Nanocarbon generator and nanocarbon manufacturing method

Abstract

To provide a nanocarbon generator and a nanocarbon manufacturing method for easily generating carbon nanobrushes.SOLUTION: A nanocarbon generator comprises a cylindrical target containing carbon and a catalyst, and a laser irradiation part for irradiating the peripheral surface of the cylindrical target with a laser at an incidence angle of 50° or more and 80° or less. The incidence angle is an angle formed by the normal of the peripheral surface of the laser irradiation part and the laser.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a nanocarbon generating apparatus and a nanocarbon manufacturing method. [Background technology]

[0002] It is known to use laser light when generating carbon nanobrushes.

[0003] For example, Patent Document 1 discloses a method for producing a carbon nanobrush containing carbon nanohorn aggregates by continuously irradiating a surface of a carbon target containing a metal catalyst such as iron with laser light. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2018 / 155627 Summary of the Invention [Problem to be solved by the invention]

[0005] The carbon nanobrushes disclosed in Patent Document 1 are obtained by irradiating a carbon target containing a catalyst with a laser, but depending on the irradiation angle of the laser, it may be difficult to produce the carbon nanobrushes.

[0006] An object of the present disclosure is to provide a nanocarbon generation device and a nanocarbon production method that solve the above-mentioned problems. [Means for solving the problem]

[0007] A nanocarbon generation apparatus according to one embodiment of the present disclosure comprises a cylindrical target containing carbon and a catalyst, and a laser irradiation unit that irradiates a laser onto a peripheral surface of the cylindrical target at an incident angle of 50° or more and 80° or less, the incident angle being the angle between the normal to the peripheral surface at the laser irradiated portion and the laser.

[0008] A nanocarbon production method according to one embodiment of the present disclosure includes the steps of: disposing a laser irradiation unit capable of irradiating a laser and a cylindrical target containing carbon and a catalyst; and irradiating the laser onto a peripheral surface of the cylindrical target at an incident angle of 50° or more and 80° or less, wherein the incident angle is the angle between the laser and a normal to the peripheral surface at the laser irradiated portion. Effect of the Invention

[0009] According to the nanocarbon generation apparatus and nanocarbon production method of the present disclosure, carbon nanobrushes can be easily generated. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view of a nanocarbon production device according to a first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view of the nanocarbon production apparatus according to the first embodiment. [Diagram 3] 1 is a flowchart of a nanocarbon production method according to a first embodiment. [Figure 4] FIG. 4 is a cross-sectional view of a nanocarbon production apparatus in a second embodiment. [Diagram 5] A cross-sectional view of the minimum configuration of a nanocarbon production device in the third embodiment. [Figure 6] 13 is a flowchart of a minimum configuration of a nanocarbon production method according to a fourth embodiment. [Figure 7] 1 is an SEM image of nanocarbon produced at an incident angle of 30° in Example 1. [Figure 8] 1 is an SEM image of nanocarbon produced at an incident angle of 45° in Example 1. [Figure 9] 1 is an SEM image of nanocarbon produced at an incident angle of 60° in Example 1. [Figure 10] 1 is an SEM image of nanocarbon produced at an incident angle of 70° in Example 1. [Figure 11]1 is a table showing the relationship between the amount of evaporation and the content of graphite at each incident angle in Example 1. [Figure 12] 1 is a SEM image of nanocarbon produced in a helium atmosphere at an incident angle of 60° in Example 2. [Figure 13] 1 is a SEM image of nanocarbon produced in a nitrogen atmosphere at an incident angle of 60° in Example 2. [Figure 14] 1 is a SEM image of nanocarbon produced in Example 2 at an incident angle of 60° under an argon atmosphere. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, each embodiment of the present disclosure will be described with reference to the drawings. Note that the drawings and specific configurations used in each embodiment should not be used to interpret the disclosure. The same or corresponding configurations in all drawings are given the same reference numerals, and common descriptions are omitted.

[0012] First Embodiment A first embodiment according to the present disclosure will be described below with reference to FIGS. 1 to 3. FIG.

[0013] (Configuration of nanocarbon generating device) As shown in FIG. 1, the nanocarbon generator 1 includes a cylindrical target 11, a laser irradiation unit 12, and a chamber . The nanocarbon generator 1 irradiates a cylindrical target 11 with a laser L to generate nanocarbon. For example, the nanocarbons that are produced include nano-sized carbon materials whose main component is carbon, such as carbon nanotubes (CNTs), carbon nanohorns (CNHs), carbon nanohorns aggregates (CNHs), carbon nanobrushes (hereafter referred to as CNBs), amorphous carbon, fullerenes, graphene, etc. CNTs are fibrous materials with diameters of 0.7 to 1.5 nm, and lengths of each fiber ranging from several hundred nm to several tens of μm. A cylindrical CNT made from a single graphene sheet is called a single-walled carbon nanotube, while a CNT made up of multiple coaxially stacked CNTs of different diameters forming multiple layers is called a multi-walled carbon nanotube. There are two types of CNTs: semiconducting type, which exhibits semiconducting properties, and metallic type, which exhibits metallic properties. The properties of the CNT change depending on the arrangement of the six-membered rings in the circumferential direction of the CNT. CNHs are cylindrical structures with a conical tip, with a cone angle of about 19°, a diameter of 2 to 5 nm, and a length of 40 to 50 nm. CNHs are spherical aggregates formed by radially assembling multiple single-layer CNHs made of a single graphene sheet. The diameter of CNHs is approximately 50 to 100 nm. CNHs also come in various shapes, such as dahlia, seed, bud, and petal-dahlia, and these shapes can be selected appropriately by adjusting the atmospheric gas during CNHs generation.

