WO2023199935A1 - Graphite crystal-containing carbon material manufacturing method - Google Patents

Graphite crystal-containing carbon material manufacturing method Download PDF

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WO2023199935A1
WO2023199935A1 PCT/JP2023/014834 JP2023014834W WO2023199935A1 WO 2023199935 A1 WO2023199935 A1 WO 2023199935A1 JP 2023014834 W JP2023014834 W JP 2023014834W WO 2023199935 A1 WO2023199935 A1 WO 2023199935A1
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iron
ions
carbon material
raw material
carbon
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French (fr)
Japanese (ja)
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棟▲ヨン▼ 柳
実 矢田
佳英 渡邉
正人 山口
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日本製紙株式会社
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/20—Graphite
    • C01B32/205—Preparation

Definitions

  • the present disclosure relates to the production of a graphite crystal-containing carbon material, and more specifically, to a method of producing a graphite crystal-containing carbon material using a carbon raw material containing a cellulose polysaccharide, and materials such as precursors related thereto.
  • Graphite is a carbon material with excellent properties such as lubricity, conductivity, heat resistance, and chemical resistance. Because of these excellent characteristics, graphite is used in a wide range of applications, including battery components, circuit paints, brake pads, oil seals, fireproof materials, and heat dissipation materials.
  • Biomass is a term originally used to express the mass of biological resources (bio), but now it is a comprehensive concept that also broadly refers to resources derived from living organisms (excluding fossil resources). It is also used as a term to represent.
  • the temperature at which biomass can be fired using devices such as rotary kilns and continuous firing furnaces that are commonly used for firing biomass is generally 1400° C. or lower, and graphitization usually does not proceed sufficiently at this temperature. It is also said that in order to obtain a carbon material containing graphite crystals, a temperature of 2500° C. or higher, especially 2800° C. or higher is required (for example, Patent Document 1).
  • graphite crystal-containing carbon material As mentioned above, in order to obtain a carbon material containing graphite crystals (hereinafter also referred to as “graphite crystal-containing carbon material” in the present disclosure), firing at a high temperature of 2500°C or higher is generally required. This requires a burden on equipment capable of such high-temperature firing. Furthermore, firing at high temperatures consumes a large amount of energy, and from the viewpoint of reducing energy consumption, it is desirable to suppress the firing temperature as much as possible. Therefore, in order to achieve sufficient graphitization by firing at a low temperature, it is also possible to use a metal catalyst. However, for example, it is difficult to uniformly disperse the catalyst by simply mixing a metal catalyst with woody biomass containing cellulose polysaccharides, and therefore it is difficult to uniformly obtain a fired product. It wasn't easy.
  • one of the issues to be solved is to obtain a carbon material containing graphite crystals by using biomass as a raw material and subjecting it to uniform firing treatment under low temperature conditions.
  • the invention presented in this disclosure can be understood as several aspects from a multifaceted perspective, and includes aspects that can be implemented as means for solving the problems, for example, as described below.
  • the invention presented in this disclosure is also referred to as the "present invention.”
  • One or more metal ions selected from the group consisting of iron ions, nickel ions, chromium ions, and cobalt ions are added to the first carbon raw material containing a cellulosic polysaccharide having an anionic functional group.
  • the first carbon raw material is one or more selected from the group consisting of papermaking pulp, regenerated cellulose fiber, and chemically modified products of papermaking pulp or regenerated cellulose fiber. The manufacturing method described in ].
  • a graphite crystal-containing carbon material can be obtained by using biomass as a raw material and performing uniform firing treatment under low temperature conditions.
  • a graphite crystal-containing carbon material is obtained even by firing at a low temperature condition below 2500° C. using a cellulose polysaccharide complex as a raw material. be able to.
  • one embodiment of the present invention refers to any one embodiment out of multiple embodiments included in the scope of the present invention, and refers to any one embodiment of the multiple embodiments included in the scope of the present invention. This does not negate or limit the existence of such embodiments, and therefore the present invention is not limited to that one embodiment.
  • the term “embodiment” may include one or more embodiments unless otherwise specified.
  • AA to BB indicates “more than or equal to AA and less than or equal to BB” (herein, “AA” and “BB” indicate arbitrary numerical values). ). Furthermore, unless otherwise specified, the units for both the lower limit and the upper limit are the same as the unit immediately after the latter (ie, "BB” here). Moreover, the expression “X and/or Y” means both X and Y, or either one of them.
  • a method for manufacturing a graphite crystal-containing carbon material is provided.
  • a carbon raw material containing a cellulosic polysaccharide having an anionic functional group is referred to as a first carbon raw material.
  • the first carbon raw material supported with metal ions capable of catalyzing the graphitization of carbon is referred to as a second carbon raw material.
  • the second carbon raw material may be prepared from the first carbon raw material, or may be obtained and prepared in the form of a second carbon raw material.
  • the prepared second carbon raw material is subjected to heat treatment under predetermined temperature conditions in an inert gas atmosphere to graphitize it, thereby obtaining a graphite crystal-containing carbon material.
  • the second carbon raw material can also be called a precursor of a graphite crystal-containing carbon material.
  • Graphite crystal is an elemental mineral consisting of carbon, and the crystal form is a hexagonal system or hexagonal plate crystal.
  • the structure of graphite crystal is a tortoise-shell-shaped layered material, in which carbon atoms are connected by strong covalent bonds (sp2-like) in the plane of each layer, but weak van der Waals forces exist between the layers (interplane). are combined.
  • the electronic state is semimetallic. Applications include bearings, sliding parts such as carbon brushes, heat diffusion sheets, internal parts of high-temperature furnaces, crucibles, electrodes for electric furnaces (artificial graphite electrodes), electrodes for electrolysis, insoluble anodes, and batteries. It is used in conductive materials, negative electrode materials for secondary batteries, and friction materials such as brake pads.
  • General artificial graphite is produced by crushing, separating, and blending coal coke, which is the main raw material, and kneading it with pitch coke or coal tar pitch, which acts as an adhesive.Then, it is fired at about 1000°C and soaked in coal tar pitch. repeat. Thereafter, it is heat-treated at about 2700°C to 3000°C to graphitize it. In terms of energy consumption, such conventional methods require high-temperature firing during production, resulting in high production costs.
  • cellulose polysaccharide refers to a fibrous polymer containing a structure in which D-glucopyranose is linked through ⁇ 1,4 bonds, and includes cellulose and modified products thereof. Modified cellulose products are included in cellulose polysaccharides as long as they maintain a structure in which D-glucopyranose is linked by ⁇ 1,4 bonds in the molecule.
  • Cellulose is usually linear, but "cellulose polysaccharides” may have side chains or branches.
  • Examples of carbon materials containing cellulose polysaccharides include regenerated cellulose fibers such as cotton, paper pulp, and rayon, as well as chemically modified products thereof. Materials containing cellulose polysaccharides may be used alone or in combination of two or more. Cotton, paper pulp, regenerated cellulose fibers, etc. may contain anionic functional groups in advance due to trace amounts of carboxyl groups being introduced during purification processes such as bleaching, or due to the coexistence of hemicellulose.
  • Cellulose polysaccharides having anionic functional groups may be used as they are, or may be chemically modified to have anionic functional groups added to them.
  • chemical modification method a known method for imparting an anionic functional group can be used.
  • Chemical modification methods include, for example, carboxyl methylation, TEMPO oxidation, phosphoryl esterification, and sulfonation, and general oxidation methods such as ozone treatment, hydrogen peroxide treatment, and Fenton reaction are There are many things that can be done.
  • a cellulosic polysaccharide having an anionic functional group such as a carboxyl group, a phosphoric acid group, or a sulfonic acid group can be prepared.
  • the cellulose polysaccharide having an anionic functional group may have other substituents, characteristic groups, or functional groups in addition to the anionic functional group.
  • An example of a preferred embodiment of the chemical modification technique may be TEMPO oxidation.
  • Cellulosic polysaccharides are treated in the presence of a catalytic amount of 2,2,6,6-tetramethyl-1-piperidine-N-oxyradical (TEMPO) and sodium hypochlorite, an inexpensive oxidizing agent.
  • TEMPO 2,2,6,6-tetramethyl-1-piperidine-N-oxyradical
  • sodium hypochlorite an inexpensive oxidizing agent.
  • carboxyl groups can be efficiently introduced onto the surface of the cellulosic polysaccharide.
  • a cellulose polysaccharide into which a carboxyl group has been introduced can be modified freely using the carboxyl group as a starting point.
  • Carboxyl groups are suitable for supporting metal ions through ion exchange treatment, which will be explained later, and from this point of view, a material containing a cellulose-based cellulose polysaccharide chemically modified by TEMPO oxidation may be a suitable material.
  • a single type of cellulose polysaccharide or a material containing cellulose polysaccharide may be used, or a plurality of types may be used in combination.
