray source: AlKα ray, half width 0.2-0.3 eV
Measuring elements: Zn2p, O1s, C1s, N1s
Analysis depth region: 3 nm from the outermost surface
The results are shown in Table 2 below.

Comparing this result with the adsorption characteristics of each sample shown in FIG. 8, it was confirmed that the nitrogen content correlates with the adsorption characteristics, and particularly with the pyrrole adsorption amount. On the other hand, since the amount of nonanal adsorbed differs greatly between sample 3 and sample 4, it is inferred from this result that factors other than the nitrogen content have a strong influence on the amount of nonanal adsorbed.

Further, a comparative sample was obtained by subjecting sample 4 to plasma treatment to remove nitrogen atoms in sample 4. The nitrogen content of this comparative sample was 1.84 atm%, which was about the same as that of sample 1. For this comparative sample, the same adsorption test as in the cases of Samples 1 to 6 above was carried out, and the adsorption characteristics of nonanal, benzaldehyde and pyrrole were investigated.

The adsorption characteristics of Sample 1, Sample 4, and Comparative Sample are summarized in FIG. In FIG. 10, A, B, and C show the results for sample 1, sample 4, and comparative sample, respectively.

According to FIG. 10, as already confirmed, sample 1 had a large amount of nonanal adsorbed and a small amount of pyrrole was adsorbed, whereas sample 4 had a small amount of nonanal adsorbed and a large amount of pyrrole. On the other hand, in the comparative sample in which nitrogen was removed from sample 4, the amount of nonanal adsorbed was large and the amount of pyrrole adsorbed was small, as in sample 1.

According to this result, when nitrogen was removed from sample 4 by plasma treatment, not only the amount of pyrrole adsorbed but also the amount of nonanal adsorbed was the same as that of sample 1 in which the adsorbed portion 111 was not observed. In view of this result, the nitrogen content affects both the pyrrole adsorption amount and the nonanal adsorption amount.

Based on the above results, it is presumed that the factors that affect the adsorption amount of nonanal are complex factors including nitrogen content and others, although they have not been fully elucidated.

5. Transmission Electron Microscope (TEM) Images Transmission electron microscope images of the nanowires 11 in each of Sample 1 and Sample 4 were taken. Images of sample 1 are shown in FIGS. 11A and 11B, and images of sample 4 are shown in FIGS. 12A and 12B. According to this result, in the case of sample 1, the nanowire 11 did not distinguish between the core portion 112 and the adsorption portion 111. On the other hand, in the case of sample 4, the wire-shaped core portion 112 and the suction portion 111 covering the core portion 112 were clearly recognized in the nanowire 11. Further, in sample 4, the core portion 112 has high homogeneity, and the crystals constituting the core portion 112 are recognized to have high orientation, whereas the adsorption portion 111 has low homogeneity, and the crystals constituting the adsorption portion. It is recognized that the orientation of is lower than that of the core portion 112. From this, it was confirmed that the orientation of the crystals constituting the adsorption portion correlates with the adsorption characteristics.

As is clear from the above embodiments and examples, the adsorbent (10) according to the first aspect of the present disclosure includes nanowires (11) containing zinc oxide, and the nanowires (11) are wire-shaped cores. It has a portion (112) and an adsorption portion (111) that covers the core portion (112), and the adsorption portion (111) contains zinc oxide and a nitrogen atom.

According to the first aspect, the adsorbent (10) can have an adsorption property different from the original adsorption property of zinc oxide.

The adsorbent (10) according to the second aspect of the present disclosure is an aggregate of a plurality of nanowires (11) in the first aspect.

According to the second aspect, the adsorption performance of the chemical substance by the adsorbent (10) can be enhanced.

The adsorbent 10 according to the third aspect of the present disclosure is an adsorbent when the adsorbent (10) is exposed to a sample gas containing 1 volume ppm each of nonanal and pyrrole for 1 minute in the first or second aspect. It has an adsorption characteristic that the value of the ratio of the adsorption amount of pyrrole to the adsorption amount of nonanal to (10) is 0.4 or more.

According to the third aspect, the adsorbent (10) can have an adsorption property different from the original adsorption property of zinc oxide.

In the adsorbent (10) according to the fourth aspect of the present disclosure, in any one of the first to third aspects, the thickness of the adsorbent (111) along the radial direction of the nanowire (11) is 10 nm. It is 30 nm or more and 30 nm or less.

According to the fourth aspect, the adsorbent (10) tends to have an adsorption property that is significantly different from the original adsorption property of zinc oxide.

In the adsorbent (10) according to the fifth aspect of the present disclosure, in any one of the first to fourth aspects, the core portion (112) and the adsorbent portion (111) have different crystal sequences from each other.

According to the fifth aspect, the adsorbent (10) tends to have an adsorption property that is significantly different from the original adsorption property of zinc oxide.

The adsorbent (10) according to the sixth aspect of the present disclosure includes an adsorbent (111) containing zinc oxide and a nitrogen atom. The adsorbent (10) is the ratio of the adsorbed amount of pyrrole to the adsorbed amount of nonanaal on the adsorbent (10) when the adsorbent (10) is exposed to a sample gas containing 1 volume ppm each of nonanal and pyrrol for 1 minute. Has an adsorption characteristic that the value of is 0.4 or more.