[0014] CNBs are nanocarbons that have both high electrical conductivity and high dispersibility, which are characteristics of CNTs and CNHs. CNBs have a fibrous shape in which single-layer CNHs are radially assembled. The diameter of a CNB is approximately 30 to 60 nm, and the length is several μm. For example, CNBs may contain catalysts, graphene, or graphite in their structure. CNB is obtained by irradiating a cylindrical target 11 to which a specific catalyst is added with a laser L. At this time, the cylindrical target 11 has a specific bulk density adjusted to have a certain amount of catalyst.

[0015] (Cylindrical target configuration) The cylindrical target 11 includes carbon and a catalyst. The bulk density of the cylindrical target 11 may be appropriately set according to the content of the catalyst. For example, the bulk density of the cylindrical target 11 is 1.5 g / cm 3 For example, the bulk density of the cylindrical target 11 is 0.25 g / cm 3 More than 1.5g / cm 3For example, the bulk density of the cylindrical target 11 is 0.50 g / cm 3 More than 1.5g / cm 3 For example, the bulk density of the cylindrical target 11 is 1.3 g / cm 3 More than 1.5g / cm 3 The following is the result. The cylindrical target 11 has a bulk density of 1.5 g / cm 3 CNB can be generated by having the following ranges: Bulk density 1.5g / cm 3 Within the following ranges, the lower the bulk density, the greater the CNB production rate. For example, the catalyst of the cylindrical target 11 may contain Fe, Ni, or Co. When the catalyst contains Fe, Ni, or Co, CNBs are generated from the cylindrical target 11 irradiated with the laser L. Furthermore, the catalyst of the cylindrical target 11 may contain Fe, Ni, or Co alone, or two or three types of Fe, Ni, or Co. For example, since the generation rate of CNBs increases in the order Fe>FeCo>Ni>Co=FeNi, Fe may be used as the catalyst. For example, the catalyst content in the cylindrical target 11 is 0.3 atomic % or more and 20 atomic % or less (at.%). For example, the catalyst content in the cylindrical target 11 is 0.5 at.% or more and 3 at.% or less. For example, the catalyst content in the cylindrical target 11 is 1 at.% or more and 3 at.% or less. The cylindrical target 11 has a catalyst content of 3 at. % or less, so that CNB can be produced. Within the range of the catalyst content of 3 at. % or less, the higher the catalyst content, the higher the CNB production rate.

[0016] For example, the cylindrical target 11 has a diameter of 3 cm. The diameter of the cylindrical target 11 may be changed appropriately depending on the power of the laser L. For example, the cylindrical target 11 may be rotatable. For example, the cylindrical target 11 may be movable in the direction of the cylindrical axis O of the cylindrical target 11 (direction D). In manufacturing the CNB described later, a laser ablation method is used in which a cylindrical target 11 is irradiated with a laser L. Since the cylindrical target 11 is rotatable, the cylindrical target 11 can always face a new surface with respect to the irradiation position P of the laser L. This allows the laser irradiation unit 12 to avoid irradiating an already irradiated surface with the laser L again, and always generate a CNB on a new surface of the cylindrical target 11. For example, the irradiation position P of the laser L may move in a spiral motion with respect to the cylindrical target 11. The rotation speed of the cylindrical target 11 is appropriately set depending on the desired amount of nanocarbon to be produced. For example, if the cylindrical target 11 has a diameter of 3 cm, it rotates in one direction (ROT direction) around the cylindrical axis O at a rotation speed of 0.5 rpm to 4 rpm. If the rotation speed is sufficiently higher than this range, nanocarbon may not be easily generated. For example, the ROT direction may be clockwise. The speed at which the cylindrical target 11 is sent out is appropriately set depending on the bulk density of the cylindrical target 11, and the power and spot diameter of the irradiated laser L. For example, the cylindrical target 11 moves in the direction of the cylindrical axis O (direction D) at a feed rate of 1 mm / min to 50 mm / min.