  • Materials containing cellulose polysaccharides include paper pulp, regenerated cellulose fibers, and Chemical modifications thereof may be suitable.
  • carbon material precursors other than cellulose polysaccharides may be used in combination.
  • Precursors that can be used in combination include biomass materials and non-biomass materials.
  • biomass-based materials include polysaccharides such as hemicellulose, chitin, and chitosan, and lignin.
  • non-biomass materials include synthetic polymers such as phenol resin and polyacrylonitrile.
  • the amount of the biomass material to be blended is not particularly limited, but may be preferably 200 parts by weight or less, more preferably 100 parts by weight or less, based on 100 parts by weight of the carbon material containing cellulose polysaccharide. From the viewpoint of sustainability, the amount of the non-biomass material used in combination may be preferably 50 parts by weight or less and 25 parts by weight or less based on 100 parts by weight of the carbon material containing cellulose-based polysaccharides. .
  • examples of the anionic functional group include a carboxyl group, a sulfonic acid group, or a phosphoric acid group.
  • the cellulose polysaccharide may have one or more anionic functional groups.
  • the anionic functional group includes, for example, a carboxy group.
  • the content of anionic functional groups in the first carbon raw material may preferably be 0.01 to 2.00 mmol/g.
  • the anionic functional group is contained in the first carbon raw material in such a range, metal ions are sufficiently supported, which contributes to smooth graphitization.
  • the lower limit of the content of anionic functional groups in the first carbon raw material is as follows. More preferably, it is 0.02 mmol/g or more, still more preferably 0.03 mmol/g or more, and still more preferably 0.05 gmmol/g or more.
  • the upper limit of the content of anionic functional groups in the first carbon raw material is not particularly limited and may be arbitrary from the viewpoint of sufficiently supporting metal ions and smoothly proceeding with graphitization, but 2. Even if it is contained in an amount of 00 mmol/g or more, the effect becomes less improved as the amount increases.
  • the content of anionic functional groups may be set to 1.90, 1.80, or 1.70 mmol/g or less, for example. Good too.
  • a predetermined transition metal is supported on a cellulosic polysaccharide and then heat-treated, whereby the transition metal acts as a catalyst and produces a carbon material containing graphite crystals.
  • transition metals having this type of catalytic action include iron, nickel, chromium, and cobalt, with iron being preferred from the viewpoint of low toxicity.
  • iron ion sources include iron(II) chloride, iron(III) chloride, iron(II) sulfate, iron(III) sulfate, iron(II) phosphate, iron(III) phosphate, and iron nitrate. (II), iron (III) nitrate, etc., hydrates thereof, and organic complex iron salts such as Prussian blue. From the viewpoint of ease of solution preparation when carrying iron ions on the first carbon material containing cellulosic polysaccharide, iron(II) chloride, iron(III) chloride, iron(II) sulfate is preferably used. , iron (III) sulfate, iron (II) nitrate, iron (III) nitrate and their hydrates, and soluble Prussian blue that partially contains potassium ions, ammonium ions, etc., and the like.
  • the number of metal ions supported on the carbon raw material containing cellulosic polysaccharide may be one or two or more.
  • a carbon raw material in which metal ions are supported on a carbon raw material containing a cellulosic polysaccharide i.e., a second carbon raw material (or also referred to as a precursor of a graphite crystal-containing carbon material)
  • an inert gas atmosphere is prepared. Heat treatment is performed below.
  • the heat treatment is preferably performed under an inert gas atmosphere.
  • inert gases include helium, argon, nitrogen, and the like. Among them, nitrogen is more preferable from the viewpoint of industrial cost.
  • the heat treatment device is not particularly limited as long as it can heat to a predetermined temperature, for example 600 to 1400° C., but preferably a gas displacement furnace is used.
  • the gas displacement furnace is preferably a batch type or continuous gas displacement furnace, and more preferably a continuous gas displacement furnace.
  • the heat treatment temperature may preferably be 600°C or higher and lower than 1400°C.
  • the lower limit of the heat treatment temperature may be more preferably 700°C or higher, and still more preferably 800°C or higher.
  • the upper limit of the heat treatment temperature does not need to be particularly limited, but from the viewpoint of general heat treatment equipment constraints and energy saving, it is preferably less than 1400°C, more preferably 1200°C or less, More preferably, the temperature may be 1100°C or below 1000°C.
  • metal ions acting as catalysts can be uniformly dispersed, so that graphitization can be performed under low temperature conditions as a heat treatment for graphitization as described above.
  • the graphite crystal-containing carbon material obtained can be homogeneous.
  • the heat treatment time is preferably 0.1 to 4 hours, more preferably 0.5 to 3 hours.
  • a graphite crystal-containing carbon material can be obtained in the form of a black carbide.
  • the residual rate (weight ratio) of the black carbide after heat treatment is preferably 1 to 40%, more preferably 10 to 30%, based on the dry weight of the raw material before heat treatment, that is, the dry weight of the second carbon raw material. It's possible.
  • X-ray diffraction (hereinafter referred to as XRD), Raman spectrum, etc. can be used.
  • XRD X-ray diffraction
  • the interlayer distance d002 is commonly used as an index of graphitization.
  • the interlayer distance (d002) is preferably in the range of 3.3 ⁇ or more and 4.0 ⁇ or less, and more preferably in the range of 3.3937 ⁇ or more and 3.4635 ⁇ or less.
  • the thickness (Lc) of the mesh plane group is preferably in the range of 10 nm or more and 200 nm or less, and more preferably in the range of 30 nm or more and 187 nm or less.
  • TEMPO oxidized pulp (anionic functional group content: 1.6 mmol/g, cation is sodium ion) was used as a raw material containing cellulosic polysaccharide (first carbon raw material). 100 ml of 0.1 mol/L hydrochloric acid was added to 3 g of dry weight of TEMPO oxidized pulp, held for 30 minutes, filtered, and thoroughly washed with ion-exchanged water to exchange cations with protons.
  • iron (II) chloride tetrahydrate as an iron ion source, add 100 ml of its 2% aqueous solution, hold for 30 minutes, filter and wash thoroughly with ion-exchanged water to remove iron ions from the cations. It was replaced with (II).
  • the obtained pulp was light brown in color, and some of the iron ions (II) were oxidized to iron ions (III).
  • the obtained pulp was used as a second carbon raw material carrying iron ions.
  • the obtained pulp (i.e., the second carbon raw material) was dried at 105°C for 1 hour, and then heat-treated at 900°C for 2 hours in a nitrogen atmosphere using a batch gas replacement furnace to obtain black carbide. Ta.
  • the residual ratio of black carbide to the dry weight of the pulp was 24%.
  • Example 4 Rayon nonwoven fabric (fiber diameter 3.3 dtex, anionic functional group content 0.015 mmol/g) was used as the raw material containing cellulosic polysaccharide (first carbon raw material), and iron (II) sulfate was used as the iron ion source.
  • Example 5 A rayon nonwoven fabric (fiber diameter: 3.3 dtex, anionic functional group content: 0.015 mmol/g) with a dry weight of 3 g was added to 100 ml of 5% hydrogen peroxide solution and immersed for 15 minutes at room temperature. After sufficiently squeezing, Fenton reaction was performed by immersing in 100 ml of 2% iron (II) sulfate heptahydrate aqueous solution for 30 minutes, and by thorough washing, an oxidized rayon nonwoven fabric was obtained (anionic functional group amount 0.12 mmol/g).
  • anionic functional group amount 0.12 mmol/g
  • Example 2 Thereafter, heat treatment was performed in the same manner as in Example 1 to obtain a black carbide.
  • the residual rate of black carbide based on the dry weight of the rayon nonwoven fabric was 18%.
  • TEMPO oxidized pulp (anionic functional group content: 1.6 mmol/g, cation is sodium ion) was used as a raw material containing cellulosic polysaccharides. 100 ml of 0.1 mol/L hydrochloric acid was added to 3 g dry weight of TEMPO oxidized pulp, held for 30 minutes, filtered, and thoroughly washed with ion-exchanged water to exchange cations with protons.
  • TEMPO oxidized pulp (anionic functional group content: 1.6 mmol/g, cation is sodium ion) was used as a raw material containing cellulosic polysaccharides. After adding 100 ml of 0.1 mol/L hydrochloric acid to 3 g dry weight of TEMPO oxidized pulp and holding for 30 minutes, the mixture was filtered and thoroughly washed with ion-exchanged water to exchange cations with protons.

Abstract

One of the problems addressed by the present invention is to obtain a graphite crystal-containing carbon material by using biomass as a material and performing a uniform baking treatment on the biomass at a low-temperature condition.　The present invention involves: preparing a second carbon material in which one or more metal ions selected from the group consisting of iron ion, nickel ion, chromium ion, and cobalt ion are supported on a first carbon material containing a cellulose-based polysaccharide that has an anionic functional group; and heating the second carbon material in an inert gas atmosphere at a temperature condition of not lower than 600°C but lower than 1400°C.