According to the sixth aspect, the adsorbent (10) can have an adsorption property different from the original adsorption property of zinc oxide.

The adsorbent (10) according to the seventh aspect of the present disclosure is, in any one of the first to sixth aspects, the adsorbent (10) in a sample gas containing 1 volume ppm each of nonanal and pyrrol for 1 minute. It has an adsorption characteristic that the value of the ratio of the adsorption amount of pyrrole to the adsorption amount of nonanaal on the adsorbent 10 when exposed is 1 or more.

According to the seventh aspect, the adsorbent (10) can have an adsorption property that is significantly different from the original adsorption property of zinc oxide.

In the adsorbent (10) according to the eighth aspect of the present disclosure, in any one of the first to seventh aspects, the adsorbent (111) has a wavelength in the range of 300 nm to 750 nm in the photoluminescence spectrum. It has a photoluminescence characteristic that the maximum peak top is 550 nm or less.

According to the eighth aspect, the adsorbent (10) tends to have an adsorption property that is significantly different from the original adsorption property of zinc oxide.

The adsorbent (10) according to the ninth aspect of the present disclosure has a nitrogen atom content of 5 at% or more and 13 at% or less in the adsorbed portion (111) in any one of the first to eighth aspects. ..

According to the ninth aspect, the adsorbent (10) tends to have an adsorption property that is significantly different from the original adsorption property of zinc oxide.

The method for producing the adsorbent (10) according to the tenth aspect of the present disclosure is the method for producing the adsorbent (10) according to any one of the first to ninth aspects. In this method, nanowires (11) are grown in an aqueous solution containing zinc ions, ammonia of 250 mmol / L or more and 750 mmol / L or less, and polyethyleneimine of 1 mmol / L or more and 3 mmol / L or less. The time for growing the nanowire (11) is the adsorption of pyrrol with respect to the amount of nonanal adsorbed on the adsorbent (10) when the adsorbent (10) is exposed to a sample gas containing 1 volume ppm each of nonanal and pyrrol for 1 minute. The value of the ratio of quantities is specified to be 0.4 or more.

According to the tenth aspect, the adsorbent 10 having an adsorption characteristic different from the original adsorption characteristic of zinc oxide can be produced.

In the method for producing the adsorbent (10) according to the eleventh aspect of the present disclosure, in the tenth aspect, the time for growing the nanowires (11) is 10 hours or more.

According to the eleventh aspect, the adsorbent (10) tends to have an adsorption property that is significantly different from the original adsorption property of zinc oxide.

The method for producing the adsorbent (10) according to the twelfth aspect of the present disclosure is the method for producing the adsorbent (10) according to any one of the first to ninth aspects. In this method, the wire-shaped base (113) is immersed in an aqueous solution containing zinc ions, ammonia of 250 mmol / L or more and 750 mmol / L or less, and polyethyleneimine of 1 mmol / L or more and 3 mmol / L or less, thereby immersing the base (113). ) Includes growing nanowires (11) by precipitating the product on the surface.

According to the twelfth aspect, the adsorbent (10) having an adsorption characteristic different from the original adsorption characteristic of zinc oxide can be produced.

In the method for producing the adsorbent (10) according to the thirteenth aspect of the present disclosure, in any one of the tenth to twelfth aspects, the adsorbent (10) is referred to as nonanal during the time for growing the nanowire (11). It is specified that the value of the ratio of the adsorbed amount of pyrrole to the adsorbed amount of nonanaal on the adsorbent (10) when exposed to the sample gas containing 1 volume ppm of pyrrole for 1 minute is 1 or more.

According to the thirteenth aspect, the adsorbent (10) having an adsorption characteristic significantly different from the original adsorption characteristic of zinc oxide can be produced.

The adsorbent (1) according to the fourteenth aspect of the present disclosure includes an adsorbent (10) according to any one of the first to ninth aspects.

According to the fourteenth aspect, the adsorbent (10) in the adsorber (1) can have an adsorption characteristic significantly different from the original adsorption characteristic of zinc oxide.

The concentrator (2) according to the fifteenth aspect of the present disclosure is a concentrating chamber (21) and an adsorbent according to any one of the first to ninth aspects arranged in the concentrating chamber (21). 10) and.

According to the fifteenth aspect, the adsorbent (10) in the concentrator (2) can have an adsorption characteristic significantly different from the original adsorption characteristic of zinc oxide.

The detection device (4) according to the sixteenth aspect of the present disclosure detects the adsorbent (10) according to any one of the first to ninth aspects and the chemical substance adsorbed by the adsorbent (10). It is provided with a sensor unit (31) that outputs a signal corresponding to a chemical substance.

According to the sixteenth aspect, the adsorbent (10) in the detection device (4) can have an adsorption characteristic significantly different from the original adsorption characteristic of zinc oxide.

The gas sensor (6) according to the seventeenth aspect of the present disclosure includes the adsorbent (10) according to any one of the first to ninth aspects and an electrode (7) electrically connected to the adsorbent (10). And.