[0017] (Configuration of laser irradiation unit) 1 and 2, the laser irradiation unit 12 includes a laser source 121 and a lens 122. In order to describe the laser L irradiated to the cylindrical target 11, the chamber 14 and the laser source 121 are omitted in FIG. The laser irradiation unit 12 irradiates the laser L. After irradiation, a plume PL is generated from the irradiation position P of the cylindrical target 11, and the heated carbon and catalyst evaporate all at once, forming high-density carbon-catalyst droplets. CNHs are formed in some of these droplets, and CNTs are formed from the catalyst in the other droplets. The formed CNHs grow into fibers using the CNTs as templates, and the CNTs and CNHs are partially bonded by heat during the cooling process to generate CNBs. The nanocarbon generated by the laser ablation method is a mixture of CNBs and CNHs (CNB / CNHs). The laser source 121 emits a laser beam L. For example, the laser L emitted by the laser source 121 may be a CO2 laser, an excimer laser, a YAG laser, a semiconductor laser, etc. As long as it can heat the cylindrical target 11 to a high temperature, the laser L emitted by the laser source 121 may be any laser. The lens 122 focuses the laser beam L, and the laser beam L is irradiated toward the cylindrical target 11 through an irradiation window of the chamber 14 . The lens 122 is a condenser lens, for example, a ZnSe lens. The operator sets the laser output from the laser source 121 and appropriately sets the spot diameter with the lens 122 so as to obtain the desired amount of nanocarbon produced. For example, the worker sets the laser output to 1.0 kW or more and 10 kW or less for the cylindrical target 11. For example, the worker sets the laser output to 2.0 kW or more and 5.0 kW or less for the cylindrical target 11. If the laser output is lower than this range, the amount of evaporation of the cylindrical target 11 is small, and it is difficult to generate a sufficient amount of CNB. For example, the operator may set the spot diameter for the cylindrical target 11 to an irradiation area of ​​0.002 cm 2 More than 0.2cm 2 The spot diameter is set to be in the following range: That is, the operator sets the spot diameter to be 0.5 mm or more and 5 mm or less.

[0018] The laser irradiation unit 12 irradiates the peripheral surface of the cylindrical target 11 with a laser beam L at an incident angle of 50° to 80°. At this time, the incident angle is the angle θ formed between the laser beam L and a normal N to the peripheral surface in the laser irradiation portion. Since the plume PL is formed on the normal N of the peripheral surface of the laser irradiated portion, it is desirable for the operator to adjust the irradiation direction of the laser L so as not to obstruct the formed plume PL and to make it easy to collect the evaporated nanocarbon. For example, the operator adjusts the irradiation direction of the laser L so that the laser L forms an angle θ with the normal N. By irradiating the laser L at an incident angle of 50° or more and 80° or less, the laser irradiation unit 12 can increase the CNB production rate compared to irradiating the laser L at other incident angles, and can produce high-purity CNB / CNHs with reduced production of impurities such as graphite that do not contribute to the electrical properties of the CNB / CNHs. For example, the laser irradiation unit 12 may irradiate the peripheral surface of the cylindrical target 11 with a laser at an incident angle of 60° or more and 70° or less. The laser irradiation unit 12 can generate CNB from the cylindrical target 11 in higher purity and in larger quantities. The laser irradiation unit 12 irradiates the cylindrical target 11 with the laser L within a plane perpendicular to the cylindrical axis O. This allows the incident angle set within the plane perpendicular to the cylindrical axis O to be converted into an actual incident angle with respect to the circumferential surface of the cylindrical target 11, making it easy for the operator to set a desired incident angle with respect to the cylindrical target 11. In addition, the energy density of the laser L on the circumferential surface of the cylindrical target 11 can be increased, ensuring the required energy density. For example, it is expected that the laser L emitted by the laser irradiation unit 12 is emitted from a position above or below the cylinder axis O within a plane perpendicular to the cylinder axis O. For example, in this embodiment, the laser L is irradiated in a plane perpendicular to the cylinder axis O from above the cylinder axis O (FIG. 2).

[0019] (Chamber configuration) The chamber 14 has an irradiation window through which the laser L passes. The chamber 14 is in a vacuum state or filled with an inert gas. For example, the chamber 14 is filled with nitrogen or argon. The pressure inside the chamber 14 is appropriately set depending on the desired amount of nanocarbon to be produced. For example, the pressure within the chamber 14 is maintained at 760 Torr when filled with an inert gas. The temperature inside the chamber 14 is set to an arbitrary temperature. For example, the temperature inside the chamber 14 is 25°C. For example, the inside of the chamber 14 is maintained at a constant pressure and temperature during irradiation with the laser L. For example, the chamber 14 has an exhaust port (not shown) and an inert gas inlet (not shown). During irradiation with the laser L, an inert gas is supplied to the chamber 14 from the inert gas inlet at 10 L / min, and the same amount of gas within the chamber is exhausted from the exhaust port. For example, the flow rate of the inert gas supplied into the chamber 14 and the flow rate of the gas exhausted from the chamber 14 are appropriately set according to the amount of evaporation of the cylindrical target 11 . For example, the chamber 14 may have a separate collection port, and an operator may collect the CNB / CNHs through the collection port.