Description

黒鉛結晶含有炭素材料の製造方法Method for producing carbon material containing graphite crystals
　本開示は、黒鉛結晶含有炭素材料の製造に関し、より詳しくは、セルロース系多糖類を含む炭素原料を用い、黒鉛結晶含有炭素材料を製造する方法およびこれに関わる前駆体などの材料に関する。 The present disclosure relates to the production of a graphite crystal-containing carbon material, and more specifically, to a method of producing a graphite crystal-containing carbon material using a carbon raw material containing a cellulose polysaccharide, and materials such as precursors related thereto.
　黒鉛は、潤滑性や導電性、耐熱性、耐薬品性などの性質に優れた炭素材料である。このような優れた特徴があるため、黒鉛は、電池部材、回路用塗料、ブレーキパッド、オイルシール、耐火材、および放熱材など幅広い用途に利用されている。 Graphite is a carbon material with excellent properties such as lubricity, conductivity, heat resistance, and chemical resistance. Because of these excellent characteristics, graphite is used in a wide range of applications, including battery components, circuit paints, brake pads, oil seals, fireproof materials, and heat dissipation materials.
　ところで、近年、持続可能な開発の促進が世界的なコンセンサスとして重視されるようになってきており、この観点から、炭素材料開発の分野においても、バイオマスを原料とした炭素材料の製造、開発が求められている。バイオマスとは、元々は生物資源（ｂｉｏ）の量（ｍａｓｓ）を表す用語であるが、現在では、広く生物に由来する資源（但し、化石資源を除く。）のことも意味する包括的な概念を表す用語としても用いられている。 Incidentally, in recent years, the promotion of sustainable development has come to be emphasized as a global consensus, and from this perspective, in the field of carbon material development, the production and development of carbon materials using biomass as raw materials is becoming more and more important. It has been demanded. Biomass is a term originally used to express the mass of biological resources (bio), but now it is a comprehensive concept that also broadly refers to resources derived from living organisms (excluding fossil resources). It is also used as a term to represent.
　バイオマスを原料として黒鉛を含む炭素材料を得る方法を検討する場合において、焼成工程およびその条件設定が必要となる。しかし、バイオマスの焼成において汎用されているロータリーキルンや連続焼成炉などの装置で焼成できる温度は、一般的に１４００℃以下であり、この温度では、通常、黒鉛化は十分に進行しない。黒鉛結晶を含む炭素材料を得るには、２５００℃以上、特に２８００℃以上を要するとも言われている（例えば、特許文献１）。 When considering a method for obtaining carbon materials containing graphite using biomass as a raw material, it is necessary to set the firing process and its conditions. However, the temperature at which biomass can be fired using devices such as rotary kilns and continuous firing furnaces that are commonly used for firing biomass is generally 1400° C. or lower, and graphitization usually does not proceed sufficiently at this temperature. It is also said that in order to obtain a carbon material containing graphite crystals, a temperature of 2500° C. or higher, especially 2800° C. or higher is required (for example, Patent Document 1).
　より効率的に黒鉛を得る方法についても開発が進められている。例えば、熱硬化性樹脂を８００～１７００℃という低温で予備焼成した後に、黒鉛化触媒として微粒子の金属及び水素原子等の存在下で加圧焼成すること（例えば、特許文献２）、さらには、鉄やニッケル、コバルト等を触媒として石油系樹脂、微結晶性セルロース等の低温黒鉛化することなどが報告されている（例えば、非特許文献１、２）。 Development is also progressing on a more efficient method of obtaining graphite. For example, after pre-calcining a thermosetting resin at a low temperature of 800 to 1,700°C, pressure-calcining is performed in the presence of fine particles of metal and hydrogen atoms as a graphitization catalyst (for example, Patent Document 2); Low-temperature graphitization of petroleum resins, microcrystalline cellulose, etc. using iron, nickel, cobalt, etc. as catalysts has been reported (for example, Non-Patent Documents 1 and 2).
特開２０００－２０３９７３号公報Japanese Patent Application Publication No. 2000-203973 特開平６－２０６７１６号公報Japanese Patent Application Publication No. 6-206716
　上述のとおり、黒鉛結晶を含む炭素材料（以下、本開示では、「黒鉛結晶含有炭素材料」ともいう。）を得るためには、一般に、２５００℃以上という高温での焼成が必要であり、そのような高温焼成が可能な装置の負担を要する。また、高温での焼成はエネルギーの消費量が大きく、エネルギー消費量低減の観点からもできるだけ焼成温度は抑制することが望ましい。そのため、低温での焼成によって十分に黒鉛化するために、金属系の触媒を用いることも考えられる。しかし、例えば、セルロース系多糖類を含有する木質系のバイオマスなどに、金属系の触媒を単に混合しても触媒を均一に分散させるのは困難であり、そのため、焼成物を均一に得ることは容易ではなかった。 As mentioned above, in order to obtain a carbon material containing graphite crystals (hereinafter also referred to as "graphite crystal-containing carbon material" in the present disclosure), firing at a high temperature of 2500°C or higher is generally required. This requires a burden on equipment capable of such high-temperature firing. Furthermore, firing at high temperatures consumes a large amount of energy, and from the viewpoint of reducing energy consumption, it is desirable to suppress the firing temperature as much as possible. Therefore, in order to achieve sufficient graphitization by firing at a low temperature, it is also possible to use a metal catalyst. However, for example, it is difficult to uniformly disperse the catalyst by simply mixing a metal catalyst with woody biomass containing cellulose polysaccharides, and therefore it is difficult to uniformly obtain a fired product. It wasn't easy.
　以上のような状況に鑑み、解決しようとする課題の１つは、バイオマスを原料とし、低温条件において均一な焼成処理を施し、黒鉛結晶含有炭素材料を得ることにある。 In view of the above situation, one of the issues to be solved is to obtain a carbon material containing graphite crystals by using biomass as a raw material and subjecting it to uniform firing treatment under low temperature conditions.
　本開示中に提示される発明は、多面的にいくつかの態様として把握することができ、課題を解決するための手段として、例えば、下記のように具現化しうる態様を含む。本開示においては、本開示中に提示される発明のことを「本発明」ともいう。 The invention presented in this disclosure can be understood as several aspects from a multifaceted perspective, and includes aspects that can be implemented as means for solving the problems, for example, as described below. In this disclosure, the invention presented in this disclosure is also referred to as the "present invention."
　〔１〕　アニオン性官能基を有するセルロース系多糖類を含有する第１の炭素原料に、鉄イオン、ニッケルイオン、クロームイオン、及びコバルトイオンからなる群から選ばれる１種又は２種以上の金属イオンを担持させた第２の炭素原料を用意することと、
　前記第２の炭素材料を、不活性ガス雰囲気下、６００℃以上１４００℃未満の温度条件で、熱処理することと、
を含む、黒鉛結晶含有炭素材料の製造方法。
　〔２〕　前記第１の炭素原料が、製紙用パルプ、再生セルロース繊維、及び、製紙用パルプ又は再生セルロース繊維の化学変性物からなる群より選ばれる１種又は２種以上である、上記〔１〕に記載の製造方法。
　〔３〕　前記第１の炭素原料中における前記アニオン性官能基の含有量が、０．０１～２．００ｍｍｏｌ／ｇである、上記〔１〕または〔２〕に記載の製造方法。
　〔４〕　前記アニオン性官能基が、カルボキシル基である、上記〔１〕～〔３〕に記載の製造方法。
　〔５〕　前記金属イオンが、鉄イオンである、上記〔１〕～〔４〕に記載の製造方法。
　〔６〕　前記鉄イオンを、鉄の塩酸塩、鉄の硫酸塩、および鉄の硝酸塩からなる群より選ばれる１種又は２種以上を用いて、前記セルロース系多糖類に担持させることを含む、上記〔１〕～〔５〕に記載の製造方法。
　〔７〕　アニオン性官能基を有するセルロース系多糖類を含有する第１の炭素原料に、鉄イオン、ニッケルイオン、クロームイオン、及びコバルトイオンからなる群から選ばれる１種又は２種以上の金属イオンが担持された、黒鉛結晶含有炭素材料の前駆体。 [1] One or more metal ions selected from the group consisting of iron ions, nickel ions, chromium ions, and cobalt ions are added to the first carbon raw material containing a cellulosic polysaccharide having an anionic functional group. preparing a second carbon raw material carrying
Heat treating the second carbon material under an inert gas atmosphere at a temperature of 600°C or more and less than 1400°C;
A method for producing a graphite crystal-containing carbon material.
[2] The above [1], wherein the first carbon raw material is one or more selected from the group consisting of papermaking pulp, regenerated cellulose fiber, and chemically modified products of papermaking pulp or regenerated cellulose fiber. The manufacturing method described in ].
[3] The production method according to [1] or [2] above, wherein the content of the anionic functional group in the first carbon raw material is 0.01 to 2.00 mmol/g.