According to the seventeenth aspect, the gas sensor (6) using the adsorbent (10) as the sensor element can be realized, and the gas sensor (6) has different detection characteristics from the case where ordinary zinc oxide is used as the sensor element. realizable.

The nanowire assembly (5) according to the eighteenth aspect of the present disclosure is an assembly of a plurality of nanowires (11) containing zinc oxide, and the nanowire (11) has a wire-shaped core portion (112) and a core. It has a suction portion (111) that covers the portion (112). The adsorption unit (111) contains zinc oxide and a nitrogen atom.

According to the eighteenth aspect, a nanowire aggregate (5) having an adsorption characteristic different from the original adsorption characteristic of zinc oxide can be obtained.

1 Adsorber 10 Adsorbent 11 Nanowire 111 Adsorbent 112 Core part 113 Base part 2 Concentrator 21 Concentration chamber 31 Sensor part 4 Detector 5 Nanowire assembly 6 Gas sensor 7 Electrode

Claims (18)

Equipped with nanowires containing zinc oxide,
The nanowire has a wire-shaped core portion and a suction portion that covers the core portion.
The adsorbed portion contains zinc oxide and a nitrogen atom.
Adsorbent. The adsorbent is an aggregate of the plurality of nanowires.
The adsorbent according to claim 1. When the adsorbent is exposed to a sample gas containing 1 volume ppm each of nonanal and pyrrol for 1 minute, the ratio of the adsorbed amount of pyrrole to the adsorbed amount of nonanaal to the adsorbent is 0.4. It has the adsorption characteristic that it is the above.
The adsorbent according to claim 1 or 2. The thickness of the adsorption portion along the radial direction of the nanowire is 10 nm or more and 30 nm or less.
The adsorbent according to any one of claims 1 to 3. The core portion and the adsorption portion have different crystal sequences from each other.
The adsorbent according to any one of claims 1 to 4. It is an adsorbent having an adsorbent containing zinc oxide and nitrogen atoms.
When the adsorbent is exposed to a sample gas containing 1 volume ppm each of nonanal and pyrrol for 1 minute, the ratio of the adsorbed amount of pyrrole to the adsorbed amount of nonanaal to the adsorbent is 0.4. It has the adsorption characteristic that it is the above.
Adsorbent. When the adsorbent is exposed to a sample gas containing 1 volume ppm each of nonanal and pyrrol for 1 minute, the ratio of the adsorbed amount of pyrrole to the adsorbed amount of nonanaal to the adsorbent is 1 or more. Has the adsorption property of being
The adsorbent according to any one of claims 1 to 6. The adsorbed portion has a photoluminescence characteristic that the maximum peak top in the wavelength range of 300 nm to 750 nm in the photoluminescence spectrum is 550 nm or less.
The adsorbent according to any one of claims 1 to 7. The content of nitrogen atoms in the adsorbed portion is 5 at% or more and 13 at% or less.
The adsorbent according to any one of claims 1 to 8. The method for producing an adsorbent according to any one of claims 1 to 5.
The nanowires were grown in an aqueous solution containing zinc ions, ammonia of 250 mmol / L or more and 750 mmol / L or less, and polyethyleneimine of 1 mmol / L or more and 3 mmol / L or less.
The time for growing the nanowire is the value of the ratio of the amount of adsorbed pyrrole to the amount of adsorbed nonanal to the adsorbent when the adsorbent is exposed to a sample gas containing 1 volume ppm each of nonanal and pyrrol for 1 minute. It is specified to be 0.4 or more,
Manufacturing method of adsorbent. The time for growing the nanowires is 10 hours or more.
The method for producing an adsorbent according to claim 10. The method for producing an adsorbent according to any one of claims 1 to 5.
By immersing the wire-shaped base in an aqueous solution containing zinc ions, ammonia of 250 mmol / L or more and 750 mmol / L or less, and polyethyleneimine of 1 mmol / L or more and 3 mmol / L or less, a product is precipitated on the surface of the base. Including growing the nanowires by allowing them to grow,
Manufacturing method of adsorbent. The time for growing the nanowire is the value of the ratio of the amount of adsorbed pyrrole to the amount of adsorbed nonanal to the adsorbent when the adsorbent is exposed to a sample gas containing 1 volume ppm each of nonanal and pyrrol for 1 minute. It is specified to be 1 or more,
The method for producing an adsorbent according to any one of claims 10 to 12. The adsorbent according to any one of claims 1 to 9 is provided.
Adsorber. Concentration room and
The adsorbent according to any one of claims 1 to 9 is provided in the concentration chamber.
Concentrator. The adsorbent according to any one of claims 1 to 9 and
A sensor unit that detects a chemical substance adsorbed by the adsorbent and outputs a signal corresponding to the chemical substance is provided.
Detection device. The adsorbent according to any one of claims 1 to 9 and
The electrode provided with an electrode electrically connected to the adsorbent.
Gas sensor. An aggregate of multiple nanowires containing zinc oxide,
The nanowire has a wire-shaped core portion and a suction portion that covers the core portion.
The adsorbed portion contains zinc oxide and a nitrogen atom.
Nanowire assembly.