[0020] (Nanocarbon manufacturing method) A nanocarbon production method according to this embodiment will be described. The nanocarbon production method in this embodiment is carried out according to the flow shown in FIG.

[0021] First, an operator places the laser irradiation unit 12 capable of irradiating the laser L and the cylindrical target 11 containing carbon and a catalyst (ST1). For example, the operator may arrange the laser irradiation unit 12 so as to irradiate the laser L within a plane perpendicular to the cylindrical axis O of the cylindrical target 11. This makes it easier for the operator to grasp the positional relationship of the laser L with respect to the cylindrical target 11 and to change the relative position.

[0022] Furthermore, for ST3 described later, when placing the cylindrical target 11, the worker may displace the cylindrical axis O of the cylindrical target with respect to the laser L. This changes the irradiation position P of the laser L with respect to the cylindrical target 11, and the incidence angle also changes.

[0023] For example, the catalyst of the cylindrical target 11 may contain Fe, Ni, or Co. When the catalyst contains Fe, Ni, or Co, CNBs are generated from the cylindrical target 11 irradiated with the laser L. Furthermore, the catalyst of the cylindrical target 11 may contain Fe, Ni, or Co alone, or two or three types of Fe, Ni, or Co. For example, since the generation rate of CNBs increases in the order of Fe>FeCo>Ni>Co=FeNi, the operator may use Fe as the catalyst.

[0024] For example, the bulk density of the cylindrical target 11 is 1.5 g / cm 3 The worker may determine that the bulk density is 1.5 g / cm 3 CNB can be produced using a cylindrical target 11 having the following range: Bulk density 1.5 g / cm 3 Within the following ranges, higher bulk densities increase the rate of CNB production. For example, the catalyst content in the cylindrical target 11 may be 0.5 at.% or more and 3 at.% or less. An operator can generate CNB by using a cylindrical target 11 with a catalyst content of 3 at.% or less. When the catalyst content is in the range of 3 at.% or less, the higher the catalyst content, the higher the CNB generation rate.

[0025] Next, the operator rotates the cylindrical target 11 in one direction (ROT direction) around the cylindrical axis O and moves the cylindrical target 11 in the direction of the cylindrical axis O (D direction) to spirally scan the irradiation position P of the laser L on the peripheral surface of the cylindrical target 11 (ST2). This allows the cylindrical target 11 to always face a new surface with respect to the irradiation position P of the cylindrical target 11. This allows the laser irradiation unit 12 to avoid irradiating the laser L again onto an already irradiated surface, and to always generate CNBs on a new surface of the cylindrical target 11.

[0026] Next, the worker fills the chamber with inert gas and controls the pressure to around 760 Torr. If the pressure is 500-1000 Torr, it is easy for the worker to control the pressure. If the worker changes the atmospheric gas (inert gas), the proportion of CNB generated changes. The larger the atomic weight, the more CNB is generated. In particular, when argon or krypton is used as the atmospheric gas, the proportion of CNB generated increases. CNB can also be generated with neon, but the gas is expensive, which poses a challenge for reducing costs.

[0027] Next, the worker irradiates the peripheral surface of the cylindrical target 11 with the laser L at an incident angle of 50° to 80° (ST3). At this time, the incident angle is the angle θ between the normal N of the peripheral surface at the irradiated portion of the laser L and the laser L. After irradiation, a plume PL is generated from the irradiation position P of the cylindrical target 11, causing the heated carbon and catalyst to evaporate all at once, forming high-density carbon-catalyst droplets. CNHs are formed in some of these droplets, and CNTs are formed from the catalyst in others. The formed CNHs grow into fibers using the CNTs as templates, and CNBs are generated when the CNTs and CNHs are partially bonded by heat during the cooling process. The nanocarbon generated by the laser ablation method is a mixture of CNB and CNHs (CNB / CNHs). Since the plume PL is formed on the normal N of the peripheral surface of the laser irradiated portion, it is desirable for the operator to adjust the irradiation direction of the laser L so as not to obstruct the formed plume PL and to make it easy to collect the evaporated nanocarbon. For example, the operator adjusts the irradiation direction of the laser L so that the laser L forms an angle θ with the normal N. By irradiating the laser L at an incident angle between 50° and 80°, workers can increase the CNB production rate compared to irradiating the laser L from other incident angles, and can create high-purity CNB / CNHs with reduced production of impurities such as graphite that do not contribute to the electrical properties of the CNB / CNHs. For example, the laser irradiation unit 12 may irradiate the peripheral surface of the cylindrical target 11 with the laser L at an incident angle of 60° or more and 70° or less. For example, the operator may change the incident angle by shifting the cylindrical axis O of the cylindrical target 11 in ST1. By changing the incident angle, the operator may be able to produce more CNB with higher purity from the cylindrical target 11.