[4] The production method according to [1] to [3] above, wherein the anionic functional group is a carboxyl group.
[5] The manufacturing method according to [1] to [4] above, wherein the metal ion is an iron ion.
[6] Supporting the iron ion on the cellulose polysaccharide using one or more selected from the group consisting of iron hydrochloride, iron sulfate, and iron nitrate; The manufacturing method described in [1] to [5] above.
[7] One or more metal ions selected from the group consisting of iron ions, nickel ions, chromium ions, and cobalt ions in the first carbon raw material containing a cellulosic polysaccharide having an anionic functional group. A precursor of a carbon material containing graphite crystals.
　本開示中に提示される発明の一態様によれば、バイオマスを原料とし、低温条件において均一な焼成処理を施し、黒鉛結晶含有炭素材料を得ることができる。より具体的な成果として、本開示中に提示される発明の一態様によれば、セルロース系多糖類複合体を原料として、２５００℃を下回る低温条件での焼成によっても黒鉛結晶含有炭素材料を得ることができる。 According to one aspect of the invention presented in the present disclosure, a graphite crystal-containing carbon material can be obtained by using biomass as a raw material and performing uniform firing treatment under low temperature conditions. As a more specific result, according to one aspect of the invention presented in the present disclosure, a graphite crystal-containing carbon material is obtained even by firing at a low temperature condition below 2500° C. using a cellulose polysaccharide complex as a raw material. be able to.
　本開示は、特許協力条約に基づく国際出願によるものであり、出願当初の言語は日本語である。本開示は、指定国および選択国へ移行の際、各国が要求する言語に翻訳されることが予定されている。本開示において、特段の記載がない限り、日本語の名詞は、本開示の全文または文脈に応じて単数または複数のいずれでもありうる。また、英語などのように、名詞について可算名詞および不可算名詞、可算名詞において単数形または複数形の区別がある言語に翻訳された際、特段の記載がない限り、本開示の全文または文脈に応じて、単数形の表示は複数の場合を含み、複数形の表示は、単数の場合を含む。 This disclosure is based on an international application based on the Patent Cooperation Treaty, and the original language of the application is Japanese. This disclosure is intended to be translated into the languages requested by the designated and selected countries upon transfer. In this disclosure, unless otherwise specified, Japanese nouns may be singular or plural depending on the full text or context of this disclosure. In addition, when translated into a language such as English where there is a distinction between countable nouns and uncountable nouns, and countable nouns in singular or plural, unless otherwise specified, the full text or context of this disclosure will not apply. Accordingly, references to the singular include the plural and references to the plural include the singular.
　以下、本発明の実施形態について説明する。本開示中、「本発明の一実施形態」との用語は、特に断らない限り、本発明の範疇に含まれる複数の実施形態のうちの任意の一実施形態であり、他の又は複数の実施形態の存在を否定または制限するものではなく、したがって本発明がその一実施形態に限定されるものではない。また、本開示において、単に「実施形態」と記載している場合は、特に断らない限り、一又は複数の実施形態を含みうる。 Hereinafter, embodiments of the present invention will be described. In this disclosure, unless otherwise specified, the term "one embodiment of the present invention" refers to any one embodiment out of multiple embodiments included in the scope of the present invention, and refers to any one embodiment of the multiple embodiments included in the scope of the present invention. This does not negate or limit the existence of such embodiments, and therefore the present invention is not limited to that one embodiment. Furthermore, in the present disclosure, the term "embodiment" may include one or more embodiments unless otherwise specified.
　本開示において、特に断らない限り、数値範囲に関し、「ＡＡ～ＢＢ」という記載は、「ＡＡ以上ＢＢ以下」を示すこととする（ここで、「ＡＡ」および「ＢＢ」は任意の数値を示す）。また、下限および上限の単位は、特に断りない限り、双方共に後者（すなわち、ここでは「ＢＢ」）の直後に付された単位と同じである。また、「Ｘおよび／またはＹ」との表現は、ＸおよびＹの双方、またはこれらのうちのいずれか一方のことを意味する。 In this disclosure, unless otherwise specified, the description "AA to BB" with respect to numerical ranges indicates "more than or equal to AA and less than or equal to BB" (herein, "AA" and "BB" indicate arbitrary numerical values). ). Furthermore, unless otherwise specified, the units for both the lower limit and the upper limit are the same as the unit immediately after the latter (ie, "BB" here). Moreover, the expression "X and/or Y" means both X and Y, or either one of them.
　本発明の一実施形態として、黒鉛結晶含有炭素材料を製造する方法が提供される。本開示おいて、アニオン性官能基を有するセルロース系多糖類を含有する炭素原料のことを、第１の炭素原料と称する。第１の炭素原料に、炭素の黒鉛化を触媒しうる金属イオンを担持させたものを、第２の炭素原料と称する。第２の炭素原料は、第１の炭素原料から調製してもよいし、第２の炭素原料の形態で入手して用意してもよい。用意した第２の炭素原料を、不活性ガス雰囲気下で、所定の温度条件で熱処理を施し、黒鉛化して、黒鉛結晶含有炭素材料を得る。ここで、第２の炭素原料は、黒鉛結晶含有炭素材料の前駆体とも言い得る。 As one embodiment of the present invention, a method for manufacturing a graphite crystal-containing carbon material is provided. In the present disclosure, a carbon raw material containing a cellulosic polysaccharide having an anionic functional group is referred to as a first carbon raw material. The first carbon raw material supported with metal ions capable of catalyzing the graphitization of carbon is referred to as a second carbon raw material. The second carbon raw material may be prepared from the first carbon raw material, or may be obtained and prepared in the form of a second carbon raw material. The prepared second carbon raw material is subjected to heat treatment under predetermined temperature conditions in an inert gas atmosphere to graphitize it, thereby obtaining a graphite crystal-containing carbon material. Here, the second carbon raw material can also be called a precursor of a graphite crystal-containing carbon material.
　黒鉛結晶とは、炭素から成る元素鉱物であり、結晶の形態は、六方晶系、六角板状結晶である。黒鉛結晶の構造は、亀の甲状の層状物質、層毎の面内は強い共有結合（ｓｐ２的）で炭素間が繋がっているが、層と層の間（面間）は弱いファンデルワールス力で結合している。電子状態は、半金属的である。用途としては、軸受け、カーボンブラシなどの摺動部品、熱拡散シート、高温炉の炉内部品、るつぼ（坩堝）、電気炉用電極（人造黒鉛電極）、電解用電極、不溶性陽極、電池用の導電材、二次電池用の負極材、ブレーキパッドなどの摩擦材などに用いられている。一般的な人造黒鉛は、主原料となる石炭コークスを粉砕、分別、配合し、接着剤の役割を果たすピッチコークスまたはコールタールピッチと混練した後、１０００℃程度での焼成とコールタールピッチ漬込みを繰り返す。その後、２７００℃から３０００℃程度で加熱処理し、黒鉛化させる。このような従来の方法は、エネルギー消費量の観点では製造時に高温焼成が必要となるため製造コストが高いという課題がある。 Graphite crystal is an elemental mineral consisting of carbon, and the crystal form is a hexagonal system or hexagonal plate crystal. The structure of graphite crystal is a tortoise-shell-shaped layered material, in which carbon atoms are connected by strong covalent bonds (sp2-like) in the plane of each layer, but weak van der Waals forces exist between the layers (interplane). are combined. The electronic state is semimetallic. Applications include bearings, sliding parts such as carbon brushes, heat diffusion sheets, internal parts of high-temperature furnaces, crucibles, electrodes for electric furnaces (artificial graphite electrodes), electrodes for electrolysis, insoluble anodes, and batteries. It is used in conductive materials, negative electrode materials for secondary batteries, and friction materials such as brake pads. General artificial graphite is produced by crushing, separating, and blending coal coke, which is the main raw material, and kneading it with pitch coke or coal tar pitch, which acts as an adhesive.Then, it is fired at about 1000°C and soaked in coal tar pitch. repeat. Thereafter, it is heat-treated at about 2700°C to 3000°C to graphitize it. In terms of energy consumption, such conventional methods require high-temperature firing during production, resulting in high production costs.
　本開示において、「セルロース系多糖類」との用語は、Ｄ－グルコピラノースがβ１，４結合で連なった構造を含む繊維状の高分子のことを意味し、セルロース及びその変性物を包含する。セルロースの変性物は、Ｄ－グルコピラノースがβ１，４結合で連なった構造を分子中に維持する限りにおいて、セルロース系多糖類に包含される。セルロースは、通常、直鎖状に連なっているが、「セルロース系多糖類」は、側鎖を有していてもよく、また分岐を有していてもよい。 In the present disclosure, the term "cellulose polysaccharide" refers to a fibrous polymer containing a structure in which D-glucopyranose is linked through β1,4 bonds, and includes cellulose and modified products thereof. Modified cellulose products are included in cellulose polysaccharides as long as they maintain a structure in which D-glucopyranose is linked by β1,4 bonds in the molecule. Cellulose is usually linear, but "cellulose polysaccharides" may have side chains or branches.