[0028] Next, the worker collects the nanocarbon (ST4). The plume PL is emitted from the irradiation position P, and the worker evaporates and collects the formed CNBs / CNHs. For example, the operator collects the CNB / CNHs attached to the wall surface of the chamber 14. For example, the operator may collect the CNB / CNHs from a collection port separately provided in the chamber 14. For example, workers may remove metal catalysts contained in CNB / CNHs when recovering nanocarbons. The metal catalysts are dissolved and removed in nitric acid, sulfuric acid, or hydrochloric acid. For example, an operator may open holes in the CNB by oxidation treatment when recovering the nanocarbon. For example, when recovering nanocarbon, an operator may heat-treat the CNB in ​​an inert atmosphere to improve crystallinity, such as in an inert gas, nitrogen, or hydrogen atmosphere, or in a vacuum. Here, we obtain high-purity CNB / CNHs with few impurities such as graphite. (Complete)

[0029] (Action and Effects) According to the nanocarbon generator 1 of this embodiment, by irradiating the laser L at an incidence angle of 50° or more and 80° or less, heat is prevented from being trapped inside the cylindrical target 11, and the cylindrical target 11 can be heated with less laser energy loss compared to other incidence angles. This makes it possible to produce high-purity CNB / CNHs with fewer impurities such as graphite, and to increase the proportion of CNB in ​​the nanocarbon generated from the cylindrical target 11. Therefore, the nanocarbon generator 1 according to the present disclosure easily produces carbon nanobrushes.

[0030] In the laser ablation method, the cylindrical target 11 is irradiated with the laser L, thereby generating shock waves on the surface of the cylindrical target 11. The shock waves scatter the graphite contained in the cylindrical target 11, and the graphite may be included in the generated CNB / CNHs. If the CNB / CNHs contain a large amount of graphite, a graphite separation process is required after production. Therefore, according to the nanocarbon generator 1 of this embodiment, the generated CNB / CNHs contain less graphite, which is useful in terms of workability in that it eliminates the need for a subsequent graphite separation process.

[0031] As a comparative example, we will show a case where an operator generates CNB by irradiating a laser onto a carbon target containing a catalyst without specifying the angle of incidence. In this comparative example, CNB, CNHs, etc. are generated in the process of cooling the evaporated carbon, but the main product of CNB / CNHs generated by the laser ablation method is often CNHs, so it is necessary to develop a method to generate a large amount of CNB.

[0032] In contrast, in one example of this embodiment, by irradiating the laser L at an incidence angle of 50° or more and 80° or less, heat is prevented from being trapped inside the cylindrical target 11, and the cylindrical target 11 can be heated with less laser energy loss compared to other incidence angles. This makes it possible to produce high-purity CNB / CNHs with fewer impurities such as graphite, and the proportion of CNB in ​​the nanocarbon generated from the cylindrical target 11 can be increased. Therefore, carbon nanobrushes can be easily produced.

[0033] In addition, CNB has excellent dispersibility and high adsorptivity, similar to spherical aggregates of CNH (CNHs), and also has high electrical conductivity. Therefore, high-purity CNB / CNHs with few impurities as in this embodiment can be expected to further improve the properties by applying them to conductive materials in lithium-ion batteries, high-capacity capacitor electrodes, polymer actuator electrodes, sensor electrodes, catalyst supports, etc.

[0034] <Modification> In the above embodiment, the ROT direction is clockwise, and the laser L is irradiated from above the cylinder axis O in a plane perpendicular to the cylinder axis O. As a modified example, the ROT direction may be clockwise, and the laser L may be irradiated from below the cylindrical axis O in a plane perpendicular to the cylindrical axis O.

[0035] In the above embodiment, the ROT direction is clockwise, and the laser L is irradiated from above the cylinder axis O in a plane perpendicular to the cylinder axis O. As a modified example, the ROT direction may be counterclockwise, and the laser L may be irradiated from below the cylindrical axis O in a plane perpendicular to the cylindrical axis O.

[0036] In the above embodiment, the ROT direction is clockwise, and the laser L is irradiated from above the cylinder axis O in a plane perpendicular to the cylinder axis O. For example, as a modified example, the ROT direction may be counterclockwise, and the laser L may be irradiated from above the cylindrical axis O in a plane perpendicular to the cylindrical axis O.

[0037] Second Embodiment In the first embodiment, by irradiating the laser L at the irradiation position P where the incidence angle is 50° or more and 80° or less, heat is prevented from being trapped inside the cylindrical target 11, and the cylindrical target 11 can be heated with less laser energy loss compared to other incidence angles. This makes it possible to produce high-purity CNB / CNHs with fewer impurities such as graphite, and discloses a nanocarbon generator 1 that can increase the proportion of CNB in ​​the nanocarbon generated from the cylindrical target 11. In contrast, the nanocarbon generator 5 according to this embodiment further includes a moving mechanism capable of adjusting the incident angle. The nanocarbon generator 5 according to this embodiment can adjust the incident angle by shifting the cylindrical axis O of the cylindrical target 11. It is also noted that the nanocarbon generator 5 according to this embodiment makes it easier to adjust the incident angle than adjusting the incident angle by changing the position of the laser irradiation unit 12. Hereinafter, a nanocarbon generating apparatus according to the present disclosure will be described as a second embodiment with reference to FIG. Components common to the first embodiment are given the same reference numerals and detailed description thereof will be omitted.