　セルロース系多糖類を含有する炭素材料としては、例えば、コットン、製紙用パルプ、及びレーヨンに代表される再生セルロース繊維など、並びに、それらの化学変性物が挙げられる。セルロース系多糖類を含有する材料は、１種を単独で、または２種以上を混合して、用いてもよい。コットン、製紙用パルプ、再生セルロース繊維等には、漂白等の精製工程でカルボキシル基が微量に導入される、または、ヘミセルロースの共存により、アニオン性官能基が予め含まれている場合がある。 Examples of carbon materials containing cellulose polysaccharides include regenerated cellulose fibers such as cotton, paper pulp, and rayon, as well as chemically modified products thereof. Materials containing cellulose polysaccharides may be used alone or in combination of two or more. Cotton, paper pulp, regenerated cellulose fibers, etc. may contain anionic functional groups in advance due to trace amounts of carboxyl groups being introduced during purification processes such as bleaching, or due to the coexistence of hemicellulose.
　アニオン性官能基を有するセルロース系多糖類は、そのまま用いてもよいし、あるいは、化学変性により、アニオン性官能基を付加してもよい。化学変性の手法は、アニオン性官能基を付与する公知の手法を用いることができる。化学変性の手法としては、例えば、カルボキシルメチル化、ＴＥＭＰＯ酸化、リン酸エルテル化、及びスルホン化等が挙げられ、また、オゾン処理や過酸化水素処理、フェントン反応等の一般的な酸化手法を軽度に行うことが挙げられる。このようにして、セルロース系多糖類に、カルボキシル基、リン酸基、スルホン酸基などのアニオン性官能基を有するセルロース系多糖類を調製しうる。なお、アニオン性官能基を有するセルロース系多糖類は、アニオン性官能基の他に、他の置換基、特性基、または官能基を有していてもよい。 Cellulose polysaccharides having anionic functional groups may be used as they are, or may be chemically modified to have anionic functional groups added to them. As the chemical modification method, a known method for imparting an anionic functional group can be used. Chemical modification methods include, for example, carboxyl methylation, TEMPO oxidation, phosphoryl esterification, and sulfonation, and general oxidation methods such as ozone treatment, hydrogen peroxide treatment, and Fenton reaction are There are many things that can be done. In this way, a cellulosic polysaccharide having an anionic functional group such as a carboxyl group, a phosphoric acid group, or a sulfonic acid group can be prepared. Note that the cellulose polysaccharide having an anionic functional group may have other substituents, characteristic groups, or functional groups in addition to the anionic functional group.
　化学変性の手法として好ましい実施形態の例は、ＴＥＭＰＯ酸化でありうる。セルロース系多糖類を、触媒量の２，２，６，６－テトラメチル－１－ピペリジン－Ｎ－オキシラジカル（ＴＥＭＰＯ）と、安価な酸化剤である次亜塩素酸ナトリウムとの共存下で処理すると、セルロース系多糖類の表面にカルボキシル基を効率よく導入することができる。カルボキシル基が導入されたセルロース系多糖類は、カルボキシル基を基点として、自由に改質することができる。カルボキシル基は、後に説明するイオン交換処理により金属イオンを担持させる上で好適であり、この観点からもＴＥＭＰＯ酸化により化学変性したセルロース系セルロース系多糖類を含有する材料は好適な材料でありうる。 An example of a preferred embodiment of the chemical modification technique may be TEMPO oxidation. Cellulosic polysaccharides are treated in the presence of a catalytic amount of 2,2,6,6-tetramethyl-1-piperidine-N-oxyradical (TEMPO) and sodium hypochlorite, an inexpensive oxidizing agent. Then, carboxyl groups can be efficiently introduced onto the surface of the cellulosic polysaccharide. A cellulose polysaccharide into which a carboxyl group has been introduced can be modified freely using the carboxyl group as a starting point. Carboxyl groups are suitable for supporting metal ions through ion exchange treatment, which will be explained later, and from this point of view, a material containing a cellulose-based cellulose polysaccharide chemically modified by TEMPO oxidation may be a suitable material.
　セルロース系多糖類またはセルロース系多糖類を含有する材料は、単一種を用いてもよいし、または複数の種類を組み合わせて用いてもよい。セルロース系多糖類を含有する材料としては、入手容易性および鉄イオンなどの金属イオンを担持させた後、余剰の金属イオンを洗浄除去する工程の容易性から、製紙用パルプ、再生セルロース繊維、およびそれらの化学変性物が好適でありうる。 A single type of cellulose polysaccharide or a material containing cellulose polysaccharide may be used, or a plurality of types may be used in combination. Materials containing cellulose polysaccharides include paper pulp, regenerated cellulose fibers, and Chemical modifications thereof may be suitable.
　炭素源を供給する炭素原料としては、セルロース系多糖類以外の炭素材料前駆体を併用してもよい。併用しうる前駆体としては、バイオマス系素材と非バイオマス系素材が挙げられる。バイオマス系素材としては、例えば、ヘミセルロース、キチン、キトサン等の多糖類、およびリグニン等が挙げられる。非バイオマス系素材としては、例えば、フェノール樹脂、ポリアクリロニトリル等の合成系高分子類が挙げられる。併用する場合、バイオマス系素材の配合量は特に限定されないが、セルロース系多糖類を含有する炭素原料１００重量部に対し、好ましくは２００重量部以下、より好ましくは１００重量部以下でありうる。前記併用する非バイオマス系素材の配合量は、持続可能性の観点から、セルロース系由来の多糖類を含有する炭素原料１００重量部に対し、好ましくは５０重量部以下、２５重量部以下でありうる。 As the carbon raw material that supplies the carbon source, carbon material precursors other than cellulose polysaccharides may be used in combination. Precursors that can be used in combination include biomass materials and non-biomass materials. Examples of biomass-based materials include polysaccharides such as hemicellulose, chitin, and chitosan, and lignin. Examples of non-biomass materials include synthetic polymers such as phenol resin and polyacrylonitrile. When used together, the amount of the biomass material to be blended is not particularly limited, but may be preferably 200 parts by weight or less, more preferably 100 parts by weight or less, based on 100 parts by weight of the carbon material containing cellulose polysaccharide. From the viewpoint of sustainability, the amount of the non-biomass material used in combination may be preferably 50 parts by weight or less and 25 parts by weight or less based on 100 parts by weight of the carbon material containing cellulose-based polysaccharides. .
　本発明の一実施形態において、アニオン性官能基としては、例えば、カルボキシル基、スルホン酸基、またはリン酸基等が挙げられる。セルロース系多糖類が有するアニオン性官能基は、１種でも、２種以上であってもよい。アニオン性官能基として好ましくは、例えば、カルボキシ基が挙げられる。所定の金属イオンがアニオン性官能基に結合することで、セルロース系多糖類上に均一に金属を担持することができ、熱処理後に得られる黒鉛結晶含有炭素材料の品質を安定させることができる。 In one embodiment of the present invention, examples of the anionic functional group include a carboxyl group, a sulfonic acid group, or a phosphoric acid group. The cellulose polysaccharide may have one or more anionic functional groups. Preferably, the anionic functional group includes, for example, a carboxy group. By bonding a predetermined metal ion to an anionic functional group, the metal can be uniformly supported on the cellulose polysaccharide, and the quality of the graphite crystal-containing carbon material obtained after heat treatment can be stabilized.
　本発明の一実施形態において、第１の炭素原料中におけるアニオン性官能基の含有量は、好ましくは０．０１～２．００ｍｍｏｌ／ｇでありうる。このような範囲でアニオン性官能基が第１の炭素原料に含まれていることにより、金属イオンが十分担持され、黒鉛化を円滑に進めることに資する。 In one embodiment of the present invention, the content of anionic functional groups in the first carbon raw material may preferably be 0.01 to 2.00 mmol/g. When the anionic functional group is contained in the first carbon raw material in such a range, metal ions are sufficiently supported, which contributes to smooth graphitization.
　炭素原料の種類や金属イオンの種類にもよるが、金属イオンを十分に担持させ、黒鉛化を円滑に進める観点からは、第１の炭素原料中におけるアニオン性官能基の含有量の下限は、より好ましくは０．０２ｍｍｏｌ／ｇ以上、更に好ましくは０．０３ｍｍｏｌ／ｇ以上、更に好ましくは０．０５ｇｍｍｏｌ／ｇ以上でありうる。
　他方、第１の炭素原料中におけるアニオン性官能基の含有量の上限は、金属イオンを十分に担持させ、黒鉛化を円滑に進める観点からは、特に制限はなく任意でありうるが、２．００ｍｍｏｌ／ｇ以上含まれていても、量が増えるのに応じたほどには効果が向上しくくなる。第１の炭素原料中におけるアニオン性官能基の含有量をできるだけ少なくしたい場合には、当該アニオン性官能基の含有量は、例えば、１．９０、１．８０、または１．７０ｍｍｏｌ／ｇ以下としてもよい。 Although it depends on the type of carbon raw material and the type of metal ion, from the viewpoint of sufficiently supporting metal ions and smoothly proceeding with graphitization, the lower limit of the content of anionic functional groups in the first carbon raw material is as follows. More preferably, it is 0.02 mmol/g or more, still more preferably 0.03 mmol/g or more, and still more preferably 0.05 gmmol/g or more.
On the other hand, the upper limit of the content of anionic functional groups in the first carbon raw material is not particularly limited and may be arbitrary from the viewpoint of sufficiently supporting metal ions and smoothly proceeding with graphitization, but 2. Even if it is contained in an amount of 00 mmol/g or more, the effect becomes less improved as the amount increases. When it is desired to minimize the content of anionic functional groups in the first carbon raw material, the content of anionic functional groups may be set to 1.90, 1.80, or 1.70 mmol/g or less, for example. Good too.
　本発明の一実施形態では、所定の遷移金属をセルロース系多糖類上に担持させた上で、熱処理を行うことで、当該遷移金属が触媒として作用し、黒鉛結晶を含有する炭素材料を生成する。この種の触媒作用を持つ遷移金属として、例えば、鉄、ニッケル、クローム、コバルト等が挙げられ、毒性の低さの観点からは、鉄が好適である。 In one embodiment of the present invention, a predetermined transition metal is supported on a cellulosic polysaccharide and then heat-treated, whereby the transition metal acts as a catalyst and produces a carbon material containing graphite crystals. . Examples of transition metals having this type of catalytic action include iron, nickel, chromium, and cobalt, with iron being preferred from the viewpoint of low toxicity.
　鉄イオンの供給源としては、例えば、塩化鉄（ＩＩ）、塩化鉄（ＩＩＩ）、硫酸鉄（ＩＩ）、硫酸鉄（ＩＩＩ）、リン酸鉄（ＩＩ）、リン酸鉄（ＩＩＩ）、硝酸鉄（ＩＩ）、硝酸鉄（ＩＩＩ）等およびそれらの水和物、並びにプルシアンブルー等の有機錯体鉄塩が挙げられる。セルロース系多糖類を含有する第１の炭素材料に鉄イオンを担持させる際の溶液調製の容易性の観点からは、好ましくは、塩化鉄（ＩＩ）、塩化鉄（ＩＩＩ）、硫酸鉄（ＩＩ）、硫酸鉄（ＩＩＩ）、硝酸鉄（ＩＩ）、硝酸鉄（ＩＩＩ）およびそれらの水和物、並びにカリウムイオンやアンモニウムイオン等を組成に一部含む可溶性のプルシアンブルー等が挙げられる。 Examples of iron ion sources include iron(II) chloride, iron(III) chloride, iron(II) sulfate, iron(III) sulfate, iron(II) phosphate, iron(III) phosphate, and iron nitrate. (II), iron (III) nitrate, etc., hydrates thereof, and organic complex iron salts such as Prussian blue. From the viewpoint of ease of solution preparation when carrying iron ions on the first carbon material containing cellulosic polysaccharide, iron(II) chloride, iron(III) chloride, iron(II) sulfate is preferably used. , iron (III) sulfate, iron (II) nitrate, iron (III) nitrate and their hydrates, and soluble Prussian blue that partially contains potassium ions, ammonium ions, etc., and the like.
　セルロース系多糖類を含有する炭素原料に担持させる金属イオンは、１種でも、２種以上であってもよい。 The number of metal ions supported on the carbon raw material containing cellulosic polysaccharide may be one or two or more.
　金属イオンをセルロース系多糖類を含有する炭素原料に担持させた炭素原料（すなわち、第２の炭素原料（または黒鉛結晶含有炭素材料の前駆体ともいう。））を用意した後、不活性ガス雰囲気下にて、熱処理を行う。 After preparing a carbon raw material in which metal ions are supported on a carbon raw material containing a cellulosic polysaccharide (i.e., a second carbon raw material (or also referred to as a precursor of a graphite crystal-containing carbon material)), an inert gas atmosphere is prepared. Heat treatment is performed below.
　熱処理時は、不活性ガス雰囲気下にて行うことが好ましい。不活性がストしては、例えばヘリウム、アルゴン、窒素などが挙げられる。中でも、産業コスト観点からは、窒素がより好ましい。 The heat treatment is preferably performed under an inert gas atmosphere. Examples of inert gases include helium, argon, nitrogen, and the like. Among them, nitrogen is more preferable from the viewpoint of industrial cost.
　熱処理装置は、所定の温度、例えば６００～１４００℃に加熱できる装置であれば特に制限はないが、好ましくは、ガス置換炉が挙げられる。ガス置換炉は、バッチ式又は連続式ガス置換炉が好ましく、連続式ガス置換炉がより好ましい。 The heat treatment device is not particularly limited as long as it can heat to a predetermined temperature, for example 600 to 1400° C., but preferably a gas displacement furnace is used. The gas displacement furnace is preferably a batch type or continuous gas displacement furnace, and more preferably a continuous gas displacement furnace.
　熱処理温度は、好ましくは６００℃以上１４００℃未満でありうる。熱処理温度の下限は、より好ましくは７００℃以上、更に好ましくは８００℃以上でありうる。炭素材料を黒鉛化する観点からは、熱処理温度の上限は特に限定しなくてもよいが、一般的な熱処理装置の制約と省エネルギーの観点から、好ましくは１４００℃未満、より好ましくは１２００℃以下、更に好ましくは１１００℃または１０００℃以下がでありうる。本発明のいくつかの実施形態によれば、触媒として作用する金属イオンを均一に分散させることができるため、上記のように黒鉛化のための熱処理としては低温条件で黒鉛化を行うことができ、しかも、得られる黒鉛結晶含有炭素材料の均質なものとしうる。 The heat treatment temperature may preferably be 600°C or higher and lower than 1400°C. The lower limit of the heat treatment temperature may be more preferably 700°C or higher, and still more preferably 800°C or higher. From the viewpoint of graphitizing the carbon material, the upper limit of the heat treatment temperature does not need to be particularly limited, but from the viewpoint of general heat treatment equipment constraints and energy saving, it is preferably less than 1400°C, more preferably 1200°C or less, More preferably, the temperature may be 1100°C or below 1000°C. According to some embodiments of the present invention, metal ions acting as catalysts can be uniformly dispersed, so that graphitization can be performed under low temperature conditions as a heat treatment for graphitization as described above. Moreover, the graphite crystal-containing carbon material obtained can be homogeneous.
　熱処理時間は、好ましくは０．１～４時間であり、より好ましくは０．５～３時間でありうる。 The heat treatment time is preferably 0.1 to 4 hours, more preferably 0.5 to 3 hours.
　熱処理により、黒色炭化物の形態で黒鉛結晶含有炭素材料を得ることができる。熱処理後の黒色炭化物の残存率（重量比）は、熱処理前の原料の乾燥重量、すなわち、第２の炭素原料の乾燥重量に対し、好ましくは１～４０％、より好ましくは１０～３０％でありうる。 By heat treatment, a graphite crystal-containing carbon material can be obtained in the form of a black carbide. The residual rate (weight ratio) of the black carbide after heat treatment is preferably 1 to 40%, more preferably 10 to 30%, based on the dry weight of the raw material before heat treatment, that is, the dry weight of the second carbon raw material. It's possible.
　得られた黒色炭化物に対して評価するためにはＸ線回折（以下、ＸＲＤという）、ラマンスペクトル等を用いうる。ＸＲＤは原子が規則的に並んだ結晶にＸ線が入射し、特定の方向で強いＸ線が観察され、回折現象が生じる。黒鉛化の指標としては層面間距離ｄ００２が汎用されている。層面間距離（ｄ００２）は３．３Å以上４．０Å以下の範囲が好ましく３．３９３７Å以上３．４６３５Å以下の範囲がより好ましい。網平面群の厚さ（Ｌｃ）は１０ｎｍ以上２００ｎｍ以下の範囲が好ましく３０ｎｍ以上１８７ｎｍ以下の範囲がより好ましい。 In order to evaluate the obtained black carbide, X-ray diffraction (hereinafter referred to as XRD), Raman spectrum, etc. can be used. In XRD, X-rays are incident on a crystal in which atoms are regularly arranged, and strong X-rays are observed in a specific direction, causing a diffraction phenomenon. The interlayer distance d002 is commonly used as an index of graphitization. The interlayer distance (d002) is preferably in the range of 3.3 Å or more and 4.0 Å or less, and more preferably in the range of 3.3937 Å or more and 3.4635 Å or less. The thickness (Lc) of the mesh plane group is preferably in the range of 10 nm or more and 200 nm or less, and more preferably in the range of 30 nm or more and 187 nm or less.