[0038] (composition) As shown in FIG. 4, the nanocarbon generator 5 includes a cylindrical target 11, a laser irradiation unit 12, a chamber 14, and a cam 15. The cam 15 has a surface that fits with a portion of the circumferential surface of the cylindrical target 11 so as to hold the cylindrical target 11 . The cylindrical target 11 is fitted into a cam 15 . The cam 15 is a movement mechanism that shifts the cylindrical axis O of the cylindrical target 11 relative to the laser L. The cam 15 moves, thereby moving the fitting position of the cylindrical target 11 fitted in the cam 15. This causes the irradiation position P of the laser L to change, and the incidence angle changes along with the irradiation position P. For example, by moving the cam 15 in the S direction, the fitting position A of the cylindrical target 11 moves to fitting position B. This causes the irradiation position P of the laser L to move in the Z direction, and the incident angle changes along with the irradiation position P. For example, the cam 15 may have a roller or rollers on a surface that fits with a part of the circumferential surface of the cylindrical target 11 and that rolls in response to the rotation of the cylindrical target 11 .

[0039] For example, the moving mechanism for shifting the cylindrical axis O of the cylindrical target 11 may be a hand chuck capable of chucking the end of the cylindrical target 11, instead of the cam 15. By separately controlling the position of the hand chuck, the cylindrical axis O of the cylindrical target 11 can be shifted. For example, by rotating the hand chuck in one direction (ROT direction) around the cylindrical axis O of the cylindrical target 11 and moving it in the direction of the cylindrical axis O of the cylindrical target 11 (D direction), the nanocarbon generation device 5 can cause the irradiation position P of the laser L to move in a spiral motion relative to the cylindrical target 11.

[0040] (Action and Effects) According to the nanocarbon generator 5 of this embodiment, by irradiating the laser L at an incidence angle of 50° or more and 80° or less, heat is prevented from being trapped inside the cylindrical target 11, and the cylindrical target 11 can be heated with less laser energy loss compared to other incidence angles. This makes it possible to produce high-purity CNB / CNHs with fewer impurities such as graphite, and to increase the proportion of CNB in ​​the nanocarbon generated from the cylindrical target 11. In addition, by shifting the cylindrical axis O of the cylindrical target 11, the incident angle can be appropriately changed, and an incident angle that can produce high-purity CNB / CNHs and increase the proportion of CNB in ​​the nanocarbon can be determined. Therefore, the nanocarbon generator 1 according to the present disclosure easily produces carbon nanobrushes.

[0041] <Third embodiment> Hereinafter, as a third embodiment, an embodiment of a minimum configuration of a nanocarbon generator according to the present disclosure will be described with reference to FIG.

[0042] (composition) The nanocarbon generation apparatus 1b includes a cylindrical target 11b containing carbon and a catalyst, and a laser irradiation unit 12b that irradiates the peripheral surface of the cylindrical target 11b with a laser Lb at an incident angle of 50° or more and 80° or less, where the incident angle is the angle θ between the normal N of the peripheral surface at the irradiated portion of the laser Lb and the laser beam L of the laser.

[0043] (Action and Effects) According to the nanocarbon generator 1b of this embodiment, by irradiating the laser Lb at an incidence angle of 50° or more and 80° or less, heat is prevented from being trapped inside the cylindrical target 11b, and the cylindrical target 11b can be heated with less loss of laser energy compared to other incidence angles. This makes it possible to produce high-purity CNB / CNHs with fewer impurities such as graphite, and to increase the proportion of CNB in ​​the nanocarbon generated from the cylindrical target 11b. Therefore, the nanocarbon production apparatus 1b according to the present disclosure can easily produce carbon nanobrushes.

[0044] <Fourth embodiment> Hereinafter, as a fourth embodiment, an embodiment of a minimum configuration of a nanocarbon production method according to the present disclosure will be described with reference to FIG. The nanocarbon production method in this embodiment is carried out according to the flow shown in FIG.

[0045] The nanocarbon production method includes a step (ST10) of arranging a laser irradiation unit capable of irradiating a laser and a cylindrical target containing carbon and a catalyst, and a step (ST20) of irradiating the peripheral surface of the cylindrical target with a laser at an incident angle of 50° or more and 80° or less, where the incident angle is the angle between the normal direction of the peripheral surface at the laser irradiated portion and the laser irradiation direction.