　以下に実施例を挙げて本発明について更に具体的に説明するが、本開示における本発明の技術的範囲が下記の実施例に限定されるものではない。 The present invention will be described in more detail with reference to Examples below, but the technical scope of the present invention in the present disclosure is not limited to the Examples below.
＜実施例１＞
　セルロース系多糖類を含有する原料（第１の炭素原料）として、ＴＥＭＰＯ酸化パルプ（アニオン性官能基含有量１．６ｍｍｏｌ／ｇ、カチオンはナトリウムイオン）を用いた。乾燥重量にして３ｇのＴＥＭＰＯ酸化パルプに対し、０．１ｍｏｌ／Ｌ塩酸を１００ｍｌ添加し、３０分保持した後、ろ過して十分にイオン交換水で洗浄することで、カチオンをプロトンに交換した。その後、鉄イオン源として塩化鉄（ＩＩ）４水和物を用い、その２％水溶液１００ｍｌを添加して３０分保持し、ろ過して十分にイオン交換水で洗浄することで、カチオンを鉄イオン（ＩＩ）に交換した。得られたパルプは淡褐色であり、鉄イオン（ＩＩ）の一部は鉄イオン（ＩＩＩ）に酸化されていた。得られたパルプを、鉄イオンを担持させた第２の炭素原料とした。 <Example 1>
TEMPO oxidized pulp (anionic functional group content: 1.6 mmol/g, cation is sodium ion) was used as a raw material containing cellulosic polysaccharide (first carbon raw material). 100 ml of 0.1 mol/L hydrochloric acid was added to 3 g of dry weight of TEMPO oxidized pulp, held for 30 minutes, filtered, and thoroughly washed with ion-exchanged water to exchange cations with protons. Then, using iron (II) chloride tetrahydrate as an iron ion source, add 100 ml of its 2% aqueous solution, hold for 30 minutes, filter and wash thoroughly with ion-exchanged water to remove iron ions from the cations. It was replaced with (II). The obtained pulp was light brown in color, and some of the iron ions (II) were oxidized to iron ions (III). The obtained pulp was used as a second carbon raw material carrying iron ions.
　得られたパルプ（すなわち、第２の炭素原料）を１０５℃で１時間乾燥した後、バッチ式ガス置換炉を用いて、窒素雰囲気下、９００℃にて２時間熱処理を行い、黒色炭化物を得た。パルプの乾燥重量に対する黒色炭化物の残存率は２４％だった。得られた黒色炭化物に対し、Ｘ線回折で分析したところ、明確な黒鉛化のピーク（２θ＝２５．５－２６．６°）が観測された。 The obtained pulp (i.e., the second carbon raw material) was dried at 105°C for 1 hour, and then heat-treated at 900°C for 2 hours in a nitrogen atmosphere using a batch gas replacement furnace to obtain black carbide. Ta. The residual ratio of black carbide to the dry weight of the pulp was 24%. When the obtained black carbide was analyzed by X-ray diffraction, a clear graphitization peak (2θ=25.5-26.6°) was observed.
＜実施例２＞
　鉄イオン源として、硝酸鉄（ＩＩＩ）９水和物を用い、かつ熱処理工程で連続式ガス置換炉を用いた以外は実施例１と同様の方法で操作を行い、黒色炭化物を得た。パルプの乾燥重量に対する黒色炭化物の残存率は２３％だった。得られた黒色炭化物に対し、Ｘ線回折で分析したところ、明確な黒鉛化のピーク（２θ＝２５．５－２６．６°）が観測された。 <Example 2>
A black carbide was obtained by carrying out the same procedure as in Example 1, except that iron (III) nitrate nonahydrate was used as the iron ion source and a continuous gas displacement furnace was used in the heat treatment step. The residual ratio of black carbide to the dry weight of the pulp was 23%. When the obtained black carbide was analyzed by X-ray diffraction, a clear graphitization peak (2θ=25.5-26.6°) was observed.
＜実施例３＞
　セルロース系多糖類を含有する原料（第１の炭素原料）として、針葉樹由来の漂白済み製紙用パルプ（ＮＢＫＰ、アニオン性官能基量０．０４ｍｍｏｌ／ｇ）を用い、鉄イオン源として塩化鉄（ＩＩＩ）６水和物を用いた以外は、実施例１と同様の方法で操作を行い、黒色炭化物を得た。パルプの乾燥重量に対する黒色炭化物の残存率は２０％だった。得られた黒色炭化物に対し、Ｘ線回折で分析したところ、明確な黒鉛化のピーク（２θ＝２５．５－２６．６°）が観測された。 <Example 3>
Bleached paper pulp (NBKP, anionic functional group content 0.04 mmol/g) derived from coniferous trees was used as a raw material containing cellulosic polysaccharides (first carbon raw material), and iron chloride (III) was used as an iron ion source. ) A black carbide was obtained by carrying out the same procedure as in Example 1 except that hexahydrate was used. The residual ratio of black carbide to the dry weight of the pulp was 20%. When the obtained black carbide was analyzed by X-ray diffraction, a clear graphitization peak (2θ=25.5-26.6°) was observed.
＜実施例４＞
　セルロース系多糖類を含有する原料（第１の炭素原料）として、レーヨン不織布（繊維径３．３ｄｔｅｘ、アニオン性官能基量０．０１５ｍｍｏｌ／ｇ）を用い、鉄イオン源として硫酸鉄（ＩＩ）７水和物を用いた以外は、実施例１と同様の方法で操作を行い、黒色炭化物を得た。レーヨン不織布の乾燥重量に対する黒色炭化物の残存率は２０％だった。得られた黒色炭化物に対し、Ｘ線回折で分析したところ、明確な黒鉛化のピーク（２θ＝２５．５－２６．６°）が観測された。 <Example 4>
Rayon nonwoven fabric (fiber diameter 3.3 dtex, anionic functional group content 0.015 mmol/g) was used as the raw material containing cellulosic polysaccharide (first carbon raw material), and iron (II) sulfate was used as the iron ion source. A black carbide was obtained by carrying out the same procedure as in Example 1 except that a hydrate was used. The residual rate of black carbide based on the dry weight of the rayon nonwoven fabric was 20%. When the obtained black carbide was analyzed by X-ray diffraction, a clear graphitization peak (2θ=25.5-26.6°) was observed.
＜実施例５＞
　乾燥重量にして３ｇのレーヨン不織布（繊維径３．３ｄｔｅｘ、アニオン性官能基量０．０１５ｍｍｏｌ／ｇ）を、５％過酸化水素水１００ｍｌに添加し、室温にて１５分間浸漬した。十分に絞った後、２％硫酸鉄（ＩＩ）７水和物水溶液１００ｍｌに３０分浸すことで、フェントン反応を行い、十分に洗浄することで、酸化レーヨン不織布を得た（アニオン性官能基量０．１２ｍｍｏｌ／ｇ）。 <Example 5>
A rayon nonwoven fabric (fiber diameter: 3.3 dtex, anionic functional group content: 0.015 mmol/g) with a dry weight of 3 g was added to 100 ml of 5% hydrogen peroxide solution and immersed for 15 minutes at room temperature. After sufficiently squeezing, Fenton reaction was performed by immersing in 100 ml of 2% iron (II) sulfate heptahydrate aqueous solution for 30 minutes, and by thorough washing, an oxidized rayon nonwoven fabric was obtained (anionic functional group amount 0.12 mmol/g).
　得られた酸化レーヨン不織布を、セルロース系多糖類を含有する原料（第１の炭素原料）として、５％硫酸鉄（ＩＩ）７水和物水溶液１００ｍｌを添加して３０分間保持し、ろ過して十分にイオン交換水で洗浄することで、カチオンを鉄イオン（ＩＩ）に交換した。得られたレーヨン不織布は淡褐色であり、鉄イオン（ＩＩ）の一部は鉄イオン（ＩＩＩ）に酸化されていた。得られたレーヨン不織布を、鉄イオンを担持させた第２の炭素原料とした。 To the obtained oxidized rayon nonwoven fabric, 100 ml of a 5% iron (II) sulfate heptahydrate aqueous solution was added as a raw material containing cellulosic polysaccharide (first carbon raw material), held for 30 minutes, and filtered. The cations were exchanged to iron (II) ions by washing thoroughly with ion-exchanged water. The obtained rayon nonwoven fabric was light brown in color, and some of the iron ions (II) were oxidized to iron ions (III). The obtained rayon nonwoven fabric was used as a second carbon raw material carrying iron ions.
　その後、実施例１と同様の方法で熱処理を行い、黒色炭化物を得た。レーヨン不織布の乾燥重量に対する黒色炭化物の残存率は１８％だった。得られた黒色炭化物に対し、Ｘ線回折で分析したところ、明確な黒鉛化のピーク（２θ＝２５．５－２６．６°）が観測された。 Thereafter, heat treatment was performed in the same manner as in Example 1 to obtain a black carbide. The residual rate of black carbide based on the dry weight of the rayon nonwoven fabric was 18%. When the obtained black carbide was analyzed by X-ray diffraction, a clear graphitization peak (2θ=25.5-26.6°) was observed.