[0046] (Action and Effects) According to the nanocarbon production method of this embodiment, by irradiating the laser with an incident angle of 50° or more and 80° or less, heat is prevented from being trapped inside the cylindrical target, and the cylindrical target can be heated with less laser energy loss compared to other incident angles. This makes it possible to produce high-purity CNB / CNHs with fewer impurities such as graphite, and to increase the proportion of CNB in ​​the nanocarbon produced from the cylindrical target. Therefore, the nanocarbon production method according to the present disclosure is easy to produce carbon nanobrushes. EXAMPLES

[0047] The effects of the present disclosure will be described in more detail below with reference to examples. The conditions in the examples are examples of conditions adopted to confirm the feasibility and effects of the present disclosure, and the present disclosure is not limited to these examples. Various conditions may be adopted in the present disclosure as long as they do not deviate from the gist of the present disclosure and the purpose of the present disclosure is achieved.

[0048] Example 1 The conditions for producing CNB in ​​the nanocarbon production apparatus 1 were as follows: The cylindrical target 11 had a diameter of 3 cm. The cylindrical target 11 contains catalytic Fe and has a bulk density of 1.5 g / cm 3 The catalyst content of the cylindrical target 11 was 3 at.%. The rotation speed of the cylindrical target 11 was 2 rpm. The cylindrical target 11 rotated in a clockwise direction about the cylindrical axis O. The speed at which the cylindrical target 11 is fed is set appropriately. The laser L emitted by the laser irradiation unit 12 was emitted from above the cylinder axis O within a plane perpendicular to the cylinder axis O. The laser L emitted by the laser source 121 of the laser irradiation unit 12 was a CO2 laser. The lens 122 was a ZnSe lens. The laser output and spot diameter of the laser irradiation unit 12 were appropriately set. The incidence angle, which is the angle θ formed between the normal N of the peripheral surface in the laser irradiation portion and the laser L, was set to four angles: 30°, 45°, 60°, and 70°. The chamber 14 was filled with nitrogen. The pressure in the chamber 14 was maintained at 760 Torr. The temperature inside the chamber 14 was 25°C. During irradiation with the laser L, nitrogen was supplied to the chamber 14 from the nitrogen inlet at 10 L / min, and the same amount of nitrogen was exhausted from the exhaust port. This allowed the inside of the chamber 14 to be maintained at a constant pressure and temperature during irradiation with the laser L.

[0049] After collecting the CNB / CNHs adhering to the wall surface of the chamber 14, the CNB / CNHs were uniformly dispersed in ethanol, and the ethanol was then evaporated, followed by treatment with a TGA (Thermal Gravimetric Analysis).

[0050] After ethanol evaporation, the CNB / CNHs were observed using a scanning electron microscope (SEM), as shown in Figures 7 to 10. Figure 7 shows the SEM images of CNB / CNHs at an incident angle of 30°. Figure 8 shows the SEM images of CNB / CNHs at an incident angle of 45°. Figure 9 shows the SEM images of CNB / CNHs at an incident angle of 60°. Figure 10 shows the SEM photograph of CNB / CNHs at an incident angle of 70°. At each incidence angle, CNBs and numerous granular CNHs attached to the surface of the CNBs were observed. It was confirmed that the generation rate of CNBs increased as the incident angle increased in the SEM images.

[0051] In TGA, the ratio of impurities contained in CNB / CNHs is measured according to the temperature during combustion and pyrolysis. At the first temperature, amorphous carbon and fullerenes with low crystallinity are burned, and at the second, higher temperature, CNH and CNT are burned. If the temperature is further increased, ultimately, graphite with high crystallinity remains. The ratio of graphite contained in CNB / CNHs is summarized in the table in Figure 11. Fig. 11 is a table showing the relationship between the amount of evaporation and the amount of impurities at each incidence angle. It was confirmed that as the incidence angle increases, the amount of evaporation from the cylindrical target 11 decreases, but the proportion of graphite contained in CNB / CNHs also decreases.

[0052] Therefore, the following can be said from this example. At an incidence angle of 60° or more and 70° or less, high-purity CNB / CNHs with few impurities such as graphite could be produced, and the proportion of CNB in ​​the nanocarbon generated from the cylindrical target 11 could be increased. The reason for this is that it is believed that irradiating the laser L at an incidence angle of 50° or more and 80° or less prevents heat from being trapped inside the cylindrical target 11, making it possible to heat the cylindrical target 11 with less laser energy loss compared to other incidence angles. In addition, since the CNB / CNHs produced in this example contained a small amount of graphite, it was shown that there is a possibility that a subsequent graphite separation step may not be necessary.

[0053] Example 2 The incidence angle θ, which is the angle between the normal N of the peripheral surface in the laser irradiation portion and the laser L, in paragraph

[0048] of Example 1 was set to 60°. The inert gas in the chamber 14 was helium, nitrogen, and argon, and the other conditions were the same, and an experiment on CNB generation was performed. The obtained sample was treated in the same manner as in paragraph

[0049] , and the CNB / CNHs after ethanol evaporation were observed by SEM. The results are shown in Figures 12 to 14. For each inert gas, CNB and a large number of granular CNHs attached to the surface of the CNB were confirmed. It was confirmed that the generation rate of CNB increased as the atomic weight of the inert gas increased in the SEM images.