＜比較例１＞
　セルロース系多糖類を含有する原料として、ＴＥＭＰＯ酸化パルプ（アニオン性官能基含有量１．６ｍｍｏｌ／ｇ、カチオンはナトリウムイオン）を用いた。乾燥重量にして３ｇのＴＥＭＰＯ酸化パルプを１０５℃で１時間乾燥した後、バッチ式ガス置換炉を用いて、窒素雰囲気下、９００℃にて２時間熱処理を行い、黒色炭化物を得た。パルプの乾燥重量に対する黒色炭化物の残存率は２１％だった。得られた黒色炭化物に対し、Ｘ線回折で分析したところ、黒鉛化のピーク（２θ＝２５．５－２６．６°）が観測されなかった。 <Comparative example 1>
TEMPO oxidized pulp (anionic functional group content: 1.6 mmol/g, cation is sodium ion) was used as a raw material containing cellulosic polysaccharides. After drying TEMPO oxidized pulp with a dry weight of 3 g at 105° C. for 1 hour, heat treatment was performed at 900° C. for 2 hours in a nitrogen atmosphere using a batch gas replacement furnace to obtain black carbide. The residual ratio of black carbide to the dry weight of the pulp was 21%. When the obtained black carbide was analyzed by X-ray diffraction, no graphitization peak (2θ=25.5-26.6°) was observed.
＜比較例２＞
　セルロース系多糖類を含有する原料として、ＴＥＭＰＯ酸化パルプ（アニオン性官能基含有量１．６ｍｍｏｌ／ｇ、カチオンはナトリウムイオン）を用いた。乾燥重量にして３ｇのＴＥＭＰＯ酸化パルプに対し、０．１ｍｏｌ／Ｌ塩酸を１００ｍｌ添加し３０分保持後、ろ過して十分にイオン交換水で洗浄することで、カチオンをプロトンに交換した。 <Comparative example 2>
TEMPO oxidized pulp (anionic functional group content: 1.6 mmol/g, cation is sodium ion) was used as a raw material containing cellulosic polysaccharides. 100 ml of 0.1 mol/L hydrochloric acid was added to 3 g dry weight of TEMPO oxidized pulp, held for 30 minutes, filtered, and thoroughly washed with ion-exchanged water to exchange cations with protons.
　得られたパルプを１０５℃で１時間乾燥した後、バッチ式ガス置換炉を用いて、窒素雰囲気下、９００℃にて２時間熱処理を行い、黒色炭化物を得た。パルプの乾燥重量に対する黒色炭化物の残存率は２３％だった。得られた黒色炭化物に対し、Ｘ線回折で分析したところ、黒鉛化のピーク（２θ＝２５．５－２６．６°）が観測されなかった。 After drying the obtained pulp at 105° C. for 1 hour, it was heat-treated at 900° C. for 2 hours in a nitrogen atmosphere using a batch gas replacement furnace to obtain black carbide. The residual ratio of black carbide to the dry weight of the pulp was 23%. When the obtained black carbide was analyzed by X-ray diffraction, no graphitization peak (2θ=25.5-26.6°) was observed.
＜比較例３＞
　セルロース系多糖類を含有する原料として、ＴＥＭＰＯ酸化パルプ（アニオン性官能基含有量１．６ｍｍｏｌ／ｇ、カチオンはナトリウムイオン）を用いた。乾燥重量にして３ｇのＴＥＭＰＯ酸化パルプに対し、０．１ｍｏｌ／Ｌ塩酸を１００ｍｌ添加し３０分保持した後、ろ過して十分にイオン交換水で洗浄することで、カチオンをプロトンに交換した。その後、硫酸銅（ＩＩ）５水和物の２％水溶液１００ｍｌを添加して３０分保持し、ろ過して十分にイオン交換水で洗浄することで、カチオンを銅イオン（ＩＩ）に交換した。 <Comparative example 3>
TEMPO oxidized pulp (anionic functional group content: 1.6 mmol/g, cation is sodium ion) was used as a raw material containing cellulosic polysaccharides. After adding 100 ml of 0.1 mol/L hydrochloric acid to 3 g dry weight of TEMPO oxidized pulp and holding for 30 minutes, the mixture was filtered and thoroughly washed with ion-exchanged water to exchange cations with protons. Thereafter, 100 ml of a 2% aqueous solution of copper (II) sulfate pentahydrate was added, held for 30 minutes, filtered, and thoroughly washed with ion-exchanged water to exchange the cations with copper ions (II).
　得られたパルプを１０５℃で１時間乾燥した後、バッチ式ガス置換炉を用いて、窒素雰囲気下、９００℃にて２時間熱処理を行い、黒色炭化物を得た。パルプの乾燥重量に対する黒色炭化物の残存率は２０％だった。得られた黒色炭化物に対し、Ｘ線回折で分析したところ、黒鉛化のピーク（２θ＝２５．５－２６．６°）は観測されなかった。 After drying the obtained pulp at 105° C. for 1 hour, it was heat-treated at 900° C. for 2 hours in a nitrogen atmosphere using a batch gas replacement furnace to obtain black carbide. The residual ratio of black carbide to the dry weight of the pulp was 20%. When the obtained black carbide was analyzed by X-ray diffraction, no graphitization peak (2θ=25.5-26.6°) was observed.
　上記の分析結果を、表１にまとめて示す。 The above analysis results are summarized in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001

Claims (7)

  1. 　アニオン性官能基を有するセルロース系多糖類を含有する第１の炭素原料に、鉄イオン、ニッケルイオン、クロームイオン、及びコバルトイオンからなる群から選ばれる１種又は２種以上の金属イオンを担持させた第２の炭素原料を用意することと、
    　前記第２の炭素材料を、不活性ガス雰囲気下、６００℃以上１４００℃未満の温度条件で、熱処理することと、
    を含む、黒鉛結晶含有炭素材料の製造方法。     One or more metal ions selected from the group consisting of iron ions, nickel ions, chromium ions, and cobalt ions are supported on the first carbon material containing a cellulose polysaccharide having an anionic functional group. preparing a second carbon raw material;
    Heat treating the second carbon material under an inert gas atmosphere at a temperature of 600°C or more and less than 1400°C;
    A method for producing a graphite crystal-containing carbon material.
  2. 　前記第１の炭素原料が、製紙用パルプ、再生セルロース繊維、及び、製紙用パルプ又は再生セルロース繊維の化学変性物からなる群より選ばれる１種又は２種以上である、請求項１に記載の製造方法。 The first carbon raw material is one or more selected from the group consisting of papermaking pulp, regenerated cellulose fiber, and chemically modified products of papermaking pulp or regenerated cellulose fiber. Production method.
  3. 　前記第１の炭素原料中における前記アニオン性官能基の含有量が、０．０１～２．００ｍｍｏｌ／ｇである、請求項１に記載の製造方法。 The manufacturing method according to claim 1, wherein the content of the anionic functional group in the first carbon raw material is 0.01 to 2.00 mmol/g.
  4. 　前記アニオン性官能基が、カルボキシル基である、請求項３に記載の製造方法。 The manufacturing method according to claim 3, wherein the anionic functional group is a carboxyl group.
  5. 　前記金属イオンが、鉄イオンである、請求項１に記載の製造方法。 The manufacturing method according to claim 1, wherein the metal ion is an iron ion.
  6. 　前記鉄イオンを、鉄の塩酸塩、鉄の硫酸塩、および鉄の硝酸塩からなる群より選ばれる１種又は２種以上を用いて、前記セルロース系多糖類に担持させることを含む、請求項５に記載の製造方法。 Claim 5, comprising supporting the iron ion on the cellulose polysaccharide using one or more selected from the group consisting of iron hydrochloride, iron sulfate, and iron nitrate. The manufacturing method described in.
  7. 　アニオン性官能基を有するセルロース系多糖類を含有する第１の炭素原料に、鉄イオン、ニッケルイオン、クロームイオン、及びコバルトイオンからなる群から選ばれる１種又は２種以上の金属イオンが担持された、黒鉛結晶含有炭素材料の前駆体。 One or more metal ions selected from the group consisting of iron ions, nickel ions, chromium ions, and cobalt ions are supported on the first carbon material containing a cellulose polysaccharide having an anionic functional group. Also, a precursor of carbon material containing graphite crystals.
PCT/JP2023/014834 2022-04-13 2023-04-12 Graphite crystal-containing carbon material manufacturing method WO2023199935A1 (en)

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JP2009268960A (en) * 2008-05-06 2009-11-19 Toyota Industries Corp Catalyst precursor, catalyst material, and method of preparing catalyst
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