[0054] Although the embodiment of the present disclosure has been described above, this embodiment is shown as an example and is not intended to limit the scope of the disclosure. This embodiment can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the scope of the present disclosure. This embodiment and its modifications are included in the scope and gist of the present disclosure, as well as in the scope of the present disclosure and its equivalents.

[0055] A part or all of the above-described embodiments can be described as, but is not limited to, the following supplementary notes.

[0056] (Appendix 1) a cylindrical target including carbon and a catalyst; a laser irradiation unit that irradiates a laser beam onto a peripheral surface of the cylindrical target at an incident angle of 50° or more and 80° or less; Equipped with The incident angle is an angle between the normal line of the peripheral surface of the laser irradiation portion and the laser. Nanocarbon generator.

[0057] (Appendix 2) The incident angle is 60° or more and 70° or less. 2. A nanocarbon generating apparatus according to claim 1.

[0058] (Appendix 3) The catalyst contains Fe, Ni, or Co. 3. A nanocarbon generating apparatus according to claim 1 or 2.

[0059] (Appendix 4) The bulk density of the cylindrical target is 1.5 g / cm 3 Is less than or equal to A nanocarbon generation apparatus according to any one of appendix 1 to 3.

[0060] (Appendix 5) The content of the catalyst in the cylindrical target is 0.5 at.% or more and 3 at.% or less. A nanocarbon generation apparatus according to any one of appendix 1 to 4.

[0061] (Appendix 6) The laser irradiation unit irradiates the cylindrical target with the laser within a plane perpendicular to the cylindrical axis of the cylindrical target. A nanocarbon generation apparatus according to any one of appendix 1 to 5.

[0062] (Appendix 7) The laser further includes a moving mechanism for shifting the cylindrical axis of the cylindrical target with respect to the laser. A nanocarbon production apparatus according to any one of appendix 1 to 6.

[0063] (Appendix 8) The atmospheric gas in the nanocarbon generating device is an inert gas having an atomic weight equal to or greater than argon. A nanocarbon production apparatus according to any one of appendix 1 to 7.

[0064] (Appendix 9) A step of disposing a laser irradiation unit capable of irradiating a laser and a cylindrical target containing carbon and a catalyst; irradiating the peripheral surface of the cylindrical target with the laser at an incident angle of 50° or more and 80° or less; Including, The incident angle is an angle between a normal to the peripheral surface of the laser irradiation portion and the laser direction. Nanocarbon manufacturing method.

[0065] (Appendix 10) Further comprising the step of recovering the nanocarbon. A method for producing nanocarbon according to claim 9.

[0066] (Appendix 11) In the step of placing, a cylindrical axis of the cylindrical target is shifted with respect to the laser. A method for producing nanocarbon according to claim 9 or 10. [Explanation of symbols]

[0067] 1 Nanocarbon generator 11 Cylindrical Target 12 Laser irradiation section 121 Laser Source 122 Lens 14 Chamber 15 Cam 1b Nanocarbon generation device 11b Cylindrical target 12b Laser irradiation section 5 Nanocarbon generator L Laser N Normal O Cylinder shaft P irradiation position PL Plume Lb Laser

Claims

1. a cylindrical target including carbon and a catalyst; a laser irradiation unit that irradiates a laser onto a peripheral surface of the cylindrical target at an incident angle of 50° or more and 80° or less; The incident angle is an angle between the normal line of the peripheral surface of the laser irradiation portion and the laser. Nanocarbon generator.

2. The incident angle is 60° or more and 70° or less. The nanocarbon generating apparatus according to claim 1 .

3. The catalyst contains Fe, Ni, or Co. The nanocarbon generating apparatus according to claim 1 or 2.

4. The bulk density of the cylindrical target is 1.5 g / cm ３ is less than or equal to The nanocarbon generating apparatus according to claim 1 or 2.

5. The content of the catalyst in the cylindrical target is 0.5 at. % or more and 3 at. % or less. The nanocarbon generating apparatus according to claim 1 or 2.

6. The laser irradiation unit irradiates the cylindrical target with the laser within a plane perpendicular to the cylindrical axis of the cylindrical target. The nanocarbon generating apparatus according to claim 1 or 2.

7. The laser further includes a moving mechanism for shifting the cylindrical axis of the cylindrical target with respect to the laser. The nanocarbon generating apparatus according to claim 1 or 2.

8. The atmospheric gas in the nanocarbon generating device is an inert gas having an atomic weight equal to or greater than argon. The nanocarbon generating apparatus according to claim 1 or 2.

9. A step of disposing a laser irradiation unit capable of irradiating a laser and a cylindrical target containing carbon and a catalyst; irradiating the laser beam onto a peripheral surface of the cylindrical target at an incident angle of 50° or more and 80° or less; Including, The incident angle is an angle between the normal line of the peripheral surface of the laser irradiation portion and the laser. Nanocarbon manufacturing method.

10. In the step of placing, a cylindrical axis of the cylindrical target is shifted with respect to the laser. The nanocarbon production method according to claim 9 .

Images